Rb26 Twin Turbo Shuffle/surge

[tommis85]

Well, I've observed the bov's doing this myself...not exactly sure how much they influence shuffle down low...they do open down low so they would take some of the air away from the turbos (sucking it back thru the recirc pipe and stealing it before it its the compressor....but after running thru afm offcourse)

The reason why the stock intake piping reduces shuffle is because it generates so much drag inside it's piping (corrugations in the rubber piping, afm mesh etc etc) that it effectively throttles the turbos by just enough to stop them getting too far ahead of themselves which would cause shuffle (too much air for engine to ingest etc)

You wouldn't happen to have posted a dyno graph in that turbo/dyno results thread? Really keen to see some of these....have been looking at GT-SS plots as thet're very similar turbos.

[Hadouken]

Lol I suppose you mean me on that one.

http://www.skylinesaustralia.com/forums/topic/378971-the-build-of-the-beast/page__st__20

Ps: I have the stock plumbing on mine. I have that hard pipe kit but need new silicone joiners. The ones that came with it are shit and I cracked the shits when installing it haha.

[levinboy]

You wouldn't happen to have posted a dyno graph in that turbo/dyno results thread? Really keen to see some of these....have been looking at GT-SS plots as thet're very similar turbos.

I have one or two -9 dyno graphs posted around the forum haha I run std intake piping but have the "twin turbo pipe" mod as I was having slight shuffle on light throttle applications when I was running 22psi with 335awkw on std engine, now I have none on current tune on 18psi 330awkw(now built engine)

[JD32R]

Im pretty interested in this topic also. have read just about every thread about it speculating, some saying this and some saying that, its all piping, its all tune, its all turbos etc etc.

Im really interested after seeing some youtube videos: type 'Gtr surging' i think for a dyno and the noise is severe! its sounds like a high pitch screetching meets external waste gate noise. that guy had it labelled as surging, i believe it was a guy from Gtroc but not 100%.

I run -7s i believe on my 32 all with stock intake piping, apexi pods and stock twin turbo pipe with no mod (have considered it). i get the choo choo choo choo *trailing off as i believe all bov pressure is released??? when going up a hill under load and releasing the gas a fraction, i can get it to do it if i work at it on flat but most prominent on hills etc. have talked with a mate and apparently thats not a problem its only a problem if you get it all the time, basically if your not trying to do it and get it *problem.

Have since bought a cusco hot pipe which replaces intercooler pipe and twin turbo pipe back in one, these are apparently suppose to help channel air through better, waiting for tomorrow on silicon joiners then going to give it a go (just for something different). keen to see if this changes anything to do with how it drives. I also have issues with restrictions through stock dump pipes. waiting on tune in a bit to swap them out for 34gtr dumps and see if this makes it worse/lesser?

Is there anything i should be looking in to or am i fine?? is my shuffling* not really a problem, car doesnt feel bad, no vibrations or shaking. turbos are being ported and balanced with larger actuators when going for my tune for bit more hp also.

[R31Nismoid]

^ sure that's not just the BOV's "bouncing" off each other? Sure sounds like it

And don't port the turbos, they are designed to work as is. Porting will hurt response and probably not make anymore power.

[tommis85]

^ sure that's not just the BOV's "bouncing" off each other? Sure sounds like it

And don't port the turbos, they are designed to work as is. Porting will hurt response and probably not make anymore power.

I concur with ya there....that's definitely the BOV's - I can make that happen with my stockies....especially when you're driving over a long crest and you gentle let of the gas to maintain constant speed. If you're running a bit of boost you can make it go on for ages...

From all that I've read now....and what people have kindly submitted on this thread, you definitely SHOULDN'T be getting with -7's and factory intake piping, turbo-to-cooler piping and stock, plumbed in BOV's.

