Advanced Suspension Setup; (Toe? Camber? Spring Rates?) Learn here!

[akuma S14]

Originally Posted by buddy

can someone go over pushrods? ?

haha i space sometimes too...LOL By changing the length of the tie rods in an S chassis you can give the car more steering angle. combined w/ TCA you can use this combo to make the wheelbase a little longer too. but it the best way to get more wheel base is by moving the rear back, b/c it has way less effect on the steering feel of the car. IMO

[D1champ]

So a drift car should perhaps have a "looser" rear-end than say a track car (assuming RWD ) so that it can break traction more easily

[Delphince]

Originally Posted by SaintDrift

http://www.niagarapca.com/autocross/ax_doanddonts.html
I always used this as a quick and brief guide.

That's like a shorter and sweeter version of:
http://rogerkrausracing.com/overundr.html

[FreeThinker]

Originally Posted by theflatlander

Front tire pressure higher: less under steer by reducing slip angels on most tires
Usable adjustment: up to 55psi hot
Symptoms of too much adjustment: no traction- tire crowned so more under steer; adds wheel spin in FF cars; jarring ride; center of tire wears out

Front tire pressure lower: more under steer by increasing slip angles on most tires
Usable adjustment: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up.

Rear tire pressure higher: less over steer by reducing slip angles on most tires
Usable range: up to 45psi hot
Symptoms of too much adjustment: no traction—tire is crowned so more over steer; bad wheel spin on FR cars; jarring ride; center of tire wears out.

Rear tire pressure lower: more over steer by incresing slip angles on most tires.
Usable range: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up

...

...Even Tire pressure helps.

Thank you so much for posting this. I have tried to tell so many people who just wont listen, but from roadracing experience this is the proper way to adjust tire pressure.

Many people think of it from the drag racing view of lower PSI means more traction..... in a straight line yes sometimes. But for cornering, absolutely not.

So all you drifters out there running 32psi front and 45psi rear in attempt to make the car oversteer more, try reversing it. Or better still if you can: 42psi all round and adjust with dampers and spring rates or anti-roll bar positions.


FYI on anti-roll bars: the holes closest to the pivot axis are the stiffer setting. The holes at the end of the bar are the softest.

[akuma S14]

I run 35 psi (cold) in the front and 32 rear (cold), when i am finished with a run my tire psi is around 38/38. just my setup that works for me. but i suck.

[cfrost]

hey terry what's max psi on those tires you're running?

[akuma S14]

i think they go up to like 50psi... but that is way to much pressure.

but they do hold up to wall riding!!!! LOL

[purpleDrifter]

Here is the stuff you wanted to know. No doubt some of the formula d guys are gonna get peaved at me for giving away their secrets F---- them. They don't want to give me their secrets, so I will give their secrets to everyone.

Ackerman: Ackerman measns that as you turn your front tires, your tires progressively toe out. cut off your steering arms (on your hub). make arms that you can adjust back and forth (you will probably need a fab shop to do this). Ackerman affects your yaw angle. More ackerman (more progressive toe), less yaw (the less your rear end slides out), less ackerman, more yaw. You can change ackerman by moving the steering arms inboard and outboard. You can measure ackerman statically by turning your wheels and measuring the difference in angle (i.e., the toe change as the wheels are turned)--if wheels are angled out, you have postive ackerman, if angled in you have negative ackerman (from the factory, nissans have positive ackerman) Note that there is more than one definition for ackerman, i.e. some manufacturers call 0 ackerman the factory setting (even though the steering tires progressively toe out)


bump steer: kazama makes tie rod ends that are adjustable up and down. this affects bump steer. the rear bump steer on a 240sx is adjusted by moving the top, most forward arm connected to the rear hub. Alex (battleversion) makes these arms. when you change height of vehilcle or put on bigger tires, you need to change bump steer on all four wheels. You shoud try for 0 bump steer. bump steer is the amount of steer your wheels make when your car dives and rolls (note that dive is not the same thing as roll). longacre makes a bump steer measuring tool. Bump steer in the rear is more critical than in the front (because you have a steering wheel attached to your front wheels to help you control steering).

