My horsepower saga
11-19-2007, 08:15 AM
#41
i agree with checking the basics like julian.
i know your confident in the engine, but you have to cover the ground first before you can start looking for abstract causes. if you dropped the car off at any performance shop, they are gonna start with exactly what julian said. a leakdown test is number one, over the years i have heard of plenty of engines failing leakdown when compression test looked fine. Then you need to verify the timing on the engine, the cam timing that is. Cars with a tooth skipped on the cam gear can do stuff exactly like this, especially on a car that uses a crank trigger for its ignition. as you know, cam timing has dramatic effects on powerband thru the RPM.
Thats all you have to do to check the engine, not that much work compared to how long you have been searching for this problem... and its hard to convince myself to sit around and think about it anymore when you havent even checked those... no offense bri but i been asking you about this for a couple weeks!
after that i would play around and check all the boost couplers... possibly even run a real pressure test on it. but i dont think thats it, it appears to build boost fine so its probably not a leak. but for the hell of it i would at least go over that, and if it wasnt the impossible to service in the car APS kit, i would inspect the compressor blades but good luck trying to do that with that kit.
last resort would be to swap out the UTEC for another one just to double check. the dyno graph at higher boost looks retarded and i would want to verify that nothing is wrong with the UTEC and what its doing with the ignition timing.
Its the process of elimination that will solve this, not the process of coming of with as many guesses as possible. Basicially, you have to verify that what you know is true. Because if the engine is good, and the EMS is good, and there turbo system is operating at its true efficiency.... then what is the problem? theres really not much to it.... you know what your car is built with, now you have to test parts and swap parts until you figure out which one is not doing its job correctly.
i know your confident in the engine, but you have to cover the ground first before you can start looking for abstract causes. if you dropped the car off at any performance shop, they are gonna start with exactly what julian said. a leakdown test is number one, over the years i have heard of plenty of engines failing leakdown when compression test looked fine. Then you need to verify the timing on the engine, the cam timing that is. Cars with a tooth skipped on the cam gear can do stuff exactly like this, especially on a car that uses a crank trigger for its ignition. as you know, cam timing has dramatic effects on powerband thru the RPM.
Thats all you have to do to check the engine, not that much work compared to how long you have been searching for this problem... and its hard to convince myself to sit around and think about it anymore when you havent even checked those... no offense bri but i been asking you about this for a couple weeks!
after that i would play around and check all the boost couplers... possibly even run a real pressure test on it. but i dont think thats it, it appears to build boost fine so its probably not a leak. but for the hell of it i would at least go over that, and if it wasnt the impossible to service in the car APS kit, i would inspect the compressor blades but good luck trying to do that with that kit.
last resort would be to swap out the UTEC for another one just to double check. the dyno graph at higher boost looks retarded and i would want to verify that nothing is wrong with the UTEC and what its doing with the ignition timing.
Its the process of elimination that will solve this, not the process of coming of with as many guesses as possible. Basicially, you have to verify that what you know is true. Because if the engine is good, and the EMS is good, and there turbo system is operating at its true efficiency.... then what is the problem? theres really not much to it.... you know what your car is built with, now you have to test parts and swap parts until you figure out which one is not doing its job correctly.
Last edited by phunk; 11-19-2007 at 08:17 AM.
11-19-2007, 08:20 AM
#42
i could be wrong... but i really doubt its just a problem with the combination of parts... im keeping in mind here that the dynojet graph he posted is STD correction, which reads a little higher than SAE. I think the car is more than just choked up on the setup... this car is hardly making more than I made on a stock engine, and supposedly some guys have gone over 500rwhp on stock heads and cams.
11-19-2007, 08:21 AM
#43
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Originally Posted by MRC Motorsports
Im gonna vote for poor compression,valve float,or improperly timed motor...
If compression is fine, you MIGHT have a valve float issue, but you'd almost certainly hear it when just revving the motor.
I think it's a simple matter of the cams/stock plenum choking the potential of the car. Take it to another dyno to confirm it's not related to the dyno itself and see if you get common results. If it is, then I'd look at the cams. Although they're a little more expensive that a simple spacer, I'm not one to believe you get fantastic results just from increasing the plenum size on a boosted VQ. Granted, they help, but it's minimal from what I've seen.
