Front wheel spin

Simple solutions are always the best. If it was rear wheel drive and wheel spin was the problem what would you do?. Wider tyres and weigh down the rear end with ballast . Ok you can only go so far with tyre width and its not so easy to add weight to the front but it can be done with lead blocks attached to the chassis . Performance wise lightness is usually king but not if tyres are spinning doing nothing.

Colin Chapman just rolled over in his grave.....

LOL. He did use wood though...

Though he does point a point...

But I'll counter that 1: it is convenient to have same size tires front and back for rotation and for the Suby AWD needing same overall diameters to avoid speed differences.

and 2: Width has different affects in different conditions. A wide tires is no fun in powder snow, but great on dry tarmac.

funkymonkey1002 said:

What front/rear swaybar are you running? I think running a front LSD might help (a helical of some sort).

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are you sure you are spinning both front wheels? i really think what youre experiencing is the terrible front diff in these cars. its my biggest complaint coming from an sti to this car, it really feels fwd to me sometimes. especially on corner exit if im not easy w/ the throttle, the tires will just spin and spin. :icon_frown: a local autox buddy was having this issue w/ his lgt(they have an open front diff also). he threw in the jdm 5spd lsd and the car claws its way out of turns now, instead of feeling fwd.

just like u said its expensive, but sooo worth it. the diff itself is 1k+ and then labor to open up the box+install is probably close to that as well... if you ever have to rebuild the trans, then its the perfect time to do it!

what are your suspension mods? like the others said, better tires, more sway bar, more spring - any of these might help a little too.

fourortwowheels said:

especially on corner exit if im not easy w/ the throttle, the tires will just spin and spin.

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Back off on the rear swaybar and go with higher rate springs in the rear. A bigger front bar seems to help too. Mine would skip occasionally but It would have to be at least a 90 degree turn.

it got much better when i added the larger front sway and wider rubber. but the diff is the real culprit here(in my case), stiffer springs will only do so much. after riding in the jdm hlsd equiped lgt, ive seen the light! he doesnt have to feather anything, he lays in2 the throttle much earlier now, just hooks and goes...

this is a great read: http://www.legacygt.com/forums/showthread.php?t=99463&highlight=jdm+rallispec

What spring rates and bar sizes are you using? With even rates F&R and a 24 front and 19 rear bar my car was neutral. I don't remember having to feather my throttle at all. Only on the tightest Auto-X tracks would I get a few skips on exit.

i forget the rates offhand, but they are rce blacks. i run a 25/22 perrin sway setup(hollow so its really like 24/21), and have swaped the sti rear bar on for comparison @ an event. i like the way the car handles w/ the 22 rear better and the front wheel spin was still there regardless...

+20% springs front and rear at -1" on STI struts (not topping out at the front - checked), 20mm rear, 19mm front bars.

Marks on road suggests both front spinning, 225 tyres (Fairly worn but still around 2mm tread, new ones going on when I get home next week), obviously the inside spins out of tighter corners but at one open local curve I can understeer the front out wide with wheelspin (revs climbing) in 2nd gear.

Certainly not going to add even more weight over the front, I want it to corner as well.....

What i think I really miss is the rear biased torque split my old Ford (and 4or2wheels STi) has.

I didn't know a 12Kgm would fit with an older rear housing (which I already have somewhere I think LOL) - handy to know!

Simon

JStorm said:

Hey Simon....you can always put a phase I tail section on your trans (if you can score a 12kg diff).

Speaking of which....any trans gurus know if phase I transfer gears will work in the phase II case? I'm working on a potential swap deal and I'll need new teeth should I pick up the parts.

On the DCCD subject, you could always use the "Spiider DCCD controller" or rig up a 12v switch similar to the torqumada lite mod..... 40/60 when you want the tail to be comin 'round, then flip a switch to lock it up to pull you the rest of the way through!!!

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The early transfer gears won't work in a new case. Well, I say that because the new-style transfer gears won't bolt into the old style cap.

I wouldn't bother with a 20KG center diff. Having driven one, it's attrocious.

Go DCCD.

The Rookie said:

(Fairly worn but still around 2mm tread, new ones going on when I get home next week)

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Fairly worn? Those things are toast especially in the wet which I'm sure you see quite often.

Here I thought you had a front LSD all this time.

As Jeff Foxworthy would say.... "well there's yer sign...." !!!! The OBX front LSD is a cabon copy of the Quaife and is worth every penny of $400-ish on fleabay. I've been running an OBX for a couple years now, other I know have been using it longer than I have, with turbo power. Some report noise from a lack of preload on the worm gears. Others report hardware issues. I report quicker corner speeds and quicker lap times.

Front LSD would be nice, but I think I'll try and get a DCCD centre first then (for the rear biased torque split)....adapted as plated or electronic control that is the Q!

Simon

JStorm said:

Here I thought you had a front LSD all this time.

As Jeff Foxworthy would say.... "well there's yer sign...." !!!! The OBX front LSD is a cabon copy of the Quaife and is worth every penny of $400-ish on fleabay. I've been running an OBX for a couple years now, other I know have been using it longer than I have, with turbo power. Some report noise from a lack of preload on the worm gears. Others report hardware issues. I report quicker corner speeds and quicker lap times.

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The OBX isn't a carbon copy of the Quaife. If you look at them side-by-side, you'll notice a TON of differences. Still, if you don't want to spend a lot of cash, it's alright for a knock-off.

BAC5.2 said:

The OBX isn't a carbon copy of the Quaife. If you look at them side-by-side, you'll notice a TON of small differences. Still, if you don't want to spend a lot of extra cash for no apparent reason at all, it's alright for a knock-off.

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I edited your post to read a little closer. You should know that it's a little too much work to remove a front diff just to look at them side by side. They feel and function identically when I step out of one car and get into the other. Aside from the lack of radius on the stubshafts, which like to rollover the axle seals upon installation, I would say teh OBX is a little better than just "alright" for a knockoff...... Many of the OBX parts pushed on ebay are not up to the quality of other brand name parts....but they got it right with the front diff.

JStorm said:

I edited your post to read a little closer. You should know that it's a little too much work to remove a front diff just to look at them side by side. They feel and function identically when I step out of one car and get into the other. Aside from the lack of radius on the stubshafts, which like to rollover the axle seals upon installation, I would say teh OBX is a little better than just "alright" for a knockoff...... Many of the OBX parts pushed on ebay are not up to the quality of other brand name parts....but they got it right with the front diff.

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If you DO happen to have both next to eachother, the differences are apparent. You might not notice a difference driving two cars back-to-back, but there are many differences.

I'd compare the OBX diff to an STi helical differential. Few worms that look rather spindly, and an overall construction clearly never intended to see high-horsepower race-duty loads.

JStorm said:

Colin Chapman just rolled over in his grave.....

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If Lotus had been involved in his funeral he would have had a lead lined shroud to cut down on body spin!.

The OEM JDM Subaru LSD is ~$1000USD. They are available from Subaru of Japan, but I don't have a part number on me right now. I'll try to find it.

Re: OBX. I was doing some more looking around, and apparently straight from the box you need to invest ~$35 in new hardware to get any semblance of durability out of the unit. The OEM bolts, apparently, are of dismal quality and often strip. Similarly, the worms are preloaded with beville washers made of tin-foil.

I don't think I'd trust something in a gearbox whose Spec'd hardwear isn't up to snuff.

Looking at the "torn apart" pictures of the OBX diff, it looks like it's made from some heat-treated mid-carbon steel. The Quaife, by comparison, looks to be made from some heat-treated high-alloy steel.