Newly Found Problem With My 33 Gtst

[R33GOD]

went to the dyno today to get my boost increased and at the same boost level of 13 psi car has lost 43 rwk

8 weeks ago my r33 gtst had 220.6 on 13 psi and now 177.

turbo is only 2500k's old, new clutch installed. nothing different.

tuner still hasnt done a compression check on it but he said the engine sounds very healthy.

there was no misfires on the dyno run or milky substances in the oil.

another thing that got me concerned is that the a/f ration were tuned at 12/1 and now they had gone up to 13/1.

rob put them back to 12/1 but no increase in power was made.

this is a huge power loss and i dont know where to begin.

mod list is here and nothing has changed

r33 gtst with

pfc, blitz fmic, 600cc hiflowed injectors, tomei fuel pump (intank), mtq hiflow turbo, z32 afm, panel filter in stock airbox.

3in turbo back exhaust with hiflow cat

need some expert advice

thankyou

[R33GOD]

anyone?

[GeeTR]

40KW is a fair bit - had you noticed the loss since last dyno? As in, has your 'seat of pants' picked up the loss?

Was your last dyno sesh on the same dyno?

Comparing is bout apples on apples. More info

[R33GOD]

same dyno. same tuner.

power didnt feel the same til after a couple weeks after last dyno.

[R31Nismoid]

If the AFR's have changed, then fuel and tune come into question.

Surely the workshop checked the basic things like fuel pressure if the AFR's weren't as they were?

Adjusting the tune without checking something like that (as a cause for wandering AFR's) is a bit silly IMO.

Could be injectors

Collapsed cat even

Many things that your only going to find by trial and error.

Also don't forget it was a bloody hot day (35-36 degrees), probably 10-15 degree's over last time so that is a factor also.

[BHDave]

drop the exhaust before the cat. see if it makes a difference. If not you have eliminated that possibility.

Check the intake pipe while it's on the dyno, make sure it isn't sucking closed.

Look for leaks in your piping. The fact that it's leaning out discounts boost leaks though as that would make it rich.

[R33GOD]

i am running no cat at the moment.

i have a hiflow cat sitting at home waiting to be put in

[tridentt150v]

Those std intake pipes sometimes get holes in them, this would mean your sucking air that isn't being measured by your afm. Worth checking.

[R33GOD]

i dont think that is the problem as it comes on boost very strong. could it be an injector problem like ash said. because they arent a name brand. their hiflowed stockies..

[BAMR33]

Injectors are an unlikely as they're not going change condition over night like that. Leaking exhaust manifold gasket would be a good place to start looking. More boost, more heat equals damage to aging parts.

[tridentt150v]

i dont think that is the problem as it comes on boost very strong. could it be an injector problem like ash said. because they arent a name brand. their hiflowed stockies..

A hole in the intake doesn't affect boost, your afm thinks its getting X amount of air past it, but the turbo is getting XX amount so your fuel map is all wrong for the power you are using.

[_Sawyer_]

A hole in the intake doesn't affect boost, your afm thinks its getting X amount of air past it, but the turbo is getting XX amount so your fuel map is all wrong for the power you are using.

A dyno and a half decent operator will pick this up staight away, so its very unlikley this is the case

[R33GOD]

the manifold gasket is basically brand new. turbo was installed bout 2 months ago

[Ultimategtr]

hey man. have you checked your timing????

[abu]

hey man. have you checked your timing????

timing shouldn't change as tune was not altered

surely they checked that too while it was on the dyno

[R33GOD]

the timing was fine. he advanced the timing abit more to see if that was the problem but it just pinged

[Ultimategtr]

what was the timing set to before he advanced it??? i know the B/T should be 15 degrees.

a similar thing happened to me.. my timing was out by about 4 degrees. when my tuner reset it to 15 again, it spun the rears till 90k or so.

its possible for the cambelt to slip a few teeth.

[Guilt-Toy]

I love reading the stuff people post in threads like this.

If it was me, i would be putting a fuel pressure / flow tester on the fuel system and run it on the dyno again and check how much fuel pressure there is, how much there is when its on boost, and how much flow returning to the tank there is.

But any workshop should know to check this anyway...

Maybe you should leave them to do their job...

[Rolls]

its possible for the cambelt to slip a few teeth.

No its not.

[R33GOD]

could it be that my standard fuel pressure regulator has failed because of the better flowing fuel pump?