SoundGuyDave
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BIG difference between a Detroit Locker and a spool, though! At least with a Locker, you get the thing disengaged when you're off-throttle...
Rear diff question
- Thread starter Roadracer350
- Start date
Not always & that is one of the problems. Driving with a locked rear end takes a lot more Finesse
A Torsen is – in my opinion – the best thing out there for cornering on pavement. No clutch pack to wear out & service regularly.
I heard down the grapevine that OS-Ginken might be developing a diff for the 8.8. If so, that might be something to seriously consider.
Anyone have details?
So...is that OS Giken diff going to be 2k, or 3k??? lol
No doubt - probably more retail
Stile - Probably the best diff available to average moes - like me
Gray Ghost GT
Road Racing Fanatic!
Torsen T2-R
skwerl
tree hugger
Why is the Torsen preferred by so many over the TrueTrac? I know the Torsen won't hold up to drag racing and costs a lot more than the Eaton.
T2R has a 4:1 bias ratio, which is the biggest out there that I know of
Gray Ghost GT
Road Racing Fanatic!
I ran a Eaton before going to the Torsen T2-R. I found the Eaton to be less durable too. The Torsen is more money, but worth every cent!
RocketcarX
95% of my weight is fuel
go for it bro!
Dick head level = expert
Roadracer350
Senior Member
+5000!!!!
Sky Render
Stig's Retarded Cousin
You're the only person I've heard say that the Eaton Truetrac isn't durable. Can you provide more details?
I'm planning on getting a new LSD in the spring, and I was seriously considering the Truetrac.
Road course and autocross are two different animals. The slowest turn on a road course is as fast as the fastest turn at an autocross. When you get into the larger radius, higher speed turns, the % difference between the inside & outside wheels is smaller. For easy math, assume a 6' front/rear track width- then a 60' radius turn has about a 10% difference in wheel speed, but a 300' radius turn is only a 2% difference.
I actually HAVE driven a car with a spool (ok, welded spider gears, poor man's spool) on a road course, and it worked just fine. It was however, fairly low powered, high grip - a Pinto on ~8" tread width slicks. It turned in fine, didn't do anything wonky transitioning back to the throttle, and was very predictable. I have no idea what the owner did to make it work that well- it might not work as well on a heavy, high powered Mustang with less grip. But the idea is not completely crazy for road courses.
For autocross, from what I've seen and friends told me who have tried it with their spool equipped road course cars, it sucks. Massive push at turn in followed by snap oversteer when you get on the throttle.
Justin
I actually HAVE driven a car with a spool (ok, welded spider gears, poor man's spool) on a road course, and it worked just fine. It was however, fairly low powered, high grip - a Pinto on ~8" tread width slicks. It turned in fine, didn't do anything wonky transitioning back to the throttle, and was very predictable. I have no idea what the owner did to make it work that well- it might not work as well on a heavy, high powered Mustang with less grip. But the idea is not completely crazy for road courses.
For autocross, from what I've seen and friends told me who have tried it with their spool equipped road course cars, it sucks. Massive push at turn in followed by snap oversteer when you get on the throttle.
Justin
Roadracer350
Senior Member
How did the Tru trac work on the road course
In the olden days before limited-slip differentials were widely economical and available for small roadrace cars, a locked rear gear was just about the only option. If you had one in your Sprite you learned to drive it and you beat the guy with an open differential. In the associations where locked rears were illegal, part of tech inspection was to push your car around in a small circle; the shudder of racing tires being dragged across pavement was a giveaway.
The economical way to lock the gears was to place the appropriate, assembled parts in some kind of bowl and pour enough molten lead in to accomplish the locking. That way you could easily recover the gears if you needed to. Something to think about in case someone is bent on trying a 'spool'.
I raced an MGB with a Detroit Locker. It took adopting some technique changes, but was indispensable once acclimated.
No doubt - probably more retail
Stile - Probably the best diff available to average moes - like me
"This post is why being fed and accepting too many cocktails is not a good thing".
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We've been asking for it for years and it was finally on display at PRI this year, or maybe it was SEMA. Can't remember. But I spoke to the reps in the booth and they said it was a pre-production unit on display, but design had been finalized and production was already underway.
The issue I see with the OSG is both cost and competition. The T2R is a fairly good diff, and very good for the price. And it's been around and is available from Ford Racing and their dealers. OSG has offered their great diff for cars with no other decent options and it's worked out well. But is it enough better than a T2R for the price? If you are competing for a championship and can afford it, yes, in my experience, it's worth it on the performance level. I can't attest to longevity. We do have an OSG in our Pikes Peak Hillclimb Subaru and will likely put another one in the front for this year.
On the topic of spools: the issue with spools is that they do not work with modern tire technology for paved surface racing. But, if you are running in loose surfaces with plenty of power, or, you are running a tire that works at very high slip angles (think skinny Firestone racing tires in the early '60s up to the Goodyear Blue-Streak), then you can set up a spool to work. Drifting is an extreme example of that, but they also have tremendous wheel spin and go through tires at a rate that would be unacceptable in racing.
In the past spools were acceptable both because the tire tech was poor, and the alternative diffs were either open or rough lockers. LSDs were not developed and some other tricks (shimming the spiders) needed constant maintenance. But, LSD and tire technology have moved on. Now better lockers, decent clutch style and great Torsen style diffs are available to suit a huge variety of conditions. And paved surface tires are so much more advanced.
If you've read Mark Donohue's book, Unfair Advantage, he speaks about using the spool much longer after his competitors abandoned it. He says that the uneven handling of the brutal lockers available made the car impossible to tune and that it was easier to have a consistent (spool) instead of the locker. But even he and Penske abandoned the spool when they went to rear sports cars with aero.
In the past spools were acceptable both because the tire tech was poor, and the alternative diffs were either open or rough lockers. LSDs were not developed and some other tricks (shimming the spiders) needed constant maintenance. But, LSD and tire technology have moved on. Now better lockers, decent clutch style and great Torsen style diffs are available to suit a huge variety of conditions. And paved surface tires are so much more advanced.
If you've read Mark Donohue's book, Unfair Advantage, he speaks about using the spool much longer after his competitors abandoned it. He says that the uneven handling of the brutal lockers available made the car impossible to tune and that it was easier to have a consistent (spool) instead of the locker. But even he and Penske abandoned the spool when they went to rear sports cars with aero.
SoundGuyDave
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Now THAT is bringing the tech!! I wish we had more of the above, and less of the "But it look whack, yo!" type of posts...
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