Tyre Pressures - R888

[Zilli]

Hey all,

Im hitting Wakefield tommorrow, and ive got brand new Toyo R888's.... I was wondering what tyre pressure anyone would recommend to me as a good starting point, and perhaps give a breakdown of what having higher and lower pressure is about and what the effects are....

Thanks all for your help

p.s. sorry i thought itd be better to starrt a new thread for this as it's more technical towards the effects of pressures on the track...

[tinkerbell]

33.5 PSI hot.

start at 31 rear and 29 front.

once it gets above 34psi hot, it gets slippery and slidey...

you will understeer more and oversteer more...

[Zilli]

ok... i'll give that a shot... lets see how long itt takes to get them hot to the extent where they will get squirmy....

[tinkerbell]

when set to 33.5 psi hot, it will take about 4 very hard laps before they 'break out' and get too hot...

but if you 'overdrive' the car by using too much steering wheel lock and too late braking, they will 'break out' sooner...

do you have coil-overs?

[Zilli]

yep buddyclub N+.... i suppose it comes down to being rough rather than smooth.... i still consider myself to be a novice anyway so i cant see myself pushing too hard, especially with the new coilovers and new tyres, im still learning...

what would you set the coilovers too?

[Danga]

why dont you start with the street settings you have for the coilovers, from this point do the following:
1. use tinkerbells tyre pressures as a base
2. change the tyre pressures to suit your driving style
3. start making small adjustments to the suspension to suit your driving style
4. repeats 2 and 3 making sure you are making changes one at a time so you know how the car behaves after each change, probably a good idea to check how your tyres are wearing at this point to get an idea of what alignment settings to run the next time you go to wakefield
5. have fun and enjoy yourself

I have probably skipped a million steps in between but that teh broad idea

[Zilli]

thanks for your help all, ended up doing a hand timed 1:16.13... im pretty pleased for a second time out there, the first time i was running on kings and Azenis RT215's

Throughout the day i made sure to have the tyres at 34ish psi when hot (measured straight after i came off) i must say it felt as though there wasnt enough pressure in them...

the car did well, its just im getting a lot of body roll as a result of the new tyres... so im getting some front left scrubbing, and it feels like the car is push understeering, making it very difficult to maintain a consistant line through corners...

I slowly upped the hardness on the N+'s... in the end on 15 front 14 rear i got my best time, a 2 second improvement throughout the day...

I wasnt sure but i thought i could have made the rears harder than the front to get a bit more of an oversteer feel... not sure if this was the case... so i went with what i had...

Any thoughts or ideas on what i can do to try and improve the handling now? i was thinking bigger swaybars to try and keep the car flat throughout corners... i do know i should have lifted the car a bit because it does sit quite low (lowest setting on the front) but i dont see why that should be an issue... im getting scrubbing on the inner guard I THINK....

Any ideas or thoughts would be great

[m0nty]

the car did well, its just im getting a lot of body roll as a result of the new tyres... so im getting some front left scrubbing, and it feels like the car is push understeering, making it very difficult to maintain a consistant line through corners...

That's not a trait of a DC2. Sway bars will help, but the car really shouldn't be rolling too much on semis with coilovers. I haven't driven on R888s before so can't really comment on their characteristics.

Do you know where abouts the tyre was scrubbing? I only had slight scrubbing on my car from turn 3 into 4 on the old surface due to direction change. If it's doing it somewhere else you may be using a little too much steering. This could have something to do with entry speed too. Do you find yourself pushing through corners and exiting slower than you entered?

Next time there try maybe braking earlier and having a slower entry speed to the point where you feel like you have to accelerate through the corner. Slow in, fast out remember. Also, try to get a feel for throttle. You should only really be putting your foot on the accelerator once on exit. If you find yourself adjusting throttle alot on corner exit you haven't got the speed right.

At the end of the day, coilovers and semis and a 1:16 is a good time. So well done.

