944S2 Track Car Project - Spa April 2019
- Thread starter edh
- Start date
Gets everywhere, doesn't it! [
]
What happened?
Regards
Mick
]What happened?
Regards
Mick
edh
New member
No bills on trackdays...
I was at Coppice, catching a Clio RS at the end of the day & got a bit greedy with the power just after the first apex.. probably a bit tired after ~160 track miles
Rear pads are very low, will probably swap the half worn fronts to the rear & replace with some new PFC 08's
I was at Coppice, catching a Clio RS at the end of the day & got a bit greedy with the power just after the first apex.. probably a bit tired after ~160 track miles
Rear pads are very low, will probably swap the half worn fronts to the rear & replace with some new PFC 08's
edh
New member
I exceeded the friction circle.... doesn't really matter what tyres they were (AD08R's in this case if you really want to know)
Fast 4th gear bend, & the rears were still busy dealing with cornering & I added too much throttle.. Not usually a problem as the slide is normally quite gentle, but I suspect I wasn't really concentrating.
Fast 4th gear bend, & the rears were still busy dealing with cornering & I added too much throttle.. Not usually a problem as the slide is normally quite gentle, but I suspect I wasn't really concentrating.
Was probably getting cold and damp too, shows you were tryingedh said:
Strangely I had to copy and post the link into a new tab to see the picture, nice souvenirs, might take a few attempts to make a garden path though
[link]https://thumbsnap.com/ohQBiX7h?src=tsd[/link]
924Srr27l
New member
edh said:
Oh ! the friction circle would be better though with softer / better tyres only the Ad08R's are quite hard (Treadwear 200) Toyo R888;s are 100 and Yoko A032R are 80 or 60, these would of been far superior to the Ad08R's.
Do you have a LSD fitted? and aren't your rears a wider rim & Tyre (Staggered) compared to the fronts?
Only this will affect which axle losing / breaks away grip first. The car as you know is as close to 50/50 weight distribution
than most cars and having a different shape contact patches on the front & rear will make one axle snappy when the slip angle is exceeded. This can be used to alter the balance, but generally a "square" set up (Same size Rim width & Tyre size) front and rear will offer a set up less prone to snap oversteer in this case.
On the 924 Racecar I've currently got too much rear grip and need to get this axle to pivot and slip more than the front to reduce the understeer........I'm looking to test 7"x16" Rims and 205/50/16 Dunlop Direzza Tyres to see how they perform.
Have you got a total weight on the car (Less driver) ?
R
edh
New member
AD08R's are a great compromise for a road legal track car - work well in wet, dry and wear rates are great. Performance is close to track tyres in my experience (and in magazine tests). the previous 08's were definitely the fastest list 1A tyres.
They are a square setup - 225/45/17 on 8J rims. No LSD (i'm a cheapskate..) but I would prefer one.
No idea on total weight - less than stock though
The car handles nicely although is possibly a touch "loose", might experiment with slightly softer rear springs. (50N rather than 60N).
They are a square setup - 225/45/17 on 8J rims. No LSD (i'm a cheapskate..) but I would prefer one.
No idea on total weight - less than stock though
The car handles nicely although is possibly a touch "loose", might experiment with slightly softer rear springs. (50N rather than 60N).
924Srr27l
New member
edh said:AD08R's are a great compromise for a road legal track car - work well in wet, dry and wear rates are great. Performance is close to track tyres in my experience (and in magazine tests). the previous 08's were definitely the fastest list 1A tyres.
They are a square setup - 225/45/17 on 8J rims. No LSD (i'm a cheapskate..) but I would prefer one.
No idea on total weight - less than stock though
The car handles nicely although is possibly a touch "loose", might experiment with slightly softer rear springs. (50N rather than 60N).
Ok good, a square set up is not the oversteer issue then, or would the power be enough to break traction in 4th gear unless it was wet, greasy etc...
Yes I agree a compromise has to be made for a car used on the road and trackdays and on a reasonable budget, I was told by a winning 944 S2 the AD08R's are terrible unless it's wet
so as they are twice as hard as R888's that I've used on and off track I've not attempted to try them!
I did 2+ years (And 6000 miles) with the 924 on the road with a few trackdays
at Donny & Oulton Park, but once it was taken off the road and used in competition for the first time the car was no where near competitive at all.
Is 60nm the only spring on the rear (Coils?) and the torsion bars are removed?
It's all weight and use related but I started with Front coils @ 30Nm and rear T bars and Coils combined at 52Nm, but the car was 10 seconds a lap off the pace and Rolled far too much, which it didn't do at
all on trackdays or on the road, but Racing is 5 levels up and then some....
