To All The Gurus

[Sydneykid]

I would add a few things to the list;

Do a leak down test, that will confirm the basic engine condition

Check the spark plug colour directly after a power run, that will tell you if one or more cylinders are the source of the pining. Maybe isolate a lazy injector, if there is one

Drop the exhaust at the entry to the cat and do one quick power run, that will eliminate an exhaust restriction as the cause

Measure the boost before and after the FMIC, more than a couple of PSI difference indicates that there is a restriction there

Cheers

Gary

[tridentt150v]

I would have said a dodgey FPR, but you say that the fuel pressure has been checked.

Is your Z32 a real one?

[SexyPete]

I got the turbo from GCG and paid for a gt3076r kit to suit an rb25 they did modify it to suit the standard dump pipe i have but this is part of the kit they have designed.

My z32 is a genuine one

We have tried dropping the exhaust at the cat to determine if that is the restriction and turned out it was not.

[Dale FZ1]

  SexyPete said:

I got the turbo from GCG and paid for a gt3076r kit to suit an rb25 they did modify it to suit the standard dump pipe i have but this is part of the kit they have designed.

We have tried dropping the exhaust at the cat to determine if that is the restriction and turned out it was not.

The trigger for my question was your comment about using a JJR dump pipe. It seems that there has been likely a 0.7 A/R OP6 Hitachi type turbine housing matched to the GT30 rotating group. A genuine GT30 turbine housing should offer a far superior flow/efficiency capacity and would have been my first recommendation. EW if the funds are available, IW if running tight.

I think you'll find the restriction is within the housing itself, due to the internal dimensions and clearances available on the combination as fitted. Turbine inlet pressures likely climb out of proportion to boost, leading to rapid drop in cylinder scavenging and extra retained heat. There will be the source of your knock when trying to push either more boost or more timing into it. In essence, the turbine is having a tough time passing more mass flow than your 235kW without adversely affecting the operation of the engine.

That said, I do know of some hybrid type GT3071 combinations making pretty good power. Simon-R32 comes to mind.

Edited May 20, 2008 by Dale FZ1

[T04GTR]

hrmmmmmm. mona i believe had the same problem. im asuming that your tuner is going off the "knock reading" from the power fc.

you need to go to a tuner who is confidant. ie: one that listens to the engine with a chassis ear or the like, not the unreliable power fc knock reading. (if they are)

how old is the engine? and is it modified at all?

[T04GTR]

that turbo on a er34 neo makes around 290rwkw at around 1.2-3 bar..

[T04GTR]

mayby expect about 270-290 with the said op6 housing. ie .63ar ish.. not the 25 one (.5ar ish)

[nizmonut]

one question comes to mind.

how many km's has your car done.....remembering that in japan most cars regardless of who makes them spend more time stuck in traffic then actually driving.

my autech Gtr version 4 had only done a supposive 65 000 kms ..... you would assume being a 1993 R32 it would have only come out of the shed for a saftey check and maybe a fang every christmas. but no

upon pulling it to bits the mechanic told me the engine appeared like it had done closer to 250'000 kms.

after a block change to a newly rebuilt rb30(thats how badly worn the 26 block was) it went from a meassily 212 kw @ all four to 287 kw @ all four.

big difference a fresh block can make. granted it was 400 cc bigger as the dyno guy said.

but 400cc wont give you that bigger difference by itself.

[SexyPete]

car is supposedly 80,000kms and i put 45,000kms of them on but if i have to change the block i will stick to 235rwkw till she blows.

[Roy]

Very good point by TO4GTR. How are they measuring knock? Puffs of black smoke out the exhaust, audible, PFc, electronic ear etc etc? If its striaght off the Power Fc then they need a better means of detecting knock. But being JEM i am sure they have the right gear and know pinging/detonation when they hear it

[tridentt150v]

Just about eliminated fuel and spark:

Only other thing........have you tried tuning it without an air filter, is there any improvement? An apexi power unit should be OK.

Otherwise, the simple things are pretty much all used up and you'll have to listen to the doomsayers.

[SexyPete]

yes it was tried whilst air filter removed and no improvement. However it was suggested to clean with upper engine cleaner to clean carbon out of engine. Could this be the problem or highly unlikely. I will most likely clean it anyway it cant hurt.

[SexyPete]

as for measuring knock i watched adam with the head phones on listening it is not just by the hand controller.

[mesmerized]

hey pete, did you manage to iron out the problem yet?

[SexyPete]

not yet dude, been heaps busy but i had heaps of suggestions i will just keep working through them when i have time.