Who's using a limited slip?, Anybody got one.............. Options

[bondo]

QUOTE (rick 918-S @ Feb 5 2006, 11:08 AM)

Brad has a line on a used Quaife, But it may not materialize. So the Phanton Grip looks like it could be a very low cost option. Doesn't look like anyone here has used one. I may be the test case in a 901. Unless Mike has some more info about the fitment being a problem. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

Hmm, I'd be very interested to see how this works out. I'm not too sure a locker is a good thing though.. seems like it could lead to some mean oversteer.

[brant]

Gavin,

the only way to cure the understeer on a locked diff is to change your driving style.

took me most of a season to learn this technique with the locked diff.
when I did I picked up 2 seconds a lap at my favorite track (using the same set of tires)

I'm trying something different this season, but have run locked diffs on -4 and -6 race teeners. (both 2.0L)

The style is much more "dukes of hazard" if that makes any sense in the great north. Basically don't even try to get the car to turn into the corner. Throw it into a slide and slide down to the apex and apply throttle when your ready to shoot out of the corner straight.

no kidding 2 seconds a lap, mostly because that using this technique you can increase your entry speed significantly and practically stop using your brakes. You can out brake anyone in the braking zone before the corner.

brant

[Eddie914]

My taildragger racing friends tell me the biggest improvement gained with the LSD is stability under braking. 911s can be very unstable under braking (ie make sure you are steering straight ahead when you apply brakes or the inner wheel will lose traction and around it goes), but that traction on acceleration is not as problematic due to the rear weight bias.

The 914 does not have as much rear weight bias as a 911 and therefore cannot run as much rear roll stiffness without losing traction on the inner drive wheel. With a LSD, additional rear sway (anti-sway?) bar can be used and therefore maintain better wheel geometry.

I'm attempting to transplant a LSD from a 915 into a 914/901 transaxle. I've been told this sway is feasible using the 915 output flanges netting six bolt flanges to 944 CVs to 914 axles to 944CVs to 911/951 stub axles to 911 hubs with 914 wheel bearings.

I have sourced most of the parts except the stub axles and hubs.

Anybody have any extras they can part with?

Thanks

Eddie

[campbellcj]

(IMG:http://www.guardtransmission.com/diffs_web.jpg)

Definitely helps under braking, and also accelerating off the apex, although my car currently doesn't have nearly enough torque or grip to take full advantage of that.

[groot]

I know of one 914 race car that runs a locked diff... er spool.

The Kirby/Finch 914.

Personally, I don't like them, but obviously they can be fast.

[brant]

I think I want to add a comment too after re-reading my post.
The locked Diff helps your lap times, more than it does in wheel to wheel.

What I mean is, that in traffic you can't always be where the car needs to be to take advantage of the style of driving necessary with the locked diff.

on open track it was 2 seconds a lap for me.

but in heavy traffic, the compromises to track position can cost the driver from realizing the full benefit. (basically by consuming HP on corner exit)

I ran a 2 hour enduro with around 80 cars on a track that is designed for 25. Needless to say there was little opportunity to take advantage of the differential's strengths

I have been carefully trying to research a theory I am developing about HP% that is used amongst the 4 different styles of differential.

(I think there are really 4 styles, because the guard clutch pack is quite different than a factory ZF)

my theory is that there is a horse power threshold, and that different styles of limited slips are better for different HP applications.

long story.... I'm keeping my locked box... but I'm also building a Torq-biasing box at the moment for next season. My theory is that the TB will be better below 250rwhp than a ZF. This belief is partially based on a converstaion with Paul Gaurd about the differential differences between a 911 and 914.

brant

[rick 918-S]

Several interesting points, but I'm really looking for experiences with the Phantom Grip. I don't have any intension of running a welded or locked diff. My car is much more a driver than a AX'er or track car. Infact my rear tire wear is even. I have no problem kicking the rear out any time I need to. So I'm looking for a low cost improvement without over kill. Anyone have any experience installing and using this type of posi unit?

[bondo]

QUOTE (rick 918-S @ Feb 5 2006, 05:42 PM)

Several interesting points, but I'm really looking for experiences with the Phantom Grip. I don't have any intension of running a welded or locked diff. My car is much more a driver than a AX'er or track car. Infact my rear tire wear is even. I have no problem kicking the rear out any time I need to. So I'm looking for a low cost improvement without over kill. Anyone have any experience installing and using this type of posi unit?

My comment was about the phantom grip.. my understanding is that it locks on acceleration. That would make it just like a spool when you accelerate, which may or may not be desiarable. If you're accelerating gently it could cause understeer, if you're accelerating hard, it could suddenly induce oversteer. It seems to me that it might make it difficult (or maybe even impossible) to find that sweet spot where you're not over or understeering.

[sixnotfour]

Anything that increases resistance in the spider gears is going to equalize the output to the axles, I would say up to a point ,100hp (I dont know) for 250.00 you will feel the diff. More power less effectiveness.
I would like to know how many ft lbs of torque resistance (friction) on the bench this unit creates.

