Garrett Turbo Upgrade Issue

[nemo]

A while ago i upgraded the turbos on my 32gtr to garrett 28/60`s-10 and when i ease on the throttle very slowly i get a chh, chh, chh, chh, chh coming from the turbo area, there on a stock manifold and got stock dumps, would be part of the problem?

Have checked all clamps hoses anything i can get to and nothing helps, please help?

[The Dan]

what ECU are you using?

[nemo]

runnin a power fc

[axe s]

sounds like ur BOV is set for to high of pressure drop... loosen up ur BOV and see if that helps...

[nemo]

we`ve tried swappin b.o.v`s and different spring rates and the standard b.o.v`s seem to cope with it betta, put trust type r b.o.v on and it messed the idol up cos of the return of air past the afm again;

[tacker]

sounds like turbo shuffle

[Brocaine]

Stock BOV's will help.

Trust Type R may not be releasing under low pressures. Trust sell two different springs for these BOV's. Soft one would probably work fine. I ended up with the hard one in mine and it doesnt open under 13psi or so.

Even with the stock BOV's, you aren't always going to be able to get rid of this noise. There's nothing wrong with the car.

[R31Nismoid]

Its the turbos causing the shuffle, compressor surge as they are making too much air as they really aren't the turbos for a 2.6ltr...

They are designed for a stroked/cam'd motor that can use the added air... -10's are too bit... Anyway...

GTR BOV's fix it to some extent as they leak @ idle, aftermarket ones will make it worse.

You've got a few options

1. Manifold "balance" pipe between the exhaust manifolds, user: GAV posted about it

2. Tune it out, it can be done with an experienced tuner, but i am unsure how one goes about it

3. Put on -5's like everyone else which are the better suited turbo

[The Dan]

Its the turbos causing the shuffle, compressor surge as they are making too much air as they really aren't the turbos for a 2.6ltr...

They are designed for a stroked/cam'd motor that can use the added air... -10's are too bit... Anyway...

GTR BOV's fix it to some extent as they leak @ idle, aftermarket ones will make it worse.

You've got a few options

1. Manifold "balance" pipe between the exhaust manifolds, user: GAV posted about it

2. Tune it out, it can be done with an experienced tuner, but i am unsure how one goes about it

3. Put on -5's like everyone else which are the better suited turbo

Yeah definately a good option on the balance pipe but I reckon option 2 is still his best bet. I put a set of HKS 2510's on a GTR with usual supporting mods. When I say, I put on, I mean they were already on the car when we started working on it but made quite a few changes before we put them back on. Mainly head porting and cams. Injectors were your usual big mofos and we deleted the tune and started from base map again with corrections for injector sizing. It surged quite harshly on cruise but it was easily tuned out. The reason for this particular surging was it was running slightly lean on cruise. Fattened it up a tad and it's smooth as sillk now.

You are right about the -5's also but you forgot to mention they are a better turbo...not just better suited.

I sold a pair to Russel Newman back when the GIANT GTR was still taking names 2 years ago and he commented on these to me a few weeks back saying that they definately went a shit load faster on the -5's than the -10's that they fitted to it later on. His advice was to wind 'em up and let 'em go. They made approx 735hp at the wheels on those turbos. - a tad off topic though but thought I would share the fact that they are real performers and the necessity to go up to a -10 is only present if chasing 750-800hp.

[R31Nismoid]

well... i didnt wanna say "better", cause -10's will make more power etc so some people would call em 'better'... but not really suited to a stock or even mild build 26.

[nemo]

when we fitted these turbos i was always goin to totally re-build the engine by puttin forged internals and all the good stuff in the head so that the turbos ran efficient and put a hks merge pipe between a new manifold.

Martin Donnon tuned my car when we fitted the turbos and he said all gtr`s get it, but i thought that cant be right, but didnt say anything knowin that he knows a hell of a lot more than me.

so its basicly the engine cant use the extra boost pressure?

[R31Nismoid]

No, it cant use the initial airflow. Once you get going it's fine... has nothing to do with boost really as the turbos are just 'coming on' when it'll be surging.

This is because the comp wheel is too big and pushed too much air and forces you into the surge zone.

You'd need more than internals... im talking a serious big $$ build like a stroker etc to really make use of the -10's.

[nemo]

o goodie!! might hav to start gettin some cash together got some -5`s i herd they are they same as the hks gt-ss version is this correct?

[R31Nismoid]

no. search will tell you whats the same as what

[The Dan]

Make sure you check your TPS calibration as sometimes this can cause surging if it has been set too low.

[nemo]

what is TPS calibration? sorry for sounding stupid but im still a bit of a learner with jap cars