diffs versus tyres
Turbo Mini Forums

anybody played with the idea of running a smaller tyre width to avoid breaking the diff or drop gears ,so the tyre spins b4 the transmission breaks,acting like a fuse i suppose .can anybody tell me what tyes they had when they broke thier diff or drops ,to see if a pattern appears ,you know super stixky wide tyres gripping enuff to break things ,oh and wat gear they were in .?? thanks robert.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Well most of us run straight cut drops and minispares x pin diff which are pretty tough. With out a LSD there is more give because one wheel will be able to spin. I think a reply is needed from anyone who has used a LSD and slicks and if any transmission problems have been encounted!!

-MINI CLUBMAN 1380 TURBO-

Is this a windup?

If not, I suggest some Crossplies.

i kind of agree with dave lol
if your goign to to light the wheels up ont eh start line on perpouse then why not just run less boost/smaller negine so you cant do it in the first place...gearbox saved?

You must me having a laugh!

Never broken any gears even on slicks!!!

JF.

Where's that picture of woodsie's layshaft...

I run Salisbury diff and 165 A032R. I rely on my driveshafts being a weak link. They will hopefully break at their weakest point before anything else.
Paul

I seriously doubt it!

a good idear is not to drop the clutch

1293 Turbo mini

thanks paul thats the sort of data i was interested in theres a couple of us on here that cant really afford at the mo to buy the s/c drops or 4 pin diffs ,so were running narrower tyres and less sticky ones ,to preserve the gear train , do you think most people have suffered breakages at launch ?? or once they are on thier way and the tyres arent spinning so perhaps the total torque loading is higher ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Im not really seeing this....

You are saying you want high boost/power - but want to spin the tires up to protect the drivetrain. OK I see what you mean - but what is the point in higher power if you cant put it down to the road?

Surely on an open diff spinning wheels will not nessasarly spin the same on each side - so surely that will put a lot of strain on the diff by doing this?


Im sure some 4 inch wide cheap remoulds would spin nicely for you.....:cool:

Edited by SumpNut on 9th Feb, 2006.

i just thought of that too sump nut, it will only spin one wheel anyway and wear the diff much worse than if you just set off, granted theres more load on it if both wheels grip... just dont launch untill you ahve the money, lol i am in the same situation with money, but if its not ready to race then dont race?

I think the main point here is that I don't think anyone has experienced an instant failure due to pure torque.

All the common failures experienced (diff planet gears, layshaft wear) can be attributed to engines with high torque, but also happen over many miles of use. I can't see tyres really having much effect on this personally.

If you can't afford to buy the expensive differentials and other stuff, then my advice would be to firstly make sure what you have it at the top of its game, e.g. rebuilt to bottom tolerances. Then, it is a simple matter of some mechanical sympathy, sometimes a smoother approach can be just as fast to be quite honest, without compromising the mechanicals of the car.

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=5276


That was an 'ultimate traction' and shed loads of torque failure...

Yes, but the oher salient point in that thread is "not touched for 2 1/2 years"......

thanks tom ,i agree with what you say ,a bit of mechanical sympathy ,and lack of clutch abuse does go a long way towards keeping the drivetrain intact .,
i was looking at it like this , for a given amount of torque the path from the crank to the wheels is capable of handling a certain load b4 it breaks ,this could be the drops, the box ,the diff or the tyres .the lower the gear ratio the higher the torque after the box ,so thats harder on the diff and the tyres,the drops and input shaft of the box experience the same torque whatever gear your in , but will experience a greater chance of breakage due to the oportunity for shock loading in the lower gears creating stress.if one wants to enjoy the increase in power of enough boost to create say 140lb /ft of torque ,but wishes to avoid the breakages that could ensue with that output it seems to make sense to run a bit less grip which will be ok above 40 or 50 mph ,but with or without wheelspinning would put less stress on the box in the lower gears due to the reduces torque handling capacity ,this would in no way affect ,say 60 to 120 times ,where ill prob most be using my engine on the rd.incedentaly, wheelspining actually piut less torque through the drive train ,but more shock ,so can be less damaging depending on how sensitive the train is to diff types of load.my tvr that runs a weakish 1st gear , i spin off the line to save gearboxes ,means it has only a 2 second 60 ft ,but it still runs a 12.85 in the quarter and doesnt break!

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

The best thing anyone can do is run a boost controller to eliminate the huge slug of mid-range torque the turbo's generate... I mean you basically map the boost target against RPM, such that at up to 4000rpm it peaks at say 14psi, 4250 it's at 15psi, 4500, 16psi, 5000, 18psi, etc....

The exact amount of 'damaging' mid-range boost (and hence torque) can then be adjusted depending on the size of your pocket! LOL!

I'll be running ECU controlled boost this year - so long as i can find a suitable solenoid valve (50+ hz and relativly high flow)...

Edited by turbodave16v on 9th Feb, 2006.

dave how bout a progressive n2o solenoid?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Apparently if your tyres break traction, grip, break traction then grip again as with any road tyre, there is more chance of something breaking than if you were to use big sticky slicks, and I probably agree with whoever told me that, but I cant remember who it was.
Paul

I seriously doubt it!

That is called 'bump load' and is indeed a MASSIVE shock loading.
The worse case we use as an example is a fully laden truck in winter. Wheels are on ice, so no traction. Driver floors the throttle in 1st gear and holds it. Slowly, the truck moves, then the tyres on the loose wheel (heavilly laden remember) grip the tarmac....


The forces are astronomical - hence large safety factors need to be adopted.

So stickier tyres are less likely to break your car than the skinny ones that this thread is all about.
Paul

I seriously doubt it!

More or less yes, if the tyres are sufficiently sticky to transmit the maximum torque produced by the engine to the road without spinning the wheels, then the loading is uniform.

Shock loading caused by wheel spin and then gripping again causes far more load to be transmitted through gearbox components. This resultant load is FAR more than produced by the engine alone.

Edited by Tom Fenton on 15th Feb, 2006.

But Skinny tyres, once they regain traction, will just as easilly become the 'fuse' and limit the ultimate torque spike... Managing to break slicks loose (say there was a bit of gravel or mud on the startline of an otherwise very-well prepared track - This would be MUCH worse!