gilwong

Referring to the Transmission diagram in the Owner's Manual, in 5th gear you should do 100 mph at 3800 rpm and 170 mph at 6500 rpm. Don't think the stock 951 has enough horsepower to pull redline in 5th gear.

mochman

a touch over 160 with my '86 140-150 a lot of times with my ex-f#$&^n biatch in the car god I hate her

Bengt Sweden

Here you can see what speed you can reach on stock tire sizes at different rpm. Since many run with 50-100% more power than stock I would believe that reaching 7000rpm in topg gear is feasible with those cars.

badass951

I have not had the chance to read this whole thread, but I just wanted to say that Promotion Racing claims that his cars will all do a top speed of 172 mph exactly. He has definitely driven them this fast before. Sounds about right to me.

hosrom_951

Bengt Sweden: That diagram perfectly fits my car, i hit ~265kms/hr at ~6,300rpm

lleroyb

I notice the diagram is for 225/50 16 tires. My '89 has 245/45s in the rear. I wonder if the lower profile results in a slightly smaller diameter??

gilwong

If you are running 245/45/16 your tire's diameter is 24.681 inches versus the stock 24.858 inches. This is about a 0.7% difference (smaller).

theedge

The width and the profile are directly related, as the post above shows, wider tire with less profile is nearly the same.

If it was a 245/50 then it would be a lot different.