well after 5 years my 383 is alive and dyno'd

S

stroker87

Active Member
hey every one its been a minute since I been around parked my truck for 5 years after the cam gear eat the dizzy gear but I got it back together and got it tuned and dyno'd

engine spec's with the last cam

Comp Cams XR269HR-12
@ .050 218 int./224 exh, 0.495 int./0.503 exh. lift, Lobe Separation 112

engine specs
350 over .030, 3.75 stroke, -16cc pistons, H beam rods & splayed caps 9.8 to 1 comp.

Dart Aluminum Pro 1, 200cc int, 64cc chambers, 2.02 int/1.60exh valves, int 264cfm @ .500" lift/28", exh 180cfm @ .600 lift/ 28" beehive springs install to new cam specs

Holley Stealth Ram fuel injection system/ 950c ecu, 36lb injectors 1000cfm

700r4, edge 3k stall 12 bolt 3.73 and 29" tire

best dyno was 293rwhp (no torque numbers since they was not able to get a tech signal)

the new set up was porting the stealth ram intake polishing the combustion chambers and mild port on the heads new cam

Lunati 54799lun
@ .050 int 231/ exh 239, .535 int. / .550 exh

the new numbers are 342rwhp again no torque numbers

I dont feel its 100% dialed in, the tuner did not like the 950 commander pro software and was annoyed by it (not enough tunablity for him) he had it at 320rwhp I pushed him some and he messed with it found another 23rwhp and said thats all he can get, I think there might be "some" HP left on the table but it cant be much? similar engine have made well over 370rwhp at this point I feel a "little" cheated / disappointed since i dont feel it has the missing 30 or so HP in it maybe 10 or so if the tune is dead on.......

Grumpy I'm interested to read your thoughts? you gave me a bunch of advice along the way and always appreciated it :mrgreen:
 
first Ive got to ask if you ported the stealth ram intake manifold rather extensively or just mildly as in stock condition, or near stock, its better than the TPI, but still no where near its full potential, as it has once opened up and has the ports and runner blended, Id also like to know the ignition advance curve and fuel air ratio at every 1000rpm step, and see clear pictures of the plugs, id also like to know the header collector back pressure reading at every 1000rpm step?
what goes in needs to go out but its exhaust scavenging thats one of the main keys to effective ram tuning an intake
you can,t make intelligent decisions without facts, and you get the facts by testing!
that cam should easily get you in excess of 400 rear wheel hp once properly tuned with those heads on a 383.
and it should be obvious that testing needs to be done under the current operational conditions at the rpm range that your concerned with.
A stock automotive exhaust might have over 5 psi OF BACK PRESSURE, AT PEAK RPMS WHERE EXHAUST FLOW IS AT MAX,or even more in a few cases, of back pressure in the exhaust system if measured at the collectors at max engine rpm, with a decent accurate pressure gauge, while a good aftermarket exhaust system will roughly cut that in half to the 3-5 psi range. BUT An excellent performance exhaust will get down in the 1-2 psi or restriction to flow range at max engine rpm. keep in mind that the efficiency of the headers scavenging the cylinders , and helping to draw in the following intake charge,is almost totally dependent on maintaining a very low flow restriction or back-pressure in the collectors ,especially at mid and upper rpm levels
volumetric.gif

exhaustpressure.jpg

EXFLOWZ4.jpg


one of the most common and least tested, factors in most engine build ups is testing for restrictions to building increased horsepower. a huge problem is in restrictive exhaust systems that can not effectively allow the headers to scavenge the burnt gases from the cylinders, a good open collector on a well designed header can reduce the back pressure at the exhaust port to a negative pressure significantly increasing cylinder scavenging out the exhaust, thus helping draw in a fresh intake charge.
holleystealthrampicya.jpg

holleystealthrampicya1.jpg

holleystealthrampicya2.jpg

porting the runners on a stealth ram is mandatory for maximizing flow rates, leaving the runner entrance like this creates a restriction and turbulence, and if your significantly increasing the air flow rates your obviously going to need a longer duration cam, better flowing cylinder heads a low restriction exhaust, efficient headers and larger injectors to supply more fuel, ETC.
viewtopic.php?f=52&t=462&hilit=stealth+ram+port

this is what you currently have :shock: and its restricting flow
stelte1.jpg

This is closer too what you want to have (you can almost see the HP) but look at the lower picture :twisted:
stelte2.jpg

porting helps flow significantly, but the walls should be smoothed and opened up carefully down 3" or more into the runner entrance and exits
portedhsr.jpg

