ok i did the math my car accidently hit 7900 racing some loud *** turboed hatchback one night.... it came out to about 139ish or so... i have 17s that are only0.4 off.. at 60 thts 60.2mph actual. my speedometer i know is off.. it seems to lag after 90 or so.... i have gone through this thing with my sense of speed not feeling right.. my car runs fine at 13.5 lbs on a stage 3 bnr. so whats all this blabbing about .. i think somethings screwy i dont believe think wind effects the gearing at all.. even with a 200 mph headwind the car should still be the same speed going 4th gear at 7000rpm should be the same as 130mph with no headwind...just would take an assload more hp to get it there but the gearing would be the same and ground speed wouldnt change... my clutch is not slipping i dont smell a thing. it just feels slow sometimes when im in 4th gear shifting up to 5th (running out of rpm in 4th) that im not going as fast. i was just barely walking past that honda at 7900 rpm. i asked them how fast do they think we were going ..it wasnt near 139.. im done this is giving me a headache..and probably giving you all one too.. so the bottom line wahtever speed i calculate for my gears is the actual spped im traveling right?... (alot of blah blah to say one thing huh?)

 

First off, what kind of tach are you using? Did it sound like 8000 grand to you? Maybe you got differant rear. If you got a NA tranny the 4th to 5th jump is quite abit larger than a T2. It is basicly overdriven from the other 4 gears.

 

Maybe it just felt faster before.

 

speedo calibration at that speed is probably way off and I know my tach can be wrong as well so unless you had an aftermarket tach we can't really do the math.

 

+1

 

7900rpm in 4th works out at 140mph with your tires. If you weren't in 4th, your speedo's broke.

 

You need to buy or borrow a GPS unit.
You get absolutly accurate speed updated every second.
I have an old DeLorme Earth Mate plugged into a laptop.