Building Suspension for Road Racing?
07-12-09, 08:44 AM
#16
It was actually my idea. But obviously the talk of a bump steer kit like this has been thrown around the forums for years. I mearly took an idea that everyone talked about and utilized it. Sorry if you guys feel like it does not work. Ill gladly keep it on my car because I actually noticed a difference.
Guess if you don't like it, don't get it. Its a free country.
Now if you wanted to be helpful, explain why this idea does not work on the SC.
Guess if you don't like it, don't get it. Its a free country.
Now if you wanted to be helpful, explain why this idea does not work on the SC.
Last edited by RedPhoenix; 07-12-09 at 08:57 AM.
07-13-09, 03:51 PM
#17
With double wishbone suspension, the bump steer is way less of a factor. The fact that you moved the tie rod, now you just added bump steer from your car rather then taking it away.
They sell those kits to circle track guys because they change thier mounting points for thier front suspension, and when you do that, then you need to beable to adjust the tie rod heights. Again, actually check what your bump steer is now and put the stock stuff back on. I'll put money down that the toe change is less with the stock stuff then with what you have pictured.
You see alot of talk on forums about bump steer and moving tie rods. The fact of the matter is that no one has actually checked what thier bump steer is and was. Then again, most people think bump steer is that the wheel moves when you hit a bump, of coarse it does, you just hit a bump. What bump steer refers to is the toe change you get as your suspension travels into compression and rebound. The word "bump" just means suspension travel. With rack and pinion steering, its easily calibrated into the design of the suspension. I dont know how many of you have driven an older car or truck with a steering box and loose suspension, you can basicly feel a disconnection to the wheel when driving down the road. Like any time you go into a turn or up a driveway, even bumps in a straight line, you feel the wheel move independently from the direction the car is traveling. That is bad bumpsteer.
They sell those kits to circle track guys because they change thier mounting points for thier front suspension, and when you do that, then you need to beable to adjust the tie rod heights. Again, actually check what your bump steer is now and put the stock stuff back on. I'll put money down that the toe change is less with the stock stuff then with what you have pictured.
You see alot of talk on forums about bump steer and moving tie rods. The fact of the matter is that no one has actually checked what thier bump steer is and was. Then again, most people think bump steer is that the wheel moves when you hit a bump, of coarse it does, you just hit a bump. What bump steer refers to is the toe change you get as your suspension travels into compression and rebound. The word "bump" just means suspension travel. With rack and pinion steering, its easily calibrated into the design of the suspension. I dont know how many of you have driven an older car or truck with a steering box and loose suspension, you can basicly feel a disconnection to the wheel when driving down the road. Like any time you go into a turn or up a driveway, even bumps in a straight line, you feel the wheel move independently from the direction the car is traveling. That is bad bumpsteer.
03-09-10, 07:21 PM
#18
Quantum-Auto has some in the works too! 
http://www.quantum-auto.com/
They should be loads cheaper than the Ikeya ones too!
http://www.quantum-auto.com/
They should be loads cheaper than the Ikeya ones too!
03-10-10, 06:00 AM
#19
no matter what you do, whether it is coilovers or highly over rated ikeya formula crap, it all means nothing without relocating suspension pickup points. your wheels more in an arc from static position(sitting still) and between compression and extension. look up the term camber curve and do some research. NASIOC has a great thread describing what it is and how to fix it.
basically whenever you lower your car you move your suspension into a different part of the camber curve. usually the very extremes(high or super slammed) makes your car handle like crap.
when you lower your car on coilovers you move your camber curve out of optimum range. if lowered too much the car will handle worse then stock. to solve this problem you need to relocate the suspension pick up points UP about the same amount as you lower you car. so you will have a lower CG but proper working suspension.
relocating suspension pickup points usually is hard and expensive to do and most people dont bother.
the problem with Ikeya Formula or any other adjustable arm is that it only correct your static suspension alignment setting so while you are sitting on the alignment rack everything looks fine. the story goes back to pretty much the same as before when you start driving. the slope of the camber curve at low ride heights causes camber/toe changes to be very high. instead of everything occuring smoothly they are done suddenly, creating for a twitchy-ish car.
