Rb26 Twin Turbo Shuffle/surge

[tommis85]

Hi all,

After spending many hours reading thru topics on here I have decided on a set of GT2860 -9 turbos for my R33 GTR but still have one niggling problem I'd like to throw to you experts out there......and that is the issue of that shuffling you get with larger BB turbos.

Now, there're plenty of topics that talk about it but a lot of them stop half way or don't quite confirm a solution. The three main solutions appear to be:

1. Keep all your factory plumbing, especially BOV return a and balance piping

2. Weld a balance pipe between the two manifolds

3. Weld a divider pipe into the "twin turbo" collector pipe.

Could anyone who has had this problem please let me know how they went about fixing it. Am hoping for solutions and comments from those who have actually dealt with the problem first hand....

I was orginally going to go for -7's that apparantly are so close to stock performance that they don't shuffle....but now that I'm going for one step up from those I'm thinking we'd be back in the suffle zone.

Thanks for your time guys ;-)

[Nee-san]

Don't worry about it.

[DVS JEZ]

U shouldnt get shuffle with -7's or -9's. But definately keep the stock intake pipes from afm's to turbo's

[sydking]

Was also told not to worry with this on -9s

[tommis85]

Thanks guys - that should be all good then

[Nee-san]

Driven 1 with what you have, 1 with the older much bigger N1's and one with GTSS and been in one with -5 mate and not a problem in any of them.

[tommis85]

Ah ok excellent - sounds good. And yes, that's a good point - I had R33 N1's on it at one stage and they never shuffled either althought technically, it has more to do with how fast and how far down low the BB cartridge makes the turbo spool up rather than just size etc etc.

But either way - sounds like I'm in the clear with the 9's

And yep, I'll be keeping all my intake piping for now anyway..

Thanks for the quick replies peeps ;-)

[Don Dada]

I get shuffle with -9s.....Stock intake piping

[Piggaz]

I get shuffle with -9s.....Stock intake piping

Try the TT pipe mod. Helps ALOT!!!

Actuators setup correctly?

[GTRsean]

Try the TT pipe mod. Helps ALOT!!!

Actuators setup correctly?

+1

I run -9's and TT pipe mod is worth it. Also, tuning plays a part.

[Don Dada]

Actually got a custom aluminium TT pipe courtesy the japs for the sole purpose of rectifying this,as I have heard it has to do with how the turbs merge....just havent slapped it on as yet

[Don Dada]

+1 I run -9's and TT pipe mod is worth it. Also, tuning plays a part.

Tuning in terms of what??..... Boost controller?

Not really seening how fuel/ign maps would have a play

[scotty nm35]

If you can increase the amount of air the engine can ingest at that point I guess they wont surge as badly, or just slow the compressor down by reducing the exhaust velocity? I would expect timing, especially valve timing could play a part in fixing the issue.

[R31Nismoid]

Tuning does without a doubt play a part.

That said, I've had two -9 setups no surge on a 2.6

My -5s on 2.6 will surge ONLY on a 4-8 degree morning in the hills, loaded up in 5th @ about 2300rpm from what i can remember. basically such a rare occurrence it doesn't bother me.

[GTRsean]

Tuning does without a doubt play a part.

That said, I've had two -9 setups no surge on a 2.6

My -5s on 2.6 will surge ONLY on a 4-8 degree morning in the hills, loaded up in 5th @ about 2300rpm from what i can remember. basically such a rare occurrence it doesn't bother me.

I had the same thing on my 32GTR with 2530's. Solved by changing down a gear

[R31Nismoid]

Yep that's just what i did

[Risking]

I've done heaps of divided turbo pipes, they do work but having done so many I also found a trick with the divider plate.

I leave a small section of the front turbos air path in plated, it allows some of the front turbos air to swirl around into the rear turbos path.

A customer of mine who is a fluid scientist type guy explained how making the front turbo swirl around the inside of the pipe before merging with the rear turbo helps promote a lamina flow and draw the air away from the compressor housing thus reducing the shuffle.

The mod does seem to improve the issue on all the cars I've ever done one for.

Can't hurt to give it a go.

[Piggaz]

Got a photo Brad?

[tommis85]

Ah damn, so there's probably a 50-50 split of people who've experienced shuffling and those who haven't with -9's

From everything I've read it would appear that the GT2860-9 turbos are on the very limit of wanting to shuffle. We're approaching winter so I guess some of these very "well working" turbos will shuffle a bit down low with the far more denser air.

[tommis85]

Maybe I should do a poll on the issue - GT2860-9, will they shuffle on a RB26 with factory plumbing - yes/no