LSD - significant benefits on a NA?

[PW@Woodsport]

Another tip is you can use a MK3 6th gear set, that is just the two 6th gear parts, in a Celica C60 and you get the best of all worlds ratio wise, the Mk3 6th pair is longer than the Celica.

When someone asks me to build a custom 6 speed with LSD i have to buy three gearboxes just to build one, a C52, a Mk3 5 speed LSD box and a Celica C60. You then have all the parts you need (apart from the new bearings/seals i normally install on a customers build).

[tottacrolla]

My LSD gives the car a desire to understeer when applying power in bends.

Give the front more grip and you go faster !

[Fab4MR2]

Forget the comments based solely regarding tire grip when it comes to an lsd's usefulness, as that somewhat overstates the need or not for an lsd. The sheer fact that power will now be given to both tires and not just one is the bigger factor. Even with moderate power an lsd makes a huge difference. I added a Quaife to an otherwise close to stock power 4agze, and was more than happy with the results. I should have remembered this from days when I drove military pick-up trucks with locked rear differentials, but it had been a long time, lol.

Sure they're a big help in wet weather, and such, but even in normal conditions just having power to the inside wheel really helps a lot. If you drive these cars much, and have a good feel for them, you know how much difference it makes when you apply power throughout a turn, which maintains power to the outer wheel. Adding the Quaife, and having power to the inside wheel, made the car feel a bit more neutral and much more secure feeling in all situations, even when letting off power in the middle of a turn, which you always have to be careful about, lol. I consider it one of the best upgrades I have ever made.

[stenky]

By no means does Quaife or torsen give power to the inside wheel. The idea is that it biases torque of the wheel with less torque (inside) and adds it to the wheel with more torque (outside) under uneven torque distribution (weight transfer during cornering).

[Polypedates]

OK, I'm certainly tempted but would be looking for an option that retains as much of the original parts as possible but particularly the standard gearbox.

Is there a direct fit LSD for the Mk1 anymore?

[Fab4MR2]

By no means does Quaife or torsen give power to the inside wheel. The idea is that it biases torque of the wheel with less torque (inside) and adds it to the wheel with more torque (outside) under uneven torque distribution (weight transfer during cornering).

In the case when the vehicle is turning and neither wheel is slipping, the inside wheel will be turning slower than the outside wheel. In this case the inside wheel will receive more torque than the outside wheel, which can result in understeer.

It may begin to adjust bias at that point, but you can't say that no power is delivered to the inside wheel, or that power is completely taken away from it..

[PW@Woodsport]

OK, I'm certainly tempted but would be looking for an option that retains as much of the original parts as possible but particularly the standard gearbox.

Is there a direct fit LSD for the Mk1 anymore?

The Mk3 Torsen is a direct fit

[IanParkhouse]

By no means does Quaife or torsen give power to the inside wheel. The idea is that it biases torque of the wheel with less torque (inside) and adds it to the wheel with more torque (outside) under uneven torque distribution (weight transfer during cornering).

In the case when the vehicle is turning and neither wheel is slipping, the inside wheel will be turning slower than the outside wheel. In this case the inside wheel will receive more torque than the outside wheel, which can result in understeer.

I can testify to this.

For me the LSD has a benefit with 190bhp, but also I'd cope without. On a standard car I don't think you'll see a benefit, with decent tyres I didn't feel like I was losing power in the 4age

[PW@Woodsport]

I think the point has to be made that in dry conditions and a stock engine there will be no gain using LSD, however on the limit of grip when the conditions are slippy it surely must be better to have double the drive than just single wheel?

A stock 4a-ge Mk1 will quite easily point the wrong way in the wet.

[IanParkhouse]

Paul the down side of the LSD for me is the way it alters the car's handling when applying power in bends, there's a tendency to plough straight on. I feel in good conditions I can't hit the fast pedal as soon in a bend with the LSD as I could without it. with the 2zz it's a compromise I'm willing to make with a 4age I'm not convinced, if I even get the compressor engine fitted I'll be wanting the LSD every day

[PW@Woodsport]

I'll be honest Ian, i've never come across any Torsen equipped car have this handling effect, certainly Mk3s don't do it and they come with that diff as standard, are you sure you haven't got a geometry issue?

