R32 Gtr Surging Torque Gauge Needle Help Please

[Muffa180]

Hello,

I have recently purchased an R32GTR and at very slight throttle cruising at 100-120 the car surges and when it surges the torque gauge bounces very slightly from what looks like 3% to 5% My vaccuum reads about 2-4 inches of mercurywhen this is happening.

Also at cruise in a GTR is 2 to 5 InHg of vaccuum correct. I have owned 3 previous skylines all gtst's and 2 180's and at cruise they have all read 10-15 inches at 100-120 kmh. Is there that much diff between the RB25 and RB26.

Thanx in advance. Michael...

[heller44]

What is the rolling diameter of your tyres like front to back.. ie are your front tyres new compared to the back, different brand, different size?

attessa will be happier if you have the largest rolling diameter on the back. otherwise you will get surge, as it sees the rears turning faster than the fronts and thinks 'wheelspin whoopie'.

vacuum sounds about right, less than I expected as well.

[Muffa180]

I have 255 40 17 on rear and 235 45 17 on front. The surging isnt there when the vehicle is cold and its not there when the car has warmed up either unless i have accelerated hard. It seems to surge alot more after my first initial hard acceleration. If i am very easy on the throttle the whole time i drive the car it will hardly surge after i boot it. it starts surging. I have bled the system which made it slightly better but now my torque gauge reads at about 8 when cruising at 110 where as before i had any surging problems the gauge only read between 3 and 5. Any ideas.

Thanx Michael...

[NXTIME]

Your rear tyres have a smaller rolling diameter at the back compared to the front - that is probably one reason why this is happening. With more tyre wear on the rear, I would say there is at least 1% difference in front to rear tyre speed.

[heller44]

That may not sound like much, but considering that mine was doing the same with 235/45/17's all round, but old ones on the back and new ones on the front, it doesn't take much.

[Angus Smart]

pull out fuse untill you can afford to buy the right tyres

but beware of loss of traction.

shouldnt a gtr have the same tyre/wheel size/width the whole way round?