Phase 2 included adding aerodynamics and an increase in spring rates to Front 75Nm and rear 113Nm coils (T Bars removed) which was a huge improvement placing the car only 2 seconds per lap
off the championship leaders, but the car still moved about too much.
This year's Racing & phase 3 will be Front 625lbs / 100 Nm and 800lbs / 140Nm Rear and more Aerodynamic aids, the car weighs 1025Kg
R
edh
New member
Rear is 60N springs + std TB's..
90N fronts
KWv3 dampers
(KW Clubsport spring spec is 90/50)
I increased the front rate after discussion with KW as I was getting roll oversteer in fast bends (like Craner Curves).
Yes I can spin the wheels in the dry in 4th if the tyres are using the majority of their available grip to corner..... I just needed to be more progressive (or a bit later) on the throttle in this instance.
FWIW the AD08R comes with a full 8mm tread, so much more than most semi slicks (5mm IIRC). It feels like a semi to drive - none of the squealing you get with most road tyres
It also wears incredibly well on tracks - unlike most road tyres it doesn't overheat and wear. I am amazed how many days I get from a set.
(In comparison I got through around 4mm of the Falkens on my Boxster in one cold/damp 'ish day at Snetterton)
I'm happy to sacrifice a bit of ultimate grip for longevity, and at just over £100 each in my size 225/45/17 they are incredibly cost effective.
90N fronts
KWv3 dampers
(KW Clubsport spring spec is 90/50)
I increased the front rate after discussion with KW as I was getting roll oversteer in fast bends (like Craner Curves).
Yes I can spin the wheels in the dry in 4th if the tyres are using the majority of their available grip to corner..... I just needed to be more progressive (or a bit later) on the throttle in this instance.
FWIW the AD08R comes with a full 8mm tread, so much more than most semi slicks (5mm IIRC). It feels like a semi to drive - none of the squealing you get with most road tyres
It also wears incredibly well on tracks - unlike most road tyres it doesn't overheat and wear. I am amazed how many days I get from a set.
(In comparison I got through around 4mm of the Falkens on my Boxster in one cold/damp 'ish day at Snetterton)
I'm happy to sacrifice a bit of ultimate grip for longevity, and at just over £100 each in my size 225/45/17 they are incredibly cost effective.
924Srr27l
New member
edh said:
It must be the lack on a LSD then as 4th gear spinning wheels in the dry at what 75mph+? and with a normal aspirated car 220bhp and 1300kg? the power to weight is much less than the 924
@ 200 bhp per ton and it doesn't wheel spin anywhere in the dry round Oulton Park, Donington or Silverstone the lowest gear used being 3rd with a 3.889 FDR box.
Your stock Torsion bars will add 24Nm of resistance to the coils, Total (84Nm) you could take out the T bars and fit coils only at 70Nm which would be far easier to set the ride height and should reduce the
oversteer "loose" rear end, you could also increase the front damping and reduce the rear settings.
Yes the AD08's have a much stiffer sidewall compared to any road only tyre even Michelin Pilot Sport's etc..which is why they can sustain the high heat generated by hard circuit driving,
which as you found out with the Jap Falken Road tyres are not ideal as with this excessive Heat the rubber compound can't cope and overheats and wears out rapidly! and vice versa why the Ado8's
last longer than Road tyres. If you went down to 215/50/16 and on 8x16 Rims each R888 is about £130 each and your performance will go up a level.
R
edh
New member
924Srr27l said:
I'm sure you could easily lose rear grip at Oulton by planting the throttle just after the apex (if you were cornering fast enough). All you have to do is exceed the maximum grip that the tyre can offer.
Removing the torsion bars is a big job (much bigger than swapping the springs anyway) Ride height is just fine at the moment.
I don't believe 888's would be much quicker (if at all on 16's) & would certainly cost much more. I'm not going to do that for ~a second a lap (I'm not racing). I'm trying to spend my money on track time, not shiny bits (although I have failed that test with the GTP lights..
)Just booked Spa for early April - what a great circuit!
I have seen (a good few years back) photos of a broken rear suspension arm on a track car with torsion bar delete, I don't know what spring rates they were running or how hard they were hitting kerbs, they were going back to running a torsion bar / lighter coil over setup though. Not entirely sure why it should happen but I guess down to leverage as the wheel rises suspension compresses, the weight of the car is acting downwards on the other end of the arm. The break was pretty much midway along the arm.
Tony
Thinking the GTP dual lens lights look great (similar to what I always fancied trying!) and will free up some under bonnet space.......
Tony
Thinking the GTP dual lens lights look great (similar to what I always fancied trying!) and will free up some under bonnet space.......
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