mark kibort

rev limiter is accurate
mathematics is accurate

just take a 26" tire and work it through a ratio of 3.2:1. for 4th and 6600rpm

visually, the tachs are not that accurate but the redline cut out is. speedos are not accurate either,as by putting on 26" diameter tires, it became accurate. the tach from the dyno is accuate usually.

the speeds for a 2.2 are 50, 80 , 118, 155mph.
take these speeds and just take 9 or 10% off for the 2.64 gear box and 14% v the 2.72 (those differences are listed in the gear ratio comparison posted.)

interestingly, i have increased the diameter of the tires to be 26.5" for on set i use, and thats another 7.5% talller rear end ratio equiv. why does it contiue to not have any adverse effect? because in some cases, it optimizes the gears to the speeds and Max hp engine RPM. so, in other words, i have changed the stock diameter of 24.5" to 26.5, which is very close to the difference of the 2.64 gear box to the 2.2 gear box (9%) and not only am i taller using the same tire diameters, i double it and make it even taller! still there is no real noticble difference . but then again, why would there be!

Mk

GlenL

Sure, tire height affects odometer speed but this official chart reflects my experience: redline in 5th in my Euro S is 180MPH.

mark kibort

[not really, tire height doesnt change speedo or odometer speed. they are fixed to your car's set up and they dont know what tires you are using.
now the question is, how fast are you really going.

GlenL

****, Mark. It changes the way the actual speed is measured.

Redline in my Euro S is close to 180 and is not close to 160. That's my experience and that's what the owners manual says.

Mail me your GPS system and I'll give it a run. Otherwise, accept the facts as presented.

mark kibort

well, if you have stock tires at 24.5", and you are running 6700rpm, the that is 177mph, so the chart looks good to me.
again, its simple math to check.