are you tired of crappy exhausts, and poor installations

grumpyvette

grumpyvette

Administrator
Staff member
face it, many, maybe, most muffler shops want you in and out of thier bays as fast as possiable and want to use the least expensive components they can find , and want to take the least effort and time they can, yet derive the most proffit, from the work. you can totally avoid that by either buying top quality components and paying big bucks, or...if your budgets like mine....
if something BREAKS , well,thats a P.I.T.A., and probably a badly designed or improperly installed component, but thats what WELDERS are designed for.....learn to weld and things like that are at most a minor repair that will usually take well under 30 minutes and its almost certain that you can put some thought into the repair and make it darn near "bullet proof"
and very unlikely to re-occure:thumbsup:
no part is immune from a bad installation.
in fact! once you learn to weld and you can weld up a totally custom exhaust that will exactly match your design and application goals for far less than you can buy one for, in cheap aluminized steel or the far better stainless steel

http://store.summitracing.com/egnse...+kit&searchinresults=false&N=700+115&y=6&x=32

http://www.mandrelbendingsolutions.com/ ... 3&total=31

http://www.jegs.com/webapp/wcs/stores/servlet/category_10001_10002_11525_-1_10245

http://www.magnaflow.com/02product/universalsatinxl.asp

http://www.flowmastermufflers.com/mufflers.html

http://www.porcupinepress.com/_bending/segmentbends.htm

http://www.borla.com/products/universal.aspx

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

you can build your own stainless steel exhaust system and personally install it and its very unlikely to cost nearly what youll pay a muffler shop, and if you shop for components carefully youll find that a stainless exhaust will cost only slightly more than the muffler shop charges for inferior aluminized steel
if yourgoing thru the work do it correctly, buy and install decent components so your not back doing it again in a year or so!

careful measurement and planing, and component sellection, will help a great deal in keeping costs low!

BUT THEN I ONLY BUY AND INSTALL STAINLESS COMPONENTS IF GIVEN AN OPTION, INSTALL THEM MYSELF, AND CAN,T REMEMBER HAVING PROBLEMS INSTALLING OR HAVING A COMPONENT FAIL IF ITS PROPERLY INSTALLED...QUALITY EXHAUST HANGERS DON,T GENERALLY FAIL AND QUALITY WELDS DON,T GENERALLY BREAK, AND IF YOU INSTALL IN CORRECTLY YOURSELF AND CAN WELD YOULL SAVE MONEY AND HAVE THE EQUIPMENT AND SKILL TO FIX IT IN THE UNLIKELY EVENT IT DID BREAK:thumbsup:

JUST ONE MORE REASON TO LEARN TO WELD AND HAVE ACCESS TO A GOOD MIG,TIG, OR OXY-ACETOLENE TORCH:D :thumbsup:
 
BY THE WAY, IF YOUR TIRED OF LEAKY EXHAUST GASKETS,
the COPPER ONES TEND TO WORK OK AND STAY PUT

http://store.summitracing.com/partdetai ... toview=sku
sce-4011.jpg

http://store.summitracing.com/partdetai ... toview=sku

sce-013286.jpg



these carbon gaskets below,also work, well, probably better in fact on a one time use basis,because thier more flexable, but are not as durable

http://www.remflex.com/exclusive_features.htm
 
EXHAUST, HEAT, PRESSURE & FLOW RESTRICTION


"So what are you saying grumpy? I am only reporting what I have read on this forum (posted by a couple of engineers). Are they mistaken?

I posted that I had read that the flow is controlled by the smallest dimension in your exhaust system. I read this in relation to mandrel bends vs regular bends that crimp the pipe. It said that if you have a 2.5" pipe with crimp bends, it will flow like a 2" pipe if that is the dimension of the pipe at the bend.

I was corrected immediately by some who explained the fact that they are running 3" pipe with 2.5" tail pipes and it doesn't effect flow because the cooler exhaust doesn't have as much volume.

Who is right?"

SHORT ANSWER, AND DEPENDING ON SEVERAL FACTORS,AT LOW RPMS YOUR CORRECT, AT HIGH RPMS YOUR PROBABLY NOT NEARLY CLOSE, YES THERES a good deal of heat lost and a reduction as the exhaust pulse travels away from the exhaust port but as the rpms increase the time drops between pulses and the heat increases dramatically

OK think it thru without getting on either side of the discussion UNTILL you’ve got some FACTS vs OPINIONS.

First it should be rather obvious that exhaust cools as it moves from its high heat point (THE EXHAUST EXITING THE HEADS) to its low point, (the outside air temp as it exits the car)
BUT were not really concerned, much with the heat levels in the exhaust unless that cooling affects the gas volume enough to measurably affect the resulting pressure that can restrict the following flow rates, of exhaust exiting the car.
Now lets look at FACTS
exhaust temp commonly runs between about 700F-800f but can get to -1300F depending on cam timing, compression ratio, ignition timing and the fuel air ratio, octane, ETC. Exhaust flow rates can easily exceed 200ft per second and its usually higher, naturally the engines displacement, gearing and RPM effect the resulting VOLUME AND RESULTING PRESSURE the exhaust needs to deal with and as the rpms go up the time allowed for heat to transfer out of the gas flow tends to be drastically reduced.
FACT as the rpm rate goes up both the volume of exhaust and the temp. of that exhaust tends to go up rapidly., as the volume goes up and the temp. goes up but the interior of the exhaust system stays constant the pressure tends to go up also.
Fact the EXHAUST GAS VOLUME is about 8-12 times larger that the intake charge that entered the cylinder, that was compressed and burned, that almost instant expansion is what forced the piston away from the heads and provides the engines power,and at peak pressure might hit 600 psi as it forces the piston down and drops rapidly as it exits the engine

FACT at only 200ft per second it takes far less than a second for the exhaust gasses to exit an exhaust, and each previous exhaust pulse has bled of or transferred some heat , so each later pulse has a less effective surface to release its heat content into.
HOW much do you think the exhaust flow cools during the trip thru the exhaust and how long does it take to bring the exhaust pipes up to a temp range where heat transfer out of the flow slows noticeably?
REMEMBER exhaust headers frequently glow cherry red in well under a minute on a dyno. And that’s not in a cramped engine compartment and usually with lots of fans blowing..
Flow rates in the exhaust are limited by the smallest cross sectional area, the temperatures and the resulting pressures, resulting from the engines displacement, compression ratio, f/a ratio, and the rpms its running at.
An exhaust that functions perfectly at 3000rpm may easily be very restrictive at 6000rpm., and as the time and temperature increases the exhaust temp tends to go up slightly as does the resulting restriction to flow.BUT the volume of exhaust is mostly linked to the engines displacement, rpms and f/a ratio

This might interest you[/color]


viewtopic.php?f=79&t=497

http://www.blksmth.com/heat_colors.htm

http://www.tech.plym.ac.uk/sme/ther305-web/Combust1.PDF

http://en.wikipedia.org/wiki/Boyle's_law

viewtopic.php?f=56&t=495
 
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