[rick 918-S]

QUOTE (sixnotfour @ Feb 5 2006, 04:54 PM)

Anything that increases resistance in the spider gears is going to equalize the output to the axles, I would say up to a point ,100hp (I dont know) for 250.00 you will feel the diff. More power less effectiveness. I would like to know how many ft lbs of torque resistance (friction) on the bench this unit creates.

Ya, I didn't see any real numbers, but with my car they wouldn't really that accurate. ( more weight, seriously more HP) I would assume HP & weight would cancel some of the effects or some of the locking effect. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[sixnotfour]

per the old manual a ZF with about 200 pounds compression (torqued together) on the multi plate clutch stacks both sides yields what porsche calls 50% limited slip

[bondo]

QUOTE (rick 918-S @ Feb 5 2006, 06:01 PM)

QUOTE (sixnotfour @ Feb 5 2006, 04:54 PM) Anything that increases resistance in the spider gears is going to equalize the output to the axles, I would say up to a point ,100hp (I dont know) for 250.00 you will feel the diff.  More power less effectiveness. I would like to know how many ft lbs of torque resistance (friction) on the bench this unit creates. Ya, I didn't see any real numbers, but with my car they wouldn't really that accurate. ( more weight, seriously more HP) I would assume HP & weight would cancel some of the effects or some of the locking effect. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

According to the description, it is only limited slip on cornering and braking. On acceleration it is a NO-slip.

QUOTE

Secondly, the Phantom Grip works as a locker in hard acceleration. The disc plates pivot, locking spiders, causing both wheels to exert equal power to the road, providing less torque steer than an ordinary differential.

That's the bit that worries me. I've never driven a car with a locker, but my understanding was that they're great for drag racing, but not much else.

[rick 918-S]

QUOTE (bondo @ Feb 5 2006, 07:15 PM)

QUOTE (rick 918-S @ Feb 5 2006, 06:01 PM) QUOTE (sixnotfour @ Feb 5 2006, 04:54 PM) Anything that increases resistance in the spider gears is going to equalize the output to the axles, I would say up to a point ,100hp (I dont know) for 250.00 you will feel the diff.  More power less effectiveness. I would like to know how many ft lbs of torque resistance (friction) on the bench this unit creates. Ya, I didn't see any real numbers, but with my car they wouldn't really that accurate. ( more weight, seriously more HP) I would assume HP & weight would cancel some of the effects or some of the locking effect. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif) According to the description, it is only limited slip on cornering and braking. On acceleration it is a NO-slip. QUOTE Secondly, the Phantom Grip works as a locker in hard acceleration. The disc plates pivot, locking spiders, causing both wheels to exert equal power to the road, providing less torque steer than an ordinary differential. That's the bit that worries me. I've never driven a car with a locker, but my understanding was that they're great for drag racing, but not much else.

Are you suggesting the phantom Grip will lock the diff all the time when moving in a straight line? That shouldn't be a problem. As long as it slips when cornering, just enough to keep the inside tire from bucking or chattering.

Does this seem to be a race part only?

Or a possible improvement for a sports car?

I could really use some input from someone that has used one of these in our transaxle.

[bondo]

My understanding is that the wheels lock together as soon as you get on the gas, whether you turning or going in a straight line. I too would like to hear from someone that has used one.

[rick 918-S]

Thanks guys, bump for more input.

[brant]

bump....

Rick, so I don't think anyone has ever tried one of these phantom brands in a 914 yet.

I don't think they even make one that would fit the box, but maybe mike muellers earlier post proves that wrong.

You might try asking the 911 guys.

My understanding from previous threads and also from import board discussions, was that it was not a great product and had mostly been tried by import tuner guys.

you may want to check with the honda guys?

I'd be a tiny bit leary to pay $500 installation labor for something that was a complete unknown, just because it would be so hard to remove, and would cost another $500 to have taken out.

At that point... if the gamble doesn't pay off... you could buy a GT style diff for the same price.

brant

[KenH]

EDDIE914

All you have to do is buy the Course Spline output Bevel Gears from Gaurd Transmission. All 901 & 915 LSD components are interchangable.

Ken

[Mueller]

Rick,

I took apart a good working 901 transmission just for the diff. to send to Phantom (not directly, thru that kid that lived in the desert that had 924's that Sammy is pissed off at for stiffing him on a radio)

According to Phantom, no dice, they couldn't make one to work and on top of that, wouldn't return the diff.....

[Andyrew]

(IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif) Really...

That sucks mike.. I really wanted to try this...

[rick 918-S]

QUOTE (Mueller @ Feb 6 2006, 10:37 AM)

Rick, I took apart a good working 901 transmission just for the diff. to send to Phantom (not directly, thru that kid that lived in the desert that had 924's that Sammy is pissed off at for stiffing him on a radio) According to Phantom, no dice, they couldn't make one to work and on top of that, wouldn't return the diff.....

That's wierd.. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif) They list one for the 915.. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif) should be the same... (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)