building an exhaust system for your car

grumpyvette

Administrator
Staff member
you might want to read thru these threads and linked info first, yes IM well aware it may take several hours to do so but it will save your many more hours and hundreds of dollars to do it correctly and safely.
Id bet 80% of the useful infos in the links and sub-links so take some time and read, and absorb and think and plan before jumping in with both feet

theres a good deal of info here in the sub links that might help,
keep in mind horse power is not dependent on engine displacement alone, its much more closely related to the VOLUME of fuel/air mix being efficiently compressed ,ignited and burnt PER SECOND in the engines combustion chambers, thus displacement ,and actual rpms, obviously have an effect, and compressing the air fed into the engine with a turbo or supercharged engine could easily increase the need for a significantly larger exhaust system

If your not all that skilled with tools or reluctant to do your own work theres several vendors who can supply a wide selection of decent exhaust system designs,
but obviously you still need mufflers that fit correctly
all back pressure is detrimental, yes you can lose power if the exhaust is too large, but thats a result of not having properly tuned headers and collectors between the engine and exhaust, once the headers are installed and you have a proper tune to maximize the torque and power, that promote exhaust and cylinder scavenging the exhaust size can't be too large only too small and restrictive
one more in and endless list of reasons any serious hot rodder needs to own a good MIG or TIG welder,
and know how to use it and acquire the skill set to fabricate custom components like headers
airratchetd.png

adding an anti-reversion baffle to a 18"-24" longer collector on open headers with the internal pipe about 1/2 the collector length tends to help scavenging on some engines
collectortuningtube.jpg

http://www.melrosecorvette.com/corvette-headers-exhaust/



yet
I can,t imagine owning a decent mig or tig welder and having the skills to use it and either decent jack stands or a lift still be willing to pay for a prefabricated bolt in exhaust system, when with some careful custom fabrication of readily available components and some time spent cutting and welding after careful measurement of components and trial fitting would easily reduce the cost to about 50%-70% of what the prefab exhaust would cost.
plus you have the added benefits of being able to add custom features like electric cut outs or dual (X) pipes or select the mufflers of your choice without worrying about ordering a system that won,t fit your car correctly.
take the time and effort to shop carefully and it helps to actually get your car up on jack stands or a lift and measure the area under the car the exhaust will fit into, and your current exhaust measurements so you don,t over or under judge whats required or what might fit, the last thing you might want is to select components that won,t ever fit or function.
learning to welds a bit like GREAT SEX, if youve never been involved you don,t see the advantages but once you are, you wonder how you could ever have gone so long not being able to enjoy the results of constantly playing with the equipment and trying new things

you don,t need a lift to do most exhaust system mods, why not temporarily, lower and remove the exhaust system , do a few tack welds or use clamps on the new components after they are assembled to verify exact placement of components, temp reinstall to verify, and remove to do the finish welding, its just not that hard or time consuming to do on a c4 corvette as theres nothing under the exhaust to make it that difficult,Ive done several DOZEN over the last 20 years that way with the car up on (4) 12 ton jack stands with only about 25" of clearance under the car.
yes theres no question a lift makes the process faster and easier but its hardly impossibly up on (4) 12 ton jack stands with a mig welder and air ratchets either .
it would be difficult to over stress how important having the correct tools and the skill to use them are on modifying parts, frankly I can,t imaging a shop without some basics like a couple welders and a drill press and a belt sander, air compressor
and die grinders etc.
theres a significant variation in spark plug location between cylinder head designs, theres both strait and angle plug heads and even the angle plug heads vary a good deal between designs, and many headers won,t work with a few cylinder heads in some applications so its almost mandatory that you call and talk too the tech support guys from both the cylinder head and headers manufacturers, to ask if any specific combo has a history of clearance issues BEFORE purchasing your headers or cylinder heads or both.
and yes there are REALLY POORLY THOUGHT THRU HEADER DESIGNS being sold.
many guys fail to think things through carefully, and use the calculators and charts provided here!
if for example you were building a 500 hp 383-406 sbc,for a c4 corvette, and used long tube headers with 1 3/4" primary's feeding a 3" diam. header collector, the twin collectors would ideally feed into an X pipe of 3" in and out pipe size, and continue at that diam.out to the exhaust so you would need two 3" low flow restriction, mufflers, or a Y pipe with a 4" diam, pipe exiting and feeding a 4" low restriction muffler design.

If you made the all too common mistake of feeding the exhaust gases from twin 3" collectors into the stock 2.5" diam. Y pipe and 2.25" mufflers you can expect to loose at least 20-30 peak horse power due to the restricted exhaust.


lsheadflowd.jpg


READ THE SUB LINKS THERES A TON OF GOOD RELATED AND USEFUL INFO
viewtopic.php?f=70&t=840&p=1273#p1273

viewtopic.php?f=60&t=77

viewtopic.php?f=56&t=495

viewtopic.php?f=60&t=1594

viewtopic.php?f=60&t=72

viewtopic.php?f=56&t=1166

http://www.pontiacstreetperformance.com ... haust.html

viewtopic.php?f=56&t=1503

viewtopic.php?f=56&t=2350&p=6204&hilit=exhaust+restrictive+dougs#p6204

viewtopic.php?f=79&t=407&p=30430&hilit=pontiac+exhaust#p30430

viewtopic.php?f=56&t=495&p=22402&hilit=side+pipes#p22402

heres some of the tools, and related info in the links you really should take the time to read thru before staring to help you out