basically if you have 4500 to blow get a shop to relocate your pick-up point and use stock arms, which are more then adequate.
the whole "you gotta pay to play" BS only works if you dont know what the hell you are buying and have money to blow. obviously some members on he definitely do
basically whenever you lower your car you move your suspension into a different part of the camber curve. usually the very extremes(high or super slammed) makes your car handle like crap.
when you lower your car on coilovers you move your camber curve out of optimum range. if lowered too much the car will handle worse then stock. to solve this problem you need to relocate the suspension pick up points UP about the same amount as you lower you car. so you will have a lower CG but proper working suspension.
relocating suspension pickup points usually is hard and expensive to do and most people dont bother.
the problem with Ikeya Formula or any other adjustable arm is that it only correct your static suspension alignment setting so while you are sitting on the alignment rack everything looks fine. the story goes back to pretty much the same as before when you start driving. the slope of the camber curve at low ride heights causes camber/toe changes to be very high. instead of everything occuring smoothly they are done suddenly, creating for a twitchy-ish car.
basically if you have 4500 to blow get a shop to relocate your pick-up point and use stock arms, which are more then adequate.
the whole "you gotta pay to play" BS only works if you dont know what the hell you are buying and have money to blow. obviously some members on he definitely do
03-10-10, 06:53 AM
#20
no matter what you do, whether it is coilovers or highly over rated ikeya formula crap, it all means nothing without relocating suspension pickup points. your wheels more in an arc from static position(sitting still) and between compression and extension. look up the term camber curve and do some research. NASIOC has a great thread describing what it is and how to fix it.
basically whenever you lower your car you move your suspension into a different part of the camber curve. usually the very extremes(high or super slammed) makes your car handle like crap.
when you lower your car on coilovers you move your camber curve out of optimum range. if lowered too much the car will handle worse then stock. to solve this problem you need to relocate the suspension pick up points UP about the same amount as you lower you car. so you will have a lower CG but proper working suspension.
relocating suspension pickup points usually is hard and expensive to do and most people dont bother.
the problem with Ikeya Formula or any other adjustable arm is that it only correct your static suspension alignment setting so while you are sitting on the alignment rack everything looks fine. the story goes back to pretty much the same as before when you start driving. the slope of the camber curve at low ride heights causes camber/toe changes to be very high. instead of everything occuring smoothly they are done suddenly, creating for a twitchy-ish car.
basically if you have 4500 to blow get a shop to relocate your pick-up point and use stock arms, which are more then adequate.
the whole "you gotta pay to play" BS only works if you dont know what the hell you are buying and have money to blow. obviously some members on he definitely do
basically whenever you lower your car you move your suspension into a different part of the camber curve. usually the very extremes(high or super slammed) makes your car handle like crap.
when you lower your car on coilovers you move your camber curve out of optimum range. if lowered too much the car will handle worse then stock. to solve this problem you need to relocate the suspension pick up points UP about the same amount as you lower you car. so you will have a lower CG but proper working suspension.
relocating suspension pickup points usually is hard and expensive to do and most people dont bother.
the problem with Ikeya Formula or any other adjustable arm is that it only correct your static suspension alignment setting so while you are sitting on the alignment rack everything looks fine. the story goes back to pretty much the same as before when you start driving. the slope of the camber curve at low ride heights causes camber/toe changes to be very high. instead of everything occuring smoothly they are done suddenly, creating for a twitchy-ish car.
basically if you have 4500 to blow get a shop to relocate your pick-up point and use stock arms, which are more then adequate.
the whole "you gotta pay to play" BS only works if you dont know what the hell you are buying and have money to blow. obviously some members on he definitely do
Do Ikeya arms actually move the roll center? If we change the pickup points "raise them", does that raise the roll center closer to the CG?
03-12-10, 09:25 PM
#21
The only way to keep the roll center in the right place when going way low is to alter the pivot points, fancy control arms will only produce a different ride height, maybe a better ball joint angle.
The reason lowered cars handle poorly is that the roll centers are put way below the car, causing a side to side pitching when you hit bumps. This makes the car feel like it's going to loose adhesion. Not fun when you're trying to be faster than the car was before you lowered it.
The roll centers are better when closer to the center of mass.
