32 Gts T Race Specs

[drifto]

Hello all

I'm rebuilding my Bilstein Coilovers for some more serious track work with my 32 GTS T.

I'm looking for information from anyone who has experience or a source regarding best overall track settings for spring rates and alignment settings.

Perhaps a GTS would be set up closer to the specs of a recent 200sx GTP car rather than a GTR Group A

Any sharing of knowledge on this one would be greatly appreciated.

[Sydneykid]

Hello all

I'm rebuilding my Bilstein Coilovers for some more serious track work  with my 32 GTS T.

I'm looking for information from anyone who has experience or a source regarding best overall track settings for spring rates and alignment settings.

Perhaps a GTS would be set up closer to the specs of a recent 200sx GTP car rather than a GTR Group A

Any sharing of knowledge on this one would be greatly appreciated.

What tyres are you using?

[Roy]

Ooohh im going to like this thread:) I was told there was 3-4 seconds improvement to be gained in better suspension and using my tyres better?!?

I know the Whiteline kit is more for spirited driving then circuit work, but for a 2 min lap, is there really that much improvement to be gained with shocks/springs/geometry etc when running tyres like D01Js.

Good to see an R32 out there getting some stick:)

[drifto]

I am running Dunlop DO1J's, tyre pressure is probulary another thread but due to only getting 9 laps in total for the day over 3 sessions i never really got a chance to play with that. For intrests sake i started with 36psi all round.

I'm very interested to see the set up on a racing 32 as the stock GTR's run heavier rear springs than the front.

I'm pretty sure the king springs in my Bilstein coil overs are rated at 350 pounds front and 200 rear.

I'm not sure if you can make a direct comparison whith a different type of car because of the varying leverage ratios of different suspension designs. But the Keioffice (Drift King's Workshop) S15 silvia runs 9kg front and back for a setup that is suited well to circuits and can go drifting with confidence.

Another S14 on that vid uses 10kg fronts and 8 kg rears.

[t01-100]

I raced an R32 GTSt in the Tasmanian Circuit Series last year called the Octagon Series.

The GTSt is a great track car as you can get the weight so slow much easier than a GTR.

I used Bilstien fully adjustable coilovers that Quadrant build from GTR shocks, these were set to they're recommendations that are on file if you call them. Its the standard GTSt track kit they can supply. The best thing to do is have the top arms in the front cut and shut to get atleast 5 degrees neg on the front, put a whiteline two stage anti-roll bar on the front and set it to the hardest, install a front strut brace and lock the diff up. I ran RE55s on R32 16" GTR rims so we could drop the ride height and they worked a treat.

The competition ready weight of the car was just on 1200kg. I ran a very mild mods, steel wheel turbo on 18psi, afm intercooler with waterspray, unichip and 3" t/b that produced 199kWs at the treads on a Dynologic.

[Roy]

Do cars with wishbone front ends need to run such excessive front end camber? I know circuit cars based on Macpherson struts erun wild amounts of camber, but wishbone cars seem to run less? Any truth or substance to that observastion?

Also with that much camber, under brakes did you find that stopping distances were effected? The inside of the tyres must get pretty damn hot?

I agree with the sway bars, i tightened mine up the other day and car feels much better, will see how the go this weekend at Phillip Island and Sandown...i may put them back to soft for Sandown...will just see how i go

[Sydneykid]

I am running Dunlop DO1J's, tyre pressure is probulary another thread but due to only getting 9 laps in total for the day over 3 sessions i never really got a chance to play with that. For intrests sake i started with 36psi all round.

I'm very interested to see the set up on a racing 32 as the stock GTR's run heavier rear springs than the front.

I'm pretty sure the king springs in my Bilstein coil overs are rated at 350 pounds front and 200 rear.

I'm not sure if you can make a direct comparison whith a different type of car because of the varying leverage ratios of different suspension designs. But the Keioffice (Drift King's Workshop) S15 silvia runs 9kg front and back for a setup that is suited well to circuits and can go drifting with confidence.

Another S14 on that vid uses 10kg fronts and 8 kg rears.

There is another thread going on front camber settings. So pop over and have a read of it as well.

Let me start off this one with my methodology.

The job of a spring is to hold the car up and allow sufficient compliance for riding the bumps. I like to run as soft a spring rate as I can, this means the tyres are in contact with the road as much as possible. As the spring rate goes up the tyres tend to skip over the small bumps and ridges, this reduces traction.

