Aftermarket lsd or standard diff?

millsy · Post by **millsy** » Tue Nov 29, 2011 1:05 pm

Hey guys, i just finished a manual conversion in my gpvr, and used the lsd from the auto box i had to the manual (change around the crown gear on the standard diff to the lsd and fits perfectly).
Problem is that the lsd is FAR too ferocious around parking lots etc due to different final drive ratio's between the gearboxes (and i am assuming it may also because i own the facelift gpvr, which does not have the same lsd as the pre facelift, and my diff can transfer up to 2.5times the spin, as oppesed to 1.5 as most lsds do)

Long story short, cracked my cv joint in one of my driveshafts. Wayyy too much presure.

Anyway, i am selling my gpvr, and now i need to either just chuck a different lsd (aftermarket most likely) in or just put in the standard diff.

If i keep it standard then i may have less chance of selling (people want an lsd in their fto gpvr otherwise they would opt the gpx) and i will have to lower the price by $1500 or so. But i dont want to pay $2000 for an aftermarket one that may still be too agressive and put people off buying it (therefor i will have to lower the price AND deal with the $1700 i payed for the part

So this is where i need your help, i want an lsd that does not scrub tires around parking lots or puts any strain on anything (i know u can adjust the clutch plates in some aftermarket ones like cusco, but is that enough not to be annoying at all?). Basically ineed a 2nd hand lsd, and also, does every single person with a manual box HAVE TO get an aftermarket lsd if they want an lsd? Or did the gpvr come out as a manual and with an lsd which can be transplanted to a normal manual? Or do you guys think to just cut my losses n chuck a standard diff in? (remembering i could get a little money back by selling my lsd to someone with an auto)

Thanks guys

Post by **Bennoz** » Tue Nov 29, 2011 1:35 pm

As i've said before, I shudder when I read what you did to that box, I also shudder when you tell me that a factory diff is so harsh it cracked a cv joint, something is seriously wrong with either that diff, or the way you've put it all togther... But who am I to judge when I just so happen to have an LSD for sale

I wont know what type it is till I pull it out, but by the feel of it, I think its helical. Its a Mitsi factory one.

Shane001 · Post by **Shane001** » Tue Nov 29, 2011 1:53 pm

Agree with Ben, a factory LSD should not be snapping cv joint shafts. Under low load a factory LSD should slip, so there should be no build up of pressure. So something is either not as you think it is or something is seriously wrong.

And lol at this

Bennoz wrote:But who am I to judge when I just so happen to have an LSD for sale

Gholdwayne · Post by **Gholdwayne** » Tue Nov 29, 2011 2:00 pm

Fahhrr I always wanted to put an lsd on my car!

millsy · Post by **millsy** » Tue Nov 29, 2011 2:28 pm

But dont most people with lsds complain that it scrubs the inner tyre at low speed and hard turning? Im pointing the finger at the fact that it is now a different drive ratio and was ment for the auto so it is now 20% (exsample) more severe than other lsds. The tires dont clunk or skid when im doing a wide 90degree turn (traffic lights and such) so it does "slip" and not stay engaged all the time. So i assume it is all working fine, just 20% more severe.

What have other people used for their manual? And the least severe lsd? And would it change the final drive ratio if ihad 25 spline wheel hubs (smaller diameter driveshaft tip, than my 27)?

BearOnFire · Post by **BearOnFire** » Tue Nov 29, 2011 2:35 pm

Could be those parking lot incidents? Regular hard take offs can put a toll CV shafts.
Ride the lightning! \m/

Shane001 · Post by **Shane001** » Tue Nov 29, 2011 2:55 pm

millsy wrote:But dont most people with lsds complain that it scrubs the inner tyre at low speed and hard turning? Im pointing the finger at the fact that it is now a different drive ratio and was ment for the auto so it is now 20% (exsample) more severe than other lsds. The tires dont clunk or skid when im doing a wide 90degree turn (traffic lights and such) so it does "slip" and not stay engaged all the time. So i assume it is all working fine, just 20% more severe.

What have other people used for their manual? And the least severe lsd? And would it change the final drive ratio if ihad 25 spline wheel hubs (smaller diameter driveshaft tip, than my 27)?

Depends on the LSD, but most factory LSD's would not do this unless they've been 'tightened'.

What was the drive ratio of the crownwheel you put on vs the one that was on there? ie how many teeth?

25 spline will make it weaker than 27 spline, and has nothing to do with the drive ratio. 27 spline are simply stronger.

Post by **Bennoz** » Tue Nov 29, 2011 3:26 pm

Shane001 wrote:What was the drive ratio of the crownwheel you put on vs the one that was on there? ie how many teeth?