The reason lowered cars handle poorly is that the roll centers are put way below the car, causing a side to side pitching when you hit bumps. This makes the car feel like it's going to loose adhesion. Not fun when you're trying to be faster than the car was before you lowered it.
The roll centers are better when closer to the center of mass.
03-17-10, 07:53 PM
#23
for the upper control arms it is a bot trickier. there is no room to go up. my plan is to take a stock aluminum cross member and machine the upper control arm perfectly flat in a bridgeport mill. after that i take an aluminum billet piece and bolt it on and make it work as an extension upwards. the billet piece will be bolted to the stock cross member. also a few welds for safe measure. no more use of the factory super long upper control arm bolt. just 2 shorter bolts. after that you would need some modified/custom outer tie rods to lever out the tie rod with the lower control arm.
this is the gist of it but there is a lot more to it and i can probably write another 10 pages of what to do. also need to get some alignment equipment to measure your current camber curves and bump steer. also measure your suspension geometry and find the roll center/axis. from there you need to figure out where it is with respect to your CG. ideally you want your CG and roll center to be in the same place. if it is not then you created a moment arm....a bad thing.
som basically to just relocate the pickup points is actually the easier thing to do. to make it actually correct and work proper take a lot of time and just plain tedious.
so for me to move along with this someone wants to donate me a spare cross member they have
preferably local. shipping would suck. im willing to buy it, just not the ridiculous amounts people on supra forums ask.
edit: btw thats just in the front. the rear is even more work and you will have to cut into the chassis since the rear subframe is already so close to the body.
03-17-10, 11:09 PM
#24
Ya it sounds like a lot of work, but the pay off should be monstrous.
I was asking around today about reliable chassis shops. There's one that's pretty involved in off roading, will check them and see if they're reasonable.
By the way, does anybody know where exactly our COG is "stock height"?? in order to figure out how to avoid creating torque/moment arm, we need to know where COG is located, then roll center should be easy to locate anyway.
I was asking around today about reliable chassis shops. There's one that's pretty involved in off roading, will check them and see if they're reasonable.
By the way, does anybody know where exactly our COG is "stock height"?? in order to figure out how to avoid creating torque/moment arm, we need to know where COG is located, then roll center should be easy to locate anyway.
03-18-10, 11:12 AM
#26
Nice vids, what suspension do you have ?
who told you that i don't take my car to the track???? you just assumed,right! Don't assume too much, people don't have to post videos of their bouts.
I do understand your point when you tell people to go out and drive. But going out and driving a boat doesn't mean you're doing anything respectable. Let me give you a Buick Lesabre and see if "you know how to drive". My point is you have to have hardware to support your driving, in order to achieve anything.
If you don't know what roll center is, then maybe it's time to use that Google button. Roll center is one of the most important factors that decide how your car behaves sideways, there are other factors of course. A lot of people coming to this forum are engineers or going to engineering schools, and this's why you may hear a lot of technical terms. i'm not satisfied with the way my car handles, and i'm not to sit down and cry about it, or just "go out and drive". I'm going to research and try doing something about it.
who told you that i don't take my car to the track???? you just assumed,right! Don't assume too much, people don't have to post videos of their bouts.
I do understand your point when you tell people to go out and drive. But going out and driving a boat doesn't mean you're doing anything respectable. Let me give you a Buick Lesabre and see if "you know how to drive". My point is you have to have hardware to support your driving, in order to achieve anything.
If you don't know what roll center is, then maybe it's time to use that Google button. Roll center is one of the most important factors that decide how your car behaves sideways, there are other factors of course. A lot of people coming to this forum are engineers or going to engineering schools, and this's why you may hear a lot of technical terms. i'm not satisfied with the way my car handles, and i'm not to sit down and cry about it, or just "go out and drive". I'm going to research and try doing something about it.
Last edited by madmax98; 03-18-10 at 11:21 AM.
03-18-10, 05:32 PM
#27
Ok there is sure alot of good talk goin on here about roll center's & center of gravity. but the only person here that has really contributed to this thread IMO is CLNSC3, great feed back. anyone can post here on this subject, but how many people are actually putting there SC to the test on a real road course. Im one of them & i dont know **** about "roll center's" but i do know how to DRIVE. Ive got vid's on youtube. i dont see anymore SC vid's on a road course on there. so how about start really DRIVING & stop talking about technical **** that will not come into play until you got the REAL basics down.
