HKS Manifold for GTR Options... Balance pipe?

[N/A®]

As seen on the pic below. The HKS Manifold had a bridging pipe that connects both manifold together. I believe it has something to do with balancing the turbines. Can anyone explain further on them? I know HKS has the same manifold for the RB26 without this pipe.

[HIRISK]

This particular HKS manifold is designed to reduce/eliminate turbo shuffle.

Turbo shuffle really only becomes an issue when using a twin turbo set up that runs 1.3bar or higher, so for this reason, it is usualy only encountered by people running HKS GT series low mounts as no one (i hope) boosts stock turbos this much.

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.

However, I have read that it is all in the tunning and if you map the GTR right you can avoid shuffle altogether without the use of these manifolds. We all know how poor some of the jap tuning can be and that is why there is a market for these, but with all the great ECU options and tuners we have in Australia, this problem can be avoided without the use of these manifolds.