Lippy951

Hi everyone, I am new to this forum and new to the 944 turbo ownership. I am having some trouble and did my best to look through these forums to help with my issue with no luck. From what I see you, you guys have some great advice. I have a 1986 944 Turbo and have owned it for a year or so. It has been in the shop for about six months getting some things done. With everything put back together. The shop and I tested it on the dyno and having boost issues with low hp. I have a wideband A/R and it is a little rich but not bad.

Symptom: Boost comes on (8psi) around 3500rpm and hits full boost (15psi) after 4500rpm. Dyno shows 217hp. Dyno was done in 4 gear.

What is going on?

My car is modified with the following along with what has recently been done:
3bar FPR
Rogue M-tune with 80lb injectors
K27 turbo, no idea of the hotside
3" LR exhaust with no cat
AEM turboost
New turbosmart Hypergate45
Exhaust manifold and crossover pipes were taken off checked for leaks, thermo coated and reassembled with copper gaskets
new vacuum lines
smoked test the intake and exhaust by shop and no leaks appeared
Timing belt was done and double checked the cam timing, all good
KLR and DME rebuilt by ECU doctors in January of this year
leak down and compression test were done and all was good

Dave Lindsey and Joshua at Rogue says I should be getting around 300 to 320hp and the turbo should be at full boost by 3500rpms.

I really need you guys help. Is the turbo turbine wheel is bad?

Any thoughts would be appreciated.

blown 944

Have you tested the bypass valve?

Lippy951

Blown 944 - the bypass is new from forge motorsports. Less than a year old. It has a spring in that can be changed out, no diaphragm. It has piston type internals with grease. I don't think it's leaking there. I could put a put a vacuum on it with gauge to see if it holds. I check the compressor side of the turbo. Looks good, no shaft play.

blown 944

It should be fine then.

I would personally be looking at a restriction in the exhaust first and then the intake.

bw993

What are your duty cycle and spring rate settings with your AEM boost controller? Sounds like you need to up the duty cycle setting.

Lippy951

blown 944 I thought so too. I have two piece crossover and it was fine. We are going to scope the second half of the crossover pipe and down pipe today. However, would a collapsed pipe or restriction give me low to no boost? It will boost to 18psi but very late.

bw993 We did 12 runs on the dyno. Spring was set to 12psi (I have a 14sping). No cycling on the wastegate. Duty cycle was increase from 25 to 60. At 60 we got 15psi boost. Before the at this duty cycle I was getting close to 20psi. My initial issue prior to work being done is the boost come on later than what it should, over 4k. Nothing changed and now the top end is weak. I am still 100hp off. Am I missing something? Thanks for the feedback

Van

Have you checked your compression and leakdown?

Lippy951

VAN I appreciate you jumping in on this, you and a lot of other guys have some great knowledge on these cars. With that said here is the breakdown of the leak and compression test:

Cylinder 1 - 8% 170psi
Cylinder 2 - 6% 170psi
Cylinder 3 - 9% 167psi
Cylinder 4 - 11% 167psi

From what I am told these are acceptable numbers. Would you agree? The compression number are higher than normal due to the head being machine. Higher compression should help my cause.

Recent change were the wastegate. Went from Tial 38 to Turbosmart Hypergate 45 because shop said it was leaking. When I pinch off the hose going to the intercooler to wastegate, boost at 3500 was around 8psi. From there, it shot right up to 18 by 4500rpm.

Are my expectations of full boost by 3500rpm based on my mods unrealistic?

My guess are bad turbo, boost solenoid or leaking wastegate. Would I lose 100hp here?

User 52121

Still kinda smells like cam timing is off to me. Shop that did my water pump for me when I was out west for work over the summer got the timing off by a tooth, and the test drive felt like you describe. Really laggy, not a lot of power, took forever to spool up, and on boost didn't feel "right".

When I told the shop to re-check it.. the first time, they just looked through the little inspection hole on the cap housing and said it was spot on. They did a bunch of checks for vacuum leaks, smoke testing, etc. After I insisted the take another look at the cam timing - they pulled the covers, etc. and found it was off. So if your shop checked it by looking through the hole - I'd suggest they pop it off and take another look.

Lippy951

I would agree. The first shop did the timing belt. They said it was off by one tooth. When I drove it, I noticed no change. I told them to double check it and they refused. Therefore, I took it to a different shop. They told me it was off by two teeth (18 degrees). They fixed it and that's when we did the dyno runs with the results we got. The second shop told me be they pulled the covers off and verified everything by the book, bell house lined up, fly wheel lock etc. Hopefully they got it right. I will ask them again. Thanks for your input, if you think of anything else let me know.

lart951

tell me about the wastegate, if stock I'll bet my last ******** it's bleeding boost badly

Lippy951

Rest assured you can keep you ********. It is not stock. I had a tial 38 on there. Shop told me it was leaking, so we replaced it with a Turbosmart Hypergate 45 with a 14psi spring. We check the valve seat and it is good and we smoked the intake system and no leaks. However, later this week we might try to swap it out with another just to test it to see if it make a difference. Appreciate your feedback. Let you know what we find. Any other thoughts let me know.

lart951

Collapsed crossover or downpipe

Lippy951

Crossover pipe is a two piece from LR. No issues with crossover, it was check and thermo coated. The first shop said they looked at the other half of the crossover pipe and down pipe with a scope and all good. Having my current shop guys double check it this week. However, I would guess that would give me no or low boost, not 18psi. You never know.

What about the chip from Rogue Tuning for my M-Tune. Could the chip have program issues throwing off my timing??

bw993

I suggest that you drop your spring rate setting to 10 lbs with your boost controller to see if that helps with you boost pressure. You may have boost oscillations occurring with your new waste gate.