Budget racing options for diff

[rb92673]

At our last race at Sonoma we were getting a lot of wheel spin on right handers such as turns 2, 4, 7 & 11. At Buttonwillow wheel spin is most noticeable at turns 2 and 10. Suspension has recently been upgraded to BNE coilovers with Koni race single adjustables, but we had the problem before upgrade. Car is a '85 745t at about 200 rwhp. I have never opened the diff, but I am pretty sure it's just an open diff.

A Gripper is not in the budget for a while, so I am looking for options and experiences for endurance racing. As far as budget options I think my options are:

- Suspension tweaks and deal with it
- Weld it, deal with the under steer
- G80 with weight cut

We plan on racing four times in 2022. Willow Springs, Thunderhill, Buttonwillow and Sonoma.

[mikep]

Lunchbox locker.

[dl242gt]

Here is another option one of our Euro members posted.
https://forums.turbobricks.com/showt...ghlight=lsd%2A

I bought one to try but haven't installed it yet.

[blkaplan]

The best extreme budget bet for a lemons car is a g80 with the weight welded in place. That shaft can break if you cut the weight so its better just to reinforce it.

[rb92673]

Originally Posted by mikep

Lunchbox locker.

Have you used one on a track? Was it locking and unlocking in corners?

Originally Posted by dl242gt

Here is another option one of our Euro members posted.
https://forums.turbobricks.com/showt...ghlight=lsd%2A

I bought one to try but haven't installed it yet.

Has anyone actually used one yet on the track?

Originally Posted by blkaplan

The best extreme budget bet for a lemons car is a g80 with the weight welded in place. That shaft can break if you cut the weight so its better just to reinforce it.

Noted, thanks.

[gsellstr]

There's some lockers on FB right now, might take a peek at the Dana 30 stuff. The Spartan's have a decent rep for quality, can't comment on performance on the track though.

[culberro]

I've had really poor experiences with g80 lockers with on track use. Mine was a low mileage unit with the weight welded down. It was ok for the first track day, but started to lock after ~1 sec of wheels spin and then stay locked. 2nd track day it was very unpredictable unless driven with absolutely no wheel spin (and then what's even the point of the diff?). It had a habit of engaging inconsistently, which meant for a lot of high speed drifting in corners where you would be full throttle.

Lunchbox locker would be what I'd do now (as MikeP mentioned), or a used detroit locker center section (or similar). Extremely predictable. Throttle on = locked, throttle off = open. You can't on-off-on the throttle in corners without it being a bit odd, but you learn quickly how to drive with them. Once again, they are very predictable and you will feel what the tires are doing.
They are easier on axles than a welded diff, and you get great turn-in with a locker.. but once on power it handles like a locked rear end.

Trans-Am and road course NASCARs used them for decades (and maybe still do).

[msweeney]

Originally Posted by culberro

Trans-Am and road course NASCARs used them for decades (and maybe still do).

I know at least a few of the TA2 front runners are using Wavetracs. NASCAR is going to a transaxle, so real diffs.

[culberro]

Originally Posted by msweeney

I know at least a few of the TA2 front runners are using Wavetracs. NASCAR is going to a transaxle, so real diffs.

Yes, there are better options out there. But the locker is at least a proven to work well in higher level motorsports applications. I know that trans-am (and cup cars) were limited by rules on what diffs could be used, but they made spool and locker cars work very well.

And you can still run a locker in a transaxle

[msweeney]

Originally Posted by culberro

Yes, there are better options out there. But the locker is at least a proven to work well in higher level motorsports applications. I know that trans-am (and cup cars) were limited by rules on what diffs could be used, but they made spool and locker cars work very well.

And you can still run a locker in a transaxle

I should have clarified, I love me a locker! Just kind of absent mindedly scrolling and volunteering info, it kinda came out wierd. The Wavetrac ain't all that special, but it seems to be sneaking in wherever people used to employ lockers.

The Next Gen uses that fancy gas-charged positive preload diff that's been in IndyCars for a while. I assume they'll have a spool for ovals, though, so it ain't too fancy for a locker if they make one that fits!

