Where is my Horsepower???

[DCJ98GST]

Originally posted by 90 EagleClaw
Like I said i have good compression, no boost or exhaust leaks...

Did you check for exhaust leaks at the exhaust manifold?

 

[90 EagleClaw]

Ok, I'm ready to give up. I was able to get a new turbo with everything minus the turbine housing to check if it would change anything. Well, it didnt. Brand new turbo, same thing. I tried swapping out the fuel injectors for my stock 450s, just to see if I was having an injector problem. Nope. The only thing left in the turbo/induction system that I havent tried touching is the FMIC setup, and the External wastegate. Could it be a wastegate problem? Nathan from DSM motorsports (where I first bought this turbo setup) said that my car should have 100 more WHP then it does at the same boost level! Something is seriously wrong, but everything checks out normal with the engine. Could this be drivetrain related?? Tranny or something putting excess drag and killing the HP output? I have tried tuning it very lean, and very rich, and everything in between and come up short. Tuning it much leaner makes it feel slightly more responsive, but not a noticeable improvement, plus it knocks like crazy so I dont like leaving it that way. My O2's were at .70! EGTs hitting 1600 in top of second. Defintetly not the way it should be I dont think. The car is very laggy in 1st gear, others arent soo bad, but under boost, even with no knock and good timing, the car just feels like its flatening out, like no power increase is happening as the RPMS go up, its just flat. I CANT FIGURE IT OUT WTF is wrong with the thing????

 

[j_woody]

what spring do you have in your tial wastegate? if it is say a 10psi spring the most boost you could run would be 20psi (anyone correct me if i am wrong).....you might even have a lower spring and that is why you cannot get any boost even with the mbc all the way up when you have the ebc and wastegate hooked up correctly (the way tial says).

the wastegate could be opening really early and letting all your exhaust bypass the turbo. that would explain the shitty boost response and lack of power

 

[90 EagleClaw]

I dont think that its the wastegate, just because I can hear it when it opens cause its just a dump tube to atmosphere. If it were leaking, i think i would hear it as it sounds like an exhaust leak.

Some interesting findings though. I put in my 450cc injectors and drove the car. I richend the AFC up to compensate, but not too much. I am running 18psi of boost on pump gas with a 50 trim T3/T4 with very little knock. Does this sound weird to anyone else?? Shouldnt the 50 trim be flowing too much air at 18psi for the stock injectors to handle? My airflow according to the logger at WOT is 1606HZ, this is with a 2G mas. Does it seem like I am not flowing enough volume of air for the size turbo I have? If this is true, maybe there is a restriction somewhere in the intake tract, but I dont think it is in the Intake manifold cause I ran mid 13's on my stock turbo and intercooler without really trying. So maybe it is my FMIC set up?? Somone please let me know if this sounds normal or not to have these airflow characterisitics. Thanks

 

[pneumo]

The logger can't read any higher than 1606 Hz, so that doesn't really tell anything. Try logging injector PW to see if the 450's are maxed, which they probably are. 18 psi is about the limit, more or less.

 

[nano]

Check for boost leaks.. Boost leaks will usually cause high EGTs, low timming and shity power. I've been down the same problems before and other peoples cars too. Really check for boost leaks. Every car should be checked even fully stock ones.

 

[90 EagleClaw]

Already did, I think I said it earlier, but I have no boost leaks.

 

[nano]

Oh.. Well if you did mentioned it earlier, sorry. I may have missed it. You also said your airflow is 1606hZ? Try reading your HZs from your AFC.. I get 1750 at 18psi and 2000hz at 21psi. A 50trim should get 2000+ and up to 2700hz at high boost.

 

[nano]

Have you checked your timming? It might be off by a bit. How's your compression?

 

[90 EagleClaw]

Timing is perfect at 5 BTDC. Compression is 155 across.