P1010016.jpg

don,t forget to port the runner exits to match the heads
 
well sad to say it might take me a little while to get you those answers, I picked it up from the dyno and took it straight to the drag strip only was able to get 2 runs in then the speedometer cable adapter housing blew off at 1/2 track spraying the track with fluid and catching fire from the exhaust (what a mess) fire was put out fast so i dont think theres to much of a mess under there but i was so annoyed I didnt even bother to look loaded it on the trailer and headed home :oops: :shock: :eek: :(

best run, strong till about 900' mark then kinda falls on its face, lest setup felt the same I dont get that? its like it just runs out of power
R/t - .413
60' - 1.89 (light spin for about 20ft)
330 - 5.47
1/8 - 8.48
MPH - 81.25
1000' - 11.127
1/4 - 13.399
MPH - 98.21

after cam porting i only picked up 1mph? stall, cam & porting only dropped 0.31 off my ET

tune is off when i was going down the track a few times it felt like I was lifting then getting back in to it when I never lifted,

the first to picks you posted is actually mine from when I ported the intake, the headers are long tube's with 3" collectors, 2.5" pipes, X Pipe electric cut out then flowmasters I dont think its the exhaust since on the dyno open made no change in HP ? headers are headman 1 5/8 in.

kinda wondering if some things wrong with 3rd gear in the trans? the engine has a new cam I added a stall tune is "ok" but 1mph just dont seam right even my 1/8 mile shows I should of ran a better time?
 
Ive seen several cars that had fuel volume and pressure supply issues, that were only cured with a different fuel pump and fuel pressure regulator, as the stock fuel supply tended to loose pressure at mid track, it was fine under 4500rpm, but could not keep up consistently for more than a few seconds with the demand required at 6000rpm, Id install a fuel pressure sensor and gauge where you or a buddy can watch it or a data logger, some times its a simple cure like a better fuel filter and larger fuel lines but most of the time it requires the larger pump and regulator also.
the problems hard to isolate because of the time lag and the fact the standard components can usually supply the engines needs to at least 4500rpm and still function at 6000rpm for several seconds
 
Fuel pressure was good on the dyno when it was not making what I thought it should started looking at things the might be holding it back I have a gauge under the hood mounted on the fuel rail it was reading around 54psi as for the pump its the one that came with the kit for the HSR 36lb injectors kit there running at 80% I ran I think it was 1/2 aluminum tube from the fuel cell used -8 fitting

If it was a fuel problem wouldn't it be noticeable in 1st and 2nd gear when there in high rpm's? WOT tuning was only done in 3rd gear on the dyno

all this stuff makes me feel like the problem is in the trans? its the only thing that would make sense for the truck not making the correct power with 2 different combo's

once I get the trans sorted out I'll do some logging
 
the "RUNNING OUT OF POWER" in third gear is frequently a classic indicator of either a restricted fuel flow reaching the engine under hard acceleration,or restricted exhaust, building up back pressure.
I would tend to think a exhaust back pressure issue or ignition related issue would come into play restricting power by the time you reached the upper rpm range in second gear, if its not appearing until your in the upper rpm band of third gear it sounds like its a fuel delivery or programing issue related to the injectors , or a sensor related to heat or your oxygen sensors in the exhaust, Id sure pull trouble codes and do some testing and if possible get access to some soft ware testing tools.
but I,d agree ,yes you could easily have a transmission related problem.

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yeah more reading but its bound to help you locate and cure the problem

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I have a electric FP gauge I'll install and see what the fuel pressure does and some logging, since this is the second combo in this truck and they both had the same nose dive in 3rd gear it cant be the engine itself so i'll look into the fuel system and exhaust see where that takes me?

but i'm really close to selling this truck or LSX swap! one or the other at this point if I cant find the problem SOON!
 
87vette81big, is a member on this site!
he may live some place with-in driving distance , from you,
you may want to see if hes in your area, as hes obviously a skilled mechanic, with experience.
 
its a long shot but an easy check... get someone to read the voltage at the pump and at the ecm during hard acceleration and see if theres any fluctuation in the pump voltage youll see a change in flow, if theres a change in voltage at the ecm then your tune could possibly change depending on the type of computer thats controlling your motor.
 
philly said:
its a long shot but an easy check... get someone to read the voltage at the pump and at the ecm during hard acceleration and see if theres any fluctuation in the pump voltage youll see a change in flow, if theres a change in voltage at the ecm then your tune could possibly change depending on the type of computer thats controlling your motor.
Click to expand...

I'll look at that, the 950 gets power from straight from the battery i know i've seen it bounce from 13.4v to 14.2v in the fuel table map but dont know what the fuel pump is getting
 
grumpyvette said:
87vette81big, is a member on this site!
he may live some place with-in driving distance , from you,
you may want to see if hes in your area, as hes obviously a skilled mechanic, with experience.
Click to expand...
I just skimmed read through Grumpy.
I seen 12-bolt Chevy Rear mentioned.
Its not a Corvette.
What kind of car are we working with ?
Its running out of fuel volume & restricted exhaust.
Most SBC Header designs are Bad.
I knew this & you too Grumpy.
Just the MPH Trap speed.....
Want at least 107- 140mph trap speed to have ET bragging rights.
Yes I am within driving distance.
Joliet, IL is just 45-55 minutes away from me.
Downtown Chicago 75 minutes away.
At 100 mph I make real good travel time to Chicago land.
 
