Board logo

busa diff help needed
joni - 16/6/12 at 08:50 AM

Hi iam building a westfield seiw at the min it will be for sprints and hillclimbs not for road use
thing is what diff to use eather the ford one or the freelander can any one help

the car will be running on 13" wheels and a hayabusa engine so the question is....... freelander with what c.w.p or
ford with what c.w.p


thanks for any help joni

phelpsa - 16/6/12 at 08:57 AM

Freelander diffs only have one ratio IIRC, 3.21:1.

I would be using a 7" sierra 3.38:1 if you plan on using slicks at any point. If you plan on going 250+bhp on slicks you will probably want to look at the 7.5" diff.

joni - 16/6/12 at 09:02 AM

what car is the 3.38 out of and are they easy got

phelpsa - 16/6/12 at 09:16 AM

quote:
Originally posted by joni
what car is the 3.38 out of and are they easy got


I'm not sure (auto springs to mind?) and not really. Give Road and Race Transmissions a call (http://www.ikent.co.uk/profile/233087/Sevenoaks/Road-and-Race-Transmissions/) and see what they have would be my advice.

joni - 16/6/12 at 09:20 AM

do some people use the 3.14 cwp in there busas

phelpsa - 16/6/12 at 10:05 AM

quote:
Originally posted by joni
do some people use the 3.14 cwp in there busas


Not very often for speed events. But it depends on what diameter tyres you are using.

[Edited on 16-6-12 by phelpsa]

joni - 16/6/12 at 11:24 AM

i take it your car is for sprints and hillclimbs do you use the atb or just the cossie lsd with the 3.38 cwp

phelpsa - 16/6/12 at 11:34 AM

quote:
Originally posted by joni
i take it your car is for sprints and hillclimbs do you use the atb or just the cossie lsd with the 3.38 cwp


I actually use a 3.62:1 with viscous LSD and 20" diameter slicks as the GSXR1100 gearing is very different to the hayabusa. However from my research when I was looking at diff ratios I found that most of the hayabusa engined cars were running 3.38:1 CWPs transfered onto a viscous LSD (or a plate style LSD), and 22" diameter rear slicks.

R&RT built mine with a good 2nd hand CWP and viscous unit and all new bearings etc using my casing for a little under £400. They had all sorts of ratios and diff units in their stores, so its worth giving them a ring.

parkiboy - 16/6/12 at 12:16 PM

i've been doing alot of research about this lately and still havent come up with a solid answer as it all seems to be a matter of personal preference.

My car is running a 3.14 diff and i was wondering if it was the right diff for me but after the IVA only time will tell i suppose!

parkiboy - 16/6/12 at 12:16 PM

*Double Post*

[Edited on 16/6/12 by parkiboy]

Nick DV - 16/6/12 at 12:38 PM

quote:
Originally posted by parkiboy
i've been doing alot of research about this lately and still havent come up with a solid answer as it all seems to be a matter of personal preference.

My car is running a 3.14 diff and i was wondering if it was the right diff for me but after the IVA only time will tell i suppose!


I'd keep the 3.14 as it's ideal for the car, and they are like rocking horse pooh!!

Cheers, Nick

joni - 16/6/12 at 05:00 PM

tis yours a road car iam realy looking to find out about hillclimb and sprint cars mine wont be on the road

parkiboy - 16/6/12 at 05:38 PM

Yes mines a road car from what I've read people favour the 3.14 for track day for the top speed on the straights but if that's not what your after ther 3.38 or 3.62 should be fine as you will get better acceleration but less top speed, although I'm not an expert this is just what I've read over the last couple of days.

joni - 16/6/12 at 06:24 PM

yea i think iam going to have to suck it and see

Eatpies99 - 16/6/12 at 08:03 PM

mines got a 3.38 in.

joni - 16/6/12 at 09:11 PM

quote:
Originally posted by Eatpies99
mines got a 3.38 in.

"

is yours a sprint car running on 13" wheels mate

Eatpies99 - 16/6/12 at 10:28 PM

afraid not my friend. road car on 15's. Still building at min.

Custardpants - 18/6/12 at 10:52 PM

I'd go for a 3.38. I have the 3.62 and run out of gears on most tracks other than cadwell. Solely for sprints the 3.62 would be okay on 13s with 60 profile Tyres.

skippad - 19/6/12 at 07:40 AM

I'm running a 1400 zzr which has very similar gear ratios, i originaly had a 3.62 lsd which was just manic, running out off puff in every gear and 118mph tops.
I changed to a hybrid 3.14 lsd (3.62 lsd with 3.14 crown) which a transmission company did for me.
Great for road 130mph + (private road) but not ideal for track or sprints, needed a bit more punch out of corners!
Ive been looking for a 3.38, missed a few bargains on ebay!