Cross Pin Diff
Turbo Mini Forums

Where's the best place to get a decent diff for my car? I've heard a lot about the minispares one, but was wondering what everyone's preferences were. Plus i'm on a tight budget, and this is one of the more expensive items on the 'to buy' list.

Intended car spec:
998 block, standard pistons, crank shaft etc
Cooper (12G295) head, standard rockers
T2 with mirage manifolds

i was only planning to run a small amount of boost due to the standard block, so i'm not expecting huge power figures.

Also intend to be able to use it on the motorway without it binge drinking, so was thinking a long FD (2.7/2.9) so i can sit on the motorway off boost?

Thoughts/Improvement welcome, as I'm just learning all this as i go along.

Edited by Mike-998 on 9th Feb, 2012.

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

If you search on here you will find that pretty much the unanimous opinion is that the minispared diff is the one to have.

IMHO it should be the first thing you do before putting more than standard power through your gearbox.

If something is worth doing, it's worth doing half of.

Okay, I'll just have to save a bit more then.

What about final drive though? Will either 2.7/2.9 allow me to do 70 in 4th off boost?

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

On Boost/Off Boost depends how hard you press the pedal. a 2.7/2.95 would mean rpm around 3300-3700.

If something is worth doing, it's worth doing half of.

Oh right? I thought it was determined by the amount of air going through the turbine? Which with my current FD would mean about 4000ish rpm at motorway speeds, which is a lot of air going through the turbine.

Also, how much will a longer FD affect the acceleration?

Edited by Mike-998 on 9th Feb, 2012.

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

Too many variables to take into account Mike.

Acceleration depends on the power/torque your motor is putting out.

You only make boost when you put load on your engine. Try revving it to 4k in neutral and you will make no boost.

Edited by John on 9th Feb, 2012.

If something is worth doing, it's worth doing half of.

No worries, i guess i'll just stick one in and see what its like, can always decide then.

Ahhhh okay, i guess that kinda makes sense... Looks like i need to do some more reading up..

Thanks for the advice though

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

Think about it like this. 4000rpm no throttle not a lot of airflow.

4000rpm WOT. shed load of airflow.

its about load not rpm. Obviously at a higher rpm stepping on the throttle will result in boost building quicker then a lower rpm.

with a 2.76:1 diff youre looking at 70 at about 3200rpm. 3600 with the 2.9 3800 with the 3.1.

Okay, so there isn't really too much difference between them? I think i'm going to get the 2.76, partly as its one of the cheapest from minisport..

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

You will find it a slug pulling away. I would go for a shorter final drive. It is easy enough to be "off boost" at whatever mph just by using your right foot.

Alright then, seeing as you guys have been doing this a lot longer than i have, i'll take as much advice as i can

When you say shorter, do you mean shorter than 2.76 or shorter than the one i have fitted at the moment?

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

I would not recommend any longer than a 2.95:1 which is what I use.

However.......

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=451816

Edited by Paul S on 9th Feb, 2012.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

The best tip I was given was to visit the guessworks website put in what components you have/want to have and it will tell you a pretty good reading of what speeds to expect in which gears.