I have the 1.04; I think for my car with the 525hp motor I wouldn’t want to go much more than this. With the current gearing I’ll say this - I wouldn’t want more hp, but I wouldn’t want less either. The gear change is going to make the car feel a bit slower so I’m a bit bummed I’ll be losing out on some of that torque so I don’t want to go too far. Cruising speed with 1.04 is going to put me at about 2500rpm, very livable.
The issue with this trans is all 6 gears are so tightly spaced. There’s no overdrive gear. So while I would like to have a better ratio for highway, I definitely don’t want to sacrifice gears 1-5 just so 6 works better. I think the 1.04 is the right compromise for me.
With more hp it might nudge you closer to the .903 but I suspect your car will be heavier which points to the 1.04. Safest bet would be to go with the 1.04 - highway speeds in Canada are lower and your engine speed at 110-120 kph will be very livable with the 1.04. If you’re going faster than 120kph then you won’t care how loud things are anyway
Maybe ping Granville for his thoughts. I think he’s about 750hp, has a heavy stereo, and has the 1.04 gear ratio in his Graz.
My main desire to re-gear isn’t necessarily for fuel economy or because the engine is being stressed at 3300rpm - it’s the noise. Engine and exhaust noise at 3300rpm are a bit much for a multi-hour drive. Then again my drive up to LA a few weeks ago went just fine while I was wearing noise canceling headphones
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Fuel efficiency was about 15mpg with the occasional high speed squirt and AC running. Cruising speed was about 80mph otherwise.
Edit - I forgot, this is going into the GTR. I don’t know what the weights are on those.
