RotorMotor

iTrader: (5)

what are the most g's id be able to pull (on a skid pad, etc) while still having a car that is "streetable" ... and what would i need to improve to get there? i realize thats a very very broad question... but with "streetability" in mind what would you guys recomend??

as for the why.... i like to corner hard, and im basically rebuliding my project car.... so nows the time to upgrade (while the entire car is torn down to the chassis). thanks guys. -heath

Riccardo

iTrader: (1)

Definetely 1g+

skunks

ummmm why not throw some slicks on, warm them up and then go for a run? haha that is actually a bad idea for a varity of reasons but the concept is right, why not just try it out for yourself? i mean seriously, how the hell would we beable to tell you what your car could possibly do with out knowing jack about the mods you already have, the mods you are willing to do and the mods you want to do???

dgeesaman

iTrader: (7)

Tires, Tires, Tires. It comes down to tires, and your definition of a streetable tire. If R-compounds have acceptable rain and wear rates for the street, then that's the way to go.

Dave

DamonB

This car bone stock will out corner most anything else. If it's mostly street driven I wouldn't bother with anything other than good tires.

PhoenixDownVII

The supra edged it out stock to stock though?

But I think it must be due to the tire size and type they came with, quite different.

RotorMotor: You already have a perfectly balanced car, just lower it (Think: Howard Coleman's suggestions), sway/strut bars and as others have said: Better/Bigger Tires.

Riccardo

iTrader: (1)

The supra edged it out stock to stock though?

This is not true
Where are you basing the information on ?
Definetely not the R1

CrispyRX7

iTrader: (139)

Skidpads maeasure sustained lateral G's only. Keep in mind sustained lateral G's do not translate in to handling agility. Where weight is the significant contributor when it comes to weight transfer. Compare a heavy Supra to a 3rd generation RX-7 to a lightweight Lotus Elise. Think a Supra can outhandle an Elise? I'd daresay that these three have very comperable skidpad numbers. Skidpad data is only one of many factors that dictate a cars capable level of grip.

Want numbers? I'll throw this out for genral consumption:
For a skidpad:
Lateral Accelleration = 1.22 x Circle radius (ft)/ [lap time (s)]^2

The circle radius is to the middle of the circle, ie the car straddles evenly
the 100ft radius circle line.

For any Circle or corner
Lateral g = [speed (mph)]^2 / (15 x turn radius (ft)]

Braking deceleration = speed reduction (ft/s) / time (s)

example 60mph = 88ft/s
so stopping from 60mph to 0 mph is a delta of 88ft/s
if it takes 3 seconds to stop
88ft/s / 3s = 29.3ft/s^2 = 0.91g's

Similarly the revers for acceleration

And FWIW I think My FD on worn and very heat cycled rock hard Yokhama A032Rs generated over 1G. Something like 1.04ish. It's been a while. And this was in novemebr temperatures on a less than perfect pad surface, aka a marked parking lot.

FWIW,
Crispy

PS the skidpad #'s came from one of the major magazines testing back in the mid 90's IIRC when the Supra first came out and the FD was still on the market. I don't recall the specifics

importrx7

Yes it did go look at the motor trend articles where they tested both cars. The supra just barely beat it in that test.

Toyota Supra Turbo: .98G
Mazda Rx-7: .97G

Kento

Exactamundo. Skidpad numbers are often bantered about like dyno numbers; too many people look at an ultra-high number like it's the Holy Grail of handling.

Driving around a skidpad allows you tons of time to carefully adjust throttle/steering input to keep the car in the most neutral turning attitude possible. You (and the car) don't have time to make those adjustments when you've just peeled into a corner to strafe the next apex. If the car's suspension or weight distribution can't handle the weight transfer that occurs at that point, or the power delivery is too rough, you'll be spending your time and speed correcting for those problems, rather than making time to the next corner.