The main job of the shocks is to control the springs, prevent them oscillating after they have been compressed by a bump. Shocks also have to control the stabiliser bars, they are a spring as well. With the sophisticated valving available these days we can also use the shocks to control the chassis movement, lessen the roll squat and dive. This means we can use even softer springs to ride the bumps and hop the ripple strips, which on many circuits is essential for good lap times.

I use stabiliser bars to control the roll, adjustable to alter the balance. They are simply the most effective method, that's why circuit race cars (all the way to F1) have ****pit adjustable bars.

The front suspension geometry is set up for anti dive under brakes, this limits the weight transfer so the rear brakes can help the front brakes.

The rear suspension geometry is set up for a little anti squat, otherwise you get excessive front end lift under power on corner exits (understeer).

The wheel alignment settings are based on maximising the tyre contact patch, the more of the tyre on the road, the more traction. I set that up using a tyre pyrometer, with the aim of equalising the tyre temperatures across the tread. Tyre pressure also have a role to play in this, if the tyre pressure is too low the centre of the tread will not have the same temperature as the outsides. This is because it will not have as much contract with the road. Vice versa for too high a pressure.

The Japanese have a tendency to try and do all of the above with the spring, so they end up with ridiculously high spring rates. They do not have our European based culture of using stabiliser bars, they didn't have a KMac or a Selbys. Plus Japanese circuits are very flat, not at all bumpy like we have here. It is also worth remembering that good Japanese mechanics charge like brain surgeons, so a bolt on solution is much cheaper to install.

Keeping that in mind, let's get specific with a GTST. The rear spring rate needs to be low enough to provide a bit of squat under acceleration, weight transfer to the rear helps the traction. Around 200 lbs is not a bad place to start, hardly ever going over 250 lbs. The front spring rate is determined by "what the tyre likes", some tyres (slicks) need a high spring rate, others (road tyres) need a low spring rate, the "R" compound tyres need something in between. Around 350 lbs is not a bad place to start for a front spring rate.

Front stabiliser bar on front engine, rear wheel drive car is of necessity pretty big. I use a 27 mm adjustable on GTST's. The rear anti roll is tricky, too high a rate and power oversteer becomes an issue. I use a 22 mm adjustable in the wet or on slippery circuits, 24 mm adjustable in the dry on grippy circuits.

Sub frame bushes on the rear are essential for a limited amount of squat, and the HICAS is not your friend, remove it. I run a small amount of toe in on the rear, 1 or 2 mm each side. Camber is not excessive other wise you loose traction under acceleration, between 1 and 2 degrees negative usually gives the best tyre temperatures.

As much caster on the front as you can get, usually 6 to 7 degrees before the tyres start hitting the front of the guards. Front camber, is again determined by the tyre temperatures. I have yet to find a circuit anywhere in Australia where I need to run more than 4 degrees. If I ever do, it will be because the spring, anti roll and shock rates are too low. So I will go up in spring rate or bar size and adjust the shocks rather than use more camber, the car will be faster that way.

That's about it for me, it's racing season and we have 3 meetings in 2 states in 4 weeks, so work beckons. Hope it was of some help.

PS; Tyre pressures are totally dependant on the tyres you use, different brands, different sizes and different compounds require different pressures. For Yokohama 032R’s (the Improved Production Control Tyre) and 048R’s (the Production Car Control Tyre) a hot pressure in the mid 30’s (34 to 36) is what the manufacturer recommends. I would start their and see what the tyre temperatures tell you.

[t01-100]

The camber certainly improved handling and general tyre wear (completely flat wear). The owner of the car and I don't really understand he technical side of suspension apart from the fundametals, so top tarmac rally driver Jason White set up the car similar to his teams 300ZX TT circuit car.

Found braking was not effected by the camber and the vehicle is not fitted with ABS. It still retains standard calipers, Pagid pads and standard size DBA slotted rotors fed cold air by 3" neo ducting right into the veins.

I've now bought an R32 GT-R V Spec 2 to go racing.

[t01-100]

Haven't used Dunlop's before, but in the Bridgstone RE540s and RE55s, 35 cold would be too high at any time. We start the RE55s at 30-32psi depending on track temp. I used RE55s the GTR on the weekend in a hillclimb that was very wet and dropped them back to 27psi with excellent results... bet everyone with a 3 second gap to 2nd!

[t01-100]

Down here we approx 45 race laps a day + free practice in the morning + quailfying.

Races range between 5 and 15 laps. The 15 lappers usually have a compulsory pitstop where a velco sash has to be removed by an official and the standard 40 speed limit applies in pitland as usual.

