first passes, what am I doing wrong?
09-07-2014, 09:13 PM
#1
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first passes, what am I doing wrong? Total let down today. I rebuilt my whole turbo setup, bigger charger, better pipe, new efi, new trans and converter. Best I could run was 11.40 @ 120. It feels like a pig at the track but a beast on the street. Here is the run down....
3200# third gen
3.50 gear, 30in tire
4l80e 3500 stall With A transbrake
Holley dominator
5.3 with 317's
Proflow intake 90mm tab
60lbs injectors @ 58 psi base
93 octane
Pt76mm 3.5 inch down pipe
Air to air
The car makes 11psi on the trans brake and goes 1.6 60 ft. Then rolls about 30ft and starts to run out ok. I checked the timing and it is correct with a timing light. Afr is good 11.5 and 15deg of timing down track. Timing is 35 deg on the brake then drops to 18 by 4500rpm after leaving off the button. It just doesn't want to rev up out of the hole. It feels like it needs more timing but I don't want to blow a ring land off yet. Any ideas? I'm lost here. This setup goes 10's and 9's all day for others on here. What do you think?
3200# third gen
3.50 gear, 30in tire
4l80e 3500 stall With A transbrake
Holley dominator
5.3 with 317's
Proflow intake 90mm tab
60lbs injectors @ 58 psi base
93 octane
Pt76mm 3.5 inch down pipe
Air to air
The car makes 11psi on the trans brake and goes 1.6 60 ft. Then rolls about 30ft and starts to run out ok. I checked the timing and it is correct with a timing light. Afr is good 11.5 and 15deg of timing down track. Timing is 35 deg on the brake then drops to 18 by 4500rpm after leaving off the button. It just doesn't want to rev up out of the hole. It feels like it needs more timing but I don't want to blow a ring land off yet. Any ideas? I'm lost here. This setup goes 10's and 9's all day for others on here. What do you think?
09-07-2014, 09:54 PM
#4
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I will get a log posted. 13 psi all the way down. Converter stays unlocked during a pass. The car went 10.30 all day on 13 psi with bad piping design and a small charger. I switched from bs3 to holley and now I can't figure this out.
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09-08-2014, 06:34 AM
#9
I don't know the gearing on the 4L80, but with a 30 inch tall tire that seems like it could hurt the setup. Otherwise, its either stall or tune related. You should be running quite a bit faster than that. How much boost once your out of the 60 ft?
09-08-2014, 10:14 AM
#12
1.) Define "better pipe"
2.) Who's "3500" converter is it? Have you checked your slippage up top? What is your stall RPM on the brake at 11psi?
3.) What was the old turbo? Do you know the hot side wheel diameters on the old and new turbo? AR sizes as well?
4.) Are you running a dished piston 5.3?
Sounds like the new trans/gear/tire is bogging it down to me. Converter will make or break a combo. Log your RPM and boost. When you release the TB does the boost/RPM drop?
The best your going to do is double the NA HP at 15ish lbs. Starting with low compression requires more boost. Don't judge what others run per PSI of boost. All setups will be different. Boost is just a number.
Lucky to make 250whp NA with a 317 headed 5.3 IMO. And I doubt your turbo setup is efficient enough to double the power per bar at your boost level. 500 crank HP and your trap speeds seem about on par to me. Your ET is down because your 60' sucks. Probably due to the converter being too tight for your power/gearing.
2.) Who's "3500" converter is it? Have you checked your slippage up top? What is your stall RPM on the brake at 11psi?
3.) What was the old turbo? Do you know the hot side wheel diameters on the old and new turbo? AR sizes as well?
4.) Are you running a dished piston 5.3?
Sounds like the new trans/gear/tire is bogging it down to me. Converter will make or break a combo. Log your RPM and boost. When you release the TB does the boost/RPM drop?
The best your going to do is double the NA HP at 15ish lbs. Starting with low compression requires more boost. Don't judge what others run per PSI of boost. All setups will be different. Boost is just a number.
Lucky to make 250whp NA with a 317 headed 5.3 IMO. And I doubt your turbo setup is efficient enough to double the power per bar at your boost level. 500 crank HP and your trap speeds seem about on par to me. Your ET is down because your 60' sucks. Probably due to the converter being too tight for your power/gearing.