[Zilli]

hmmmm.... the biggest offender was turn 1 and the second last turn... looking back i was probably steering too much, leaving the turnin too late...

for example, coming into turn 1, id be towards the top end of 3rd... maybe 90-100km/h and id turn in and and get a fair bit of scrub and its hard to hold the line.... ive got video footage, i may ned to examine closer...

its scrubbing (i think, pending inspection) on the front left, on the inner part of the tyre, essentially the inner wheel well...

[m0nty]

hmmmm.... the biggest offender was turn 1 and the second last turn... looking back i was probably steering too much, leaving the turnin too late...

for example, coming into turn 1, id be towards the top end of 3rd... maybe 90-100km/h and id turn in and and get a fair bit of scrub and its hard to hold the line.... ive got video footage, i may ned to examine closer...

its scrubbing (i think, pending inspection) on the front left, on the inner part of the tyre, essentially the inner wheel well...

I think you mean turn 2. Turn 1 is a 5th gear slight turn, almost straight. You go from left of straight to hit apex and finish in the braking zone for turn 2. It is a late turn in for turn 2 but your wheel shouldn't be anywhere near scrubbing there. Turn 2 in a DC5 is 3rd gear and about 4,500rpm. Never really looked at speed there but could always tell rpm thanks to VTEC engagement on the exit.

If you're turning in and getting understeer you've come in far too quick. You should be roughly 50% throttle at the apex taking you to the outside left. If you're still understeering try a slower entry speed with a plan to be on the gas when you hit the apex.

I've got some video of me at WP on digicam tapes but I don't know how to get them onto my HDD without taking up GB of space. If anyone knows how to do it I may be able to post it up. In the mean time I'll search for some stuff on Youtube.

[Danga]

sounds like you are overspeeding into the corner and using too much steering angle to try and compensate for your entry speed...

smooth is fast...

[m0nty]

sounds like you are overspeeding into the corner and using too much steering angle to try and compensate for your entry speed...

smooth is fast...

Perfect example of pushing the car into a corner right HERE. Could've gone quicker with a smoother technique. He used a full turn of the wheel at turn 10 and his exit has a good 10' right of where he could've been. A quick lap but alot of work and fighting with the car to get there.

Sorry if it's anyone from here. Constructive criticism I guess.

[ChargeR]

hmmmm.... the biggest offender was turn 1 and the second last turn... looking back i was probably steering too much, leaving the turnin too late...

for example, coming into turn 1, id be towards the top end of 3rd... maybe 90-100km/h and id turn in and and get a fair bit of scrub and its hard to hold the line.... ive got video footage, i may ned to examine closer...

its scrubbing (i think, pending inspection) on the front left, on the inner part of the tyre, essentially the inner wheel well...

Hmmm. I have already responded to your thread on ozhonda but I had a few more of my random thoughts to add. I agree with monty and danga in that you may be trying to come into turn 2 too hot. My experience with Wakefield is limited (having only tracked there for the first time 5 days ago) but I also had trouble entering turn 2 too fast.

[Zilli]

Monty... thanks a lot for your input man... i did mean turn 2...

I really think my problem is overspeed, and the car is just a little too low... it just felt like it was rolling so much you know... but coming in too hot i think may be the problem... the "smooth" principle is important i think... i was wrestling the car, obvious by the huge roll, the movement off line mid corner and screaming tyres...

The thing is i was accelerating through the turn, i was on the gas towards the end... but i wasnt relaxed, i was really pushing very hard... i suppose i just have to relax

[Zilli]

Perfect example of pushing the car into a corner right HERE. Could've gone quicker with a smoother technique. He used a full turn of the wheel at turn 10 and his exit has a good 10' right of where he could've been. A quick lap but alot of work and fighting with the car to get there.

Sorry if it's anyone from here. Constructive criticism I guess.

that really looks like how i was... his times are quicker, but my car is stock bar an intake and flywheel...

i think we've nailed the issue fella, this is a driver issue not the car!

Thanks boys!