195/50/15 R888 versus 225/40/16 A539?

[dgh.mr2]

oh arr 5000miles is including alot of road work purely for track use in 1000miles you can kill them depending on power etc. one advantage of the same size tyres is you can front to rear them to last a bit longer wear wise. as for wet use well on all the track days ive been on or watched nearly every car thats not only gone off but kissed the barriers nicely has had r888's on they just cant shift heavy water out the way. im guessing its your second car though so getting away with it is more manageable.

I initially thought that they would be crap in the wet, but they are far better that a539's in the wet/very wet.
I wasn't as lairy (but went quicker) as garrick was and actually felt i had more grip in the wet than on any other setup we have done so far TBH.

Also travelling down to the sprint in a downpoar the car didn't aquaplane as i thought it might.

Tom - the LSD will take a bit to get used to but will do wonders for getting the power down

Can't resist joining in with (A.) a remark and (B.) a question, sorry for the hi-jack on this one but relates to a similar issue with an unfamiliar LSD.

(A.) Now, I know I've posted replies on this before but I have done thousands of miles both road and track in all conditions, including very wet and standing water, with 888s on MR2s and BMW M3s and reckon their 'dodgy in wet weather' reputation is very undeserved. I've had minor aquaplaining in very heavy standing water but reckon I would have even with the F1s previoulsy fitted (+ find loading c.20 to 30Kg in the frunk does help). Other than that I've found the grip good and that they were very communicative - last winter in an sc. was a joy as it was wet and greasy nearly everyday so the car could be slid around playfully (empty roads of course) without worry. I loved them!

(B.) now to the question - I've just bought back my old supercharger and Alex and Anna fitted an sc box, the effects of which they described. Now, I've had LSDs in the M3, Chevette HSR and a Lotus Sunbeam but this feels totally different and is spooking me (14" x 185 section A539s fitted) so how will I get used to it, what should I expect it to do/feel like & how should I drive to make the best of it?

On some well known, favourite bends it feels like it has a mind of its own shuffling power from left wheel to right - it almost feels like some 'clever' electronic thing trying to 2nd guess me and NOT doing what I want. The main problem being when the road camber/ crests fall away to the left on right hand bends when it begins to feel like it's starting to fall down the crown and then switches from under to over steer and back again in a series of twitches and pushes. The particular, 3rd gear, bend I'm thinking of is tight, narrow and uphill and it seems to need more room than I'd have if there were traffic coming - luckily there is enough visibility to avoid an issue but it has unnerved me.

Sorry this is a poor description but I'm just trying to imagine and translate the feelings I've experienced 3 times on the same bend this week; it's weird!

[crazybrightman]

ok so this place seems a good price...
http://www.reyland.co.uk/Details.asp?ProductID=146
now hich are the harder compound 2g? as they are cheaper so i hope so

dgh.mr2 what sort of lsd are you running torque bias or a slipper type?
i know my torque bias diff (on a fwd) shifts the power all over the place but gives much better cornering you just have to get used to it moving the car slightly. having said this it allows the wheels to turn freely still so theres no understeer or feel of the wheels trying to rotate at different speeds.
if how ever you have a slipper type then fitting sticker tyres will make it harder for the tyres to rotate at different speeds so probably making the car feel slightly strange when cornering.

[dgh.mr2]

ok so this place seems a good price...
http://www.reyland.co.uk/Details.asp?ProductID=146
now hich are the harder compound 2g? as they are cheaper so i hope so

dgh.mr2 what sort of lsd are you running torque bias or a slipper type?
i know my torque bias diff (on a fwd) shifts the power all over the place but gives much better cornering you just have to get used to it moving the car slightly. having said this it allows the wheels to turn freely still so theres no understeer or feel of the wheels trying to rotate at different speeds.
if how ever you have a slipper type then fitting sticker tyres will make it harder for the tyres to rotate at different speeds so probably making the car feel slightly strange when cornering.

Sounds stupid but I'm not really sure - it sounds like your description of the torque sensing one but I think it is likely to be a standard(?) sc. plate type which I assume will be a slipper type?

It does seem to be shifting power from left to right etc. rather than the smooth, drift type effect of the BM diff. I am getting some spare wheels with stickier track tyres so it will be interesting to see how it feels with these.

I intend getting it out on an airfield day to try to get used to it before getting back on to a real track as it just feels so different from how I last remember it at Donington or Cadwell and I'd hate to try to do the same things and come a cropper!

[Lauren]

It will be a plate type diff. Normally when they lock up thats it, there isn't IME any constant transferring of power between the wheels.

[Speedy]

It will be a plate type diff. Normally when they lock up thats it, there isn't IME any constant transferring of power between the wheels.

Yup, plate type. The hooligans choice

[dgh.mr2]

It will be a plate type diff. Normally when they lock up thats it, there isn't IME any constant transferring of power between the wheels.

Yes, apologies for my poor description - I don't think it is actually moving power constantly, more that it feels as if it is in the sensation it gives on certain (sloping, steep, crested and cambered) bends. I'll try it again when I get back but suspect it's the transition from understeer to sudden oversteer as it drops a wheel down the camber of the road that's unsettled me.

It's only happened on a couple of similar corners so I suppose I'll have to get used to it!