60 Foot times not so great.
1.5 be better.
1.2-1.3 be nice.
Chassis suspension not tuned.
 
87vette81big said:
60 Foot times not so great.
1.5 be better.
1.2-1.3 be nice.
Chassis suspension not tuned.
Click to expand...

this is a 1987 chevy R10 silverado 2wd 1/2 pickup 3900lb with driver (me)

truck as for suspension work is only lowered 2" front and 4" rear nothing more, the truck has 1.7x 60' with the old setup a bunch of times I think a 1.6 might be possible with the right tire and tune since now its lunching much harder and I can do a burn out with ease. my current drag radials are old and tired but had to see it run since it sat for so long......

if the exhaust is holding it back it has to be the headers maybe? I have electric dumps right after the X pipe in the system maybe 12" to 15" from the header collectors and open made no extra power? full exhaust is 2.5" from the collectors to tail pipes, the air intake system is a little restrictive when the dyno operator removed it we got a 7rwhp gain some thing i'll be changing

i'm not sure where he has the timing set he did play around with it and I remember him telling me he added 2* and it made no change so he took it out (if that means any thing to you guys? )

"if" the exhaust was restrictive "or" it was not getting enough fuel wouldn't it show in 1st and 2nd gear?

I cant get over how well it moved till i shifted in 3rd I really thought the gt500 mustang hit nitrous the way he ran from me then I seen my ticket and relized its just still falling on its face in 3rd AGAIN!!
 
Tell me more about your current fuel system layout.
Fuel cell used.? Stock gas tank ?
Welded sump & gravity fed pickup point to fuel pump ?
What size lines ?
AN Race fuel hose fittings used ?
#6 Or #8.
I have custom plumbed 8-second Renegade 5.0 Mustangs with a friend on several cars in the past in Joliet -Lockport area.
Even 12 second ET car or truck takes thought & execution to do correct.
Pickup trucks never had drag race in mind stock other than the GMC CYCLONE Or Ford Lightning.
Your working the 700R4 real hard with 3900lb race weight .
Don't expect it to last forever.
Turbo 400 be better or 4L80E.

Unbolt the Header collector. Run open exhaust at strip.
3"- 2-1/2 " big choke point restriction.
Need at least 3" inch mandrel bent system to be a Race Hero.
 
Tell me more about your current fuel system layout.
Fuel cell used.? Stock gas tank ? 20 Gallon cell in the bed with sump
Welded sump & gravity fed pickup point to fuel pump ? gravity pump is under bed on frame rail
What size lines ? all 1/2" aluminum tube last 24" to fuel rail is braided hose (still -8)
AN Race fuel hose fittings used ? yes
#6 Or #8. -8

87vette81big said:
I have custom plumbed 8-second Renegade 5.0 Mustangs with a friend on several cars in the past in Joliet -Lockport area.
Even 12 second ET car or truck takes thought & execution to do correct.
Pickup trucks never had drag race in mind stock other than the GMC CYCLONE Or Ford Lightning. agreed but not looking for 9's would be really happy with mid 12's on engine 11's with nitrous
Your working the 700R4 real hard with 3900lb race weight . its been build been holding up nicely until Friday the speedometer housing blew out of it
Don't expect it to last forever.
Turbo 400 be better or 4L80E. i think i'm about done buying big parts for this setup i'm really close to selling it right now i love/hate it

Unbolt the Header collector. Run open exhaust at strip. i'll have to move the o2 sensor i think its after the collector
3"- 2-1/2 " big choke point restriction. I was told 2.5" would support up to 650hp?
Need at least 3" inch mandrel bent system to be a Race Hero.
Click to expand...
I might just install 3" electric cut outs right after the collectors if I find that to be my problem full 3" pipe are pretty loud to have full time,

this was a kit Holley Stealth Ram EFI 91405201 it cam with 36lb injectors, fuel rails, regulator, pump, filter & etc. was told it can handle between 480-575 HP, on the dyno the injectors was @ 80% again in 3rd gear
 
Do You have A wideband O2 AFR TO USE ??
THEY HAVE COME DOWN IN PRICE TO BUY NEW.
AEM.
AUTOMETER.
INNOVATIVE.
 
87vette81big said:
Do You have A wideband O2 AFR TO USE ??
THEY HAVE COME DOWN IN PRICE TO BUY NEW.
AEM.
AUTOMETER.
INNOVATIVE.
Click to expand...

yes using a AEM wideband and the holley ECM is using it for signal (its been adjusted so every thing is getting the correct signal)
 
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