Fulcrum2000 Posted March 10, 2020 Share Posted March 10, 2020 Hi All Ok so I finally managed after basically rebuilding my Supra underneath and having my engine rebuilt to achieve BPU today with the HKS EVCVI being fettled in by a tuner. The car is superb but I have a couple of questions that I am sure other owners have come across at BPU I need help with. I'll post them separate so here goes for this one: At BPU my car has significant wheelspin from the line I'm currently on Pirellis front and Falkens rear (they have the shortest brake distances for my 18s apparently according to the tests) but now I need to get as much grip s possible are Pilot SPort 4s the best way to go? Most people agree they are but a tuner I know says Nankangs are actually a better tyre for a Supra? ALso I'm on a 35 side wall all round, he says I need to go 30 would we agree or does it make no handling difference at all? I'm happy to buy a new set of boots all round if it increases handling even though my current tyres have only done a few hundred miles and now I have CW fast road pads my stopping distance is good anyway. Any advice would be welcome. Quote Link to comment Share on other sites More sharing options...
Boyne Posted March 10, 2020 Share Posted March 10, 2020 If you launch manual bpu supra as hard as possible no tire will stop wheel spin, however mixing tyres on car with 400+ hp not good idea, I ran 245/45/17 up front 265/40/17 rear handbook ventus I have newer falken fk510 on the 18tte wheels 285/35/18 there very good. I have new set Michelin pilot sport 4 going on 17s soon will update what think them. Another really good one I use on daily driver is good year eagle f1 asymmetric 5. You might want make sure the tracking is set up correctly that could help with traction to. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted March 10, 2020 Share Posted March 10, 2020 Been using goodyear asymmteric 1 & 2 on my BPU, no issues. I had Falkens, not as good as the GY, and wore out very fast. Currently PS4 or GY asymmetric 5 are would be a good choice. I have the asymmetric 5 on my GTI, they are really good. Quote Link to comment Share on other sites More sharing options...
rider Posted March 10, 2020 Share Posted March 10, 2020 I must be doing something wrong as I have never managed a wheel spin in the dry, although it is something very easily achieved in the wet. The Falken tyres are quite a soft compund tyre. Good for grip but not the longest life tyres around. So you can't really move to a much grippier tyre. Assuming the tread is in good shape, your only option to increase grip would be to go for a wider tyre and drop the pressure a little. Myself, I find its best to leave the launch starts for dry conditions and the premium (Bridgestones at the moment) 245's grip all day long. Quote Link to comment Share on other sites More sharing options...
rider Posted March 10, 2020 Share Posted March 10, 2020 As for thinking of going for a lower profile tyre to increase grip, that is entirely the wrong direction. A higher profile tyre or smaller wheel will give more flex in the tyre which increases the grip under acceleration. Fit standard 16 inch wheels (on a jspec) with a soft 50 profile tyres and that'll help. Quote Link to comment Share on other sites More sharing options...
Fulcrum2000 Posted March 10, 2020 Author Share Posted March 10, 2020 If you launch manual bpu supra as hard as possible no tire will stop wheel spin, however mixing tyres on car with 400+ hp not good idea, I ran 245/45/17 up front 265/40/17 rear handbook ventus I have newer falken fk510 on the 18tte wheels 285/35/18 there very good. I have new set Michelin pilot sport 4 going on 17s soon will update what think them. Another really good one I use on daily driver is good year eagle f1 asymmetric 5. You might want make sure the tracking is set up correctly that could help with traction to. Mines a JDM Auto and I noticed it had wheelspin pre 400 before I finally added the BC to take it to full BPU to be honest. Clearly Falkens arent the way to go. Interesting about tyre wall though, so it would be better to stiffen the suspension and stick to better 35s we think like Pilot 4s? Quote Link to comment Share on other sites More sharing options...
Dnk Posted March 10, 2020 Share Posted March 10, 2020 I think adapting how you drive the car is the best solution Also have you ever had the geometry looked at ? Quote Link to comment Share on other sites More sharing options...
Fulcrum2000 Posted March 10, 2020 Author Share Posted March 10, 2020 I assume you mean camber etc? I actually put a separate thread on about this this morning. When i had the car restored I put another rear subframe with fully adjustable arms on but I wondered if anyone knew what settings to use on it as I dont have a clue. Anyone have any ideas? I dont mind uneven tyre wear if it increases handling. Quote Link to comment Share on other sites More sharing options...