Sorry if i sound like an Ahole, its saint patrick's day & ive been, takin part.
check out my vid's, then say im full of **** all vid's in street tire's. www.myspace.com/barron771
1 in my 92 & the other 2 im my 98 no LSD that i have now.
Sorry if i sound like an Ahole, its saint patrick's day & ive been, takin part.
check out my vid's, then say im full of **** all vid's in street tire's. www.myspace.com/barron771
1 in my 92 & the other 2 im my 98 no LSD that i have now.
knowing how to drive is great and all. it takes a real driver to be able to jump into any car and adjust to it and be good. most importantly though not only good but consistent. driving skill will only take you so far though. so you drive a certain car and you know it completely. most importantly you know its limits. wouldnt it be nice if you can improve on the car so you can push its limits?
you have to understand how the modifications improve or hurt your car. 75% of the modifications most people do to their cars make it look more race or RICE and actually hurt its performance whether it is on the street or the track.
actually most people will say that after certain suspension or chassis modification their car handles so much better on the street....key word street. for road racing completely different rules apply.
i want to see someone take their "super stiff" JDM tyte yo coilovers with 20+k spring rates to the track. it will slide like a cow on ice.
if you are not going to add anything productive to this thread then just stay out of it and observe. you might learn a thing or two...we all will actually. there is no reason clutter this up with "shut up and drive" BS. im not trying to be a **** but your comments are just unnecessary.
03-18-10, 05:57 PM
#28
5SP JZZ30, aside from the "shut up and drive" lol, how much improvement are we looking at by raising the roll center in the front only, as opposed to both front and rear? Also do you happen to know where the COG on the SC is?
Thanks
Thanks
Last edited by madmax98; 03-18-10 at 06:02 PM.
03-18-10, 06:31 PM
#29
^ my bad, it was the alcohol talkin. i didnt meen to assume. i wiki'd roll center, i got the defintion & your right, it very important. i guess what im wondering is how low are we talking about to make the handling worse, are we talking the slam that alot here are doing or like 2". Suspension wise im running Tein Flex w/edfc, daizen sway's & front & rear strut bars. i havent been to the track on my rear strut bar yet, but it has helped reduce my body roll even more. That sounds really good what 5sp jzz30 is saying about what he wants to change but, why go through so much work to change the roll center, i meen my car handles awesome & even better with the rear strut bar & track tires. the car is still gonna be a 3600lb, the lighter you go the less roll, right.
Last edited by spdrcr771; 03-18-10 at 07:07 PM.
03-18-10, 07:06 PM
#30
^ my bad, it was the alcohol talkin. i didnt meen to assume. i wiki'd roll center, i got the defintion & your right, it very important. i guess what im wondering is how low are we talking about to make the handling worse, are we talking the slam that alot here are doing or like 2". Suspension wise im running Tein Flex w/edfc, daizen sway's & front & rear strut bars. i havent been to the track on my rear strut bar yet, but it has helped reduce my body roll even more. That sounds really good what 5sp jzz30 is saying about what he wants to change but, why go through so much work to change the roll center, i meen my car handles awesome & even better with the rear strut bar & track tires. the car is still gonna be a 3600lb, the light you go the less roll.
your car looked pretty good in the vid, it looked flat in turns, but it might be the camera. Regardless, i was laughing my *** off when that dude spun off over the wet spot LOL
Imagine your car handling like a go-kart and less like a boat. The more you lower your center of gravity towards your center of roll <in a certain range> the more your car will lose roll. If you take roll out of the equation, then weight can be countered by tires and brakes that can handle it <very simply of course>. The further you place COG from COR, the more magnified the weight problem.. If the COR and COG are on the same level <which i haven't seen on street cars>, then theoretically you'll have no roll. However, when the car is moving, parts start moving in relation to each other and it gets complicated.
I hope that helps
Edit: how heavier were the Daizens compared to stockers?
Last edited by madmax98; 03-18-10 at 07:12 PM.