My horsepower saga
Originally Posted by D350Z10
I have the exact same problem man.... there were no answers Sharif did every sort of trial and error but couldn't come up with anything, my compression was fine to according to the leak down test. So now The enitre motor is being tore down again and rebuilt. He thinks that either the valves or ringlands could be the problem. This has been such a huge headache, 5 + months and still no running car. I only made power up till 12psi and after that there was nothing. Ignore all these people that are saying its cause of your stock components... they dont know what there talking about, even with stock heads and cams your car should still produce good power. 16...17 psi and only 509hp... somthing is serioulsy wrong.
I'm running C2 cams and a plenum spacer though.
Basically my car will make 530whp or so no matter how much boost it's running now.... Hopefully we'll find out soon if it's related...
valve float could be an issue too. perhaps you have a bad valvespring? it wouldnt be a terrible idea to check it if you run thru everything else. you can check it by machining an intake port blockoff plate and tapping a hole in it for an air compressor fitting, then use a pressure regulator to push 20psi at it to make sure the valves dont push open? i have never done this before or heard of it done, but just an idea and i cant think of why it wouldnt work.
Thread Starter
Joined: Oct 2002
Posts: 7,303
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From: West suburbs of Chi-town
Originally Posted by taurran
What's funny is that my car is doing about the exact same thing. So far we've been looking at the turbo system but wouldnt it be funny if it was something else like this all along.
I'm running C2 cams and a plenum spacer though.
Basically my car will make 530whp or so no matter how much boost it's running now.... Hopefully we'll find out soon if it's related...
I'm running C2 cams and a plenum spacer though.
Basically my car will make 530whp or so no matter how much boost it's running now.... Hopefully we'll find out soon if it's related...
Do you have JWT valvesprings and retainers?
Originally Posted by taurran
What's funny is that my car is doing about the exact same thing. So far we've been looking at the turbo system but wouldnt it be funny if it was something else like this all along.
I'm running C2 cams and a plenum spacer though.
Basically my car will make 530whp or so no matter how much boost it's running now.... Hopefully we'll find out soon if it's related...
I'm running C2 cams and a plenum spacer though.
Basically my car will make 530whp or so no matter how much boost it's running now.... Hopefully we'll find out soon if it's related...
My motor is already tore down, I will be getting an anaylsis this week so I will post the results. I have Stage 2 Cams Scott Performance, and a Crawford plenum. This time I am going wth a different piston though, and they will bore, rehone and balance the motor. I really hope its not anything to do with my valves.... I do have stock valvetrain
This thread also sounds like the same case which taurran and I have encountered
Thread Starter
Joined: Oct 2002
Posts: 7,303
Likes: 1
From: West suburbs of Chi-town
Originally Posted by taurran
Yes, at least they were specified in the build.
Originally Posted by BriGuyMax
It's an outside shot, but maybe a few bad sets of JWT valvesprings were shipped out.
I would reccomend you follow the advice of several members of this forum and do the following first:
Check the cam timing
Check the ignition
Check the plug gap
Check the clearances on the motor
Do a compression test
Also I may have missed it but sometimes if the engine is not broken in yet the rings will not seat under higher boost levels.
Good luck.
Originally Posted by BriGuyMax
It's an outside shot, but maybe a few bad sets of JWT valvesprings were shipped out.
Thread Starter
Joined: Oct 2002
Posts: 7,303
Likes: 1
From: West suburbs of Chi-town
Responses imbedded in quote
Originally Posted by MRC Motorsports
I just dont think you want to accept what many are telling you, and you currently may be in denial.
I would reccomend you follow the advice of several members of this forum and do the following first:
Check the cam timing How? Cipher?
Check the ignition how? Cipher again?
Check the plug gap done they are gapped to .028 inches as stated before. I did it last week
Check the clearances on the motor Wouldn't that require completely disassembling the motor? If so that's not a option at this point.