Dnk Posted March 10, 2020 Share Posted March 10, 2020 (edited) I assume you mean camber etc? I actually put a separate thread on about this this morning. When i had the car restored I put another rear subframe with fully adjustable arms on but I wondered if anyone knew what settings to use on it as I dont have a clue. Anyone have any ideas? I dont mind uneven tyre wear if it increases handling. Yes camber toe castor This is what center gravity set my car up too, it was running 11" wide rears with 295 35 19 and was lowered on Eibach pro sport springs with OE dampers and TRD roll bars Tyres i used on it were RE05's and Contisports contacts I don't re call having any issues in the dry other than the driver running out of talent at Silverstone one day Edited March 10, 2020 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Fulcrum2000 Posted March 10, 2020 Author Share Posted March 10, 2020 Wow thats so helpful thanks so much I will ask a mechanic to do this for me Quote Link to comment Share on other sites More sharing options...
Dnk Posted March 10, 2020 Share Posted March 10, 2020 No problem Quote Link to comment Share on other sites More sharing options...
Scooter Posted March 10, 2020 Share Posted March 10, 2020 At BPU the 1st to 2nd turbo transition can be brutal and unsettle the tyres at WOT. Getting the geometry done will rule that out, do you perhaps have an open diff? That can make the spin up/loss of traction easier (and then when it happens it'll stay happening longer/require more throttle easing) Quote Link to comment Share on other sites More sharing options...
Fulcrum2000 Posted March 10, 2020 Author Share Posted March 10, 2020 At BPU the 1st to 2nd turbo transition can be brutal and unsettle the tyres at WOT. Getting the geometry done will rule that out, do you perhaps have an open diff? That can make the spin up/loss of traction easier (and then when it happens it'll stay happening longer/require more throttle easing) I dont have an LSD I have the standard diff - I chose the HKS as it controls both turbos and we have calmed the transition somewhat but yes it is a kicker! I feel the Falkens are especially the cause - ar emost people running 285s as oppose to my 275s then? my rear wheels can take 285s they're 9.5 I think Quote Link to comment Share on other sites More sharing options...
Dnk Posted March 10, 2020 Share Posted March 10, 2020 I think you need an lsd Quote Link to comment Share on other sites More sharing options...
Fulcrum2000 Posted March 10, 2020 Author Share Posted March 10, 2020 I think you need an lsd Yeah I thought so too until I talked over it with people on here and they dont seem to be absolutely essential, many people who upgrade have said its not really particularly better if you've 'learnt' the car without one but obviously not having one I dont know. I might consider it but its definitely seemingly tyres that are giving or at least it feels that way to me. Quote Link to comment Share on other sites More sharing options...
Dnk Posted March 10, 2020 Share Posted March 10, 2020 Yeah I thought so too until I talked over it with people on here and they dont seem to be absolutely essential, many people who upgrade have said its not really particularly better if you've 'learnt' the car without one but obviously not having one I dont know. I might consider it but its definitely seemingly tyres that are giving or at least it feels that way to me. I struggled to light my rears up in my UK car which had an LSD, in the dry it just squatted and took off Quote Link to comment Share on other sites More sharing options...
Scooter Posted March 10, 2020 Share Posted March 10, 2020 Yeah I thought so too until I talked over it with people on here and they dont seem to be absolutely essential, many people who upgrade have said its not really particularly better if you've 'learnt' the car without one but obviously not having one I dont know. I might consider it but its definitely seemingly tyres that are giving or at least it feels that way to me. Ah the smoothing of the transition via the boost controller will help, but the thing with the open diff is that once the traction is lost from the tyre with less grip, that one will spin up and no drive is given to the other wheel with more grip so you have to ease off a fair bit to stop the wheel spin - it goes from 100% to 100% wheel spin with little in the middle! All things (tyres road conditions throttle input etc) being equal with a lsd it'll wheel spin later and require little/sometimes no throttle change to stop. With a LSD it can seem 'lively' though if you are used to an open diff. The open diff's nature means the rear doesn't tend to go sideways much on wheel spinning. The LSD grips more but when, even with this advantage you over power the wheels, you over power both at the same time and so if you are not in a straight line when it happens you can get a far more pronounced rear drift/shift than you're used to. All high powered sporty fwd drives benefit from having one too, it's good for traction but also handling/balance/control as you get nearer 10/10ths. Quote Link to comment Share on other sites More sharing options...
