[Mgs] Welded rear axle? Need advice

[Dodd, Kelvin]

Matt:

I can't think of too many things that would be more fun to do.

I am not an expert, so I'm open to over ride. From the little experience
I've had with welded rear axles, they don't seem to be the best setup
for Auto X. You will have enough power to light up the tires, so it is
an option, but spinning the tires to get the car to go round tight auto
x turns then trying to get bite out of the turn is a tricky technique.
Any chance of swapping in a cheap (used) limited slip rear end from
something?
Welded rears are most effective when you have a little bit more time to
get the back end wrung out in the correct direction. I learnt this when
the pro rally car I was co-driving drove head on into a fence post
because the driver hadn't had a chance to get the back end of the car
around in time.

I'd also suggest checking out the back issues of GRM to see what luck
others have had on the challenge with welded rears. The combination of
drag race and autox makes it important to get a balance.

Kelvin. FWIW


> -----Original Message-----
> From: mgs-bounces+doddk=mossmotors.com at autox.team.net
> [mailto:mgs-bounces+doddk=mossmotors.com at autox.team.net] On
> Behalf Of Matt Trebelhorn
> Sent: Thursday, November 08, 2007 12:47 PM
> To: MG List
> Subject: [Mgs] Welded rear axle? Need advice
>
> No MG content, so apologies in advance.
>
> I'm part of a team (loosely speaking) building a car for an
> event called the GRM $2008 Challenge.  GRM is a magazine,
> $2008 is the budget.
>
> The challenge itself is in three parts: concours, autocross,
> and drag race.  Looks like a fun event, so we're giving it a try.
>
> Partly for oddball-value, partly because we found one cheap,
> we're building a 1978 Toyota Corona.  Front engine/rear
> drive, 4-door, double wishbone front, rear axle on leaf
> springs.  Hoping for a final weight around #2300.  We're
> using a turbocharged volvo 4-banger -- because the guy who's
> the real motivating force behind the team has experience
> building them up.  Shooting for 225-250hp.  15x7 wheels, r-
> compund tires.
>
> I'm the only one on the team who's ever autocrossed (or
> driven at a track day), so I'm pretty much in charge of
> trying to get it to handle.  The fly in the ointment is that,
> because we're doing a dirt- cheap drag racer, we're welding
> the axle solid.  Never having driven such a beast, I'm not
> sure how to go about setting the car up for it, or what to
> expect first time out.  It might move under its own power
> this fall, but I doubt it -- we're aiming to test and tune at
> an autox event in late March.
>
> What to expect, and how to make it work?  Assuming the car
> starts out understeering, I'm guessing that the axle will
> make it worse...put a big sway bar on the back to balance it,
> or just drive like a hooligan and try to steer with the gas?
> I'd rather not do that too much, as it will eat up the tire budget!
>
> So: what advice can you give?  Other than, you know,
> suggesting more productive things to do with my time ;-)
>
> Thanks
> Matt