Since an LSD seems out of reach right now I'm wondering what people think of locked/welded diffs. I've heard they tend to cause understeer at low speeds. Maybe the trick is to keep it a little sideways around the turns?

weld it up they are great fun

on a 1200? talk to bobs1200. he's a dedicated autox guy from bay area

yeah locked diffs are fun, however for reliability on a stock 1200 H145 setup Id recommend the open diff option.Eventually you WILL break an axle. If you install a ute diff feel free to lock it as they are alot stronger for this type of work. Id also go for a 4.11 ratio 3.9 is a bit too tall

I would say if wheelspin is a problem with an open diff then go the locker, but otherwise stick with the open

My dad used to do oval-track racing, and they always locked the diff, because of wheelspin. They would then put the car in a proper 4 wheel drift, and maintain a much higher speed through the turns. A proper 4 wheel drift is where you are still going around the turn/bend, but with your wheels facing slightly in the way you are going, no counter steer, then it doesn't count...

Not like this new drifting thing where you have to counter steer to keep from wiping out. It looks far more spectacular, but it much slower.

If you are gonna be making left & right turns with a locked diff. then make sure you have no stagger on the outer circunfrence of your tires. in the rear, because if you do then the one that is smaller will turn more revolutions than the bigger one = bad handling.

Unless you have a fairly stout motor do not weld up the spider gears to create a locker. Lockers work great for oval track because you can run stagger (smaller inside wheel).
The car will understeer with the locked rear end and given how tight some of the hairpins at autocross are you WILL be hating life. (some of the courses are tight for my son's Jr Kart) I've driven some open wheel cars with locked rear ends on road courses and the same class of car with a LSD and the handling differance is worth every penny.
An easy way to tell what to do is , get one of the more experianced/faster guys to drive your car, if they go faster then the car has more speed just the way it is..........personally save your pennies for a LSD and deal with the car in the meantime.
I should have asked first but what class are you running H-stock , DSP or EP??

Tom

It would be running in street prepared class. It looks like the 1200 is in FSP now according to the moutons SCCA site.

What class/setup are you running?

The only time locked diffs are fast is when you have huge amounts of power. With lower power setups the open diff is the winner.

Locked diffs also give your car a Jekel and Hyde personality. At lower cornering forces the car understeers like crazy. As the cornering force increases you reach a point when the weight transfer causes the inside wheel to loose most of it's grip. At this point the car switches to oversteer. Basically your car will understeer or oversteer.

Locked diffs are lots of fun but can be slower with a lower power car.

One mod I did years ago (and just receintly too) is to shorten the radius rods and pull the front wheels forward. 3 things are gained with this mod. 2 big gains and a small gain...

Big gains-
1. Wheels forward shifts weight to the rear.
2. Pulling wheels forward increases the castor (think dynamic camber).

The increased camber from the castor during turns will increase the grip of the front. This allows you to reduce the roll stiffness of the rear suspension or increase the front roll stiffness of the suspension tuning. Either one will help keep more load on the inside rear wheel helping the wheel spin issue.

Small gain-
Increasing the angle of the strut away from vertical increases the rotational antidive of the front suspensioin which can help breaking a bit.