Hi all,
I have been browsing and posting for some time on this forum, my intention was to convert my BEC chassis and use a sierra XR4x4 turbo donor car....anyway after seriously looking at the project I decided to abandon my plan and to go with BEC (probably will be early 90's carb'd blade)

anyway

chassis is currently built & welded for live axle configuration (suspension brackets not done yet)

just wondering (at this stage) before it gets too far is there any major benefit in changing the rear end to IRS instead of live axle (weight or otherwise)...
If I did stay live axle whats the best diff/axle combo to go for ?? bearing in mind I would want an LSD...


anyone in the midlands got a jig for lining up the front wishbone mounts I could "borrow"

[Edited on 15/8/05 by 4bturbo]

where abouts in stoke are u?

Phil

p.s. i havnt got jig and i dont think u need irs

am in clayton (newcastle-under-lyme)

r u on msn messenger?

yeh
jay@tech-pc.co.uk

What do you want to use it for? If mostly road use, I would recommend strongly that you go the IRS route as a live axle car (particularly one set up for some track use too) are a bit harsh on the road and don't like the bumps (thats coming from someone who owns such a car!)
If for track use, assuming you're not planning on competing I would probably go for the live axle, I think ultimately you probably get a smidge more grip with IRS, but if Westfields are anything to go by, the limits are easier to find with a live axled car and its more fun on the limit (getting the arse out etc).
IRS does offer you a cheap route for an LSD though, using the viscous sierra unit. If live axle, you'll need something like a Quaife ATB which are ~£400, so nearer £500 by the time youve had it fitted into a CWP.

As for ratios, about the only suitable Mk2 Escort ratio is the 3.54, you can get away with a 3.7 or 3.9 with certain engine/wheel combinations, but it does limit you. Sierra diffs - anything from a 3.6 or below would be OK, most seem to go for a 3.38 or so, or a 3.14 if you can find one / need it for the engine you pick.

thanks for the info, Am intending to use on the road. Track day and possible hillclimb/sprint...

Do you guys go with 13" or 15" wheels?

Either! Good sticky rubber is now more available on 15 inch than it used to be with the help of companies like Toyo. Remember it will affect your gearing.

based on say 15" rims what diff ratio is best to keep an eye out for?
thanks

will probably be sticking with live axle..

about to weld on front chassis brackets this weekend, is it best to mount them to the wishbones and tack as an assembly or weld the brackets loose?

It ultimately depends on the tyres rather than the rims, 195/50-15" tyres are about the same radius as 205/60-13" for example. Both of these are commonly used sizes on BECs, so the choice of diff would be the same for either, ie what I said above pretty much.
If you download this spreadsheet you can put in different engines, diffs, and tyre sizes and see what your speed in the gears will be. Just double check on the rev limits for some of the engines in the "Data" page, Ive filled them in as much as I know but some are guesses.

Chris