[tommis85]

I have one or two -9 dyno graphs posted around the forum haha I run std intake piping but have the "twin turbo pipe" mod as I was having slight shuffle on light throttle applications when I was running 22psi with 335awkw on std engine, now I have none on current tune on 18psi 330awkw(now built engine)

Ah ok, I'll will have to have a look. If I do get some shuffle I'll have to look into that TT pipe mod as well - there seem to be a couple guys on here who've nutted out some pretty good designs.

[tommis85]

I have one or two -9 dyno graphs posted around the forum haha I run std intake piping but have the "twin turbo pipe" mod as I was having slight shuffle on light throttle applications when I was running 22psi with 335awkw on std engine, now I have none on current tune on 18psi 330awkw(now built engine)

So do you think the new tune made it go away or was it the TT pipe mod?

[tommis85]

Lol I suppose you mean me on that one.

http://www.skylinesa...st/page__st__20

Ps: I have the stock plumbing on mine. I have that hard pipe kit but need new silicone joiners. The ones that came with it are shit and I cracked the shits when installing it haha.

Ooh a build thread nice work! Yep agree with what you said in it - always more fun in a threesom ;-) You still happy with your -9's? I'm assuming they leed a shuffle-free life??

[Hadouken]

They cause me no troubles.

Still very happy with them.

[tommis85]

They cause me no troubles.

Still very happy with them.

Yeh they look quite fun on the video....bed she pulls pretty hard in 2nd

[levinboy]

So do you think the new tune made it go away or was it the TT pipe mod?

I think a little of both, it wasnt massive amounts of shuffling but enough for me to notice, annoy me and yea I'm a perfectionist but all good now

I had a member on here ,craved is his username did mine very happy with his work

[tommis85]

I think a little of both, it wasnt massive amounts of shuffling but enough for me to notice, annoy me and yea I'm a perfectionist but all good now

I had a member on here ,craved is his username did mine very happy with his work

That's the way, so I take it that it got rid of it completely? I'll be sure to be back on here in a flash if I get some suffle ;-)

[tommis85]

I have one or two -9 dyno graphs posted around the forum haha I run std intake piping but have the "twin turbo pipe" mod as I was having slight shuffle on light throttle applications when I was running 22psi with 335awkw on std engine, now I have none on current tune on 18psi 330awkw(now built engine)

Those are some pretty impressive figures too! Is she still a 2.6? Just wondering tho - how would you compare the response of the -9's to the standard ceramic terbs? Mine are in the post now and am hoping that they're not going to be too big for around town driving...

[DVS JEZ]

They are fine for around town

[tommis85]

Good good

[Moodles2]

I didn't notice much difference in response from stock ceramics to -9s

[fatz]

just got one of these twin turbo pipes from brad did a group buy for them as well people if you want one

http://www.skylinesaustralia.com/forums/topic/399459-gtr-divided-turbo-pipes-helps-shuffle-180-exchange/

[levinboy]

Those are some pretty impressive figures too! Is she still a 2.6? Just wondering tho - how would you compare the response of the -9's to the standard ceramic terbs? Mine are in the post now and am hoping that they're not going to be too big for around town driving...

Yea still a 2.6

Response is nearly as good as stock but don't fall over in the upper rev range

You will have no trouble around town with -9s

But ultimately it will come down to the tune and boost level, make sure if you don't already have them to get some adjustable cam gears

[tommis85]

Ah that's the way peoples....looks like the -9's are the turbo of choice for a mildly modified GTR hoping to break the 400hp mark. Yeh it's the falling over in the top end that makes the car perform so pitifully once you're past 1st and 2nd

I'll be putting these in with a set of cam gears and injectors (already have computer, pump and coil packs along with zhorst etc...so all the basics)

As for the TT pipe mod, I'll see how I go first and then go from there as a lot of people have said on here that there shouldn't be shuffle with these. Some say there will be some but they're also running much better/higher-flowing intake plumbing / hard pipe setups (i think...from memory). I'll be running all stock plumbing for now so see what happens.

Will have to enter my results into the turbo upgrade thread on here ;-)

Leviboy, you wouldn't happen to recall by how much you changed your intake/exhaust cams by with the gears??