viewtopic.php?f=81&t=1871&p=4917&hilit=tubing+exhaust#p4917

viewtopic.php?f=60&t=1594

http://www.popularhotrodding.com/engine ... 505em_exh/

viewtopic.php?f=79&t=407&p=501&hilit=+stainless+exhaust#p501

viewtopic.php?f=56&t=185

viewtopic.php?f=56&t=2002

viewtopic.php?f=56&t=1503&hilit=tubing+exhaust

viewtopic.php?f=56&t=1730

viewtopic.php?f=56&t=961

viewtopic.php?f=56&t=496

viewtopic.php?f=56&t=255

viewtopic.php?f=60&t=4605

http://www.classicchambered.com/classic/products.html

http://store.airflo.com/exhaust-adapters.html

http://www.mk5cortinaestate.co.uk/calculator5.php

viewtopic.php?f=60&t=1669

viewtopic.php?f=27&t=26&hilit=helmet

viewtopic.php?f=59&t=811&p=1184&hilit=helmet#p1184

http://www.metalgeek.com/static/cope.pcgi

http://pipemastertools.com/store/page1.html

viewtopic.php?f=56&t=1503

viewtopic.php?f=44&t=1518&p=3473&hilit=preforated#p3473

http://www.mandrelbendingsolutions.com/ ... StoreFront

http://www.millerwelds.com/swf/flv/flas ... &h=250&v=8

viewtopic.php?f=56&t=495

viewtopic.php?f=56&t=260

http://www.millerwelds.com/products/mig ... 2_autoset/

http://www.millerwelds.com/products/mig ... 1_autoset/

viewtopic.php?f=56&t=352&p=433#p433

http://www.stainlessheaders.com/index.aspx

http://www.youtube.com/watch?v=HYCck4pT ... sgodXiPPsg

viewtopic.php?f=56&t=789&p=1169&hilit=+pipe#p1169

http://www.superchevy.com/technical/eng ... index.html

http://www.centuryperformance.com/exhau ... g-137.html

viewtopic.php?f=56&t=45

http://www.ssheaders.com/header.htm

http://victorylibrary.com/mopar/header-tech-c.htm

http://www.burnsstainless.com/TechArtic ... heory.html

http://www.vetteweb.com/tech/vemp_0401_ ... index.html

viewtopic.php?f=56&t=352

viewtopic.php?f=56&t=255

viewtopic.php?f=56&t=961

http://www.bgsoflex.com/auto.html

viewtopic.php?f=79&t=497&p=615&hilit=+pipe#p615

posting.php?mode=edit&f=60&p=2185

viewtopic.php?f=60&t=530

viewtopic.php?f=60&t=72

viewtopic.php?f=56&t=496
ok, first point, In most cases your going to be limited by under car clearances, obstacles, like the rear suspension and drive train, so your options are limited and ground clearance can be a problem, and your more than likely restricted to the use of commercial headers and components, so basically youll be trying to route the exhaust flow from the header collectors to the mufflers and out the tail pipe while maintaining as low of a restriction to flow rates and generally a significant reduction in sound levels , while maintaining decent ground clearance.
Cost is also a factor, but depending on the application the life expectancy of the system comes into play, a stainless steel exhaust and ceramic coated headers or stainless steel headers can easily be two , or three or four times the cost of aluminized steel, but not having to replace it once its installed can make the higher cost well worth it on a car youll keep for decades.
theres four basic designs

side pipes,
http://www.corvettefever.com/howto/4680/index.html
p35800_image_large.jpg

http://www.jegs.com/p/Hooker/753672/10002/-1

http://www.stainless-specialties.com/products2a.htm

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like some corvettes and cobras had

https://www.drgas.net/mediaitem.php?itemid=40

camoarox.jpg


IMG_1291x.jpg
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keep in mind installing an (X) almost increases the effective cross sectional area,of the dual exhaust ,to double what it had been behind a single header collector, by doubling the area that the exhaust flow sees, dropping the restriction to flow almost in half
x-pipe002.jpg

cutoutex.jpg

c4st1.jpg

xpipehel.png

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DUAL X-PIPES TEND TO RESULT IN MORE EFFECTIVE CYLINDER SCAVENGING,BY BLENDING EXHAUST PULSE DURATION, AND A BROADER TORQUE CURVE AND MELLOWER EXHAUST TONE
http://www.antechlabs.com/K0GFM/pipechart.gif

an exhaust that exits directed out in front of the rear wheels like some stock cars use
torquecurvespipe.gif

torquetri.gif

exhaustpressure.jpg

watch video
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keep firmly in mind that the header exhaust scavenging ,efficiency and intake runners ability to effectively fill the engines cylinders is very much dependent on carefully matched, cam timing, headers designed to match the engines displacement, intended rpm band, ,maximum compression ratio, for the fuel octane used,and a low restriction exhaust behind the header collectors, when all the factors are well matched correctly theres an easy 20% or higher power gain over most stock engines in this area alone.
correctly matched headers, compression, cam timing, displacement etc, can easily increase the cylinder fill efficiency, and intake runner air flow velocity by over 30%

http://www.wallaceracing.com/intake-runner-length.php

http://www.bgsoflex.com/intakeln.html

http://www.velocity-of-sound.com/velocity_of_sound/calculator3.htm

http://www.velocity-of-sound.com/velocity_of_sound/velocity_stacks.htm

http://www.swartzracingmanifolds.com/tech/index.htm

http://www.melrosecorvette.com/corvette-headers-exhaust/
c_4_system.jpg

MELROSE SELLS A VERY EFFECTIVE EXHAUST SYSTEM FOR C4 CORVETTES
melroseheadersex1.JPG


melroseheadersex.JPG


BTW on my last BIG BLOCK C4 swap I had TWO 3" (X) pipes and got a bit creative and well built a DUAL (X) exhaust that was similar to this PICTURE BELOW. the result was a rather unique exhaust tone, a nice smooth rumble note in the sound and a very nice smooth low and mid rpm torque curve, now Im not sure if the exhaust mod added or subtracted from the power curve because I didn,t try it with a different exhaust config. but I got the strong impression that it helped, I know it made the sound distinctive and more mellow

dualxmod.jpg


the common exit to the rear past the bumper most street cars come with
h8072_example.jpg


and the lake pipe style some roadsters use.

