Drag set up

[norachelhere]

Ok so heres the situation. You want to build a car for drag, but you also want to be able to drive to the track.
You've got a FWD and a RWD that you want to do up. you've got the engines perfect. you've got the body perfect. you've got everything perfect but the suspension hasn't been touched.
How do you set up each car to get the most out of it for the race, but still be able to drive to and from the track? (don't have to be comfortable on the ride to and from, but don't want to die either...)

[xnissan240x]

:wiggle: do research

[Kouki Crisp]

jus get some expensive coilovers mayne. with adjustable dampening you should find good for street and track use.

[xnissan240x]

not with drag! you want softer suspension for drag and most coilovers dont go that soft

[norachelhere]

maybe i was expecting too much.....
I know that for RWD you want softer in the back so the weight transfer can keep the tires on the ground
I know that for FWD you want super stiff to keep the tires on the ground...

I was looking for a little more like what suspension you would put where and why. Something is telling me that the stock location isn't the best possible set up. i was looking for things like suspension geometry, and why and stuff like that. not a simple, go to the store and buy a pre set set up and be happy...

[Suicidal Racing]

well what are u using for the rwd.

qa1 shocks,switch springs out maybe,pinion angle.

[norachelhere]

lets say that we are using a 240sx (s13) for the RWD platform
and
a civic hatch for the FWD platform

Those seem to be really popular.
hell, lets even do the domestic side, foxbody mustang, and/or camaro, and/or the next generation newer than the foxbody mustang.
I don't know of any FWD domestics that would be worth trying to do this to....

[norachelhere]

how about this,
instead of limiting it to a certain car,
just say what kind of car you would do what set up to....
everyone has their opinions and what not and they are based off of a certain car... so whats your opinion on the best set up for what car?

[3tc power]

here is my 84 sr5 corolla rearend setup....i can't wait for the punishment to happen to my victom on the streets of tampa:D
still not finished with the car yet. still needs undercoating, a trip to the paint booth, and to put the motor in. it is and ford 8.8 with posi, 3.73 gears disk brake....QA1 coilover convertion kit 12 way adjustables(also available in 24way adjustables too). Real Speed in clearwater did the setup for me.


http://images7.pictiger.com/thumbs/fe/b9944281c4021e19af69dcae6af5cdfe.th.jpg (http://server7.pictiger.com/img/286522/picture-hosting/p-1010001--.php) http://images7.pictiger.com/thumbs/30/064010df4cdb13061d05971dca4d7430.th.jpg (http://server7.pictiger.com/img/286523/picture-hosting/p-1010002--.php) http://images7.pictiger.com/thumbs/cf/b61e2d332de26a935a54c2f78adcebcf.th.jpg (http://server7.pictiger.com/img/286524/picture-hosting/p-1010003--.php) http://images7.pictiger.com/thumbs/13/d2bdbf8fd7b9b52fbfe8c1fbe9332813.th.jpg (http://server7.pictiger.com/img/286525/picture-hosting/p-1010004--.php) http://images7.pictiger.com/thumbs/6e/0726b581ec5b621a23bee65b3a7a446e.th.jpg (http://server7.pictiger.com/img/286526/picture-hosting/p-1010005--.php) http://images7.pictiger.com/thumbs/4a/caf96d92f9d123fcfa2571dd9b0c114a.th.jpg (http://server7.pictiger.com/img/286527/picture-hosting/p-1010006--.php) http://images7.pictiger.com/thumbs/98/b1c720cb38f1322a686ceb49e3867898.th.jpg (http://server7.pictiger.com/img/286528/picture-hosting/p-1010007--.php) http://images7.pictiger.com/thumbs/cb/618aa49fcdc64de40fceefa24608c5cb.th.jpg (http://server7.pictiger.com/img/286529/picture-hosting/p-1010008--.php) http://images7.pictiger.com/thumbs/a1/6f55914d57cebfefc45040a5e017e9a1.th.jpg (http://server7.pictiger.com/img/286530/picture-hosting/p-1010009--.php) http://images7.pictiger.com/thumbs/6e/0aef6aa98e71e6d0cab84a531d06416e.th.jpg (http://server7.pictiger.com/img/286531/picture-hosting/p-1010010--.php)
http://images6.pictiger.com/thumbs/2f/33b732677bf7859a9275e6f24c68802f.th.jpg (http://server6.pictiger.com/img/287842/picture-hosting/p-1010011--.php) http://images6.pictiger.com/thumbs/80/45f69e773f3235704afcb3da0390f580.th.jpg (http://server6.pictiger.com/img/287843/picture-hosting/p-1010012--.php) http://images6.pictiger.com/thumbs/5d/2da889693ac3cc5e8be53a04d6864a5d.th.jpg (http://server6.pictiger.com/img/287844/picture-hosting/p-1010013--.php)