[dgh.mr2]

It will be a plate type diff. Normally when they lock up thats it, there isn't IME any constant transferring of power between the wheels.

Yup, plate type. The hooligans choice

Can I learn to be a hooligan?! Well not on that bend as it's too tight and dodgy to mess around on but I can't wait to get it out on track for a try out.

[Speedy]

Like I said with that car, the LSD effect is very aggressive - partially I suspect because of the gear oil, and partially because of the high profile tyres, so you'll find it pulling left and right when you make large throttle movements - tail wagging the dog syndrome.

When you get some lower profile tyres, it will make it better.

Although if you think it's nervous now, wait until you put 888s on it again, then it'll be pulling you all over the place

[dgh.mr2]

Like I said with that car, the LSD effect is very aggressive - partially I suspect because of the gear oil, and partially because of the high profile tyres, so you'll find it pulling left and right when you make large throttle movements - tail wagging the dog syndrome.

When you get some lower profile tyres, it will make it better.

Although if you think it's nervous now, wait until you put 888s on it again, then it'll be pulling you all over the place

Well, that does sound like a pretty good description of the effect, though I didn't think I was being too rough or on-off with the throttle?

Would changing the diff oil make it less aggressive do you think?

Oh, and oops . . it's in now having a rear (1/2) cage fitted and new wheels with, you guessed it 888s for the track . . oh dear, maybe I should beef my insurance up!!!

[Speedy]

You could try putting a suitable friction modifier in there - you don't have to be too aggressive with the throttle to get it to do it, but remember, it's certainly more powerful now than when you last drove it

Well, the good news is that the 888s should cure the tail-dog wagging situation at the back. They will make it follow camber like crazy though

[dgh.mr2]

You could try putting a suitable friction modifier in there - you don't have to be too aggressive with the throttle to get it to do it, but remember, it's certainly more powerful now than when you last drove it

Well, the good news is that the 888s should cure the tail-dog wagging situation at the back. They will make it follow camber like crazy though

Thanks for the advice. When you say that, "you could put . ." the modifier in, given that I'm mechanically illiterate, are there any 'experts' / companies you'd recommend who could do this (assuming I don't get on with it as it is) because I wouldn't know where to start.

Power wise it is different! It doesn't feel particularly slower than the 1.5 which had a supposed 225 ish minimum + no lag, hurrah! Really does shift now . . .

Cheers

[Speedy]

Power wise it is different! It doesn't feel particularly slower than the 1.5 which had a supposed 225 ish minimum + no lag, hurrah! Really does shift now . . .

I have absolutley no idea what it's running now. Totally off the top of my head, it'll be running slightly less than it was before the HG was done, since the HKS is thicker than the Toyota one it replaced, lowering the CR - you never know, if you get it remapped there might be more advance in there.. (hey, that's crazy talk - it's working, i'd leave it be )

Glad to hear it's working for you though

Thanks for the advice. When you say that, "you could put . ." the modifier in, given that I'm mechanically illiterate, are there any 'experts' / companies you'd recommend who could do this (assuming I don't get on with it as it is) because I wouldn't know where to start.

Er, at the moment it's running Motul gear 300 in the gearbox, which is supposed to be safe for LSDs - but you could always try a different LSD oil. I can't remember what that would be off the top of my head though. Somebody like oilman might be able to help

[dgh.mr2]

Thanks again. I'll let you know how I get on with it once the wheels and tyres are fitted.

[Tom G]

Thanks for the advice. When you say that, "you could put . ." the modifier in, given that I'm mechanically illiterate, are there any 'experts' / companies you'd recommend who could do this (assuming I don't get on with it as it is) because I wouldn't know where to start.

Er, at the moment it's running Motul gear 300 in the gearbox, which is supposed to be safe for LSDs - but you could always try a different LSD oil. I can't remember what that would be off the top of my head though. Somebody like oilman might be able to help

Is it not a sealed diff? On the mk2 gearboxes, the stock LSD is sealed, so type of oil makes no difference.

[System-G]

You get used to it. Ours behaves in a similar fashion, but you learn to deal with it

[Speedy]

Is it not a sealed diff? On the mk2 gearboxes, the stock LSD is sealed, so type of oil makes no difference.

Not AFAIK, no.

[mr2mk1chick]

Er, at the moment it's running Motul gear 300 in the gearbox, which is supposed to be safe for LSDs - but you could always try a different LSD oil. I can't remember what that would be off the top of my head though. Somebody like oilman might be able to help

Try castrol hypoly LS (the LS is for plate type LSD boxes)
we have that in our sc and it seems to work a treat

[dgh.mr2]

Just got back from holiday so apologies for the late response but thanks again to all of you offering help.

I'll try the Castrol oil mentioned - as for getting used to it, how? Just learn what it will do or become a better, quicker acting driver?! I feel really rusty now, probably me that needs a different oil . . .

[mr2mk1chick]

probably me that needs a different oil . . .

LOL

try the imoc trackday on the 13th sept.
best way to get used to a car without trashing it on the road.

[dgh.mr2]

probably me that needs a different oil . . .

LOL

try the imoc trackday on the 13th sept.
best way to get used to a car without trashing it on the road.

I'd love to - and will get to one some day - but will be working then.

Once it's back I intend going back to an airfield venue to get back into the swing of things in a relatively safer environment given how different the car feels, so far . . .