Positive caster: more positve caster equals more dynamic camber. Positive caster also increases your front tire slip angles when counter-steering, and pushes your steering into counter steer. In other words it helps a lot with counter steer. About 7 degrees positive caster seems to work best on 240sx's. I would, however like to take out all my static camber and try 9 degrees pos caster and see what happens. Caster, however, causes your front wheels to move (up and down and forward and backward)--which makes it more difficult to control your car, so too much caster is not a good thing. More caster on the right front than the left and your car will tend to pull to the left (and visa-versa), but will decrease the amount your steering wheel will want to push into countersteer (because you are countersteering to the right).

steering angle: more steering angle, more countersteer. You can increase your steering angle by moving your rack mounts forward (on a car with the rack mounted behind the axle center line) you will probably need a fab shop to do this after you pull out the engine cross member. You can move the rack mounts up to 1 inch forward. This will change your ackerman. So what? You already threw your steering arms away. You can also put extensions on the tie rod ends that mount to the rack. You can get some from kazama (1/4 inch) or you can have a fab shop make them. you can also remove the rod from inside your rack and have a machine shop put more grooves in it. then have the machine shop make extensions as long as you want to screw into the end of the rack rod. this too, will change your ackerman and maybe your bump steer. Make your extensions too long, and you will hit suspension components--but you can just put in a stop.


Mac Strut: this is the reason why your 240sx understeers so much. get a front suspension off a honda accord. measure everything (very, very carefully). mount everything in the same relative place as it was on the honda (you will have to have a rail fabricated to attach your upper a arm and upper shock mount). You will have to also modify your mounting points for your lower control arm and your tension rods--I did not use the tension rods off the honda--i just welded my rods to the honda lc arms--do not know if this is the best way to do it. It might be better to use the tension rods off the honda and keep the mounting points in the right place. You can use your same rack and steering assembly, but will need to modify the honda steering arms--but you are going to cut those off and throw them away and make your own steering arms anyway. You can get skunk upper arms to adjust camber, and can do a 5 lug conversion.

[sonnysmr2]

Originally Posted by purpleDrifter

Here is the stuff you wanted to know. No doubt some of the formula d guys are gonna get peaved at me for giving away their secrets F---- them. They don't want to give me their secrets, so I will give their secrets to everyone.

Ackerman: Ackerman measns that as you turn your front tires, your tires progressively toe out. cut off your steering arms (on your hub). make arms that you can adjust back and forth (you will probably need a fab shop to do this). Ackerman affects your yaw angle. More ackerman (more progressive toe), less yaw (the less your rear end slides out), less ackerman, more yaw. You can change ackerman by moving the steering arms inboard and outboard. You can measure ackerman statically by turning your wheels and measuring the difference in angle (i.e., the toe change as the wheels are turned)--if wheels are angled out, you have postive ackerman, if angled in you have negative ackerman (from the factory, nissans have positive ackerman) Note that there is more than one definition for ackerman, i.e. some manufacturers call 0 ackerman the factory setting (even though the steering tires progressively toe out)


bump steer: kazama makes tie rod ends that are adjustable up and down. this affects bump steer. the rear bump steer on a 240sx is adjusted by moving the top, most forward arm connected to the rear hub. Alex (battleversion) makes these arms. when you change height of vehilcle or put on bigger tires, you need to change bump steer on all four wheels. You shoud try for 0 bump steer. bump steer is the amount of steer your wheels make when your car dives and rolls (note that dive is not the same thing as roll). longacre makes a bump steer measuring tool. Bump steer in the rear is more critical than in the front (because you have a steering wheel attached to your front wheels to help you control steering).

Positive caster: more positve caster equals more dynamic camber. Positive caster also increases your front tire slip angles when counter-steering, and pushes your steering into counter steer. In other words it helps a lot with counter steer. About 7 degrees positive caster seems to work best on 240sx's. I would, however like to take out all my static camber and try 9 degrees pos caster and see what happens. Caster, however, causes your front wheels to move (up and down and forward and backward)--which makes it more difficult to control your car, so too much caster is not a good thing. More caster on the right front than the left and your car will tend to pull to the left (and visa-versa), but will decrease the amount your steering wheel will want to push into countersteer (because you are countersteering to the right).

steering angle: more steering angle, more countersteer. You can increase your steering angle by moving your rack mounts forward (on a car with the rack mounted behind the axle center line) you will probably need a fab shop to do this after you pull out the engine cross member. You can move the rack mounts up to 1 inch forward. This will change your ackerman. So what? You already threw your steering arms away. You can also put extensions on the tie rod ends that mount to the rack. You can get some from kazama (1/4 inch) or you can have a fab shop make them. you can also remove the rod from inside your rack and have a machine shop put more grooves in it. then have the machine shop make extensions as long as you want to screw into the end of the rack rod. this too, will change your ackerman and maybe your bump steer. Make your extensions too long, and you will hit suspension components--but you can just put in a stop.