Do a compression test Already done and it came back perfect 152-156psi in all cylinders
Also I may have missed it but sometimes if the engine is not broken in yet the rings will not seat under higher boost levels. Engine has almost 4000 miles on it, it's broken in
Good luck.
I would reccomend you follow the advice of several members of this forum and do the following first:
Check the cam timing How? Cipher?
Check the ignition how? Cipher again?
Check the plug gap done they are gapped to .028 inches as stated before. I did it last week
Check the clearances on the motor Wouldn't that require completely disassembling the motor? If so that's not a option at this point.
Do a compression test Already done and it came back perfect 152-156psi in all cylinders
Also I may have missed it but sometimes if the engine is not broken in yet the rings will not seat under higher boost levels. Engine has almost 4000 miles on it, it's broken in
Good luck.
Last edited by BriGuyMax; Nov 20, 2007 at 07:27 AM.
Originally Posted by BriGuyMax
Responses imbedded in quote
There is most likely an issue with the motor,just accept that and start to diagnose from there.For the pwoer to fal off up top it is most likely timing related,combustion pressure loss related, or a bottleneck in the exhaust system and turbo kit design,such as the TN kits. And since your rocking an APS with dual 3" down pipes, the last one is 99.9% not the issue...
I would start simply looking at it as a weak motor, since there are no signs of it breaking up up top, correct?
It sucks, but its part of playing the game.
Thread Starter
Joined: Oct 2002
Posts: 7,303
Likes: 1
From: West suburbs of Chi-town
Originally Posted by MRC Motorsports
To check the proper cam timing, your going to have to take the front engine cover off, there is no way around it..We have also seen weak/cracked valve springs in some cases,but you upgraded your springs correct?
There is most likely an issue with the motor,just accept that and start to diagnose from there.For the pwoer to fal off up top it is most likely timing related,combustion pressure loss related, or a bottleneck in the exhaust system and turbo kit design,such as the TN kits. And since your rocking an APS with dual 3" down pipes, the last one is 99.9% not the issue...
I would start simply looking at it as a weak motor, since there are no signs of it breaking up up top, correct?
It sucks, but its part of playing the game.
There is most likely an issue with the motor,just accept that and start to diagnose from there.For the pwoer to fal off up top it is most likely timing related,combustion pressure loss related, or a bottleneck in the exhaust system and turbo kit design,such as the TN kits. And since your rocking an APS with dual 3" down pipes, the last one is 99.9% not the issue...
I would start simply looking at it as a weak motor, since there are no signs of it breaking up up top, correct?
It sucks, but its part of playing the game.
Do you know if I can check cam timing with a cipher? I have JWT valvesprings and retainers. I'm going to start with a leakdown test and if that comes back good then I'll start tearing **** apart.
Motor isn't breaking up up top at all.
Just rain on my parade
Originally Posted by MRC Motorsports
I just dont think you want to accept what many are telling you, and you currently may be in denial.
I would reccomend you follow the advice of several members of this forum and do the following first:
Check the cam timing
Check the ignition
Check the plug gap
Check the clearances on the motor
Do a compression test
Also I may have missed it but sometimes if the engine is not broken in yet the rings will not seat under higher boost levels.
Good luck.
I would reccomend you follow the advice of several members of this forum and do the following first:
Check the cam timing
Check the ignition
Check the plug gap
Check the clearances on the motor
Do a compression test
Also I may have missed it but sometimes if the engine is not broken in yet the rings will not seat under higher boost levels.
Good luck.
Thread Starter
Joined: Oct 2002
Posts: 7,303
Likes: 1
From: West suburbs of Chi-town
Originally Posted by synth19
Sorry to hear about your issues Brian, Irshad does have cipher loaded on their laptop in case you don't have it.
I'm aware, but my car is "put away" for the winter so any diagnosis I do will have to be in my garage.
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Joined: Jun 2002
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From: Chicago, IL
Originally Posted by BriGuyMax
I'm aware, but my car is "put away" for the winter so any diagnosis I do will have to be in my garage.