Gtr Understeering To Much

[luke james]

Any pointers to stop a R32GTR understeering would more negative camber on the front help? semi slicks? any other mods on the front to stop this?

Edited September 20, 2008 by luke james

[ISC-Performance]

also increase front castor, set up decent ride height, torque splitters also work very well to stop understeer.

Ryan

[luke james]

also increase front castor, set up decent ride height, torque splitters also work very well to stop understeer.

Ryan

So set the castor more to the front or back of the gaurd what sort of ride height lower at the front ? and have already got torque control system thought this maybe half the prob? running r33gtr wheels to not sure if this makes much of a difference? luke

Edited September 20, 2008 by luke james

[Duncan]

and the right toe out too.

what is your suspension set up, what sway bars if any, what alignment settings (ride height, toe, caster, camber), and when does it understeer (turn in, mid corner or corner exit)

[luke james]

and the right toe out too.

what is your suspension set up, what sway bars if any, what alignment settings (ride height, toe, caster, camber), and when does it understeer (turn in, mid corner or corner exit)

Just standard GTR suspension eg (swaybars all arms) but have tein coilovers sems to happen mid corner and exit conrner but more mid under power this was very noticable on the track had tyres at right pressure etc

[MrStabby]

Sway bars are the biggest bang for you buck upgrade. Get adjustables and you can tune the understeer/oversteer balance. You stiffen the end you want to do more work. Ie if you're understeering, stiffen the rear to make it work harder and take some of the pressure of the fronts. I run soft at the front and hard at the rear, and i'm still a bit understeery, but its way better than stock.

Also check the Suspention/Handling Articles sticky for more info.

[luke james]

Sway bars are the biggest bang for you buck upgrade. Get adjustables and you can tune the understeer/oversteer balance. You stiffen the end you want to do more work. Ie if you're understeering, stiffen the rear to make it work harder and take some of the pressure of the fronts. I run soft at the front and hard at the rear, and i'm still a bit understeery, but its way better than stock.

Also check the Suspention/Handling Articles sticky for more info.

Thanks for the info where and what are the better sway bars to get? anyone have any pictures of the set up?

[White GTS-T]

http://www.skylinesaustralia.com/forums/R3...tel-t87521.html

[luke james]

cheers for the info...

[ISC-Performance]

So set the castor more to the front or back of the gaurd what sort of ride height lower at the front ? and have already got torque control system thought this maybe half the prob? running r33gtr wheels to not sure if this makes much of a difference? luke

you need positive castor meaning push the wheel forward, as for ride height as long as the car isnt slammed it should be fine, I usually have my ride height so there is a couple cm clearnace between the tyre and the gaurd etc. What torque controll system are you using (hopefully not a cheap ebay one). There are alot of different brands and they controll alot of different aspects of the attessa system.

Ryan

[luke james]

Im pretty sure it was bought from Manta racing whom arnt cheap for anything if you know what I mean it was about $500 and has a 2wd to 4wd switch on it as well it seems to work excellent I think the front of the car is a bit higher than the back so might drop that down a little and do what you said have a couple of centimeters above the gaurd and ill buy some adjustable caster arms and change that also that may fix the problem and should knock a couple of seconds of my times around mallala track hopefully down to the 1.20s.....

cheers for the info Ryan...

Edited September 22, 2008 by luke james

[Duncan]

jesus that controller sounds a lot like the $200 ebay one - does it just have a dial 1-10 and an on-off switch? For the sort of price you paid the one MountainRunner on these forums make is far superior. And yes they do make a big difference.

What wheel alignment settings do you have?

[luke james]

yeh 1-10 dial and a toggle switch which says 2wd at the bottom and 4wd at the top and you just flick it up or down it was on the car when i bought it but think receipt said $500 ......whats the difference between them?

[djr81]

Any pointers to stop a R32GTR understeering would more negative camber on the front help? semi slicks? any other mods on the front to stop this?

Well for a start all R32 GT-R's understeer. It is an inherent trait because of poor weight distribution. There are some setups that can help but ultimately you will never "fix" it. You have the same size tyres front & rear & yet the 60/40 weight distribution is asking the front to provide 50% more grip. So ofcourse it will understeer......

Anyway:

You need to determine at what stage of the corner you are concerned with. Eg turn in, mid corner or corner exit.

You also need to think about your driving style & make sure it is matched to the chassis characteristics. No point firing into a corner and then missing the apex by a yard or two. Think about your apex speed, how much you trail brake, your cars rake adjustment (GT-R's are sensitive to this) and lastly your throttle application.

With regard to suspension set up a few pointers come to mind.

1. Front end negative camber helps. Alot. You then need to constrain the roll of the car to ensure the camber changes are effective.

2. Don't use too much rear camber. Get the guards lips rolled if your tyres are scraping.

3. Sway bars are a must have item. You will end up running the rear on hard & the front on soft. Play with the front end to see if the increase in roll stiffness has a corresponding grip increase because of better roll constraint (Which is the opposite of what normally happens - you need to try it to see if it works as per the text book or not)

4. Spring rates are a matter for your own preference. Somewhere in the range of 5 or 6kg/mm front & 4 or 5 kg/mm rear are good numbers for R compound tyres. Softer for ordinary tyres.

5. R32 GT-Rs run very little castor. Something in the order of three degrees. It is possible to increase this but IMHO the changes increase suspension wear too much (to the upper link) and don't help that much because you start with such a low base number. In any case the amount of camber increase a small castor change makes at approx a quarter of steering lock is not large.

6. Don't run the car at too low a ride height.

If you are getting corner exit oversteer (without an Attessa controller) then the cure is simple. Get the rear diff fixed as you are almost certainly single spinning for the, err, win.

Another good tip is to purchase a book on tuning car suspension (Carroll Smiths stuff is good) & make sure you are ontop of what the car is doing.

[luke james]

Thanks djr81 ill definatly look at all thos points and do you know where I might be able to buy that book from? im interested in gettin it thanks again for the help luke...

[Z1LLA]

jesus that controller sounds a lot like the $200 ebay one - does it just have a dial 1-10 and an on-off switch? For the sort of price you paid the one MountainRunner on these forums make is far superior. And yes they do make a big difference.

What wheel alignment settings do you have?

I was contemplating buying that one on ebay. In what way is the one made by Mountainrunner more superior? Just wondering...

Thanks

[Lunatikk]

Paul's 4WD Controller will run rings around just about, if not all other controllers out there & I'm not just saying that because I'm running the Group Buy either. These things really are the business & if you need the proof, just ask anyone who's fitted one to their own GTR how much it transformed the car

4WD Controller Group Buy

[Duncan]

I don't want to get too far off this topic, but the ebay controller is basically a $20 variable resistor being sold for 200. Whereas Paul's unit is a very professional unit with multiple maps, displays, adjustable curves etc.

Either is better than nothing but Paul's one gives far better control

[luke james]

Shit looks like you hve to be a rocket scientist to operate it

[Lunatikk]

There are a lot of variables available, but like suspension settings, once you get them to where you personally like the feel you pretty much leave it at that. One great feature is the 2-map toggle where you can literally swap between 2 settings on the fly so relatively subtle for normal driving if you wish & instantly go to a more aggressive front split literally at the flick of a remote switch that can be mounted anywhere. You can even go from full 100% RWD for the burnout to an aggressive split for the drags etc.

The possibilities are almost endless, but don't let that become too daunting. Once you play with the unit for a 'lil while it becomes very apparent what it does & isn't difficult to use at all (like any new gadget )