Changing Twins - 2860r-5s to what?

[DougTaylor]

As well as going single (BW EFR 7670) I'm thinking about changing the twin GT2860r-5s to some other twins this year to get rid of this compressor stall. I'm happy to go with lower power to get higher response, but still want to stay well above stock. Can you make some recommendations about what is working for you? Criterion are something around 400-500hp, low rpm spool, and no compressor stalls (ch ch ch ch ch) ever in your experience. Let me know what you have - turbos, spool rpm and hp.. Might make a nice list for others thinking of changing turbos as well. As a start, my dyno chart is here:

http://photoshare.shaw.ca/image/c/2/4/156417/dyno-0.jpg?r=t

, but mine stall at low rpms..

[Goodlucks7even]

You mean compressor surge ?

I'd go with HKS 2530 with some goodies to improve the response such as I/C piping and stuff.

Compressor outlet pipe cause the "Ch Ch CH CH" your telling, the air is coming in and out of the turbos, and since the pressure isn't high enough to open the BOV.

[TrevoR32]

You mean compressor surge ?

I'd go with HKS 2530 with some goodies to improve the response such as I/C piping and stuff.

Compressor outlet pipe cause the "Ch Ch CH CH" your telling, the air is coming in and out of the turbos, and since the pressure isn't high enough to open the BOV.

not to hijack the thread... but i do experience similar issue at cruise. the shuffling on my -5's is unacceptable. like you said its when it hangs around 0 +/- its like pulling an accordion fast in and out. any thoughts to help this?

[Goodlucks7even]

The turbo shufflelin is cause by an unbalance pressure level between both turbos. The turbos are fighting against each others. It happens a lot with ball bearing turbo as they spool faster. To resume :

Problem : turbo shuffles
What is it : the sound comes from the air that is going throug the opposite turbo.
When does it happens : on turbo load when boosting at ~0psi (you are cruising on 5th gear and play at 10-15% of throttle.)
What is the solution : equalize the turbo pressure to the same to prevent a turbo from overboosting the other one.
How to fix ? In my opinion, a join section between the two exhaust manifolds would prevent shuffle but may slow the spool from the turbos.
A divided "twin turbo pipe" is also recommend.

[Goodlucks7even]

The other solution. Go single PTE 6265.

[DougTaylor]

The turbo shufflelin is cause by an unbalance pressure level between both turbos. The turbos are fighting against each others. It happens a lot with ball bearing turbo as they spool faster. To resume :

Problem : turbo shuffles
What is it : the sound comes from the air that is going throug the opposite turbo.
When does it happens : on turbo load when boosting at ~0psi (you are cruising on 5th gear and play at 10-15% of throttle.)
What is the solution : equalize the turbo pressure to the same to prevent a turbo from overboosting the other one.
How to fix ? In my opinion, a join section between the two exhaust manifolds would prevent shuffle but may slow the spool from the turbos.
A divided "twin turbo pipe" is also recommend.

Thanks , the 2530s are on my list now as they have a lower surge line. Someone told me once i would get rid of the surge with the divided pipe so now I'm running a greddy twin entry ic and separate piping from both turbos. Still surges.. Have tomei expreme manifolds so I'm reluctant to drill holes for the equalization pipe. Rather replace the turbos I think..

[Goodlucks7even]

2530 can shuffle too. If I had to change my turbos again (i went from OEM to GT28') I would probly go with a fast spool setup single turbo.

The turbo market on the performance scene isnt doing much R&D in small turbo size, it all comes to mid/big size. Thats why I would buy a twin scroll BB turbo with a badass manifold, faster spool than a dual, more room in the engine bay, and a lots of worries that you can forget such as turbo shuffle and stuff.

[EggplantS14]

Do rb26's usually run that lean? 13.3 thats scary.

[NismoS-tune]

2530 will shuffle like -5s.

Go -7 or SS and you should be fine.

If you're set on a badass set of 2530s, I think Velders has a set up for grabs.

Twins shuffle. Go Single or ignore it.

[TrevoR32]

The turbo shufflelin is cause by an unbalance pressure level between both turbos. The turbos are fighting against each others. It happens a lot with ball bearing turbo as they spool faster. To resume :

Problem : turbo shuffles
What is it : the sound comes from the air that is going throug the opposite turbo.
When does it happens : on turbo load when boosting at ~0psi (you are cruising on 5th gear and play at 10-15% of throttle.)
What is the solution : equalize the turbo pressure to the same to prevent a turbo from overboosting the other one.
How to fix ? In my opinion, a join section between the two exhaust manifolds would prevent shuffle but may slow the spool from the turbos.
A divided "twin turbo pipe" is also recommend.

good info. i actually do have a divided turbo pipe... so i really dont know. ha

[DougTaylor]

Do rb26's usually run that lean? 13.3 thats scary.

That's what you can do with something like the fcon vpro and a good tuner.. It 's only scary if it could lean out and the fcon and afk (air fuel knock sensor) I have won't let it do that..

[xcye]

Hi, Doug:

I am running a pair of Nismo LeMans turbos. There is no shuffle noticed.

[dsmart]

I put a set of Garrett -9's on my r33 and are very happy with them. Before I had it tuned I noticed a slight shuffle as you described but after tuning it's all but gone. I managed to get 420hp on the dyno at 17psi which leaves lots of headroom for more power if I decide. I'm not sure why nobody considers the -9's as they spool faster than the -7's and can make equal to or more power.

[curtisgoodman]

i almost went -9's but nobody could give me feed back about them so i went with -5's and i also have minimal shuffling... just turn up your music, what shuffle?

[MattiasJacobs]

I run -7's, only shuffle i ever noticed is cruising up big hills at around 0psi. Hardly noticeable without actually listening for it.