OK once you've got some basic ideas as to what you want you should either decide to buy a commercially available set-up or fabricate your own custom built exhaust system, buying will be easier but your limited to whats currently available in your price range, if you can weld and have some skills your obviously far less restricted in the design you can use, but generally a 2.5"-3" or rarely a 3.5" dual system with an (H) OR (X) to equalize the flow rates and reduce the restriction will be what most muscle-car applications will respond well to.
keep in mind the goal it to reduce noise levels without increasing the back pressure and increase scavenging of the engines cylinders if possible, now the headers and collectors will do most of the scavenging, if they are designed correctly, PROVIDED your exhaust system, past the collectors does not cause a restriction to flow that lowers their efficiency at ,maintaining that low pressure wave or suction at the exhaust ports that draws fuel/air mix thru the cylinder during the cams overlap duration period. its important that the rushing gases flow quickly out the exit point so their inertia tends to draw the following mass of exhaust will it in a constant high speed flow,. Keeping that flow rate high will require the smallest diam. and cross sectional area that does not represent a restriction to the upper rpm flow rate for the displacement and rpm range the engines designed to run efficiently in.

the question often comes up about use of mandrel bends vs crimp bent exhaust pipes, in designing an exhaust system, well it should be noted that its the cross sectional area much more than the shape of the pipe thats the more important factor, while its true that mandrel bends do maintain a more consistent cross sectional area, simply selecting a slightly larger diameter non-mandrel bent exhaust pipe size with its larger cross section can frequently be the less expensive route. as long as you've got an (X) pipe in the system , mounted as close as clearances under the car allow, to the header collectors and the tail pipes are nominally the same diameter, as the formulas suggest are required, IE lets say 2.5" or 3" the type of bend at that point, (past the (X) PIPE, will be all but meaningless due to the fact that by that point the exhaust pulse strength and velocity has been significantly reduced thru cooling distance, the effect of the (X) pipe splitting the pulse,and the lack of significant restriction.
every test Ive ever seen shows that an (x) pipe mounted near the header collectors and mandrel bends on collectors do help flow, but youve effectively almost doubled the cross sectional area after the (x)and because the engine fires every 90 degrees the pulse of exhaust past the (x) is significantly reduced in exhaust pressure, your exhaust will normally require an exhaust pipe that will handle the flow based on the engines air flow rate and horse power
you can use the info posted

tubsed.png

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knowing a few constants in engine pressure and flow helps

an engine usually requires approximately 2.257 cubic feet per minute per horsepower to maximize intake flow and exhaust flow at about 115 cfm per square inch, of exhaust pipe diameter
exhaustpressure.jpg

so assuming your building a 500 hp engine / 2 (divided by 2 as there's normally two header collectors on a v8) we have 250hp per header collector, (open header collectors) multiply that by 2.257 cfm and you see you need 565 cfm and divide that by 115/square inches and we see we need a 4.9 square inch minimum exhaust collector pipe, per side (open header collectors), this would effectively be matched at the max flow of a pair of 2.5" exhaust pipes on a dual exhaust on a 500hp engine.

as a cross check 500hp /8=1129/8=142 hp per header primary , 2.257 x 142/115=2.76 sq inches 0r a header primary a bit larger than 1 3/4 and smaller than 2" or a 1 7/8 to maximize peak hp, per header primary, but keep in mind you'll spend most of your time below peak rpms so a slightly smaller 1 3/4" primary on a street strip engine that sacrifices a bit of peak hp for better mid rpm torque makes sense, and once you install longer exhaust pipes and mufflers you'll need to steep up the exhaust pipe size cross section past the header collectors or they will tend to be restrictive at the minimum size the formula predicts
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These three circles illustrate the difference in internal square-inch area between 2.25-, 2.50-, and 3-inch exhaust pipes. Weâve calculated the area based on a wall thickness of 0.065. The 2.25-inch pipe has a flow area of 3.80 square inches, a 2.5-inch system increases the area 25 percent to 4.7 square inches, and a 3-inch pipe pumps the area up to 6.8 square inches.
viewtopic.php?f=56&t=1730&p=5392#p5392

viewtopic.php?f=56&t=495

viewtopic.php?f=56&t=1503

52021311k4.jpg


the basic MELROSE SYSTEM PICTURED ABOVE is an excellent basic lay out, but keep in mind your goals and budget, if you can weld and fabricate you can save several hundred dollars on a stainless exhaust and almost that much on a standard aluminized steel exhaust in many cases, but most guys will buy commercial headers , and only build an exhaust from the header collectors rearward, so adding a smooth flow design,and low restriction mufflers and locating them where there's the necessary clearances are their main concerns.
some very careful measurement and planing ahead can save a great deal of wasted materials, time and effort


heres an example of some fabricated work being done

http://www.ssheaders.com/header.htm

[
if you've got a decent welder and some basic fabrication skill , and a place to work with at least decent jack stands but preferably a lift theres little reason to NOT build a custom exhaust system for your corvette

the melrose system is a nice design to copy or just purchase
c_4_system.jpg


http://www.harborfreight.com/underhoist ... 60759.html

http://www.harborfreight.com/2-ton-capa ... 41860.html
HF PART NUMBERS 41860 or 60759... these come in very handy during exhaust system fabrication
41860.gif

http://www.harborfreight.com/underhoist ... 60759.html



This under hoist safety stand provides an extra point of support while working on exhaust systems, struts, transmissions and engine mounts. The wide stable base and precise adjustment on this transmission stand lets you support components during removal and replacement.

All steel construction
Six height adjustments
Fine screw adjustment
Large 3-1/8" x 4-1/2" saddle
Sturdy tripod base

Specifications
Name Underhoist Safety Stand
SKU 60759
Brand Pittsburgh Automotive
Capacity 4000 lb.
Maximum height (in.) 93-1/2 in.
Minimum height (in.) 49-3/4 in.
Product Height 49-3/4 in.
Product Length 24 in.
Product Width 24 in.
Jack recently started fabricating a custom exhaust for his car and while he had access to both a friend of his shop with a good mig welder and a two post lift to make the job much easier, he did not have two of the tall support jacks that come in so handy when doing that type of work.
well harbor freight has them listed (I bought two of these about 9 years ago for my shop) I offered to loan him mine but he decided it might be better to have two he owns personally as it gave him as good excuse to buy them and he fully intends to get a lift in his garage in the future.
I helped him assemble those two stands and I don,t remember the ones I purchased being that difficult, Id strongly suggest you read the instructions carefully and remember to install the assembly bolts only very loosely in ALL LOCATIONS allowing a small amount of flexibility during the assembly process, because getting all the braces, and bolts in place , in the tall support stand if any of the bolts in place are tightened,becomes a huge P.I.T.A. if they are tight, which makes the assembly process much more difficult.
yes these stands come in very handy at times if you own a lift in your shop, and yes I recommend you get two .
BTW theres three of the bolts that are 25mm and the rest are 20mm length the three are for the upper triangular plate and youll need a 17mm wrench and 17mm ratchet and socket or second 17mm wrench.
and don,t forget to grease the bearing and screw threads with a good coat of MOLY grease it makes it far easier to use