Mac Strut: this is the reason why your 240sx understeers so much. get a front suspension off a honda accord. measure everything (very, very carefully). mount everything in the same relative place as it was on the honda (you will have to have a rail fabricated to attach your upper a arm and upper shock mount). You will have to also modify your mounting points for your lower control arm and your tension rods--I did not use the tension rods off the honda--i just welded my rods to the honda lc arms--do not know if this is the best way to do it. It might be better to use the tension rods off the honda and keep the mounting points in the right place. You can use your same rack and steering assembly, but will need to modify the honda steering arms--but you are going to cut those off and throw them away and make your own steering arms anyway. You can get skunk upper arms to adjust camber, and can do a 5 lug conversion.

thanks very interesting

[FreeThinker]

Originally Posted by purpleDrifter

Here is the stuff you wanted to know. No doubt some of the formula d guys are gonna get peaved at me for giving away their secrets F---- them. They don't want to give me their secrets, so I will give their secrets to everyone.

Some of the stuff you mentioned is pretty good. There's a lot to add to your ackerman advice though.

And your caster theories are pretty far off.

Originally Posted by purpleDrifter

Mac Strut: this is the reason why your 240sx understeers so much. get a front suspension off a honda accord. measure everything (very, very carefully). mount everything in the same relative place as it was on the honda (you will have to have a rail fabricated to attach your upper a arm and upper shock mount). You will have to also modify your mounting points for your lower control arm and your tension rods--I did not use the tension rods off the honda--i just welded my rods to the honda lc arms--do not know if this is the best way to do it. It might be better to use the tension rods off the honda and keep the mounting points in the right place. You can use your same rack and steering assembly, but will need to modify the honda steering arms--but you are going to cut those off and throw them away and make your own steering arms anyway. You can get skunk upper arms to adjust camber, and can do a 5 lug conversion.

Yea, Formula D guys run Honda front suspension..... hahahahahahahahaha, since it's illegal to even change mounting points in 2006, much less change complete suspension design from strut to a-arm..... wow

And how did you get the secrets anyway since you yourself say they wont tell you???




If anyone is interested I'd be happy to add some reality to all this.

[ToplessFC3Sman]

yea, your ackerman explanation is going in the right direction, but its not all there, and is explained in an odd way. Its true that a front double wishbone suspension will offer better camber-curves, but the effort and skill required to competantly fabricate a new frame rail and swap the suspension components over is much higher than to mess with camber plates, spring/shock rates, and anti-roll bar stiffnesses.

[purpleDrifter]

Alex Pfeiffer promulgated the Formula d rule regarding oem suspensions to save people from going to the extraordinary expense of changing their front suspension. After drfting for a year, in my Camaro, my front suspension in my 240sx is still not done, and probably never will be. After drifting the last year, I have come to the conclusion that it is pretty hard to improve handling by changing the OEM design. It was way better to simply improve the operation of the existing design (and a lot easier and cheaper). Of course this does not mean one does not sometimes need to get extremely creative. It took me a year to figure out why my camaro could not "catch" the turn at horsetheif mile. I finally figured it out. It is a suspension issue, it is a rear suspension issue, one that can be remedied through improving the operation of the existing, floating rear axle suspension design. Has anyone else noticed? floating rear axles usually do not fare well on that turn at horsetheif. If anyone thinks there are secrets they are not being told, they are wrong. But now I know why those secrets are being kept. Why would I tell anyone how to make their floating rear axle car drift at horsetheif after no one would tell me? Although, I will admit that Vaughn Giffen did give me the information I have given you. And, I will give you this clue, there is a reason why a solid rear axle is called a "floating one", while an IRS is not; if you can figure out how to minimize the floating part, then you should fare way better in braking drifts like the one at horsetheif. This Saturday is the big day; we will see how my solid rear axle does.