dyno results hurt!!
Teching In
Joined: Sep 2007
Posts: 20
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A p600 on a 383 with afr heads and that cam with 8:1 compression!
That blower has to be WAY out of it's efficiency range.I had a p1sc spinning it to 60k to get 10psi out of my 9:1 357ci engine.
BUt your numbers do seem low even so.
That blower has to be WAY out of it's efficiency range.I had a p1sc spinning it to 60k to get 10psi out of my 9:1 357ci engine.
BUt your numbers do seem low even so.
Damned gov computers. I cant see anything but red x's. That high knock count is more than likely the blower. That's why the SES 43 was tuned out. Now if you look, maybe you still have knock retard pulling timing, but not showing the light because it is turned off.
The compression is really low and blower is freakin small and Drivetrain is not helping the dyno numbers at all but still low numbers.
Hope you get this fix and maybe you should get F1 Procharger with 383.
Post a thread in Forced Induction section you'll get more replies,
Hope you get this fix and maybe you should get F1 Procharger with 383.
Post a thread in Forced Induction section you'll get more replies,
i would love to upgrade to the F1 procharger or at least a grade up. if anyone has one for the lt1. but would love to figure the problem out first. i know this car can make 600 wheels easily
also looked at all the plugs and regapped to .035.
found that 5,7,8 cylinder numbers plugs were fouled to almost fouled. which is rediculous. i will try to run it longer tomrow and get it up higher in rpm. and check plugs to see if something is happening to them again.
also looked at all the plugs and regapped to .035.
found that 5,7,8 cylinder numbers plugs were fouled to almost fouled. which is rediculous. i will try to run it longer tomrow and get it up higher in rpm. and check plugs to see if something is happening to them again.
http://www.youtube.com/watch?v=RuYkOpbd7Ls&NR=1
2psi more but only a 355. sooo. that shows there is something wrong with my setup. i know comparing engine setup its one thing. and all **** can be way different. but my engine was professionally built and professionally dyno'd. so i dont know what else to check
2psi more but only a 355. sooo. that shows there is something wrong with my setup. i know comparing engine setup its one thing. and all **** can be way different. but my engine was professionally built and professionally dyno'd. so i dont know what else to check
TECH Veteran
Joined: Sep 2003
Posts: 4,540
Likes: 0
From: Las Vegas, NV
That motor has more compression, a bigger blower, a smaller cam, and the 2psi more. Spinning your blower that hard makes for hotter air as well as a slow to rise boost. If you put a D1SC on there you should have no problem making more boost. To be happy with your car you're going to need to change the compression or stick the 20psi to it that you set the compression up for. Even if you'd made 14psi your compression is too light. If your compression were 10:1 instead of 8:1 you'd be certainly making closer to the power you'd expect out of your build. One of the guys I know as an example had a GTO with a 112HH on it. With the stock LS2 and bolt on's it made somewhere around 530RWHP. With a well built forged LS2 in it at 9:1 compression, bigger cam, ported heads, etc. it made 470RWHP. Even with the cam and ported heads the lower compression killed the hp from the blower being too small.
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Brett Foote still comes down to there is definately something wrong. i can definately tell that cylinders 5,7,8 werent firing all the time because the plugs were covered black while the rest of them were that brown perfect burn color.
here is another datamaster file with fuel pressure at 40psi
http://www.mediafire.com/?sharekey=1...4e75f6e8ebb871
http://www.mediafire.com/?sharekey=1...4e75f6e8ebb871
Can you post a pic of the file again?
The miss could be during idle &/or non-WOT driving. Am not sure how fuel management is set-up on an an LT operating system. If it's anything like an LS operating system, the idle & normal driving fuleing is commanded from different tables than is the WOT fueling. It is possible to tune for WOT & neglect the other. Especially, if intake related madifications have been made.