I reckon this is where the problem is going to lie... which tells me its not the diff causing the problem... its the final drive gears locking up *winces*

Shane001 · Post by **Shane001** » Tue Nov 29, 2011 3:42 pm

Yep, that's what I'm thinking as well

Post by **Bennoz** » Tue Nov 29, 2011 3:49 pm

I think your next port of call should be to drain the box oil, see if there's any significant quantities of metal floating around in it.

FYI, here's my expereince with different diff types. I've driven FTO's with 4 types of diff in them, the 2 factory variants viscous & helical, the viscous is the softest of the 2, it has a bunch of wafer like platters spinning in a special goo in the centre of the diff. The helical type was margianlly stiffer, but neither of them shuddered or jolted under any driving circumstance. The only diff I've used that's done that is the Cusco MZ type. Notorious for being a harsh clutch plate style diff, and I never blew a CV joint with it, I did however destroy the diff, one of the planetary gears in it exploded.

And lastly, the one I'm currently using, which is a Wavetrac. A Helical style diff with a unique centre section that deals with zero torque scenarios. It rarely shudders either, only very rarely during slow speed manouvering like parking etc. Oh & btw, brand new, they only $900 bucks

Shane001 · Post by **Shane001** » Tue Nov 29, 2011 3:52 pm

And to add to Ben's experience above, my racecar has a Cusco LSD, and yes it shudders a little around the pits at slow speed, but it gets a hell of a workout and I've only ever broken one shaft, and I've since put this down to a metal fatigue fault in the shaft itself, as if it was a problem I'd be breaking the suckers left right and center

(touch wood

)

Gholdwayne · Post by **Gholdwayne** » Tue Nov 29, 2011 4:28 pm

Hey Ben, I should ride in your FTO sometime, I wanna see what that clunking is about... But can you get the clunking to happen on purpose with your wavetrac though?

Post by **Bennoz** » Tue Nov 29, 2011 6:09 pm

Scare a philo day!

Yeah I can show you

bass_twitch · Post by **bass_twitch** » Tue Nov 29, 2011 6:32 pm

Bennoz wrote:Scare a philo day!

Yeah I can show you

*waits next in line...*

AJ · Post by AJ » Tue Nov 29, 2011 6:42 pm

bass_twitch wrote:
Bennoz wrote:Scare a philo day!

Yeah I can show you
*waits next in line...*

Take a virtual ride now while you wait.

Taz · Post by **Taz** » Tue Nov 29, 2011 11:07 pm

So it looks like my manual GPR box is going to actually be worth something when i rip it out and try to sell it?
Score, might pay for my new one

Shane001 · Post by **Shane001** » Tue Nov 29, 2011 11:46 pm

Actually, regarding the 'crown' gear, it may not be a problem.

The two gear ratios I've confirmed from the gearboxes I've pulled apart both had 16 tooth shaft gears of the same diameter.

The 4.625 ratio had a 'crown' gear with 74 teeth, the 4.3125 ratio had a 'crown' gear with 69 teeth, but the shaft gear was the same on both.

Now these were both manual boxes, but what you would need to do is confirm the number of teeth and the diameter of the shaft gear in your auto box vs your manual box to know whether you could just swap the 'crown' gears or not.

Taz · Post by **Taz** » Wed Nov 30, 2011 1:26 am

Just get a manual GPR box

millsy · Post by **millsy** » Wed Nov 30, 2011 3:13 am

remember, the crown gear im using was originally in this manual box, attached to a standard diff. the auto lsd had slightly more (or less :s?) teeth than what i attached it to, but that means the final drive ratio is altered by the actuall lsd/diff rather than the crown gear on it.

and also, my c.v deffidently broke because of the lsd, the steering wheel wants to snap back and it feels like there is barely any power steering there is that much pressure for the wheel to spin, i am not going to drive it with that diff in any more before something real bad happens,

so there are brand new lsd's for $800? i am willing to pay $800 for a sure fire way of fixing/keeping preformance up.as long as some one can verify that it works with my manual then im happy. any other diff ideas?

Shane001 · Post by **Shane001** » Wed Nov 30, 2011 8:44 am

millsy wrote:remember, the crown gear im using was originally in this manual box, attached to a standard diff. the auto lsd had slightly more (or less :s?) teeth than what i attached it to, but that means the final drive ratio is altered by the actuall lsd/diff rather than the crown gear on it.

So you've used the crown gear that came with the manual gearbox, so this should not be the problem.

millsy wrote:but that means the final drive ratio is altered by the actuall lsd/diff rather than the crown gear on it.

No, the diff itself has absolutely no affect on the final drive ratio, the 'crown' gear and the shaft gear determine the final drive ratio, the diff itself has nothing to do with ratios.

Sounds like there is something wrong with the LSD and/or it's not what you think it is, maybe it's a Cusco.

FTO AUSTRALIA