Welded Diff?



  • Hi, I have built a MX3 grasstracker which if as fast as anything else I race against. The only issue I have is getting off the line better. I have been told that if I weld the diff, it will make a huge difference. I've never done a FWD diff, only ever done RWD. Has any of you guys ever welded the diff, and if so, was it as good as I've been told.
    Thanks



  • I would go for a cheap LSD like a phantom grip, there was one on here going cheap a while ago ?. Think it may have been Barrywhite

    Think with welded diff your get better grip off the line but less cornering grip and possible under steer issues



  • @d80c9d9a8d=Garfy1981:

    I would go for a cheap LSD like a phantom grip, there was one on here going cheap a while ago ?. Think it may have been Barrywhite

    Think with welded diff your get better grip off the line but less cornering grip and possible under steer issues

    Thanks for the quick reply, I did wonder about the possibility of a understeer issue



  • I've never heard of a welded diff being tried on a mx3. It would be interesting to see the results of a comparison if you have a spare box and the time / skills to keep removing and re fitting



  • Wouldn't a welded diff on FWD cause incredibly terrible understeer though? I know the concept of welding a diff on a RWD car for drifting to optimise rear wheel spinning, but on FWD, would just be dangerous surely?



  • I would't use a FWD welded diff on the road it would be dangerous.

    On grass the wheels can slip much easier than on a road so it wouldn't be as bad as using on the road, but surely it would greatly affect your steering. It would be really hard to turn in on the corners. I'd stay away.

    There are other things that will help though:

    • Tyres make a huge difference, go as wide as you can and a decent set aimed at grasstrack / forest rally.

    • LSD will definately help, there are a few options for the MX-3

    • Decent rally type suspension up front to keep the power down.

    • I'd also see if you can find somewhere to practice, experience makes a big difference. Plus you can test things out without having to do it at an event.

    You could get two mates with cameras to record you from both sides, while you practice some starts and then compare footage to see whats going on. e.g Both wheels spinning exactly the same, then you need more grip not an LSD.



  • A welded diff in a FWD is only good in a straight line.

    If you go for a phantom grip I would source new springs that are stiffer. That seems to be the fix for them not working correctly.

    Another thought, I don't know if you are running a RS or GS but if you are running a G series trans then you can install a MazdaSpeed Protege LSD. They are a lot cheaper than other LSD's on the market and they should hold up just fine.

    I just picked one up for 200 USD brand new that had the outside rivets welded (which was the issues with the earlier units). You can find them used for that quite often.



  • Thanks for all your replies. Still unsure what to do just yet. I have good quality forest tyres so i think I'll do some work the suspension and look at LSD's
    Cheers guys



  • Anyone know if any other mazda diffs will fit?

    As an example, I know the MX-5 internals can be swapped with the FC and also FD, just wondered if the mx-6 and mx-3 would enter into the equation too?



  • Yeh i had a phantom grop i think jaymx3 bought it, agreed with garfy it will get you off the line fast as both wheels will spin or not together however when cornering it will be much worse. I say no to welded diff and maybe on a phantom grip. But i would spend money on the one marco has… erm was it Mfactory?



  • Swappable mazda diffs would be i think from a ford probe, mazda 626, Mazda mx6. maybe more but those are the ususal suspects.


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