molygreasecan.jpg


viewtopic.php?f=56&t=2002

viewtopic.php?f=56&t=1503

viewtopic.php?f=56&t=45

http://www.millerwelds.com/products/mig/millermatic_252/

http://www.millerwelds.com/products/mig/millermatic_180_autoset/

installing a (X) pipe ,or if clearance is a big issue an (H) pipe, as close to the header collectors as under car clearances allow,effectively reduces back pressure , each bank of cylinders works against,and almost cuts the restriction to flow in half, it tends to mellow the tone of the exhaust and reduce the peak noise levels and frequently results in a increase in horsepower

viewtopic.php?f=56&t=1503

viewtopic.php?f=56&t=495

a well thought thru design on an (X) pipe and cut outs
xpipecutout.jpg


exhaustdesign.jpg


having low restriction mandrel bent exhaust pipes and adding an (X) pipe in the exhaust at approximately the point the header collectors should exit tends to reduce restriction and increase the engine torque curve
pipechart.gif


x-pipe vs h-pipe.jpg

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mock2.jpg

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http://www.pontiacstreetperformance.com ... aust3.html

http://www.parts123.com/parts123/yb.dll ... Z50000050F
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Last edited by a moderator:

grumpyvette

Administrator
Staff member
96ex1.jpg

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above you'll find pictures of the exhaust on a c4 corvette on a 4 post lift, that show how limited the room is to route the exhaust, this obviously requires careful measurement and fabrication

guys IVE done a good deal of testing on headers over the years, IN LOTS OF CARS and your correct if you think the long tube headers tend to work better than the shorties, but ONLY if matched to a low restriction exhaust behind the headers, a decent 3" exhaust with an (X) installed just after the trans tail with low restriction 3" mufflers will really wake up a corvette, or camaro, etc. compared to a stock exhaust that was designed mostly for low price, low expense and ease of install, once the cars equipped with decent flowing cylinder heads and a cam that allows the engine to breath correctly, a low restriction exhaust is a huge plus to a cars performance, (ESPECIALLY IF YOUR GOING TO USE NITROUS)
keep in mind what goes in needs to exit, you can restrict either the intake or the exhaust on a corvette and get really pathetic performance even if the other sides got top quality parts.
slap a stealthram, super ram, or mini-ram on killer 200CC-210CC AFR, or brodix heads and put a killer crower, crane or TPSI cam in that 383-406 SBC engine and leave a restrictive stock exhaust, and stock rear gearing and it will be a totally different car than basically the same combo with a 3.73:1 rear gear., 3200 STALL CONVERTER, FULL LENGTH 3"FREE FLOW EXHAUST EQUIPPED CAR WITH A SIMILAR ENGINE BUILD
thanks for the info!
hedman68608.jpg

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HEADERS LIKE THIS SET PICTURED ABOVE< ARE VERY POORLY DESIGNED, AND ALMOST WORTHLESS, AS THEY WILL DESTROY THE SPARK PLUG WIRES WITH HEAT RAPIDLY
http://www.paraglidingteam.nl/PPGTechni ... 795969.pdf

http://www.youtube.com/watch?v=6grztIXf ... re=related

http://store.summitracing.com/egnsearch ... &x=37&y=14

682252.jpg


stainless 3" is the way to go as far as IM concerned.

BTW DOES ANYONE KNOW any GOOD sources for different designs in low restriction STAINLESS 3" in and out MUFFLERS???

THERES SEVERAL GOOD SYSTEMS OUT ON THE MARKET BUT THIS IS A GOOD EXAMPLE OF WHAT WORKS, YOU COULD FABRICATE SOMETHING SIMILAR OR EVEN BETTER FOR LESS IF YOUR SKILLED WITH A WELDER AND SHOP CAREFULLY BUT THE EASY OF BUYING IT READY TO INSTALL HAS ITS GOOD POINTS.

http://www.melroseheaders.com/products/smooth_flow_exhaust_systems/c-4.php

c_4_system.jpg


http://www.harborfreight.com/cpi/ctaf/d ... mber=37354

viewtopic.php?f=56&t=1166

make an alignment tool from a clamp, tack weld with your welder, move clamp about 90 degrees repeat
0705kc_10_z+keeping_it_cool+hose_clamps.jpg


in an ideal world the exhaust pulses in each (Y) in a custom header will be evenly spaced as they enter the header collector, to equalize the exhaust pressure and restriction to flow...look carefully at the diagrams, below.
but in the real world the improvement that results in horsepower from a true 180 degree header, is in most applications, not financially worth the gains vs the cost or practical from a manufacturing or ease of installation, or clearance issue.
now there are gains to be had but chasing the last possible potential hp, is rather a waste of money considering that there are far less expensive and easier ways to gain hp, that will fit and function, such as better cylinder heads, nitrous, turbos etc.

v8-firing-flowchart.png

v8-sound.png

MTCooksoon.jpg


SBC cylinder numbering;
-2-4-6-8
1-3-5-7


this is what you would need to build, but look closely, your frame clearance and oil pan, to road clearance will be a huge consideration in the design
Headers.jpg


http://www.stahlheaders.com/docs/2006catalog.PDF
for those guys doing LS engine swaps, theres a whole bunch of different shorty headers
heres just a few of many

lssht1.jpg

lssht2.jpg

lssht3.jpg

lssht4.jpg

lssht5.jpg


If your looking to reduce noise installing several x-pipes in series, blends and reduces the exhaust pulse strength,yes Im sure it could, if theres enough physical real estate under the car, or truck ,available to allow it to be installed,
but I found a full length 3" exhaust with just two 3" X-pipes mounted as close as you can get them too the header collectors
installxpipe11.jpg

x-pipes like this in series and, two 3" inlet and dual outlet ,
mount the mufflers as far back as you can and be sure to have the tail pipes exit past the cars bumper and point back and downward at about a 45 degree exit,
what your trying to accomplish, is basically two goals,
(1) you want to keep the exhaust gas velocity fairly high so its exiting inertia will help scavenge the engines cylinders, on most mild street engines a 2.5" full length exhaust with an (X-PIPE) will be ok, but once you exceed about 370 cubic inches of displacement AND/OR 6000 rpm,
you can usually benefit from the larger and lower restriction of a full 3" exhaust system.