[norachelhere]

here is my 84 sr5 corolla rearend setup....i can't wait for the punishment to happen to my victom on the streets of tampa:D
still not finished with the car yet. still needs undercoating, a trip to the paint booth, and to put the motor in. it is and ford 8.8 with posi, 3.73 gears disk brake....QA1 coilover convertion kit 12 way adjustables(also available in 24way adjustables too). Real Speed in clearwater did the setup for me.


http://images7.pictiger.com/thumbs/fe/b9944281c4021e19af69dcae6af5cdfe.th.jpg (http://server7.pictiger.com/img/286522/picture-hosting/p-1010001--.php) http://images7.pictiger.com/thumbs/30/064010df4cdb13061d05971dca4d7430.th.jpg (http://server7.pictiger.com/img/286523/picture-hosting/p-1010002--.php) http://images7.pictiger.com/thumbs/cf/b61e2d332de26a935a54c2f78adcebcf.th.jpg (http://server7.pictiger.com/img/286524/picture-hosting/p-1010003--.php) http://images7.pictiger.com/thumbs/13/d2bdbf8fd7b9b52fbfe8c1fbe9332813.th.jpg (http://server7.pictiger.com/img/286525/picture-hosting/p-1010004--.php) http://images7.pictiger.com/thumbs/6e/0726b581ec5b621a23bee65b3a7a446e.th.jpg (http://server7.pictiger.com/img/286526/picture-hosting/p-1010005--.php) http://images7.pictiger.com/thumbs/4a/caf96d92f9d123fcfa2571dd9b0c114a.th.jpg (http://server7.pictiger.com/img/286527/picture-hosting/p-1010006--.php) http://images7.pictiger.com/thumbs/98/b1c720cb38f1322a686ceb49e3867898.th.jpg (http://server7.pictiger.com/img/286528/picture-hosting/p-1010007--.php) http://images7.pictiger.com/thumbs/cb/618aa49fcdc64de40fceefa24608c5cb.th.jpg (http://server7.pictiger.com/img/286529/picture-hosting/p-1010008--.php) http://images7.pictiger.com/thumbs/a1/6f55914d57cebfefc45040a5e017e9a1.th.jpg (http://server7.pictiger.com/img/286530/picture-hosting/p-1010009--.php) http://images7.pictiger.com/thumbs/6e/0aef6aa98e71e6d0cab84a531d06416e.th.jpg (http://server7.pictiger.com/img/286531/picture-hosting/p-1010010--.php)
http://images6.pictiger.com/thumbs/2f/33b732677bf7859a9275e6f24c68802f.th.jpg (http://server6.pictiger.com/img/287842/picture-hosting/p-1010011--.php) http://images6.pictiger.com/thumbs/80/45f69e773f3235704afcb3da0390f580.th.jpg (http://server6.pictiger.com/img/287843/picture-hosting/p-1010012--.php) http://images6.pictiger.com/thumbs/5d/2da889693ac3cc5e8be53a04d6864a5d.th.jpg (http://server6.pictiger.com/img/287844/picture-hosting/p-1010013--.php)

disk brake as in one?
ok i'll admit, i'm new to the whole drag race thing, so you'll have to forgive some of the ignorance...
same thing with the bar you've got going from the top of one wheel hub to the bottom of the other

just looking for an understanding, not just knowledge...

