32 Gtr Understeering

[T04GTR]

due to the complete lack of input to my last post on handling.

im aware of the many variables involved with seting up suspension on a gtr.

im guesing that -2deg camber on the front is aceptable. thats not my major hurdle:

basicly my main question is:

i have the adjustable white line swaybars.(front and rear) what spring rates are these suitable for?

ie: are they designed to be used with the standard rate springs? i understand that stifening the bar gives les grip at that end.(bar efectivly reduces the amount of force bieng pushed down on the iside tyre,hence reducing its grip.)

let me rewind for a minute, my 32gtr is understeering once settled into the corner.

its as if the back is simply pushing it across the lane. evan going uphill!

the rear is quite nervouse. it sortof bucks around abit. like its got traction and as the front torque cuts in it gets grip and pushes the front.

it does this the whole time when pushed. or can i not drive for shit

the front end is all adjustable.

i need to know if my springs are corect. front:10kg/mm rear:7kg/mm

i know that changing them will alter how the shocks operate(they are adgustabe)

has anyone actualy set up a gtr for the street/(street tyred)for occasional track use with these bars?

or am i better of using the stock bars with heavier springs?

somone please tell me what is a good spring rate to use with these swaybars

ANY HELP IS GREATLY APRICIATED

ps.geting a wheel alignment after each guestimated camber adjustment is becoming xpencive!!

i have destroyed a set of tyres trying to get this close to rite

[oRiCLe]

are you running castor adjustment?

whats the toe settings like on the front?

i went down to CRG and bought a go-kart wheel alignment kit that does camber/castor and made up a toe setting system from a few pieces of metal, maybe cheaper than getting tyre shops to do wheel alignments all the time

[djr81]

due to the complete lack of input to my last post on handling.

im aware of the many variables involved with seting up suspension on a gtr.

im guesing that -2deg camber on the front is aceptable. thats not my major hurdle:

basicly my main question is:

i have the adjustable white line swaybars.(front and rear) what spring rates are these suitable for?

ie: are they designed to be used with the standard rate springs? i understand that stifening the bar gives les grip at that end.(bar efectivly reduces the amount of force bieng pushed down on the iside tyre,hence reducing its grip.)

let me rewind for a minute, my 32gtr is understeering once settled into the corner.

its as if the back is simply pushing it across the lane. evan going uphill!

the rear is quite nervouse. it sortof bucks around abit. like its got traction and as the front torque cuts in it gets grip and pushes the front.

it does this the whole time when pushed. or can i not drive for shit

the front end is all adjustable.

i need to know if my springs are corect.          front:10kg/mm rear:7kg/mm

i know that changing them will alter how the shocks operate(they are adgustabe)

has anyone actualy set up a gtr for the street/(street tyred)for occasional track use with these bars?

or am i better of using the stock bars with heavier springs?

somone please tell me what is a good spring rate to use with these swaybars

ANY HELP IS GREATLY APRICIATED

ps.geting a wheel alignment after each guestimated camber adjustment is becoming xpencive!!

i have destroyed a set of tyres trying to get this close to rite

<{POST_SNAPBACK}>

I have been trying to set my car up with the Whiteline swaybars & near standard springs & not having much success. In saying that they are great for the road, but not so great on the track.

There are alot (ALOT) of variables on how the car behaves & indeed on how you want it to behave. So have a think about the type of handling characteristics you are chasing.

Also the spring rates listed are high - they are much more track orientated than for the street. Stock springs are about 1/3rd the rates you have. Even the Whiteline gear is less than half (About 3.5kg/mm for an R32 GT-R - slightly higher at the front, lower at the rear.)

Springs/dampers/sway bars are all interrelated & to be honest I doubt you will have a huge amount of success running the 10 & 7kg/mm springs.

[Sydneykid]

I agree with djr81, 10 kg/mm is ~550 lbs per inch, that's way to high a spring rate for the front. Around 300 lbs per inch is more like it if you do a lot of track work and around 250 lbs if you only do the occasional track day.

7 kg/mm is ~400 lbs per inch, is a rediculous spring rate for the rear. Around 250 lbs per inch is more like it if you do a lot of track work and around 200 lbs if you only do the occasional track day.

What you are describing is mid corner understeer, which is a dead give away for too high spring rate as you have sufficient negative camber for that not to be the issue.

You also need to be carefull with the ride height, GTR's do not handle very well when they are very low. Particularly at the front, we never go lower than 350 mm centre of wheel to guard. If you have it set lower than that then you need to raise it up. With the front at 350 mm, the rear needs to be no lower than 340 mm. Rasing the rear ride height will help with understeer.

