sleeper? bet he's never heard it called that before!

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2 grand is a bit steep for a rear end set up like the r31 dont you think?
Ive search all other the site and net, and found no cheaper alternative. Found a few guys converting to IRS and thats most likely my best and cheapest option.

unless anyone else has a good option that can handle 350-400whp and launch on slicks (just incase I try them someday lol) ofcourse must be lsd

I'm just going to leave it. you've asked the same question, about 'why not a 155' (albeit slightly differently worded) and I've answered it multiple times- that eventually you get to the point it just over taxes the small amount of tyre, it overheats or just plain tears it up, and it lets go. Oddly enough it _is_ actually proof that the tread is gripping as well. It's just that it ends up tearing itself (at the microscopic level) away from the tyre. I could just as easily ask 'well why not run tyres 2 metres wide?'

At 2 metres wide put more camber on that, and you'll get to the point that the outside half of the tyre never touches the ground during cornering. At that same camber level a thinner tyre can and will make full contact. I realise it's an 'out there' example, but it illustrates the point.

Of course it isn't that simple, and that's what I'm getting at. you'd have to factor in where the weight is being transferred, and look at optimising it to hit the middle (more or less) of the tyre contact patch.

You could also (demonstrably) get to a point with tyres where they are just so large (admittedly beyond the scope of any practical fitment) that it's impossible to get enough heat into them to make them work, in a competition sense.

Take any sport bike, and with a competent rider, they will pull more g's for longer periods, under hard braking, than they can accelerate. The front does probably more than 90% of the braking? But oddly enough, using a smaller tyre than the rear. Now of course I'm deliberately doing an apples and oranges here. The rear tyre is bigger, so that (at similar overall treadwear rates for a given stressor on the same compound front and rear) the rear lasts the distance, since it is (overall) being used to transmit force for most of the time, the front doesn't come into play (relatively) much at all during the point of corner exit where the bike is mostly upright, and so on.

You also want to factor in scrub radius changes, changes in offset and track (which I've mentioned).

Like it or not, within sensible ranges, tread compound is important. As is suspension geometry configured to maximise download/weight transfer onto the tyre.

They were the two points I made and I stand by them. Beyond that I'll agree to disagree.

With regard to tyre temps, I used the term pyrometer, but I meant it as a more general term, I was just curious about tyre temps, of the previous set and subsequent set you used as the example. I wasn't nitpicking about _how_ they might have been measured. To which end, if you could expand upon whatever data you got on tread temps, I'll certainly read (but as mentioned I won't respond, it's clearly of no productive value).

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D, there is a reason most if not all the supercar beating tb48 turbo patrols running huge hp are in dubai...... money is not a limit
And everything is compared to a 2jz(3 liter motor made in 1992),including tb48t, for a reason....

In regards to the tire temps, what type of equipment do they use to record such data as car is being driven?and where would the sensors be installed to measure the heat and wear in the tires and g-force on car?

and there is a v8 4wd 240z in Victoria,Oz and it apparently handles very well.Many victorians might have seen it in easternats sandown before they closed/stopped the event.This 240z was very fast!!!Also runs wide rims/tires.
Heres the link to one of its hillclimb events,

http://www.youtube.com/watch?v=AQjXsvEhLyQ

anyone knows which 4wd system he was running as it could help this thread?

lets get through your temp/overheating variables as well - a 155 won't have the same grip as a 195 when its dead cold launching from a standing start, or in the first couple of laps before its overheated, or in a short squirt through a couple of corners during general street driving (where tyres don't get excessively hot).

As I said, my example of the wider tyre was on the rear, so there is no scrub radius consideration! All I changed was the tyre width, not the wheel, so no change in track or offset which is why I didn't mention them.

I have data that shows I was generating a fairly consistent 0.1-0.15 more G with the wider rear tyres on because instead of braking traction with the rear end, they just keep on gripping. You can throw in as many inapplicable variables as you want and theories as to why wider tyres don't offer more grip, but you'll have a dickens of a time convincing my accellerometer and timing system that wider tyres don't grip better.

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real time data would be infra-red temp sensors. G force is simple accellerometers. There's heaps of affordable GPS timing systems with accellerometers available these days - every second guy at sprints/track days has them.

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saw it a few years ago at the Aus Hillclimb CHampionships up here. He said it was using a Hilux transfer case, so its a locked 50:50 front:rear drive. Surprised me because transmission bind/wind-up should be an issue...