[Sydneykid]

Sorry, I left out tyre pressure, to make that post complete I have added it, so please have a reread above.

[drifto]

That's great information guys, thanks heaps.

I will post up the mods that i make to the current set up and the results from Oran Park supersprint which is in a couple of weeks.

I believe the rear end definately loses accelerative traction from exessive neg camber. After having the car set up with about 1.5 neg on the front and zero on the rear i now have 3.5 neg on the front with 2.25 neg on the rear. Combined with 3mm toe out on the front and 2mm two out on the rear it is no wonder the car was struggling to get power down and trying to swap ends even in third gear on turns 3 , 4 , 5 & 11 at EC.

The toe out on the rear is suppossed to reduce power over steer. When power is applied the wheel will move forward and reduce the toe out. If you start with toe in the tyre moves further forward under acceleration and apparently break traction quicker because it has a greater lateral angle through the corner. (so i have been told )

It would make more sense so me to use tow in on the rear to prevent the back of the car trying to turn around the front which is what mine wants to do rather then keeping the back of the car tight pushing it towards the inside of the corner.

Alternate theories ??????

My sway bars are standard too, so i don't know where that leaves me but looking at photos of the car from the EC supersprint, you can see the excessive weight transfer to the front out side corner on corner entry. The rear inside wheel is nearly completely unloaded. That also squares up the front tyre and all but eliminates the 3.5 degrees neg camber.

Keep the info coming in i hope it's benificial to lots of members.

[drifto]

Going in today to adjust rear settings.

Taking the camber from -2.25 to around -.5

Changing the toe from 2mm toe out to 2mm toe in.

After Oran Park on Sunday, the next thing we'll change is the coils and valving.

The current coils are variable rate which i forgot to mention so there gotta go. Next test will be at Wakefield then after that i can do back to back test at Wakefield trying different things like swaybars etc.

The plan is to do one mod at a time and record times and feel. I'll keep data on this thread for others.

[Roy]

Please...it looks liek the car isnt selling so want to go gung ho wiht the susp setup now, only the shocks i want are $3500:( Maybe wait a bit longer for Group 4s to become available

[someonestolecc]

Go Roy go. I wouldn't mind taking some tips from you when I get my car working and out there (sometime this year hopefully)

[Roy]

Dont listen to me, i dribble nonsense and cant particularly drive. Talk to Duncan / Fatz etc if you want tips:)

[Gts-t]

First off thanks for the info SK i had my car around at bridgestone just today.

For what its worth i have recently installed new coilovers and whiteline adjustable swaybars.

Settings were:

front

camber around 1.8 neg

caster around 5.8

toe: .3 total .6 in

rear

camber around 1.8 neg

toe: .2mm total .4mm in

I will be intalling whitline front camber/caster, rear camber kit and rear subfame shit, lol, as soon as i get time.

At this point i figure when i install these kits i will set them (the eccentric tubes or whatever) to change the setting(ie front camber) as much as possible in the desired direction(ie closest to .5 neg). And so on.

Another problem im seeing is possibly say for example when i press in the new castor rod bushes, then press the eccentric/metal tubes into them; will i beable to adjust them???? the fit to me looks pretty tight

I dont think i will run different caster side to side as SK has said is benificial, and i think i will adjust the coilovers untill the heights are even side to side. Atm i have set the heights very briefly(15 min) thats why i have aprrox values above as these values change slighly depending on the height you set.

Any advice would be appreciated, cough, SK

Cheers all hope that made some sense its late

[Roy]

Well my rear tyres yesterday were the same temp across the face of the tyre, so i figure that means the rear susp geometry is spot on. But my fronts are 12-15deg C higher on the outside edge then on the inside, so i guess that means i need more camber or need to so something about the body roll?!?!?!...

But ill have a closer look once i get my new shocks...looking to get some DMS 50mm adjustable shocks...so fingers crossed that will make the car a little more balanced, the Whiteline kit is awesome on the street, and fun and neutral on the track, but would like to get something a little more suited to track work:)

Too much bodyroll:( With road tyres....

A...and even worse with the semis...

[Gts-t]

Do u have the adjustable swaybars roy?

[Roy]

Yeh, thats my car at the top so its got all the fluff that Whiteline sell for the R32 GTST, thats part of the reason i was wanting to get the Group 4s:) So have got the 24mm adjustable front and 22mm adjustable rear set to the stiffest

http://www.whiteline.com.au/docs/fact_shee...line_R32GTS.PDF