[rb92673]

Thanks for that feedback. I know several racers that are disappointed in the TruTracks/Wavetracks. Interesting experiences with the G80s.

Forgive my ignorance, but a Spartan locker for a Dana 30, 27 spline is what I should be looking at assuming I have an open diff?

[culberro]

Originally Posted by rb92673

Thanks for that feedback. I know several racers that are disappointed in the TruTracks/Wavetracks. Interesting experiences with the G80s.

Forgive my ignorance, but a Spartan locker for a Dana 30, 27 spline is what I should be looking at assuming I have an open diff?

A TruTrac is crushingly disappointing when they lift a wheel. I've driven fast fwd cars that were set up stiff in roll and they would inside wheelspin on the track, especially if you got on the curbing.

And yes, D30, 27-spline locker. I've had great luck with the Spartan brand.

FYI: You will need to pull the carrier and ring gear (and cut off the oil slinger if you have it on), to remove the center pin on the diff. Unless you have a really good slide hammer setup that will grab the inside of a roll-pin.

[culberro]

Originally Posted by msweeney

I should have clarified, I love me a locker! Just kind of absent mindedly scrolling and volunteering info, it kinda came out wierd. The Wavetrac ain't all that special, but it seems to be sneaking in wherever people used to employ lockers.

The Next Gen uses that fancy gas-charged positive preload diff that's been in IndyCars for a while. I assume they'll have a spool for ovals, though, so it ain't too fancy for a locker if they make one that fits!

No worries. I love the higher end road racing experience you bring into posts

I'm curious how the new cup cars will do on the ovals. The changes should make them much better on a road course, and I'm really hoping for some V8 supercars type of action!

[redblockpowered]

Something like a lunchbox seems like it would be a huge upgrade over a welded diff or G80 both in terms of durability and handling.

No experience with it, though. I hated my G80 with a passion.

[Swedbrick]

My lunchbox locker worked well, but boy were roundabouts and slow corners a challenge at times. Changed it out for the LSD option dl242 linked which I got from TurboDutch and it's much nicer to drive.

The LSD kit is only 25% lock however and will cause some silver in your diff oil, so not ideal for longevity, but the same was probably true for the lunchbox. The amount of wear on your spider gears will also affects it's working. For the lunchbox the diff center might not fit, which Sjeng encountered on his 16v build, requiring a different one.

A note of caution on the lunchbox for high hp is that is will lock and unlock when you go off throttle. I know a guy that managed to spin his 240 whilst racing a gtr that way, as he got slightly sideways off throttle and then hammered it. I also had some unintended sideways action on rainy days even with the N/A engine, although that could be considered a way of life if you are opting for welding as well

[rb92673]

Originally Posted by Swedbrick

My lunchbox locker worked well, but boy were roundabouts and slow corners a challenge at times. Changed it out for the LSD option dl242 linked which I got from TurboDutch and it's much nicer to drive.

The LSD kit is only 25% lock however and will cause some silver in your diff oil, so not ideal for longevity, but the same was probably true for the lunchbox. The amount of wear on your spider gears will also affects it's working. For the lunchbox the diff center might not fit, which Sjeng encountered on his 16v build, requiring a different one.

A note of caution on the lunchbox for high hp is that is will lock and unlock when you go off throttle. I know a guy that managed to spin his 240 whilst racing a gtr that way, as he got slightly sideways off throttle and then hammered it. I also had some unintended sideways action on rainy days even with the N/A engine, although that could be considered a way of life if you are opting for welding as well

Thanks for the feedback. My car is 100% track only. It is not even legal for the street. I wouldn't consider it high horsepower either.

[mikep]

I was replying to the “cheap” request.
I have a locker, looks like a spartan. I have not tried it, and was going to send it to eric (badvlvo), but i can install it to try it out. I’m still a fan of clutch types as well as truetracs, but i am aware of the limitations of each.

[rb92673]

I think the end state answer is a gripper, but I need to do a fuel cell first.