(2)
obviously youll want significant noise reduction , below about 4000 rpm where youll spend more than 90% of the time driving on the street.

volumetric.gif

exhaustpressure.jpg

EXFLOWZ4.jpg

3indual.jpg

low flow restriction mufflers does a reasonably good job at reducing the sound levels, a 3" inlet and dual 2.25" outlet exhaust muffler design works reasonably well, but do your research as different brands have wildly different flow characteristics. and yes dual 2.25" outlets can flow equally to a single 3" inlet, and remember as the exhaust gases cool volume is reduced
fe008cfd.gif

3" o.d = 2.87" diam. inside--approximately 6.5 sq inches of area
2.75 o.d = 2.62"diam. inside--approximately 5.4 sq inches of area
2.5 o.d = 2.37" diam. inside--approximately 4.4 sq inches of area
2.25 o.d = 2.12" diam. inside--approximately 3.5 sq inches of area


dualxmod.jpg


dxpipe3.jpg

that adding just two, 3" x-pipes in close series does make a significant difference in noise levels , is well proven, if you could fit 3 that would certainly not hurt.
xpipehel.png



GrumpyThe Grumpy Grease Monkey mechanical engineer.Staff Member
more numbers for ya'll who like numbers.
mufflercfm1.jpg

All tests via an independent lab
All tests @ 15” wc

2 “ Straight Pipe 283 CFM
2 ¼ “ Straight Pipe 365 CFM
2 ½ “ Straight Pipe 521 CFM

2 ¼” Typical Bent tailpipe 268 CFM
2 ½” Typical Bent Tailpipe 417 CFM

2 ¼” Inlet/Outlet_ Glass Pack Tips- No Louvers- Smooth 274 CFM
2 ¼” Inlet/Outlet- Glass Pack Tips-Louvered 133 CFM
Same as above set for reverse flow 141 CFM
2 ¼” Cherry Bomb 239 CFM
2 ½” Cherry Bomb 294 CFM

2 ½” Inlet/Outlet Dynomax Super Turbo 278 CFM
2 ½” Inlet/Outlet Ultraflow Bullet 512 CFM
2 ½” Inlet/Outlet Gibson Superflow 267 CFM
2 ½” Inlet/Outlet Flowmaster ( 2 Chamber) 249 CFM
2 ½” Inlet Outlet Flowmaster ( 3 Chamber) 229 CFM
2 ¼” Inlet/Outlet Thrush CVX 260 CFM
2 ½” Inlet/Outlet Maremount Cherry Bomb 298 CFM
2 ½” Inlet/Outlet Hooker Aero Chamber 324 CFM
2 ½” Inlet/Outlet Hooker Max Flow 521 CFM
2 ½” Inlet/Outlet Borla Turbo 373 CFM
2 1/2" Inlet/Outlet Magnaflow 284 CFM

airflowen.png


in the ideal exhaust system youll want to have less than .5
(thats 1/2 a PSI of back pressure) at the engines peak rpm
expsize.png


exarea.gif

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/


http://www.pontiacstreetperformance.com/psp/exhaust.html

http://www.mk5cortinaestate.co.uk/calculator5.php

http://forums.superchevy.com/super-...-calculate-muffler-size-and-exhaust-pipe-dia/


http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/

http://garage.grumpysperformance.com/index.php?threads/x-or-h-pipe.1503/

http://garage.grumpysperformance.com/index.php?threads/calculating-required-exhaust-pipe-size.11552/
 
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grumpyvette

Administrator
Staff member
http://www.etoolcart.com/browseproducts ... D2031.HTML

http://www.tooltopia.com/index.asp?Page ... opzilla_r1

viewtopic.php?f=56&t=7590

http://www.weldingsuppliesfromioc.com/miller-millermatic-212-auto-set-mig-welder-907405/

http://www.algrovetoolsupply.com/cgi-bin/item/LIS31500

like most things EXPERIENCE HELPS, but if you mock up whats needed its not going to be difficult to do.
generally you carefully measure, the length and angles and buy a few pipes to cut and weld and use a pipe expander
480.jpg

my exhaust pipe expander needs to be sprayed with oil and tightened and loosened several times, to expand 3" exhaust pipe enough to allow a second 3" exhaust pipe to slide inside the first, but it will get the job done eventually so while its not ideal it is functional and DIRT CHEAP, compared to a decent professional grade tool.


something like this might be better, but remember the tool surface must slide easily so the inner pipe surface and tool must be kept well lubricated
http://www.etoolcart.com/e-zpipeshaperlarge.aspx

http://www.etoolcart.com/pipe-stretcher-kit.aspx
LIS17350.jpg


http://www.mytoolsforyou.com/automotive-tools/MTC-71650.html

http://www.aliexpress.com/store/pro...OPPER-STRONG-PACKING/532410_32283853201.html#!

http://www.amazon.com/Generic-Hydraulic-Expander-Expanding-Swaging/dp/B00M537NJ6
cuttool.jpg

to make one end female so you can slip the normal pipe inside a slip fit giving you some leway on exact length.
682252.jpg

http://www.grainger.com/Grainger/items/ ... al-_-1MUE6
05983.gif


3pipes.jpg


You are buying 1 box of (10) 3" stainless steel straight pipes. Our stainless steel pipes are ideal for fabricating intercooler piping, headers, intake or exhaust systems. These 304 stainless steel pipes come in 3ft sections and are fully polished in order to give your project the highest possible level of finish. This gives you 30 feet of piping.