EFS.O

I've hit nearly 1.1 lateral G's with 4 years old michelins in stock rims,with "untuned" koni yellow's,and 60.000 miles stock springs,but in "brand new" asphalt road.G-tech is the proof

Kento

Um, yeah, it also shows that you never got above 3000 rpm, and that the span of the swerving from left to right you did took less than 12 seconds...

EFS.O

Yep,it was just for fun.I will log it on the track when i get new tyres and adjust my suspension.

CrispyRX7

iTrader: (139)

EFS.O
Those are not sustained G's which is what a skidpad is measureing...but I'm sur eyou knew that . Instantaneous dynamic G loads can in some instances exceed 2 G's.
Want to test? Go to a parking lot and run in a few *complete* circles and then average the G load for a complete circle
BTW the G-tech although accurate will skew the results due to the roll of the car on it's suspension during cornering. I don't know if the newer G-tech can compensate for this yaw. My data points were also taken with a G-tech and confirmed with a stopwatch around a measured circle. The peak G-tech values were slightly off from the timed/measured/calculated average around the circle

Love the traction circle function of that software BTW.
Regards,
Crispy

DamonB

This was during rain; concrete surface. Chart on left was on 245/45/16 Victoracers and chart on right was on 225/50/16 Kumho MX. Both on stock wheels, stock springs, Koni shocks and a Tripoint front swaybar.




This pic is a different day on the same dry surface on 245/45/16 Hoosier SO3 with the friction circle displayed as well.

EFS.O

As i said b4,it was just for fun.I have some "g-experience" from my racing go-kart(those things pull some serious G's).As i mentioned before,the truth awaits at the racetrack

PS That g-tech really rocks for its price.....

RotorMotor

iTrader: (5)

its actually not perfectly balanced any more with that extra rotor hanging over the fron axle . im still waiting to tow it in to one of hte local shops that can tell me my corner weights... but i bet its not TOO far from stock.

RotorMotor

iTrader: (5)

the mods i already have? the only thing that came with my project car are some KYB's and some lowering springs, and some stock rims. this is all being junked for a set of Tein HA's (highly recomended to me by howard coleman ), and some of the 99 spec 17" rims (235's up front, and 255's in the rear). tires are still TBA... i have some S02's on my other 7 and i dont like how they feel at the limit, and their ability on wet roads could be better. im considering toyo t1's for various reasons (i have them in the 225's on my miata now... yeah yeah its a different car... but whatever compound they use seem to be easier to recover when they break free, not to mention how great they are once it starts raining).

those are the planned modifications so far in addition to some (relatively) agressive alignment specs. im wondering (while the car is torn apart and im in the parts buying stage) if there is anything else that the experienced people would recomend being upgraded (ie tow links, sway bars, new bushings, etc etc). hopefully thats a little bit more specific. thanks guys. -heath

RotorMotor

iTrader: (5)

im gonna give this a bump, if any one else has suggestions

M104-AMG

iTrader: (8)

What software and who's data acquisition are you running ?

Can it be installed easily onto a stock FD ?

:-) neil

Kento

Check out the Race Car Tech section for DamonB's thread here.

DamonB

Ran the Kumho V710 for the first time ever yesterday and am still getting the car sorted on the new tires. The good news? It ain't perfect yet and I'm pulling over 1.3g!!!!

I'll have results in the Geez thread within a couple days.

RotorMotor

iTrader: (5)

so the question then becomes... what is your suspension set up? is this for a strictly track car? personally, my application would be for street/tract (mostly street) for my 20b build up. -heath

DamonB

My car is startlingly stock. Suspension wise I have Koni yellows with stock springs, a Tripoint adjustable front sway bar and of course R compound tires. Alignment is currently 2 degrees of negative camber front and rear with 1/8" of toe-in in the rear and 1/16" of toe-out in the front, but that may change a little soon. My car is daily driven.

DamonB's garage

YELLOWGSLSE

iTrader: (7)

1994, Car and Driver tested the R2 at .99g. One of the highest numbers for a mass produced car at the time.