For fune tuning the balance (decreasing the understeer) using the adjustable stabiliser bars, more rear antiroll and less front wil help.

Once you have it more balanced in its handling, you should consider a torque split controller (Duncan sells them). I wouldn't do it until you were happy with the suspension tune as it will confuse the issue greatly.

Cheers

[GTRsean]

what tyres do you run and what size? They can affect handling and understeering a lot too as I found out when trying out 235 cheap tyres from 245 and 255 tyre sets all round.

[T04GTR]

thanks sk

i thought they were abit high.

ive spoken to a couple of people and im considering using 450lb front 350rear

ive been advised that 550front 400rear is a pretty good rate for the track. along with 5degrees neg on the front.

(im asumig because of the extra grip from race tyres?)

i think if i can get the spring rate close to acceptable the rest is just a mater of how fast i want my tyres to ware out!!

could you please explain what "antisquat" in the rear is

ie:"im running 30%anti squat in the rear"

why do all of the aftermarket coilovers come with such heavy springs in them?

mine origonaly had 13kg front 8kgrear.

the term "firm"is an understatment!

any way thanks.

ps. im more at home to late brake fast turn-in powerout. im trying to get more smooth in my cornering. i tend to turn in abit to agressivly.

you get that from man-handling a 440rwhp dr30 up the old pac

pps. the field ets controler is quit handy in this respect.

il let you know how i go. cheers

[Sydneykid]

thanks sk

i thought they were abit high.

ive spoken to a couple of people and im considering using 450lb front 350rear

ive been advised that 550front 400rear is a pretty good rate for the track. along with 5degrees neg on the front.

(im asumig because of the extra grip from race tyres?)

i think if i can get the spring rate close to acceptable the rest is just a mater of how fast i want my tyres to ware out!!

could you please explain what "antisquat" in the rear is

ie:"im running 30%anti squat in the rear"

why do all of the aftermarket coilovers come with such heavy springs in them?

mine origonaly had 13kg front 8kgrear.

the term "firm"is an understatment!

any way thanks.

ps. im more at home to late brake fast turn-in powerout. im trying to get more smooth in my cornering. i tend to turn in abit to agressivly.

you get that from man-handling a 440rwhp dr30 up the old pac

pps. the field ets controler is quit handy in this respect.

il let you know how i go. cheers

<{POST_SNAPBACK}>

Who the hell told you 550/400 was a good spring rate for the track?

Maybe if you are using slicks, but certainly not road or R type tyres.

I don't think we have ever run 5 degrees negative camber, even at Philip Island (big G forces, long/fast corners) we only run up to 4 degrees maximum. But I can't recall 5 degrees anywhere, the braking would be terrible.

The Japs don't seem to know much about stabiliser bars, their shocks are very simplistic in their valving, anti squat and anti dive adjustments are alien to them. The concept of changing the roll couple by adjusting the ride height goes totally against there basic philosophy of lower is always better.

So they try and do EVERYTHING with the springs, this means rediculously high spring rates. We use springs ot hold the car up, stabiliser bars to control the roll, some antidive geometry in the front to control the dive under brakes and a lot of antisquat in the rear to improve the corner exit power down. We adjust the ride height to alter the roll couple.

It comes down to whack some rock hard springs in there and they don't have to worry about anyhting else, it's a quick and easy bolt on solution. Remember good mechanics in Japan charge like brain surgeons. Now that might work on billiard table smooth surfaces, but we don't have any of those, our tracks are rough, full of ridges, not at all smooth and fast times require much ripple strip jumping.

GTR's are more of a smooth turn in, trail brake, late apex and early power out style of chassis. Use the 4wd traction to make the straights longer.

Antisquat is the amount of suspension geometry resistence to squat under power application. If you have too much rear squat, it transfers the weight off the front wheels and you get understeer as a result. If you have too much antisquat the rear goes very stiff under power application and you get power oversteer.

Antisquat is adjusted by changing the angle of the rear subframe, placing polurethane bushes above and/or below the rear subframe. In the race cars we have stackable bushes so that we can adjust the antisquat. My "30% antisquat" comment represents 2 small bushes at the front between the subframe and the chassis and one large bush below the rear of the subframe. This is fairly similar to the Whiteline kit (pineapples) which has 6 bushes.

Some people have had problems reading/understanding the Whiteline instructions for the rear subframe bushes. Courtesy of Emanuel, I have numbered the bushes in the pictures and numbered the corresponding bushes in the Whiteline instructions. If you are lucky I have got them right, it is so much easier when I am actually doing it. Please do a quick check just to be sure.

