Supercar Diff's?

[sihorton]

I'm at the point now where i'm just about ready to sort the diff's for the impreza i'm building, but the options out there are mind blowing.

So, for the people in the know...

What sort of diffs tend to be used at the front and rear on supercar / div1 and do many people use a viscous central diff (need to replace the electronic central diff sti scoobys usually have)

I know a lot of drivers keep the transmission details to themselves, but any insight as to what is used in rallycross would be helpful as this is a whole new ball game to me

si

[subaru man]

it all depends on what type of gear box you are going to use i have broke loads with big hp subaru engins

[sihorton]

I'm going to be running a PPG 5 speed straight cut dog box.

[chunder]

Sell your kidneys then go and speak to Quaife!!

[subaru man]

what gearbox caseing version 3 /5 or the 6 speed with the five speed kit ??
its all down to bhp the 6 speed caseing allows for the fitting of bigger gears and diffs. what year is the doner car?

[rx-guru]

http://www.schanche.com/

People in the know? Have a word with him!

[sihorton]

Originally Posted by subaru man

what gearbox caseing version 3 /5 or the 6 speed with the five speed kit ??

Kit is going into a early box. Had the option on the 6 speed, but they are 40kg heavier which isn't a proplem for stage rallying, but makes a big difference in rallycross. Spoke to ppg and other uk gearbox specialists in detail about what i was doing and they all recommended the earlier box due to weight and all suggested the straight cut ppg to take the power.
Rear will be a plated r180 diff, just deciding on manufacturer. Shafts are going to be GKN motorsport.

I think i might not have made the question clear in the first place, what i was ment to ask is if people run 1.5 or 2 way diffs and if they are mechanical or viscous in rallycross. Also on the centre, do people tend to use a neutral 50/50 or a split like 40/60?

[subaru man]

an sti ra in road going spec is 1250 kg so the extra 40kg for the six speed should not be a problem. what is the weight limit in rallycross ?? . i think you should find out the weight of your car and then make your mind up . what are the other subarus useing in rallycross. i used gkn shafts with 600 bhp and they will break on hard starts on a subaru .

[sihorton]

upto 2000cc the min weight limit is just 930kg!! and even 2500cc is 1030kg.

I know the impreza wont be that light, but adding an extra 40kg isn't really what you want to be doing.

Not sure on McCann's box, but Van Mechelen uses a kaps sql box (but thats budget i wish i had )

Glad too hear someone else using GKN shafts at that power.

[WJM]

Originally Posted by sihorton

upto 2000cc the min weight limit is just 930kg!! and even 2500cc is 1030kg.

Won't you use a turbo engine?

[M.Lowe]

Si, contact ex prodrive man Martyn Spurrell
http://www.autosportif.co.uk/

[mivec]

Originally Posted by sihorton

upto 2000cc the min weight limit is just 930kg!! and even 2500cc is 1030kg.

I know the impreza wont be that light, but adding an extra 40kg isn't really what you want to be doing.

Not sure on McCann's box, but Van Mechelen uses a kaps sql box (but thats budget i wish i had )

Glad too hear someone else using GKN shafts at that power.

Is Division I not maximum 2000cc with Turbo? (If you would like to go ERC)

Think Van Mechelen uses a normal gearbox with a system called "SEQSHIFT" that looks like a sequential box. You shift like a sequential, but it is just a normal box. It work with plates around the gear lever and... not easy in English, so take a look here.
Jan Huybs with the Mitsubishi Lancer uses the same system.

[rx-guru]

Originally Posted by mivec

Is Division I not maximum 2000cc with Turbo? (If you would like to go ERC)

Current FIA rules:
3.7 Supercharged engines (Division 1 only)
For supercharged engines of Division 1 cars, the maximum
cylinder capacity authorised is 2058 cm3 for petrol engines and
2333 cm3 for diesel engines.