weld or not weld diff!!!????

boosted · #1 10-04-2007, 19:43

Recently completed my first track day in silvia (car just for track so not going on road) and it's the first RWD car ive driven without an LSD. And to be frank found it annoying coming out of bends and lighting the inside wheel up. Tried all manor of different driving techniques to eliminate but still losing traction exiting bends.
Have not got the time/cash or patience to do an LSD conversion so spoke to mate of mine who has vast motorsport experience and he said would give excellent drive out of fast bends but would create understeer in hairpins and slower tigter bends.
Having not driven a car with a fixed diff was after some advise from someone that has or done this on a silvia.Don't what to ruin car as apart from this the car performed brilliantly.

Inaddition i can arc weld but where about on diff to weld up and can this be done without removing the diff?

Many thanks
Boosted

30psi · #2 11-04-2007, 01:12

It will create a lot of understeer at the front unfortunately. I was surprised at how bad this was when I drove a friends S12. For drifting though you cant really beat it.

For grip I would avoid it to be honest.

boosted · #3 11-04-2007, 10:07

Cheers mate, think i'll try another trackday as is, prob strap a bag of cement in rear spare tyre well. Whole back end is stripped out so maybe a bit of weight will help with traction. Got worse as i used fuel up throughout day. In the end on a right hander bend after apex i was steering very quickly to left and back to counteract body roll. Seemed to work but i did spin once with that approach!!! HA LOL.

JackieFan · #4 11-04-2007, 11:29

What tyre pressure were you running in the rear? Might be worth trying to drop a few pounds if you're really suffering from inlift. Bear in mind that if you use normal compressed air your pressure will increase by a few pound (depending on the weather). The harder the tyre the less it'll grip for you. I'm not saying it'll cure inlift totally because it won't but it might help to return drive sooner.

The other option is an obvious one but not a much fun, just don't get back on the throttle as quick, wait a fraction of a second later to go wide open and you might carry more speed from apex to exit back by not wasting time waving an inside wheel around

If all that fails then just weld the bastard! At the end of the day it'll be 10 times better than an open jobby and trackday cars should always be setup for a little understeer anyway

Have you got another day booked?

Conkers · #5 11-04-2007, 14:31

I am running a welded diff in my S12, but I also have decent suspension and road legal slicks for track days. I haven't been out on a track with it yet though, so can't comment on just how understeery it will be, but so far the messing around I have done is a good indication that it turns in a treat, and has a lot of grip... in slow corners, roundabouts and junctions it's almost like someone pulled the handbrake on as soon as you turn the steering, this is due to the welded diff... swings and roundabouts really (excuse the pun). a LSD would be a better option for performance road use and occasional track days, but if you want to keep it within a reasonable budget, I would certainly reccomend welding the diff.
The negatives are the scrubbing tyres, and the punishment the driveshafts get whilst turning slowly.... it almost feels more humane to dump the clutch and spin the rear of the car around, rather than letting the inside wheel hop skip and jump around....

I did see a "how to" somewhere on here... and it wasn't difficult, but I would reccomend you to remove the diff, (remove rear axle from the car and the diff cage from the axle housing) clean out the oil, cover the bearings up and then spend a while getting weld spatter off the surrounding area afterwards. I used a mig welder and welded the planet gears to the sun gears, just put the welder on max and blasted the bejeesus out of it...... carefully.... side for side and letting it cool before doing the next bit...

LSD is better for road use, more expensive than welding, but probably not that much more work to fit it.
Welded diff is better for drifting.... and cheaper... pays yer money and makes yer choice....

Mike.

s12Rob · #6 15-04-2007, 17:53

im welding my diff, maily to help me off the line on the 1/4 mile and drifting and have a normall diff for road use.