Also available in single piece units. For more information, email us at info@streetimports.com, call 1-800-839-4536, or see our other listings.

http://www.harborfreight.com/cpi/ctaf/d ... &zmap=5983
having a decent MIG welder helps
miller180.jpg

http://www.millerwelds.com/products/mig ... 0_autoset/
http://www.millerwelds.com/products/pla ... 5_x-treme/
http://www.millerwelds.com/products/plasma/

I really wish you were local,
this is a common issue that a custom exhaust would help resolve,
and a custom or modified exhaust could be a noticeable benefit here
https://www.chevydiy.com/c3-corvette-modifying-exhaust-systems/
one more in an endless list of reasons anyone seriously into modifying cars need a decent welder and to learn the required skills to use it.
building a custom cross member with the room for a full dual 3" exhaust pipe exhaust system is generally the preferred route if you choose to not go the side exhaust on a c3 corvette.

the baffles that you show
are unlikely to do more than restrict exhaust flow and reduce peak power
, yes they may reduce the (drone at lower rpms but thats also unlikely to be worth the resulting loss in power),
the cross sectional area of the holes in those baffles you show is significantly less than an open exhaust pipe they slide inside.


they make very inexpensive exhaust pipe expansion tools for similar issues

https://www.harborfreight.com/medium-tail-pipe-expander-63703.html?_br_psugg_q=exhaust+pipe+expander

Id also suggest use of an x-pipe and kit. mounted as close to the header collectors as space allows under the car (yeah its limited in a c3 vette)
https://www.summitracing.com/parts/sum-642122
but that will require a welder
generally oxy-acetylene torch use , is about the most flexible
and some fabrication and accurate measuring skills

there are exhaust pipe inserts that maintain the same open cross sectional area as open pipe

https://www.jegs.com/i/Dynatech/329...B_o0V3V3TFtnBKUL_mGm4R4sgc-6Cr6AaAhSdEALw_wcB

related info
http://garage.grumpysperformance.com/index.php?threads/exhaust-h-pipe-leading-into-a-x-pipe.15118/

http://garage.grumpysperformance.com/index.php?threads/x-or-h-pipe.1503/

http://garage.grumpysperformance.com/index.php?threads/calculating-required-exhaust-pipe-size.11552/

http://garage.grumpysperformance.com/index.php?threads/building-an-exhaust-system-for-your-car.1166/

http://garage.grumpysperformance.com/index.php?threads/replacing-entire-exhaust-on-a-c3.9296/

http://garage.grumpysperformance.com/index.php?threads/exhaust-system-tools.2002/






read related threads
http://garage.grumpysperformance.com/index.php?threads/spiral-mufflers-anyone.10365/#post-42725

http://garage.grumpysperformance.com/index.php?threads/c3-side-pipe-exhausts.793/#post-1150

http://garage.grumpysperformance.co...ders-that-work-with-sidepipes.2350/#post-6204

http://garage.grumpysperformance.co...lap-on-factory-headers.3155/page-2#post-66721
 
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Dustytrix

Active Member
Grumpy, I am going to put my own exhaust together. I am an electrician so bending the pipe wont be a big ordeal. But how critical is it to keep both pipes the same length ? This will be under a 1990 camaro.
 

grumpyvette

Administrator
Staff member
Dustytrix said:
Grumpy, I am going to put my own exhaust together. I am an electrician so bending the pipe wont be a big ordeal. But how critical is it to keep both pipes the same length ? This will be under a 1990 camaro.

the truth is, if its fairly close in length, it will work just fine, now theres guys that spend days getting things within an inch or so but every test Ive seen shows that your going to be fine if your fairly close,in the lengths that the calculators suggest you use, theres calculators that you can find and use posted on this site, in this and other threads.
if you measure commercial headers and then use the calculators youll quickly see that the vast majority of header primary tubes are far to short and not equal length.
lets say the calculators say your primary tubes should be 39" long and after you prefit the custom headers you design you find the headers have 39" ,38", 39.5" and 37.7" tubes, if you think thats not going to work better than a commercial header with two 32" and two 34" tubes your in for a huge shock on the dyno, now the collectors should be as close to equal distance as you can get, lets assume the calculator says a 19" is ideal, but your collectors need to be 18" and 21" to match the (X) pipe, again, the difference in potential power produced is minimal if measurable at all, on a low restriction exhaust past the (X)
keep in mind the ideal length changes with rpms, compression and cam timing so if the header primaries or collector length varies slightly it only means each cylinder reaches max scavenging at a couple rpm higher or lower, in the power band ,...again play with the calculators and youll see theres a good cushion in the rpms vs length, its not exact, its a power band that's over several hundred rpm, in the real world your engine rpms vary so fast theres almost no way to measure the difference in headers if they are ball park length, and Id point out how most commercial headers are far shorter than ideal, yet they still help produce increased hp even when your engine rarely if ever reaches the effective tuned length.

pay close attention to the math,and do your best to fabricate the ideal header and exhaust, but don,t go crazy, getting very close to the calculated ideal, is just as effective, in the real world as getting it exactly correct, simply because theres so many variables that (exactly correct) is more theory than fact in a car where clearance issues, getting parts to fit and function and cost are more important factors
or put a different way, do you really think youll know the difference if every cylinder hits peak power at lets say 5780rpm or if 3 cylinders hit peak efficiency at 5760rpm,3hit at 5790rpm and two hit at 5800rpm
http://www.superchevy.com/how-to/exhaust/0505phr-exh/

http://www.hotrod.com/how-to/engine/mopp-0412-tti-exhaust-system-and-header-components/

adding an X-pipe to a dual 3" exhaust behind your muslecars engine is almost always going to result in a bit mellower exhaust tone and at least a couple extra horse power due to the slightly lower back pressure and generally more effective exhaust scavenging it can allow

http://www.pontiacstreetperformance.com/psp/exhaust.html

http://www.pontiacstreetperformance.com/psp/exhaust3.html

xpipetys.png

recex.png

ID also point out that I rarely see dual 3" exhaust systems with an x-pipe not provide the best power

