im having problems with my gtr at 0 boost the car surges badly.
sort chu,che,chu,che,chu,che.
is this familiar to anyone.
on the boost guage it only happens at 0,above and below 0 its perfect.

Hmmm, not good.

Probably a stupid question, but is the MAP sensor OK??? Have you tried a different one??

Good luck

J

all the sensors etc have been checked via the power fc,all ok

Yes I know exactly what it is and have experienced it, both on my R33 which ran 1.3bar on stock turbos (with steel exhaust wheel) and my R34 which runs 1.5bar on 2530s.

The effect is most obvious on a low throttle at low rpm at low or zero boost. If you are running bigger turbos, especially ball-bearing ones eg the HKS GT range, then it is worse.

Running 1.5bar on Ball-bearing turbos you can get huge shuffle and the car actually shakes, it stops if you back off or drive through it.

My understanding is that it is caused by the turbos fighting against each other at different pressure levels, this is worse with ball-bearing turbos as they spool up faster.

Whilst you can partially mitigate this effect with the mapping, the only true way to remove it is to use a manifold with a balance pipe between the turbos, to equalise the pressure. I fitted the HKS tubular manifold with balance pipes and it removed the shuffle effect on the car. It still makes the shuffle noise some times as the pressure modulates up/down, but no longer causes the shaking effect.

I know many other people who have complained of shuffle, usually with HKS GT series turbos.

The other way to get rid of it is go for single turbo.

Guy

thanks for that excellant reply,this is exactly what i thought just didnt want to buy the manifold and find out it wasnt going to help,
how much did u pay for your manifold.is this the only manifold they make .do i need a specific one.does it have a part no or a name.
and yes i have 2540s at 1.3bar making 303kw @4 wheels.

I have a GTR and never had that. I would almost sound as though one of your turbos is dying causing this problem. The Turbos have to be not only balanced but flow the same. That is where the trick in this type of twin turbo set up is.

if youve got standard turbos you probably wont unless your running high boost up around the 1.2-1.3bar level.i didnt have it a 1.2bar,but i have it a 1.3bar.
there are a lot of gtrs with gt series turbos suffering this problem,some worse than others.my cars always had some shuffle,but i was easy to drive through at 1.2.but now its a real pain at 1.3

On the 2540's the compressor wheels are to big, especially with ball bearing cores at cruise, going up a hill or low boost, the wheels generate to much air for the motor to handle, so the turbos stall each other and thats what the noise is. When garrett designed there 300 hp roller bearing turbos they only used a 47 mm compressor wheel to stop this problem, a 2540 compressor wheel is 53mm way to big, but alright for top end flow. If you have .48 housing on the exhaust side this problem is enhanced. I am currently running a garrett 350 hp core's 49mm comp wheel, 47mm turbine wheel machined into standard GTR housings .42 comp and .48 turbine, these work well and spool up a lot quicker than the hks .64 exhaust housings with only a small amount of compressor surge at part throttle, full boost 1.3 bar by 4000 rpm and 300 kw's on the dyno and virtually no lag, definetly less than standard turbos. The best way to fix your problem is to fit smaller turbos you can make the same amount of power with smaller turbos, less lag and quicker response.

why didnt i have this problem with 1.2bar and standard afms.
it now is 1.3bar and 80mm afms.

This is a weird as I know of quite a few GTR owners who never had this problem with the factory or after market turbos. I will have to check with a few of them again to make sure though.

i think you will find this is only an issue with 2530-2540s.

The shuffle happens at high boost 1.3bar or more.

It also happens badly on 2510s, so its not just the larger turbos. A friend of mine has 2510s and has the HKS balanced manifold. He has no shuffle with the manifold. Recently he broke the flexible baffles that attach the balance pipes from the two half manifolds and blanked the balance pipe off. This caused massive turbo shuffle. This is conclusive proof that the balance pipe removed the shuffle. (He is running 1.6bar)

HKS make the balanced manifold in 2 types I believe, one that has fittings for external wastegates and the one that is for HKS GT25 series turbos using the standard internal wastegates. Both manifolds fit all the GT25 range.

Guy

ive been told these manifold are about $1500us,that seems excessive.
i wonder if a twin exhaust frt to rear would have the same affect.

