Turbo Lag

[gillies2001]

Hi there

I have just fitted a series 1 RB25 turbo to my 89 GTST/4 RB20

Every thing was ok with the RB20 turbo, but now nothing much happens until 4000rpm +

The car has a front mount, dump pipe, manual boost control (set at 14lb)

When it does come on boost it really goes hard but below 4000rpm its a pig, real laggy

The engine is healthy, good compression (about 165lb x 6 ) Also the new turbo is smooth and spins free.

I read the forums, and it would appear that lag should not be a problem doing this conversion.

Any help would be appreciated

[Cheddle]

i would point a finger at the wastegate actuator...

there is virtually no noticible difference in response between these turbos on an rb20...

make sure that the wastegate arm is as tight as possible, i remember when i changed my turbo on my r32 last time the bolts were ever so slightly loose on the actuator bracket and ti caused epic wastegate leakage

for what its worth i think that running the RB20 turbo actuator on the RB25 turbo results in more boost... i think, could be the other way around tho lol...

[lachlanw]

rb20det + anythign = laggy

flat mate has a rb20det with a neo turbo on it(bigger rear housing ) that reaches full boost at 4100 on the dyno graphs .

do you have a boost gauge

[gillies2001]

Thanks Chaddle

Yes the actuator rod was too long, formed it for pre tension.. ALL FIXED

Thanks again

[Rb25det123]

I've got this problem with my rb25det and stock turbo boost don't come on till 4000rpm would it be same problem?

I brought a aftermarket turbo if I just do change over will that fix it 2?

[GTSBoy]

Maybe.

Maybe.

[Cassbo]

I've got this problem with my rb25det and stock turbo boost don't come on till 4000rpm would it be same problem?

I brought a aftermarket turbo if I just do change over will that fix it 2?

Read this

[Dose Pipe Sutututu]

Buy an EFR7670 I wanna see results 

[Missileman]

8 hours ago, Dose Pipe Sutututu said:

Buy an EFR7670 I wanna see results 

Have there been any results with these or 7064s on stock 25s yet?

[Dose Pipe Sutututu]

one result.. but it's not a stock RB25 and it has silly duration cams at 272.. car would be better if it had smaller cams.. and also not even twin scroll.

[Missileman]

Pity, that single scroll 7064 IWG has me interested when it's time to get rid of my RB20