read

viewtopic.php?f=56&t=260

viewtopic.php?f=56&t=1303

viewtopic.php?f=56&t=1503

viewtopic.php?f=56&t=495

viewtopic.php?f=56&t=185

viewtopic.php?f=56&t=961
 
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grumpyvette

Administrator
Staff member
3" stainless components

the first time you think about doing this I,m sure you'll have dozens of questions and probably realize you don,t know most of the tricks or have some of the tools required, obviously having access to a lift and welding equipment is a huge advantage, the good part about building your first few exhaust systems is that in most cases, most of the welding is not all that easy to inspect while the cars being driven so if your just learning to weld a a few less than skilled welds won,t be a huge eye sore on your car.
remember youll want to complete the project in a reasonably short time (usually a weekend) so make sure you have all the tools and components before you start, because finding something like a extra 3" stainless (X) or (S) bend on a weekend can be a royal P.I.T.A. at times.
BUT USE A MINIMUM 16GA 18 GA is too THIN, FOR STAINLESS HEADERS OR EXHAUST PIPE, AND DON,T FORGET TO PURGE THE BACK GAS WHEN WELDING
just remember the old carpenters rule of MEASURE carefully TWICE before CUTTING ONCE!, and take the time to think thru the route the exhaust pipes, must take, any clearance issues and muffler to suspension or frame clearance, etc.
lay it all out before you permanently weld any connection, between sections or components and make sure you make allowances for the future temporary dis-assembly, at some point, if the mounted exhaust blocks access to the drive train.
use vibration or rubber damper strap mounts to prevent annoying harmonics or vibrations .
remember stainless welds must have the back of the weld area shielded so both ends of the pipe covered with aluminum duct tape and fill the pipe with a flush of shield argon gases is a good idea, mig or tig works (I vastly prefer TIG) but remember to use stainless mig wire or tig fill rods and argon tends to work ok as a shield gas.
we have a welding tips section you might want to browse thru
viewforum.php?f=60

http://www.youtube.com/watch?v=4TIQYEv1 ... ure=fvwrel

http://www.youtube.com/watch?v=ANFXXKMR ... re=related

http://www.youtube.com/watch?v=zzvy3Rd0 ... re=related

http://www.youtube.com/watch?v=DzNcHI7r ... re=related

http://www.youtube.com/watch?v=KdaVNRcy ... re=related

http://www.youtube.com/watch?v=8KrApq04 ... re=related

http://www.youtube.com/watch?v=02U0H15_ ... re=related

CRISS POSTED THIS INFO
"You can mig stainless just fine. I use stainless wire, the mix isn't really that important, C25, tri mix etc. The best results are with 100% Argon or a Argon/Helium mix.
What IS more important is the back side of the weld, you should use either a shielding gas on the backside or solar flux B which is a powder you mix with rubbing alcohol and coat the back of the weld to prevent oxygen contamination. Without the coating you will get black crystals or sugar in the weld on the backside that makes the weld weak.

Tig welding is really the best way to weld stainless, but mig welding it is very doable as well. "

IF YOU WELD STAINLESS EXHAUST PIPE without a back flush you can get weld crystallizing or SUGARING , an ARGON back flush and taping both ends to exclude oxygen helps reduce this significantly as will tig paste

Cans.jpg


http://www.solarflux.com/Pages/Productinfo.html
Sugaringonstainlesssteellr.jpg

weld%20crystalizing.jpg


http://garage.grumpysperformance.co...eld-gas-selection-for-welding.1108/#post-2185

http://www.stainless-specialties.com/products2a.htm

http://www.magnaflow.com/wideopen/wideopen.asp

http://www.spiderautomotive.com/benttubing.html

http://www.stainlessworks.net/cart/inde ... 66a68a046a

http://www.pypesexhaust.com/accessories.html#03

http://www.weldingtipsandtricks.com/wel ... steel.html

http://www.pypesexhaust.com/xpipes.html

http://www.classictube.com/products_exhaust.asp

http://www.gowelding.org/TIG_Welding.html

http://www.weldingtipsandtricks.com/wel ... steel.html

http://www.discountexhaustsystems.com/

http://www.autoanything.com/exhausts-mu ... 3A0A0.aspx
 
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grumpyvette

Administrator
Staff member
having a good welder (usually a MIG) and the exhaust pipe trim and cut tools , and pipe expansion tools mentioned earlier in the thread helps,
but if you have a lift youll need at least two of these jack stands to work on an exhaust fabrication project.
youll want to mock up the exhaust, on the car to verify it fits correctly but after tack welding it to hold angles and location, youll want to drop the exhaust and weld the exhaust pipe seams that won,t be using clamps, off the car for easy access .
I just finished a few minor repairs on a friends exhaust and having a lift, tall jack stands, clamps and a decent MIG welder made the whole project go smoothly, and having struggled in the past with less than ideal tools I look back and really appreciate the difference having the correct tools and a lift makes in the fabrication process. I feel really good about both the minor repair work , It gives me a sense of accomplishment and pride in my skills and appreciation for the tools Ive acquired, and the fact that I saved him over $100 on a simple repair, a section of pipe cost me less than $20 the local shop wanted $139 to repair the exhaust, at that rate its obvious that buying a welder and learning to use it, will pay for itself fairly qickly
(replacing a crushed section of pipe he got when he stupidly drove over a parking lot space concrete space end barrier)
parking-lot.jpg


HERES THE MIG I PURCHASED
MILLER 252
http://www.welders-direct.com/mm5/merch ... gory_Code=
FOR MY SHOP, (IT COST $2200) IT HAS AN OPTIONAL KIT THAT WILL ALLOW YOU TO MIG ALUMINUM< BUT ITS RATHER EXPENSIVE
(about $1100)
http://www.welders-direct.com/mm5/merch ... ode=130831
but its a TOP QUALITY MIG THAT WILL HANDLE 95% OF AUTOMOTIVE WELDING IF YOU GET THE OPTIONAL KIT
millermatic252.jpg


READ THIS THREAD
viewtopic.php?f=60&t=77

http://www.harborfreight.com/2-ton-capa ... 41860.html
41860.gif
41860.gif


band1.jpg

http://www.jegs.com/i/Dynomax/289/33226/10002/-1
band2.jpg

http://www.summitracing.com/parts/SUP-0 ... /?rtype=10
band3.jpg


http://www.jegs.com/i/JEGS/555/30732/10002/-1

http://www.donaldson.com/en/exhaust/sup ... 057171.pdf

http://www.verociousmotorsports.com/Sho ... aust-Clamp

http://garage.grumpysperformance.com/index.php?threads/c3-muffler.7806/#post-35279

these clamps are frequently MIS-used the connected pipes are rarely supposed to butt end to end and actually form the gas sealing surface over the exhaust flow
the pipes are supposed to be a male/female slip fit with the clamp forcing the outer pipe to form a high friction fit with the inner pipe as the clamp tends to slightly reduce the outer pipes inner clearance, effectively clamping the outer female pipe around the inner male pipe surface
cutting a short slot in the outer female pipe tends to aid clamp force.
occasionally the clamps are used to connect two similar size pipes, that are not a true slip fit, and they can be used that way but they tend to leak over time when used that way.
keep in mind clamps are used where the pipes must be able to be dis-assembled at times, its much better to weld any connection that's not located where occasional dis-assembly is mandatory

Accuseal Clamps

Accuseal 100% stainless steel exhaust clamps are a simple, effective way to connect exhaust system components (pipes, mufflers and converters). Unique seal and high clamp loads are provided without permanent distortion to exhaust members. Exhaust connections are serviceable and easy to disassemble.

