Boost Leak/ Torque Drop Problem

[tkdbboy]

Hey guys,

I think my 32 seems to have a possible air leak somewhere which is making my torque drop just after my turbo fully spools.

Heres some info of what we've done so far:

(RB25 engine) Forward facing plenum has been machined and so has the manifold

Gaskets replaced

Turbo is a GCG Hi Flowed R33 turbo

Greddy cooler has been tested for leaks

Piping has been flared and silicon hoses have been secured and some replaced

Car was also dyno'd with the exhaust taken off from the dump but results didn't change

Here's the dyno graph, sorry its a bit blurry, was in a rush.

Mine is the green one.

If you guys have any ideas or need some more information, please shout out

Cheers.

Edited March 18, 2010 by tkdbboy

[tkdbboy]

Oh forgot to add that we've also ran the car with the airbox open (running stock airbox instead of poddy) but still same results

Any help will be greatly appreciated!!

[MrStabby]

If you have a boost leak it will run very rich - what were the AFRs like? Also, the boost seems to be holding very well, so my ignorant guess would be tune not boost leak.

[Harey]

as above the boost seems to be holding very well.

a plot of the afrs would be very helpful if you have it.

[tkdbboy]

AFRs were on a stable 12. The other graph plotted is of another rb25 r32 with an almost identical setup, main difference is that has a gcg r34 neo turbo high flowed and stock plenum setup (im running a greddy forward facing). So its very unlikely its a tuning problem

[geraus]

did you check the boost controller?

acutator? hmm

[Harey]

I really dont understand why you think it is a boost leak??

The boost pressure looks excellent, very constant.

I would class it as a lack of power and appears to be some sort of restriction.

My initial thoughts are blocked exhaust, maybe a blocked cat or something. Have you tried dropping the cat and doing a dyno run?

[wlspn]

Harey, read the first post again. Exhaust was dropped at dump already with no change...

Have to agree with most that its not a boost leak. Strong, steady boost plot!

Out of interest exactly what mods do you have? Have a very similar setup so would just like to know but may also help with diagnosis...

Edited March 22, 2010 by wlspn

[hypergear]

I had this sort of reading with my test car before it popped. This was due to stock intake pipe sucked shut intermediately under heat and pressure.

[tkdbboy]

Thanks for the replies guys!

Mods are as follows:

gcg hi flow r33 turbo

3 inch exhaust all the way through

splitfire coilpacks

manual mechanical boost controller

forward facing plenum with 100mm throttle body

greddy FMIC

Power FC

Adjustable cam gear set to stock timing

Bosch 040 fuel pump

Although I am running a stock 33 airbox with a Greddy filter but also with stock piping running to the turbo and also no BOV. So Stao could be onto something

[wlspn]

yeah, would look at replacing piping between airbox & turbo with either a solid pipe or one of the silicon items exact same fitment as stock...

[tkdbboy]

Sussed out the piping and its not getting sucked close nor is there any restriction affecting the performance.

Any other ideas guys?

Cheers.

[Dose Pipe Sutututu]

try running less boost, possible valve float or some sort holding back the power, looks quite dodgey

[rob82]

What ecu? Any chance its say 10-15deg retarded?