It's a bit hard to draw #3 as it goes above the sub frame, which you can't see in the picture. The bushes that go above the subframe have cuts in them. This is so you can slip them over the bolts/studs and don't have to remove the whole subframe to do it.

Cheers

Edited November 24, 2005 by Sydneykid

[hrd-hr30]

Who the hell told you 550/400 was a good spring rate for the track?

Maybe if you are using slicks, but certainly not road or R type tyres.

who the hell told you 300/250 are good track rates. I used similar rates on my 850kg Improved Production car. Hardly ideal for over 1400kg of Skyline.

I don't think we have ever run 5 degrees negative camber, even at Philip Island (big G forces, long/fast corners) we only run up to 4 degrees maximum.  But I can't recall 5 degrees anywhere, the braking would be terrible.

tell that to all the national and international categories that run in the order of 7 degrees static camber. They all seem to manage to stop.

The Japs don't seem to know much about stabiliser bars, their shocks are very simplistic in their valving, anti squat and anti dive adjustments are alien to them.  The concept of changing the roll couple by adjusting the ride height goes totally against there basic philosophy of lower is always better.

your grandfather die in the war or something?

[Roy]

Is there a difference in the way a car with wishbone front suspensions and Machpherson struts use front static camber...i think thats your answer why some cars like different spring rates and camber settings.

Then there is also driver preference. There are some cars/drivers that i know of running R type tyres that love their spring rates through the roof....600pounds on an EVO V etc.

If your comfortable with how the thing drives, and utlimately its using its tyres then i suppose thats all that matters. I would think a car with average shocks and big spring rates would make for a hard car to drive...but whatever suits you i suppose.

Hell from what i understand Murphy used to like throwing spring rates at the car whilst Kelly liked bigger swaybars... (last year)..i suppose it was what suited the driver.

[NickR33]

whos running 7º neg camber!? thats ridiculous for any modern car!

[blk180]

SK is a Skyline Guru do you know what your talking about hrd-hr30. But as has been said it comes down to the driver whats fast for one persons style may not be for another.

[hrd-hr30]

SK is a Skyline Guru do you know what your talking about hrd-hr30. But as has been said it comes down to the driver whats fast for one persons style may not be for another.

<{POST_SNAPBACK}>

yeah I know, how dare i not agree with him!

but its good of you to point out to him that there's more than one way to skin a cat. 4 deg camber is all you'll ever need. full stop.

whos running 7º neg camber!? thats ridiculous for any modern car!

Perhaps if you don't know, you should refrain from making ridiculous statements...

[djr81]

Fellas - as my Grandmother used to say - ITS NICE TO BE NICE - so be nice (please).

Please be careful throwing around numbers. Remember that the original request was for road suspension with occassional track use. Anyone here volunteering to use 7 or even 4 degrees neg camber on the road? Track suspension castor/camber/toe settings will always be more extreme than those for the road.

What works on one track may be hopeless on another - the same can be said for cars and drivers and tyres and weather conditions and spring rates and sway bar settings and a whole heap of other things.

Edited November 25, 2005 by djr81

[NickR33]

Perhaps if you don't know, you should refrain from making ridiculous statements...

<{POST_SNAPBACK}>

my hero... mate your advice isn't much use to 99% of the people on here so why don't you head over to the race car groupie forum

at least SK takes time out to explain his opinions and help people with realistic solutions to their problems instead of just picking fights... why should we listen to you... you haven't contributed anything except for rhetoric

[Sydneykid]

who the hell told you 300/250 are good track rates.

Race wins, lap records and championships told me.

cheers

[T04GTR]

thanks for the input. now i know the tern anti...... thanks sk.

no im not concidering running that camber on the road.(that is slicks spec etc,race car)

settings fromals some other people have set up and maintained racing 32s.(it sdemms abit dangerouse to drom some names)

aparently some cars use a 27mm adjustable front one. and a 24mmrear or a 22mm rear if its raining.

5.75neg on the front.

8deg caster

550f 4000r springs 200 and 220mmlong respectivly

2.5deg neg on rear 30%anti squat

1.5deg toe out on the front

1deg toe in on rear(i dont kknow the converion from degrees to mm in toe.)