I had my whole car checked out today at a DSM shop and they came up with only 2 possible things after looking the whole car over. For one they think that the exhaust housing is too big at .63AR and think I should switch it to a .48 and see what happens, because I have stock 7.8 compression and stock cams. The other thing they said is that I might have N/T cams in the car and they have too much overlap to spool the turbo up fast enough. The head was redone by the previous owner and seeing some of the crappy work that was done to the car I almost wouldnt doubt it. But I dont know what would be better to check first, both are pretty decent sized jobs to do, I need opinions on what sounds more probable as the problem with the car.

 

[Phoenyx]

Originally posted by nano
Oh.. Well if you did mentioned it earlier, sorry. I may have missed it. You also said your airflow is 1606hZ? Try reading your HZs from your AFC.. I get 1750 at 18psi and 2000hz at 21psi. A 50trim should get 2000+ and up to 2700hz at high boost.

PMFJI, but I got 2063Hz at 16psi on a 14b!!!! Is this normal with a SuperAFC-II???


-M

 

[90 EagleClaw]

Well do you think cams could be the reason for the low airflow reading

 

[Unreal]

I got a stock ### motor with 135psi compression and I'm running a 50 trim in a .63 housing. I get full boost around 3900 and have ran 122mph traps consistantly on a bad clutch.

Its not the .63 housing.

 

[nano]

Originally posted by Phoenyx


PMFJI, but I got 2063Hz at 16psi on a 14b!!!! Is this normal with a SuperAFC-II???


-M

If you have a 1g maf your readings are going to be different then 2g maf readings.. My buddy on he's big 16g on he's 2g gets 1750 at 17psi.

 

[nano]

Originally posted by 90 EagleClaw
Timing is perfect at 5 BTDC. Compression is 155 across.

I had my whole car checked out today at a DSM shop and they came up with only 2 possible things after looking the whole car over. For one they think that the exhaust housing is too big at .63AR and think I should switch it to a .48 and see what happens, because I have stock 7.8 compression and stock cams. The other thing they said is that I might have N/T cams in the car and they have too much overlap to spool the turbo up fast enough. The head was redone by the previous owner and seeing some of the crappy work that was done to the car I almost wouldnt doubt it. But I dont know what would be better to check first, both are pretty decent sized jobs to do, I need opinions on what sounds more probable as the problem with the car.

.63 a/r is perfectly fine.. It's the smallest you should run on a big turbo like that.. .48 is way to tiny.. If it does have a/t cams that would defenetly hurt it.

 

[blackvr4]

why was the timing advanced so much?

 

[DCJ98GST]

Originally posted by DCJ98GST


Did you check for exhaust leaks at the exhaust manifold?

Just a suggestion, but you never said wheather you checked for leaks in the exhaust manifold? I assume you have the turbonetics manifold. Did you install a gasket? Is it leaking at the waste gate flange? Is there a crack in the manifold? Obstruction in the manifold?

If there is a leak before, you will have a lot more lag because the exhaust energy does not reach the turbine wheel. People with the 1G's that have leaks have complained about the same issues as you have: lots of lag and lack of power.

 

[90 EagleClaw]

yes there are no exhaust leaks anywhere

 

[umiami80]

If you have a BIG turbo like that but are only reading like 1600HZ on the SAFC, you are missing air, maybe a MASSIVE boost leak at your TB of another area you have not checked? GET a PMS, set timing to 25+ and run C116, and then like 25PSI, if your car is still slow, then you know it's not the timing

 

[nano]

Boost leaks don't make your Hzs drop.. The turbo still sucks as much air, it's just not making it all to the engine. Only way your HZ drop if there's air bypassing the maf. Check your turbine wheel, and your compressor wheel for damage, also check for shaft play. Something is messing your maf readigns. Either air is being bypased from a hole in the intake between the turbo and maf, or your turbo is damaged and not working very efficiently, or your maf is screwed up.. Do you have any honeycombs removed? That will also alter your maf readins, and dosen't necessarly mean it's not flowing much, it's just bypasses air. Try another MAF if you have too.