2.9 diff
Turbo Mini Forums

hi just wandering if anybody has any probs with a diff ratio this tall (on 10's) i think it will be ok but am planning on running a t2 with 18cc pistons and a 30cc head t compensate for off boost driveability, what dya reckon?

I like the feeling this diff give on turbo engines, 3.21 is a litle short, 3.1 slightly better, 2.9 is good
qu: 18 cc piston + 30 in head?? do you'll run 30psi of boost?
fab

Turbo dave has a 2.95 I sent it to him

Metro turbo weekend driver,Mini turbo in the making again!

gav have you calculated your CR properly matey? As I have a 27.5cc head and 15cc pistons, my CR is 8.08:1 on paper. When taking measurements such as piston to deck height when building the engine, this CR drops to something around 7.9:1.

With a 30cc head and 18cc pistons you are down to 7.32:1 before you have taken into account dceck height and ring land volume etc.

If you've already got the parts then you are stuck I suppose, but if not think carefully about if you really need that much volume from your head and/or pistons, as 7.3:1 CR is going to make the engine VERY sluggish off boost.

Edited by Tom Fenton on 10th Jul, 2005.

cheers i'll go for 15cc omegas insted then

15cc Pistons and 30cc head gives 7.72:1 CR.

I'm not sure, but maybe it is more cost effective to go for a smaller chamber head than 30cc? As I am guessing the more work needed to extract those extra cc's bumps the price of the head up? And then get the CR you want from the piston dish?
Up to you to decide I suppose!

got the head already from sauber so cant change that lol only the pistons, think he used 18 and 15 cc dish and found the 15cc better for driveability so i'll prob go for that, pretty sure he had 200 bhp with that so should do me fine! : )

don't think TD is running a 2.9.

I am it's a great diff for motorway work.

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com

I'm not currently running a 2,95 - but that doesn't mean I won't be running one at some point!

2.9 does work well especially on the motorways, just a bit of a trick to get of the line a santa or avon.

always looking for them bigger bunches of bannanas

same here wolfie

always looking for them bigger bunches of bannanas

and here

Best 1/4 mile 13.2 seconds @116 mph
First 5 port miniturbo to make over 200 bhp on a carb?
First 5 port miniturbo to make over 200 bhp on Injection?

http://www.mattwoodsphotography.com