Will a 2.95 FD work well with Straight Cut Gear Ratios
Turbo Mini Forums

I have built a 1293cc supercharged engine, aprox 150 bhp and 140 pd/ft torque. I have a 2.95 diff and 10 inch wheels which a few people on here seem to favour. I am considering changing my gearbox to SC CR:
Has anybody tried this ratio set up. What will the acceleration be like with a straight cut 1st gear ratio and a 2.95 FD. Will it help acceleration due to less wheel spin? Or will it be impossible to get off the line? Cheers

Daz

mines fine with the same setup but a 3.1 diff, i'm pretty sure MW uses a 2.9 diff in his aswell.

Edited by Nick on 10th Nov, 2006.

Benross on here uses the same setup, I've driven his car a few times and it works well in my opinion, setting off up a steep hill probably would be a bit tricky but other than that the longer gears suit the torque of a forced induction engine well. I've also got the same gear setup in my own car, but I've not driven it yet as the rest of the car isn't finished.

like to add tom, mines on 13s with 50 tyres

10s in my opinion is perfect!

Used a 3.44 last time, was thinking of a 3.2 this time but decided to stick with the 3.44. Since you have a wide power band, you may as well stick with wide ratios and have the benefits of a good take off gear and a good top speed. I was under the impression a mini would be good going about 115 final speed but it's just a waste of energy, leave it at 100 but get there bloody fast. Use a 3.44 and a close set. In my opinion, a huge wide power curve suits a spread ratio box more, for the road.

1293/bini blower/etc/in bits again

Bugger off, I'm getting there.

Thanks for the useful info. Are you guys who are having success with 2.95 diffs and straight cuts using milder cams, eg phase 2, 266, mg metro etc. I should have mentioned that my cam is a 544 (1.3 rockers). Not a popular choice for this aplication however Stuart at VmaxScart says the cam will work with his supercharger kit. I think it may be just too much for the 2.9 diff and sc cr gearbox though?

the 2.9 will be fine but as said getting of the line is a tad slow, but from 10mph to a ton will be bloody rapid, i makes full use of the torque you have, plus yours will be even better as you have a super charger not a turbo.

always looking for them bigger bunches of bannanas

This is good to read because this is the same setup as im building and i was unsure of how well it would work.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

So a 544, that's 286/286 isn't it? I would have thought it would be a bit of a clutch burner to pull off in.

Pointless talking about boost, how overdriven is your blower? Pulley ratios?

Bugger off, I'm getting there.

Good question. My Kent 544 is quoted as 274 degrees (quoted at a checking height of 0.4mm) duration on Kents website. A BMC 544 should be 288/288. I'm trying to get to the bottom of the discrepancy. The last time the cam was used was in a 1380 NA. It was very drivable so I'm hoping it will work with the Supercharger.
I think Stuart at Vmaxscart said I'll be running 8psi when it's finished. The CR will be 8:1

it's because your checking it at .4mm, 288 will be the seat timing.

There are a few SPI cams on ebay for pennies, I reckon they are the ticket for about 8 Psi. Either that or a PH2. That's my well thought out hunch

Bugger off, I'm getting there.

I prefer the longer gearing with a blown motor, usually 3.1:1 or 3.2:1. Nat asp I like 3.44:1

Not a fan of 10" wheels, never have been so I run either 175/50/13 or 165/60/12's with those FD.

For a road car anything that incourages you to light it up of the line is very bad IMHO as it's that sort of behaviour that murders gearboxes. You'll have enough torque to murder most hot hatches and even some of the bigger stuff too.

Every day is a school day ...........

How fast and how expensive ...... the same question...