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i own a near stock 1991 V-Spec GTR, when im on the motorway at 100km/h and put my foot down a 1/4 and build up abit of boost, i can hear one or both of the turbos making a "CHOUF CHOUF CHOUF CHOUF CHOUF" noise and my boost guage bounces backwards and fowards between 0-5psi and if i put my foot flat it goes upto 14psi and hold and revs smoothly, has anyone had this problem before? someone please help..... :bawling::bawling::bawling::bawling::bawling::bawling:
 

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yep, that's normal. It can be reduced through mapping, installing a backpressure bung in the tailpipe (silencer - but that causes other problems), or modifying the twin turbo pipe with a plate welded in so that the turbos don't fight each other. What you're hearing is one turbo spooling, but instead of pushing air in the right direction, it's forcing it backwards through the other turbo, which then fights back.

Shuffle is very important to avoid because stalling turbos isn't particularly good for them, and you are taking in air and then running it backwards through the MAFs, making the car think there's a lot more air in the system then there is. At cruise I'm at 14.5~15:1 AFR, but if I get shuffle, that immediately drops to 9.5:1 - excessively overfueled.

One thing though is that you need to learn how to drive the GT-R on the highway. For a long time, I piddled about at 90kph on cruise, simply because I could not get the car to run at a constant speed above that without shuffling. I literally did not know how to drive the car at other than wide open throttle on the highway. So I'd surge at high power, then coast, then pull hard, and coast.

I've now learned to "pulse" power; give it some beans then let off, repeat, always trying to keep the throttles either closed or open enough to avoid shuffle. It can be done enough in 5th gear to avoid big changes in speed.

But the twin turbo pipe mod (search, there's a big thread on it here), and a remap of the 3000-4000rpm zone of your ECU will sort it permanently. And the bigger the (twin) turbos you fit, the worse turbo shuffle is.
 
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