It's funny you all mention that....I was told not to boost above 1.2 Bar (I have the 2540's)....but I believe my internals are strong enough (of course my injectors may not be big enough to keep up with the air flow). You guys boosting 1.3 and 1.5....what are you running (injectors, internals)? I'll look into the cost of this manifold....If list is 150,000 Yen...I can probably pick it up somewhere for 1000USD flat.

hi 2.7,
im running 1.3bar with 550cc inj and bosch pump.its got 303kw at 4 wheels.with standard internals.
the injectors are at there max,but i think also the internals probably are too.
if i go to 700cc inj i could got 340kw at wheels at 1.5bar.initially we set at 1.5bar ,it went 340 but the injectors were at 115%.
injectors now at 95% at 1.3bar.
im not going any further i just want to fix this shuffle problem.
can you please get the price for the exh manifold for me.

HKS has a manifold designed for twin 3037's with a crossover pipe between the 3-1X2's...it's advertised for 198000Yen....which is a about 2900AUD. That's list....and I can usually pick things up for less than that. My connection has been up at the Tokyo Auto Salon for the last few days...which is why I've been dragging feet on everyone's requests....
But the show ends today, so he should be around tomorrow. I'll ask him about a manifold for the GT2540's....It makes sense to me it would cost the same or less for them than the 3037's.

im still interested in the manifold.
any chance of a photo of it b4 i place an order.its a lot of money for a manifold and i want to b sure its right

Performance Metalcraft in Sydney make and sell these manifolds for $3250 the pair, www.hioctaneracing.com.au/page18.html
personally I think they are a waist of money the stock ones are good enough.

thay are a flat out ripp off,lets face it $200 worth of steel a jig and 6 hrs of labour.
good profit huh.
these dont have a balance pipe either,i doubt the gains with these manifolds would justify the money

The funny thing is they export and sell them in Japan, your right the are ripoff so dont waste your money buying the HKS ones because they are even dearer. The Performance Metalcraft ones are a direct copy of the HKS ones.

i just checked out the hi octane website,are these people smokin or what.
everything on that website is ridiculously priced.
radiators--$1600-worth $900
oil catch tank $580--everyone quotes around $350 to make.
these people really look after the enthusiast huh.
new manifolds are a last resort,i will endevour to sus this problem out.
but i keep hearing balance pipe.
i reckon a decent twin exhaust would have the same effect and probably some more power gains too

If you put a twin exhaust on that will help reduce the back pressure and could fix the problem definetly a better idea than the manifolds, why dont you contact Tilbrook Auto and Dyno in SA (Mark) he is supposed to be an expert on the 2540 conversions HPI and Zoom articles and is quite helpful on the phone, if he does not know then no one will.

Twin exhaust won't help. The purpose of the balance pipe is to equalise the pressure on the input side of the exhaust wheel of the turbos, to prevent one turbo out-accelerating the other.

I paid a lot more than you guys for the manifold as all parts are expensive in the UK (taxes etc) - I paid £1,800 = $2,600 = AUD $5,000

I have driven my R34 with and without the balance pipe and my friends R33 with/without, (both cars are circa 600bhp) and the balance pipe works.

I have also driven in about 30 other GTRs of varying specifications as well as dynoed over 50 GTRs on a rolling road (I organise the UK GTR Rolling Road Shootouts) so I will tell you my opinion again based on all this GTR experience:

To remove shuffle you need a balance pipe.

Guy

PS See 20 GTR Dyno charts from my most recent day here:

http://www.tuningjapanese.co.uk/graphs/shootout_sept01.htm

thanks ukgtr,
your opinions are obviously based on 1st hand experience.
i have listened to lots of differing opinions on a few different forums.
i guess the hard part is forking out the cash only to find out it doesnt solve my problems.
do u know where i can see a photo of this manifold.
im really curious to see what it looks like.

It sounds like you need a balance pipe, but I am just wondering why the car that was making 343 kw on the Tilbrook Auto Dyno does not have this problem and they are using standard manifolds? Why dont you make your own balance pipe and join the 2 stock manifolds should be easy!

i guess it could be done,just have to find someone who can weld cast.
would have to be done on the car too.or atleast tacked together.

must admit im still a little lost with the whole theory.
the balance pipe is before the turbos.
ukgtr said its too prevent one turbo from out accelerating the other.
so this is an engine issue rather than a turbo issue.either the frt 3 or rear 3 cylinders are exhaling more exhaust than the other.maybe this shufle is more of a problem on worn engines and thats why its not present on all gtrs.asume you had a broken ring on 1 cyl ,that would decrease the amount of exhaust gasses from 1 cyl.then you would have less pressure from 1 group of 3 .
by linking the 2 manifolds together u are giving each turbo an even amount of exhaust pressure.
ok lets assume theres no balance pipe and 1 turbo is spinning at 20000rpm and the other 18000rpm.these (figures are just examples)
why would it surge.can someone explain why.
ok if my explanation is correct.its possible for i turbo to spin slower.
but i still dont understand why the shuffle.is the shuffle coming from the plenum side or the exhaust side.
SORRY FOR ALL THE (MAYBE DUMB)questions.
but i just dont understand

I'll post a pic tomorrow....