Fulcrum2000 Posted March 11, 2020 Author Share Posted March 11, 2020 Ah the smoothing of the transition via the boost controller will help, but the thing with the open diff is that once the traction is lost from the tyre with less grip, that one will spin up and no drive is given to the other wheel with more grip so you have to ease off a fair bit to stop the wheel spin - it goes from 100% to 100% wheel spin with little in the middle! All things (tyres road conditions throttle input etc) being equal with a lsd it'll wheel spin later and require little/sometimes no throttle change to stop. With a LSD it can seem 'lively' though if you are used to an open diff. The open diff's nature means the rear doesn't tend to go sideways much on wheel spinning. The LSD grips more but when, even with this advantage you over power the wheels, you over power both at the same time and so if you are not in a straight line when it happens you can get a far more pronounced rear drift/shift than you're used to. All high powered sporty fwd drives benefit from having one too, it's good for traction but also handling/balance/control as you get nearer 10/10ths. It sounds like I may need to look into LSDs then but the first thing I need to do is get the geometry set up and put better tyres on I feel and see how that goes. I'm always capable of catching any tank slappers at speed (he says) but it is just off the line where I really need less wheelspin most but it sounds like an LSD may be the way forward. I guess I'm really used to driving without one though, my daily driver is a 535D which is very powerful and for some reason was never given an LSD as well. Excuse my ignorance but when I looked there are several types, 2 way interchangable and the likes, which one is the one for the Supra? - - - Updated - - - Ah the smoothing of the transition via the boost controller will help, but the thing with the open diff is that once the traction is lost from the tyre with less grip, that one will spin up and no drive is given to the other wheel with more grip so you have to ease off a fair bit to stop the wheel spin - it goes from 100% to 100% wheel spin with little in the middle! All things (tyres road conditions throttle input etc) being equal with a lsd it'll wheel spin later and require little/sometimes no throttle change to stop. With a LSD it can seem 'lively' though if you are used to an open diff. The open diff's nature means the rear doesn't tend to go sideways much on wheel spinning. The LSD grips more but when, even with this advantage you over power the wheels, you over power both at the same time and so if you are not in a straight line when it happens you can get a far more pronounced rear drift/shift than you're used to. All high powered sporty fwd drives benefit from having one too, it's good for traction but also handling/balance/control as you get nearer 10/10ths. It sounds like I may need to look into LSDs then but the first thing I need to do is get the geometry set up and put better tyres on I feel and see how that goes. I'm always capable of catching any tank slappers at speed (he says) but it is just off the line where I really need less wheelspin most but it sounds like an LSD may be the way forward. I guess I'm really used to driving without one though, my daily driver is a 535D which is very powerful and for some reason was never given an LSD as well. Excuse my ignorance but when I looked there are several types, 2 way interchangeable and the likes, which one is the one for the Supra? Quote Link to comment Share on other sites More sharing options...
Chris Bailey Posted March 11, 2020 Share Posted March 11, 2020 I’ve recently purchased a pair of Maxxis Victra Sport VS5’s, they get a better dry and wet rating than the Michelin Pilot Sport 4’s and worked out £50 a corner cheaper for my GT86. I am very impressed with them so far, grip has vastly improved over the Toyo Proxes T1R’s I had before! They were awful tyres. Might be worth considering the Maxxis, have a look at the reviews and make your own mind up Quote Link to comment Share on other sites More sharing options...
Scooter Posted March 11, 2020 Share Posted March 11, 2020 It sounds like I may need to look into LSDs then but the first thing I need to do is get the geometry set up and put better tyres on I feel and see how that goes. I'm always capable of catching any tank slappers at speed (he says) but it is just off the line where I really need less wheelspin most but it sounds like an LSD may be the way forward. I guess I'm really used to driving without one though, my daily driver is a 535D which is very powerful and for some reason was never given an LSD as well. Excuse my ignorance but when I looked there are several types, 2 way interchangeable and the likes, which one is the one for the Supra? My new 645 BMW doesn't have a LSD diff either..........and my Supra doesn't currently but I have one to put in. I'm just busy and old now and so rarely miss the LSD, however the BMW is manual and I know it would be more fun with one. The Supra deals with general driving and wot ok as is but again due to my age I just don't find myself 'on it' much and so don't miss it 'much' (or not enough to fit the one I have in the garage yet) With BMW I think they dropped it for the cost but also that 99% of drivers wouldn't notice and the traction control systems got better such that they can mimic a LSD to a degree, the 645 has a full on traction/stability mode (that's you barely feel it working) and then a half way house (allows a little play but then kicks in) and a totally off (which is when the lack of a real lsd shows itself most and is frustrating) But yeah see how the goemetry and really good tyres goes, they both will help Quote Link to comment Share on other sites More sharing options...
Dnk Posted March 11, 2020 Share Posted March 11, 2020 It will be interesting to see what the geometry is now before they do any adjustments, it could be one side is quite a bit different to the other letting it spin up more easily. I'd do the geo before changing the tyres Quote Link to comment Share on other sites More sharing options...
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