Take up Alberto on the Crawford plenum swap idea and see if it really helps that much. But again, I'd check out the tune on another dyno just for peace of mind before going much farther.
11-19-2007, 08:39 AM
#46
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Originally Posted by BriGuyMax
I've ruled out the motor as the issue. It it was making very poor power all the way through the powerband then I would buy the motor being bad theory, but the fact is it make good low end and midrange power.
ok... but just so you know... my friend had the similar looking dynosheets too...so do not blame people for just pointing at that(engine) as the issue
.and +1 on post #42
11-19-2007, 08:43 AM
#47
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.
11-19-2007, 08:54 AM
#48
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Originally Posted by phunk
i agree with checking the basics like julian.
i know your confident in the engine, but you have to cover the ground first before you can start looking for abstract causes. if you dropped the car off at any performance shop, they are gonna start with exactly what julian said. a leakdown test is number one, over the years i have heard of plenty of engines failing leakdown when compression test looked fine. Then you need to verify the timing on the engine, the cam timing that is. Cars with a tooth skipped on the cam gear can do stuff exactly like this, especially on a car that uses a crank trigger for its ignition. as you know, cam timing has dramatic effects on powerband thru the RPM.
Thats all you have to do to check the engine, not that much work compared to how long you have been searching for this problem... and its hard to convince myself to sit around and think about it anymore when you havent even checked those... no offense bri but i been asking you about this for a couple weeks!
after that i would play around and check all the boost couplers... possibly even run a real pressure test on it. but i dont think thats it, it appears to build boost fine so its probably not a leak. but for the hell of it i would at least go over that, and if it wasnt the impossible to service in the car APS kit, i would inspect the compressor blades but good luck trying to do that with that kit.
last resort would be to swap out the UTEC for another one just to double check. the dyno graph at higher boost looks retarded and i would want to verify that nothing is wrong with the UTEC and what its doing with the ignition timing.
Its the process of elimination that will solve this, not the process of coming of with as many guesses as possible. Basicially, you have to verify that what you know is true. Because if the engine is good, and the EMS is good, and there turbo system is operating at its true efficiency.... then what is the problem? theres really not much to it.... you know what your car is built with, now you have to test parts and swap parts until you figure out which one is not doing its job correctly.
i know your confident in the engine, but you have to cover the ground first before you can start looking for abstract causes. if you dropped the car off at any performance shop, they are gonna start with exactly what julian said. a leakdown test is number one, over the years i have heard of plenty of engines failing leakdown when compression test looked fine. Then you need to verify the timing on the engine, the cam timing that is. Cars with a tooth skipped on the cam gear can do stuff exactly like this, especially on a car that uses a crank trigger for its ignition. as you know, cam timing has dramatic effects on powerband thru the RPM.
Thats all you have to do to check the engine, not that much work compared to how long you have been searching for this problem... and its hard to convince myself to sit around and think about it anymore when you havent even checked those... no offense bri but i been asking you about this for a couple weeks!
after that i would play around and check all the boost couplers... possibly even run a real pressure test on it. but i dont think thats it, it appears to build boost fine so its probably not a leak. but for the hell of it i would at least go over that, and if it wasnt the impossible to service in the car APS kit, i would inspect the compressor blades but good luck trying to do that with that kit.
last resort would be to swap out the UTEC for another one just to double check. the dyno graph at higher boost looks retarded and i would want to verify that nothing is wrong with the UTEC and what its doing with the ignition timing.
Its the process of elimination that will solve this, not the process of coming of with as many guesses as possible. Basicially, you have to verify that what you know is true. Because if the engine is good, and the EMS is good, and there turbo system is operating at its true efficiency.... then what is the problem? theres really not much to it.... you know what your car is built with, now you have to test parts and swap parts until you figure out which one is not doing its job correctly.
As for cam timing. How do I verify that? And if it was that then why would my car preform nearly identically @ 10psi as it did on the stock motor but perform worse as boost increased.
The uncorrected numbers were about 3hp lower than the STD numbers.
Boost is there, compression in there, fuel is there and I have data logged pulls and the timing is there.
Give me a call if you get a chance so I can get a leakdown test out of the way.
