Helical VS Clutch Type Differentials?

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fidel
http://www.drenth-gearboxes.com/products/differentials/honda-civic-type-r.html
if its in the budget

It's such a shame that so many people make great diffs for the Ford 7.5" differential but nobody makes a reasonable final drive. I could probably stomach spending the dough for a Gripper or Drenth differential if I didn't also need to spend another $2k for a decent final drive ratio in the stock Merkur differential.

Side note on Drenth and Kaaz. A friend here in Colorado continually had problems with the Kaaz in his VW 020 gearbox. I think there was 2-3 DNFs related to it. He got to the point where he was about to just spend the $9k or so on the Drenth box and call it good. He then decided it was smarter to swap to the 02A or J or whatever the newer box is called. I think it was around halfway through the swap where he decided racing mountain bikes fast through trees was also super fun and he didn't drive halfway across the country and spend 5 days and a few grand to race only to end up with a mechanical problem on the first few stages.
I think I'll be able to convince him to buy a BMW once he spends a day in Dave's Compact or the 325i I'm starting on in about 20 minutes.

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Grant Hughes

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NoCoast

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fidel
http://www.drenth-gearboxes.com/products/differentials/honda-civic-type-r.html
if its in the budget

It's such a shame that so many people make great diffs for the Ford 7.5" differential but nobody makes a reasonable final drive. I could probably stomach spending the dough for a Gripper or Drenth differential if I didn't also need to spend another $2k for a decent final drive ratio in the stock Merkur differential.

Side note on Drenth and Kaaz. A friend here in Colorado continually had problems with the Kaaz in his VW 020 gearbox. I think there was 2-3 DNFs related to it. He got to the point where he was about to just spend the $9k or so on the Drenth box and call it good. He then decided it was smarter to swap to the 02A or J or whatever the newer box is called. I think it was around halfway through the swap where he decided racing mountain bikes fast through trees was also super fun and he didn't drive halfway across the country and spend 5 days and a few grand to race only to end up with a mechanical problem on the first few stages.
I think I'll be able to convince him to buy a BMW once he spends a day in Dave's Compact or the 325i I'm starting on in about 20 minutes.

there are 7.5" final drives at 4.27....but they're rare and pricy and the whole cost escalates drastically...post from UK, bearings, seals etc.
What did you pay for the Supra complete units you have?

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

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If you have a D-series (limited options), and especially if you're just starting out and don't want to spend a bunch of money, I'd put a spool in or weld the diff.

I use KAAZ diffs in my Civic and Integra, and they handle well, good grip, but I dont' have them preloaded enough to be able to drive out on a busted axle or anything.

Nice thing about the welded diff, is it is pretty cheap, handles pretty well/consistently. Downside is you'll have to change your driving style a bit to adjust for the corner entry understeer you're going to experience.

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john vanlandingham
there are 7.5" final drives at 4.27....but they're rare and pricy and the whole cost escalates drastically...post from UK, bearings, seals etc.
What did you pay for the Supra complete units you have?

I know. I've seen them occasionally. And a 4.56 that was only like 1000 GBP. That's what I was saying, if there was a decent CWP for cheaper, I would have considered something like a Gripper. But yeah, becomes a $3k diff pretty quick.
Supra diffs, 60, 60, and 45, the latter needing bearings/rebuild. All 4.3.

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Grant Hughes

I absolutely love my gripper, worth every penny

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NoCoast

It's such a shame that so many people make great diffs for the Ford 7.5" differential but nobody makes a reasonable final drive.

Not related to the 7.5" used in V6 Thunderbirds? ('89-whenever they made the 8.8 standard)

Summit shows 4.56 and 5.13 gearsets for those. http://www.summitracing.com/parts/RMG-6903481/


Is there any stage experience with the diff, forget its name but it is a helical that has clutch packs to give some preload? I've seen a Golf with one driving around with one axle.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Shoulda said Euro Ford 7.5.
No relation to anything else in Ford's US lineup.

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Grant Hughes

This is probably a dumb question, but while we're talking about clutch diffs and Grippers, what's an ideal breakaway torque to set it at? When I talked to Gripper, they suggested 60 ft lbs for gravel rally and that's roughly what I set it up at on the bench (with the assembled diff lubed up with gear oil). I have to try it now with 2 - 3 events on it, it may be less after a few events.

Supposedly the Swift currently puts out around 100 ft lbs at the wheels on the dyno, so unless I'm an idiot setting it much higher would almost mean it never breaks away, right?

I'll say that so far Gripper support has been good. I got a rebuild kit from them and they included an upgraded redesigned cross pin with it at no additional cost.

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AlexeiS
Supposedly the Swift currently puts out around 100 ft lbs at the wheels on the dyno, so unless I'm an idiot setting it much higher would almost mean it never breaks away, right?

Shiiiirly 1st 2nd and 3rd gears will put down a bit more than those 100ftlbs.

That being said, too much preload also creates different handling characteristics/problems that need to be dealt with in conjunction with suspension geometry, like more caster for weight jacking purposes and witchcraft like that.

I did a quick search for some diff setting explanations and this reading has some explanations on it http://www.intothered.dk/simracing/differential.html

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Cosworth
Shiiiirly 1st 2nd and 3rd gears will put down a bit more than those 100ftlbs.

*smacks head* I am an idiot after all I knew there had to be other things like that or when the power is on vs coasting and crap. Thanks for the link, that looks like a good read. Bookmarked for the next time I pull the diff out.