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Im after some info on peoples change's in top speeds when they changed there diff ratio.
so what did you find when you went from 3-9 to 4-1???
I've been doing a lot of calculations but im after some real info

Thanks Chris

Edited by Chris Dillow on 26th Feb, 2013.

In short chris, a decrease in top speed and you engine reving its tits off..

can you give us some spec of your motor and wheel size, tyres and what you want the car for road, track or both ?
turbo or N/A ?

1293, 320 cam webber 45 rediculess head force 13" wheels with 175/50r13 yoko a0's

Or is it a 310 cam.? I have your mini mag feature in a moving box atm normally to hand

- 120mph 4th @ 8000rpm with a 3.9 70mph about 4500rpm
- 115mph 4th @ 8000rpm with a 4.1 70mph about 4800rpm
- 111mph 4th @ 8000rpm with a 4.2 70mph about 5050rpm

Edited by Paul R on 26th Feb, 2013.

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Yes Paul it's 310
Well I'm crossing the line at 93-94 @6500ish with 4.1 std 1.1 drops i want to go lower to use peak power @ 7300
If I go 4.1 with 1.04 drops 7500 will be 99.22mph but that's IF the car revs that much, further by dropping the ratio???

Edited by Chris Dillow on 26th Feb, 2013.

Whats your max revs?

Ill answer the next bit for you lol

4.350:1 7500 rpm is 102mph peak power at 97.something mph
Cooper s option ratio

Edited by Paul R on 26th Feb, 2013.

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Carry on Paul. Peak power is 7300 but I can rev it to 8

7320rpm is 99mph

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Yes but will the car be able to get to 7300 in 1/4 that's the question

Yes.

Other option

1.1364:1 drops
4.267 fd
185/60 r13 tyres
7300rpm roughly 95mph

Edited by Paul R on 26th Feb, 2013.

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

I like your optimism

No goals then no wins. Can get your goals bigger tyres and more power is the solution. Dont give up keep tying also read above

Edited by Paul R on 26th Feb, 2013.

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

You should try a 4.9 cwp,
101 mph at 9000 rpm over the line on the strip with some gas,
94 mph @ 8400 without ,all this was a long time ago,lol

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

whats the bhp ? chris

130 baldwins

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

so thats about 100 bhp then, i took my grandaughters dolls pram out of the boot placed it on peters rollers and it made 3 bhp with her pushing it ........ lol

seriously place a 3.6 in there, and i would opt for the 649 cam to go with the diff change

well that sounds like a step backwards....

joe
if you look at the peak torque & hp of the 649 in combination, with that diff, it will nicley shove the car over the line faster

Ok 4.1 with 1.04 drops it is then

Chris, you want to end up with 4.2 fd

I seriously doubt it!

To put another view on this. The lower your FD, the higher wheel torque you have. Seems obvious as that's why we have gears.

To optimise your speed you want to have an FD that allows you to cross the line at maximum rpm. as you are in 4th at high speed, I'd use the max power rpm rather than the 'it will rev to' figure.


So I'd go with the 4.2. this will give 101 mph at 7300rpm. the lower the better.

My car used to cross the line at 7500rpm and 104mph(ish). with the extra power I have I hit the rev limiter at 7.5k way before the line.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

thats alvery well assuming the 649 is better than his existing cam... which i dont think it is.

Thanks Wil that's the sort of figures is was after.
Ill be sticking to the 310 thanks

if you want to sell the 1:1 drops.....and send them to holland..i'm your guy!!!

greetz bas