explore

heres one for you all say your scoobys top speed is 144 how do you increase that?

highlander68k

- Change the gearing or final drive.
- Fit a wheel/tyre package with a larger diameter
- Increase the rev limit

explore

thanks mate its just something i have always wanted to know.

harvey

iTrader: (48)

You need to change to 3.9 diffs and a box with .738 top gear in place of .825 you probably have now.
Taller tyres will also help. 205 50 16 are taller than 215 40 17. 215 55 16 are taller still.
If you have 4.44 difs then 4.11s would be an intermediate increase.
What is your gearbox number??? TY752??? and I can give you some calculations.

harvey

iTrader: (48)

P.S. Typically with a 7k rev limit, 205 50 16 tyres, .825 top and 4.11 diff, your true speed is 137 mph despite the speedo reading 146ish.

C 8HEP

i have a v limited RA version 2 with a top speed of 143 @7750rpm rev limiter. i put gps on it the other day and it is spot on. i got upto 130mph on speedo and gps said 130mph. are you saying that it isnt a 4.11 diff because it is all accurate? (205 50 16)


my dads 22b is 8mph out @ 80mph!!


thanks

highlander68k

C 8HEP - were you driving at a constant speed of 130mph when you took the readings?

I'm very dubious about taking speed readings from GPS systems due to nature of how they work.

Just for the record, my previous top speed with a reading of 153 mph on the clock gave me a timing gear reading of 142mph - A 6-8% difference in readings was pretty much consistent with the other Impreza runners.

Trouble is now, I don't have a clue what's been put in the box even though I was told it was exactly the same - it doesn't have the same top end as it used to before the rebuild.

C 8HEP

yes it was constant. all speeds and the highest i managed was 130mph.

i would be a bit upset to change something identicle then find out its different.shame that the only was you really find out is when its too late

i understand that maybe all speedos are out a few % especially imported scoobies and especially with different mph/km paper for speedo. as i say my dads 22b was out 8mph by 80mph and mines still spot on at 130mph. when he was behind me along motorway he said we were doing 150mph and i replied mine doesnt go that fast. my mate followed me and said we were doing 145(uk scooby) along a motorway and again i replied my car doesnt do 145 mph. therefore i think i am lucky that my car is that accurate and i do trust globa positioning satalite as i have no reason not too.

harvey

iTrader: (48)

Also wheel and tyre size for accurate calculation.