11-19-2007, 08:58 AM
#50
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Originally Posted by IIQuickSilverII
ok... but just so you know... my friend had the similar looking dynosheets too...so do not blame people for just pointing at that(engine) as the issue
.and +1 on post #42
That motor had poor compression and barely made over 400whp...hardly a good comparison.
11-19-2007, 09:11 AM
#51
11-19-2007, 09:28 AM
#52
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Originally Posted by BriGuyMax
That motor had poor compression and barely made over 400whp...hardly a good comparison.
sure it made:
400rwp at 9psi
400rwp at 16psi
400rwp at 21 psi
BUT the point being, that the more you threw at it, the worse the power drop off at 5400 rpm and, the tq increased, power did not.
I am not trying to start anything up, but i am just letting you know, that if you have been messing around this issue for a while now and my guess is that you have checked all the connections on the turbo setup and they are good.(leaks, etc)..then its either the utec(try a different unit)... or something MAY BE UP with the engine...
Follow phunks advice...
Last edited by IIQuickSilverII; 11-19-2007 at 09:32 AM.
11-19-2007, 09:40 AM
#53
Originally Posted by BriGuyMax
Can anyone show me a dyno of a setup like mine with STOCK cams and STOCK upper and lower plenum @ 14+ pounds of boost? I can't find any setup like that.
11-19-2007, 09:52 AM
#54
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Originally Posted by roncfpz
Not sure if this helps you Brian. Sorry no torque reading in shootout mode. This was at 16psi, stock heads, stock plenum, stock cams. I figure this is about 550whp on a DJ. Good luck getting it sorted out.
11-19-2007, 10:17 AM
#55
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Originally Posted by BriGuyMax
I don't want you guys to turn this thread into a BZM bashing thread...the motor is FINE. The car made basically the same power with the built motor on 10psi that it made on my stock motor on 10psi.
11-19-2007, 10:24 AM
#56
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Originally Posted by BriGuyMax
That's unfortunately what I was afraid of...thanks....
Looks like the stock top end isn't the issue after all... While it sux to know that the issue seems to be deeper, it's good at least to know where you shouldn't be spending your time troubleshooting. Please keep us posted.
11-19-2007, 10:38 AM
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Originally Posted by TENGAI
Wow, that would be something. How in the hell does an engine builder improperly time a VQ? You'd have to be blind and an idiot to boot... Don't think that would be one on my list of things to check, but I suppose anything is possible.
.
.
I HIGLY doubt the UTEC is at fault
I HIGLY doubt the A/F has alot to do with it..
some other things to consider:
Spark plugs improperly gapped
Faulty coils
incorrect piston to cylinder clearance
rings not seated fully yet..Put 1000 more miles on it on regular oil NOT synthetic.
TB closing to soon
11-19-2007, 11:22 AM
#59
keep in mind this engine has variable cam timing. the variable timing has a range of adjustment... depending on how much and which direction the chain was set incorrect, the cam timing can probably compensate for it under some circumstances and then its range of adjustment will max out at some point and not be able to compensate any further. now personally, i would figure this would trip a SES light since we have cam triggers on each intake cam and a crank trigger for reference... but it might take a while before the ECU detects the issue, I have no idea... because I have never put the chain on wrong before to see what happens. This is why it has to be looked at, unless someone on here can tell us if the ECU detects it instantly and trips a SES when the cam phasing is out.
11-19-2007, 12:09 PM
#60
Let me try to add to the discussion here:
I would borrow a Cipher from someone, check what the ECU is seeing in terms of ign timing and cam timing.
Given that your AFR is reasonable, and the UTEC supposedly is giving good ign timing, I would agree with what's been mentioned that cam timing could play a role here.
Luckily cipher is a quick and non-invasive way to check it out.
Here's an example on my car (non-revup, intake variable cams only)
https://my350z.com/forum/attachment....8&d=1157731474
I would borrow a Cipher from someone, check what the ECU is seeing in terms of ign timing and cam timing.
Given that your AFR is reasonable, and the UTEC supposedly is giving good ign timing, I would agree with what's been mentioned that cam timing could play a role here.
Luckily cipher is a quick and non-invasive way to check it out.
Here's an example on my car (non-revup, intake variable cams only)
https://my350z.com/forum/attachment....8&d=1157731474