Accuseal clamps are available in standard industry sizes ranging from 1-3/4'' (44.5mm) through 6'' (152.4mm). Unitized construction reduces part number complexity, and efficient use of materials reduces weight, and assembly costs.

Accuseal's unique fastening system stretches the band using its tensile strength permitting the use of thinner gauge, corrosive resistant materials. The reaction block provides a full 360 degree equal distribution of stretching force, prohibiting pipe distortion while completing a seal around the joined exhaust components.

AccuSeal Clamps are designed to be used on ID/OD style connections. For example, if you have a 2.50" exhaust, the clamp is designed to fit over tubing that has been flared to a 2.50" ID, or over an exhaust component such as a muffler that has a 2.5" ID inlet or outlet. For optimal sealing, the larger side of the connection (the ID side) should have relief cuts/slots in it.


pvd10.jpg

look closely at the strait end of these tail pipe extensions youll see the connecting end is flared to form a receiving end for a slip fit, of the standard diam. male pipe end it will be attached too.

Pipe-Expander-1MUE5_AS01.JPG

http://www.grainger.com/Grainger/WESTWA ... Pid=search
If your exhaust pipes not factory swagged to form a female end an expander tool can form the correct diam


if you need to cut exhaust to length this tool works in the often very restricted areas, under a car
Adjustable-Pipe-Cutter-1MUE6_AS01.JPG

http://www.grainger.com/Grainger/WESTWA ... Pid=search

If I ever get any spare cash I can actually use on tool purchases, Im going to look into a good metal cutting cross cut miter saw, I could use for a multiple of projects..but finding one I can use that comes with a good vise to hold material securely and designed for cutting at lease 6" x 6" tubing is not all that easy, plus my older son , 36 years old, recently moved back into my home with his kids as he needs constant medical care and financial assistance due to medical issues so I don,t see any spare cash flow in the near future

radsaw.jpg


RELATED THREAD
viewtopic.php?f=27&t=3184&p=29745&hilit=miter+saws#p29745

 
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grumpyvette

Administrator
Staff member
allen said:
Hey guys
Does anyone know if somebody sells a bolt in front y pipe for my newly installed,long tube hooker headers? for my c4 corvette ? I have searched around on a couple catalogs and web sites with no luck. Id like to have it bolt up to the single catalytic converter on my 1985 corvette, and header collectors??.

damn near any exhaust fabrication shop can make you up one that custom fits the application OR you can avoid a great deal of similar work in the future if you buy and learn how to use one of the little MIG welders, components are not expensive and you can do the work easily enough on 4 12 ton jack stands, just test fit, accurately mark, cut, and weld off the car.
honestly I don,t see working on cars and paying a $100-$400 in labor for something I not only enjoy doing but do better than most of the shops I used to sub out work too, so for me its a no brainer to buy a fairly cheap welder and a few sections of exhaust pipe, and the welder will pay for itself many times over in saved labor cost over the next few years, especially when you can frequently complete the job for less than 1/3rd of what a shop charges.
you can buy a really nice 140 amp welder for under $800, youll easily pay that over time in labor charges alone
blacksidepi.jpg

http://www.harborfreight.com/12-ton-jac ... 34924.html
12tonstand.jpg


vettejack1.jpg

http://www.summitracing.com/parts/jex-u6-6

http://www.summitracing.com/parts/hed-1 ... 7Aodn1UAYw



http://www.jegs.com/i/Hedman/500/18700/ ... gQode7gAPw

http://www.summitracing.com/parts/wlk-8 ... l/corvette


http://www.welders-direct.com/mm5/merch ... ry_Code=MW

http://www.welders-direct.com/mm5/merch ... ory_Code=L

http://www.eastwood.com/mig-welders-175 ... 7AodnEoAZA
 
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8

87vette81big

Guest
Hooker sells the correct C4 Y-pipe for thier Super Comp SBC Headers still Grumpy .
Summit Racing.
I never purchased the Y-pipe because its expensive, taking 3" header collectors and merging into a single 3" inch outlet.
Outlet should be 4" inch.
Better off Fabricating your own as you stated when it comes to Corvettes.
Avoid the Corvette Tax.
Parts available dont Maximize Torque & HP . Easy installation the top factor only.

I like the Hose Clamp with the window cutout for aligning and holding 2 pipes together then Tack welding with a MIG WELDER.
I WILL TRY IT NEXT TIME I WELD JOIN 2 EXHAUST PIPES .
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member

interesting and informative video, well worth watching to the end, and you might take notes on a few mods and tuning tweaks
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
related and nostalgic info on a dodge, makes me truly nostalgic,
and wishing you could still find and buy these semi reasonably,
built like the originals before they screwed them up completely.
and yeah a BBC or BBF in a AC COBRA CLONE could eat these alive,
performance wise, if correctly built by someone with knowledge and skills




keep in mind the 406 displacement SBC RICK BUILT for his T-bucket,
makes maybe only a bit less or similar power and torque, (
roughly 440hp/500 rear wheel tq)
in a much lighter weight car,
and I know I've built a bunch of 496 BBC engines over the years,
that would exceed the vipers nearly stock power level
obviously with a few changes that vipers v10 could be tweaked,
to produce noticeably more power,
but both RICKS SBC and the VIPERS engine are built for brisk street performance,
and dependable transportation, not racing

 
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T-Test

solid fixture here in the forum
Many years ago when I first started making exhaust systems for my cars, I used a torch and coat hangers dipped in borax. Had to pay others to bend the pipe but had the expanders to make anything that pertained to exhaust.

Tried to use Hooker equal length headers and 2&1/2 inch pipe on all small blocks . Anything over 400 ci I used 3 inch pipe. Fenderwell headers on my '55 chebby with.cutouts just in front of the doors and the pipe coming from the side of the headers at a 45* angle.

Now I just mig/Tig all pipe.
 
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