[IanParkhouse]

Hi Paul

I don't want to hijack the thread..... I've TRD settings on the front and standard on the back. the same effect is apparent in Mark's car. It is small but it's there. I've an SMT mk3 at present and it doesn't have the same impact there, though I'm not sure if the SMTs have an LSD. It's not a problem because there's benefits to having the LSD.......... but there's a downside too. Could it be the pre-load should be different, can't say I know anything about how this is setup though?

One more thing Paul I love my car, great work you did there. I've had no more noises from the gear box since I changed the oil and haven't had to do any work since I picked it up other than engine & gearbox oil and new brake calliper. She's a joy to drive.

[gavsdavs]

there's a tendency to plough straight on

Understeer on exit to the corner.....this sounds like you haven't completed the corner yet, the power unweights the fronts and will indeed charge straight on.

I do something similar myself - never realised until someone pointed it out.
You spend a lot longer waiting for the car to if you're pushing the front through the corner.

I wouldn't put this down as a 'problem' with an lsd - it's just slightly better at getting equal drive to both sides. Are you sure an equivalent car without an lsd would behave better ?

Its only really at the limits of traction you will see a difference in car behaviour with/without LSD. when everything is grippinng, they are largely invisible....

[Lauren]

MK1's always want to understeer anyway, they are terrible for turn in.

I can see how an LSD can make this worse, however, having owned MK1's with an LSD, if you're getting understeer you need to change how you drive it.

In a MK1 you have to lift off way before the turn in point because you know it's going to understeer. Also trail braking can help. But you need to get the rear mobile as otherwise it won't turn in. This is when an LSD can be exploited.

SMT do have LSD's. I remember driving a friends turbo one round Dijon and Magny Cours many years ago, so there is no difference in the diff due to the transmission system used.

[IanParkhouse]

After 9 years I'm pretty used to the handling of a Mk1 by now and Ian Clements will confirm I can make full use of all grip in the corners. Maybe there's something funny with mine but really I think I'm just being super critical. The effect is small but still noticeable


Good to know the SMT has a LSD, I brought it as it was the best auto I could find after a knee op. I've only had two real blasts in it so far so I'm still really getting used to the thing and haven't pushed it to the limits yet.

[Lauren]

I'm not criticising your driving. An LSD can promote understeer, I get this on my AE86 to an even larger extent. That has a 2 way LSD apparently.

Not such an issue (well no issue at all) on the GT86, but that has a far better chassis and is set up to tend to oversteer far more than a MK1 which will generally understeer more on the limit.

The MK1 really needs a decent lift on turn in, or trail braking to help quell the understeer. An LSD can cause more of an issue, so a bigger lift, but if you've got the power you can steer it on the throttle. This works best in the wet as the MK1 is never short of traction in the dry due to the weight over the rear wheels.

[PW@Woodsport]

Also remember that with the Torsen diff, when you lift off the gas, it instantly becomes an open diff again, it only locks when enough torque is applied to it, so any ill handling effects on lift off have nothing to do with the Torsen.

[Lauren]

I've only got experience of plate diffs in a MK1 really. Ditto in AE86. GT86 is a Torsen which doubtless doesn't add understeer on turn in, which would make sense when you think of it. The issue is more of a problem in my AE86 with it's two way LSD.

With the MK1 with the optioned TRD LSD which is what I've worked out about all it can be in an SC E51 box, it doesn't promote more understeer than normal but with the greater traction if you get on the power too early it can push the nose wide. It's all about timing of course.

[IanClements]

After 9 years I'm pretty used to the handling of a Mk1 by now and Ian Clements will confirm I can make full use of all grip in the corners.

Not wrong there Ian!

Your car felt strange from the passenger seat, almost as though the rear end was constantly trying to break loose but then finding more grip at the last moment.

[IanParkhouse]

I feel this thread has been well and truly hijacked.

Ian hope you're car's going well. Would be good to meet up again soon. See if my Mk3 keeps up with you 1MZ.