As far as the power, it appears that the likely issues is the compression ratio compared to the blower size. The examples stated where LESS than 8:1 VOLUME combustion chamber sizes produced the anticipated numbers because the blower had a smaller volume of air to move. Your blower simply cannot keep up with the demand. Maybe you could deck the heads to increase the compression ratio to 9:1 or a little more (reducing the chamber volume). There also seems to be a timing issue. Because of the 43 off code, it seems as though the knock sensors are turned off in order to keep them from reacting to the sound of the blower. So maybe the plug fouling is a result of pre-detonation missfires that cannot be adjusted by the knock sensors.
If it were my car, would modify compression or change the blower size, investigate timing set-up to ensure that it is correctly set, see if the knock sensors could be dampened as opposed to being turned off, check idle & normal driving fueling & then re-tune for WOT under boost.
The miss could be during idle &/or non-WOT driving. Am not sure how fuel management is set-up on an an LT operating system. If it's anything like an LS operating system, the idle & normal driving fuleing is commanded from different tables than is the WOT fueling. It is possible to tune for WOT & neglect the other. Especially, if intake related madifications have been made.
As far as the power, it appears that the likely issues is the compression ratio compared to the blower size. The examples stated where LESS than 8:1 VOLUME combustion chamber sizes produced the anticipated numbers because the blower had a smaller volume of air to move. Your blower simply cannot keep up with the demand. Maybe you could deck the heads to increase the compression ratio to 9:1 or a little more (reducing the chamber volume). There also seems to be a timing issue. Because of the 43 off code, it seems as though the knock sensors are turned off in order to keep them from reacting to the sound of the blower. So maybe the plug fouling is a result of pre-detonation missfires that cannot be adjusted by the knock sensors.
If it were my car, would modify compression or change the blower size, investigate timing set-up to ensure that it is correctly set, see if the knock sensors could be dampened as opposed to being turned off, check idle & normal driving fueling & then re-tune for WOT under boost.
curious if you have found anything more on the car-def think the starting comp is low, the P1SC has a lot of ground to make up, and with 220 heads, needs upper RPM's to shine-what are the cam specs, cranking comp. #'s
might be a little mismatch with the cam and comp./boost
still, i think there is more power to be had with what you have
did you run it with the air intake on or off, seen some power loss thru them
i cant add anything on computers, as i run a blowthru carb, but sounds like maybe something in the computer land is not controlling things
was there a chart of AFR's thru the whole run? i agree on the .035 gap with a blower, at least
good luck with it, can be frustating
might be a little mismatch with the cam and comp./boost
still, i think there is more power to be had with what you have
did you run it with the air intake on or off, seen some power loss thru them
i cant add anything on computers, as i run a blowthru carb, but sounds like maybe something in the computer land is not controlling things
was there a chart of AFR's thru the whole run? i agree on the .035 gap with a blower, at least
good luck with it, can be frustating
TECH Enthusiast
Joined: Jul 2008
Posts: 669
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From: Memphis, tn
My trans am is doing the same thing. It is not giving full power. When I drove it before I test drove it, It was WAAAAAAYYYY Faster, But now it's alot slower. 0-60 is about 7 seconds. When I test drove it 0-60 was about 5. It is possibly clutch because it drags hard in talk of
in that log you posted is it idling at 1700rpm? if you are idling that high you can have a myriad of issues. I just recently fixed a 383 LT4 Vortech car that was idling really high and having miss issues. No codes were thrown, no external vac leaks were found at all. The IAC motor had taken a dump and the pintle would get in a stuck position while the counts would still read somewhat normal. I know something like this is a long shot but anything can be a problem. If you have an intake leak you would idle high, misfire, bleed boost off and be low on power. How long can you drive the car? Enough that the fuel trims can adapt and would show an intake leak?
And i'm a dumb *** for not seeing this is from 2009............this is what happens when i try to help.
And i'm a dumb *** for not seeing this is from 2009............this is what happens when i try to help.
my guess is the car was blowing out the spark plugs. .045 gap is way to much for a blower car. thats probable why some of the plugs were fouled out b/c they were being blown out. in the graph it looked like it just fell off to thats my guess. i bet changing the plugs will fix alot of your problem
