I'm changing to R1 power!

[twcullen]

As title says. However my diff at present is a 3.89, should I be changing this? If so what to and where can I get one from? Can I get a slippy diff? Got a live axle Westfield by the way!

[Tim.C]

Which model R1 - will make a difference. What do you intend to use the car for etc etc?

[Furyblade_Lee]

My 2003 inj R1 has a 3.38 diff i believe? Think it is a regular Sierra ratio, but has been retro fitted with the LSD from an XR4x4. 3.89 is way too low really, probobly give you about 110mph top speed!

[LocoBlade]

Ive got an 03 R1 in a live axle'd Locost and unless you're only hillclimbing it or are prepared for a proper ear bashing at road cruising speeds, Id suggest finding a 3.54 diff which is the highest available for the Escort "English" axle (Im assing that's what you have?). That will give you about 120-125mph top end depending on tyre size, the 3.89 will be a good 10-15mph less than that which will limit you on track a bit and man you'll be forever changing gear.

As to getting an LSD, because of all the Rally heritage of the Escort, there's plenty of options but personally I went for a Quaife ATB, which is fit and forget, doesn't make any noticable noise, and is probably the cheapest option at about £400. There are small theoretical performance disadvantages with the torque biasing diffs like the Quaiffe over plate diffs (do a search) but they're pretty much irrelevent to road / track driving in a Locaterfield IMHO as its only when you lift one wheel significantly that it becomes an open diff momentarily.

Edited by LocoBlade on Thursday 20th December 18:03

[robcollingridge]

Some stuff to help you decide here:
http://www.robcollingridge.com/kitcar/design/trans...

There are some spreadsheets you can plug diff ratios and wheel sizes into.

I'm running a Fisher Fury with a 2003 R1 and a 3.38 Sierra diff. Damn fast and 130mph at max rpm in 6th.

[Furyblade_Lee]

Sorry, Live Axle or Sierra IRS? As stated, English axle means 3.54 is the best one you can get. It is an RS2000 item. Sierra is the 3.38. IRS cars can go to a Freelander diff, even taller, but it is £1,000 with a quaife ATB and may take the "edge" off the acceleraition. And it can give about 150mph top speed with big wheels, which is a bit irrelevant on the the roads and most UK circuits bar about 3.