Don't know what causes it specifically, but it happened on my R34 that has only done 7,000 miles so its's not due to a worn engine.

I thought about trying to make a balance pipe for the stock manifolds, but was concerned about the strength of any welding and also the flow characteristics into the balance pipe. Given one could be bought from HKS thats what I did.

It might be worth a try, but you would junk a stock manifold if you get it wrong......

the reason they shuffle is becaust the compressed air feeds back into one , partially stalling it then the exhaust gas builds up behind that one and it accelerates to faster than the other one , in turn partially stalling that , the balance pipe will stop the exhaust gas building up , the turbos might go different speeds but they wont fight against each other . I have a small pic of the manifold with the balance pipe , the one on the left is the one without the balance pipe , sorry about the quality , it was taken with a camera from the hks catalouge .


Edit , I cant attatch images to this forum , I have the pic if you want me to email it to you , my email is brenhan@hotmail.com

me again,after spending half the day talking to all the experts.(tilbrooks,cas,bd4s etc),i have come to 1 conclusion,theres more to this than meets the eye.every single tuner (and i only spoke to ones with a good knowledge of gtrs).they allsaid the same thing.TUNING.every single one with no exception told me its in the mapping and turbo shuffle only appears when the gtr hasnt been tuned properley.1 even guaranteed if he fitted an autronic to my car guaranteed no shuffle.
so now im even more confused,so it going back on the dyno.most suggested its too lean when on 0 boost and that it needs some fiddling with the cam gears.one even suggested the power fc isnt up to the task when after market cams are fitted.
uk gtr,what sort of computer are u using,you seem to have a similar setup to me.a couple said the hks exh manifold is only masking the problem and suggested that the shuffle is appearing because of bad tun ing.maybe a couple of cylinders not operating correctly because it running too rich or lean.
i dunno any thoughts anybody

The Turbos are to big HKS 2540 are good for 350hp each thats 700hp the pair, HKS 2530 are good for 320 hp thats 640hp the pair. 303 kw at the wheels is about 505 flywheel hp so 2530's are good for 600 no worries will spool up heaps quicker and will get rid of your shuffle guaranteed because they use a smaller wheel 47/60 against the 2540 52/76. Too much air and no where to go so the compressor's stall each other. Ring Garrett Turbochargers in Sydney 0297553311 and ask for Bob he will explain it all.

your calculation at 505hp,is that 2wd or 4wd.should be more than 505hp.
still doesnt explain why some cars suffer with this and some dont.
tuning?

vspecv,
To answer some of your own questions or theories:
1. Do a compression test on your motor. This will tell you the conditon of each cylinder allowing only 10% variance between the highest & lowest readings.
2. Dyno tune the vehicle & specifically tune the fuel map i.e rich or lean off in graduations through the rev range whilst observing A/F ratios on the graph.
Just a suggestion for you, as sometimes going back to checking the basics can save you a lot of heartache & $$$$$$$$$$:D

I've seen shuffle on 2510, 2530 and 2540, when all running over 1.3bar.

This has also occurred on an engine with stock turbos where the exhaust wheel was replaced with steel wheels (allowing higher boost) - smaller turbos still shuffle.

This shuffle occurred on my very low mileage R34 engine and also a freshly built Trust 2.7ltr engine, so they weren't worn.

Changing the map (I have an FConV by the way, others have PowerFC) means you can reduce the effect, but on several different cars we never eliminated it. The only other way to eliminate it may be to run without dump-valves, though this is not good for the turbos.

However, if you set a map to avoid the shuffle, you will compromise the overall map and won't have a map to make the best power your engine can, but a map to reduce shuffle and by definition they are very different. We gained 30lb ft of torque on my car when we adjusted the map after fitting the manifold......

hi ukgtr,
can u explain one thing for me you suggested this is a problem with cars running boost over 1.3bar.
when the shuffle appears it is the transitional period between vacuum and boost.
so why would it matter what boost you are running.the waste gate is closed.