(these are for race rubber)

please dont have a fight with HRD-HR30 about what is a good................he has got some very valid points. i recon with both of you going at it know one else needs coment. its very educational.(not having a go so dont be ofended)

this is just a way for me to get a GENERAL idea on how to set up the suspension based on these white line swaybars.

it seems getting these technical settings is like getting blood from stone.

its like its a big secret. im not going to run off and tell evry one whos racing. lets not bring thbe race car politics into the threads.

at the moment if got 550front 400rear. yes its stiff. but springs are abit pricy.

im going to borrow some from my mate mick carueso.

i think running standard rate springs is abit of a gay idea. i mean im no suspension expert but an upgrade has to be a good thing.

just for referance the mines 32gtr uses 10kfront 8krear for their street time bla bla bla cars (with very expencive biltien coil overs with remote gas canisters etc.)

what hapens when you go around a corner and a inside rear comes of the ground?

this has been fixed with my new springs. and rear bar adjustment.

any way cheers for the input. i understad how it works now.

[Sydneykid]

thanks for the input. now i know the tern anti...... thanks sk.

no im not concidering running that camber on the road.(that is slicks spec etc,race car)

settings fromals some other people have set up and maintained racing 32s.(it sdemms abit dangerouse to drom some names)

aparently some cars use a 27mm adjustable front one. and a 24mmrear or a 22mm rear if its raining.

5.75neg on the front.

8deg caster

550f 4000r springs 200 and 220mmlong respectivly

2.5deg neg on rear 30%anti squat

1.5deg toe out on the front

1deg toe in on rear(i dont kknow the converion from degrees to mm in toe.)

(these are for race rubber)

please dont have a fight with HRD-HR30 about what is a good................he has got some very valid points. i recon with both of you going at it know one else needs coment. its very educational.(not having a go so dont be ofended)

this is just a way for me to get a GENERAL idea on how to set up the suspension based on these white line swaybars.

it seems getting these technical settings is like getting blood from stone.

its like its a big secret. im not going to run off and tell evry one whos racing. lets not bring thbe race car politics into the threads.

at the moment if got 550front 400rear. yes its stiff. but springs are abit pricy.

im going to borrow some from my mate mick carueso.

i think running standard rate springs is abit of a gay idea. i mean im no suspension expert but an upgrade has to be a good thing.

just for referance the mines 32gtr uses 10kfront 8krear for their street time bla bla bla cars (with very expencive biltien coil overs with remote gas canisters etc.)

what hapens when you go around a corner and a inside rear comes of the ground?

this has been fixed with my new springs. and rear bar adjustment.

any way cheers for the input. i understad how it works now.

<{POST_SNAPBACK}>

It is actually very simple, try whatever you like, then get a pyrometer and measure the tyre temperatures (inside, centre and outside of the tread). That will tell you whether you have too much camber or not. Based on 5 years of racing Skylines, a 550 lbs per inch front spring with a 27mm front stabiliser bar and 8 degrees of caster shouldn't need 5.75 degress of negative camber. Even with very soft low frequency bump rates in the shocks, it simply isn't going to roll enough to need that much camber to maximise the tyre contact patch.

The bottom line, the tyre temperatures will tell you.

cheers

Edited November 26, 2005 by Sydneykid

[blind_elk]

SK,

Always value your input on suspension matters, but I'm having trouble interpreting the pineapples install.

The photos show 1,2 being used on the REAR of the subframe, but the diagrams show 1,2 being used at the FRONT. Similar arse-about-ness for 3,4.

Or am I misunderstanding the the relationship between the photos and the diagrams?

[T04GTR]

thanks.

but i know il never run that exact setting. it primarily a streetcar at the moment. so 2deg on the front is ok for me. il set it up around that.

front bar on soft rear on hard. it seems alot more stable/predictable now.

also as you sugested dampers would hav a influence on springs to. as mine are probably quite simple in design.

im only guessing but with a good damper that has go 5 or so adjusters ie:one for big bumps/little ones/fast ones/etc you could get away with a lighter spring?

speaking of pyrometers. have you read the latest "race car enginering mag" its got a mad article on a new pyrometre.

it is basicly like a infared camera. but live. it shows a "preditor" style image of the whole tyre with user programable contrast for the variation of temp.

very cool. it was origonaly designed to test tyre warmers for their efectivness i think.

ps. cheers for the subframe diagram. iv got mine by the look of it set up for squat.

il be changing that i think

Edited November 27, 2005 by T04GTR

[MerlinTheHapyPig]

The Japs don't seem to know much about stabiliser bars, their shocks are very simplistic in their valving,

<{POST_SNAPBACK}>

I think I asked this in another thread, but you may have not seen it.

Care to elaborate on this?

What aspects of shock valving improve shock performance?

It's a very broad statement, you can pay from $1k - $10k for a set of japanese shocks, you can't put them all in the same basket