09-08-2014, 10:18 AM
#13
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I'm busy at work today but I will get the log info up this evening. 4l80 has the same gearing as a th400. Same converter as the old setup. The old turbo was a 66 mm the new is a 76mm. Cam is a tick stage 1 turbo cam. I changed from a ls6 intake to a proflow. I had headers now I have truck manifolds and a 2.25 crossover. Went from bs3 to a holley dominator. I did notice the fuel pressure dropped 10 psi from 4000 to 6500 in every gear. The ecu caught it and was compensating.
09-08-2014, 10:22 AM
#14
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I'd think you would be up and around 130mph pretty easy on that setup. Post a screenshot of the log if you can. That will at least give us an idea of how the car is doing during the pass. Might be sensing some KR and pulling timing. Do you know if you had a flat KR, what timing you were at, and IAT's?
09-08-2014, 10:33 AM
#15
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Old pipe was 2.5 hot side new is 2.25. Old turbine was 68mm new is 78. I had 1.75 primary headers and went to manifolds. It's a gen 3 5.3 with dished pistons. The old unit was running 10.30 all day on the same boost. The converter and trans are all from abruzzi racing (I work there). I can get to 4300 on the trans brake and that's it. The boost goes right to 13 when I leave and stayed there. I have the 317 heads on it to go high boost but I want to get this worked out first. They were on there with the old setup.
09-08-2014, 12:19 PM
#17
Out of curiosity how did you verify TDC so you could “check your timing” ? Running an aftermarket keyed crank pulley?
AR housing sizes on the 2 turbos?
1/8th mile ET/MPH differences?
Converter locked up?
I’d also guess you shifted your power band up with that intake/cam and lost some low end power over the LS6 intake. The fact that your geared so low you may never get the RPM high enough to take advantage of the new intake/cam/turbo combo?
Guessing the 3200lbs is not with driver? A 317 headed LM7 is only 8.6:1. That makes for a wheezy turd NA. (I know I built one) Hp to weight calculator puts 3400lb car at 470hp with a 120 trap. Seems right on to me. I wouldn’t worry about it. That turbo is nowhere near it’s “happy zone” at 13lbs. And crossing the traps at 5600 your not reving the motor near high enough to take advantage of your intake/cam IMO. I’d much more RPM and turn the boost up.
I don’t get how your old setup was running so well to be honest. What MPH were you doing on the 10.30 passes? I’ve sure never seen an 8.6:1 5.3 run 10.30’s at 13lbs at 3400lbs.
My dished piston LM7 with 317 heads went 11.2 @ 125 at a 2850 race weight. S475 turbo Zr1 cam LS1 intake. Went 8.93 @ 153 at 24ish lbs.
AR housing sizes on the 2 turbos?
1/8th mile ET/MPH differences?
Converter locked up?
I’d also guess you shifted your power band up with that intake/cam and lost some low end power over the LS6 intake. The fact that your geared so low you may never get the RPM high enough to take advantage of the new intake/cam/turbo combo?
Guessing the 3200lbs is not with driver? A 317 headed LM7 is only 8.6:1. That makes for a wheezy turd NA. (I know I built one) Hp to weight calculator puts 3400lb car at 470hp with a 120 trap. Seems right on to me. I wouldn’t worry about it. That turbo is nowhere near it’s “happy zone” at 13lbs. And crossing the traps at 5600 your not reving the motor near high enough to take advantage of your intake/cam IMO. I’d much more RPM and turn the boost up.
I don’t get how your old setup was running so well to be honest. What MPH were you doing on the 10.30 passes? I’ve sure never seen an 8.6:1 5.3 run 10.30’s at 13lbs at 3400lbs.
My dished piston LM7 with 317 heads went 11.2 @ 125 at a 2850 race weight. S475 turbo Zr1 cam LS1 intake. Went 8.93 @ 153 at 24ish lbs.
09-08-2014, 12:24 PM
#18
Used 94 for the cir. of a 30" tire. Think thats right?
http://www.wallaceracing.com/converter-slip.php
09-08-2014, 01:03 PM
#20
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I shift at 6000 right now. I worked a long time to get the old setup to run good. It shouldn't be this hard to make it run. Should I just throw the meth and boost at it?