thanks

[3tc power]

disk brake as in one?
ok i'll admit, i'm new to the whole drag race thing, so you'll have to forgive some of the ignorance...
same thing with the bar you've got going from the top of one wheel hub to the bottom of the other

just looking for an understanding, not just knowledge...

thanks

that bar has a couple of names but i call it a panhard bar. one side is connected to the chassis and the other end is connected to the rearend housing. this bar basically keeps the rearend from swaying side to side.

[norachelhere]

i thought so, i just heard it called so many different things and had it descrebed so many different ways that I wasn't sure what it was when I saw it...

[neondriver]

i got lucky with my acr neon which comes stock with koini struts. theres a spot on the top that you can turn and adjust the stiffness of th suspension, it made it nice since it was a daily driver and a track car.

[BLUE2KSS]

here is my take for RWD

i would go with VERY adjustable coilovers in front. when the driveshaft is under load, the driveshaft wants to rotate clockwise (looking at it from the back), and the rest of the car wants to rotate counterclockwise fromt the engine and trans mounts. this is all relative to roll stiffness

with that said, we can run a very large anti roll bar in the rear, and a smaller diameter in the front. but those are hard to come by and not readily adjustable at the track. preloading the right rear tire will allow you to cancel out some of that motion. using wheel scales will greatly help in your quest to equalize rear tire loads in motion. (this will require some practice runs of course, since this is only a static solution to the problem)

there are much better dynamic ways to do this of course (four links and so forth, but i dont know much about them to be honest. other than playing with the angles, i dont know if there is anymore adustability in them than that)

you can also assume a lower spring rate in the left front to help too

hope this helps, its a low dollar adjustable solution

[Enigma97]

Alright, I have an idea to go along with Blue2kSS's standpoint - feel free to shoot it down or make suggestions.

Since cornerning is not an issue for a drag racer, roll centers can be adjusted to counter-act roll moments. The closer the roll axis (the line between the roll centers) is to the CG of the car, the less the car will roll in cornering. However, I'm not sure how this pertains to gyroscopic moments. My idea is that you can create suspension geometry that moves the roll axis to a location that minimizes the moment arm of the forces that create the greatest rolling forces in drag racing. For instance, if the roll axis were to pass right down the center of the driveshaft (on a FR car) then the driveshaft would not create any rolling forces. If the crankshaft also lies on the same line as the driveshaft, then you have an easy solution.

Also, as far a longitudinal weight transfer, anti-geometry could be used so that your suspension linkages absorb some of pitch moments created in acceleration and the car would lift less and also transfer weight to the rear faster. The weight transferred would still be approximately the same, but the car would lift less and transfer weight faster, giving traction to the rear tires faster.

What do you guys think?

-Joel

[norachelhere]

this is what i was looking for
rep to you guys

lets keep this discussion going...

[senor honda]

3tc has a pretty good setup. RWD's have better weight transfer.I would not drag race a front wheel drive car, unlesss it's all I had.-Bob

[BLUE2KSS]

Alright, I have an idea to go along with Blue2kSS's standpoint - feel free to shoot it down or make suggestions.

Since cornerning is not an issue for a drag racer, roll centers can be adjusted to counter-act roll moments. The closer the roll axis (the line between the roll centers) is to the CG of the car, the less the car will roll in cornering. However, I'm not sure how this pertains to gyroscopic moments. My idea is that you can create suspension geometry that moves the roll axis to a location that minimizes the moment arm of the forces that create the greatest rolling forces in drag racing. For instance, if the roll axis were to pass right down the center of the driveshaft (on a FR car) then the driveshaft would not create any rolling forces. If the crankshaft also lies on the same line as the driveshaft, then you have an easy solution.

Also, as far a longitudinal weight transfer, anti-geometry could be used so that your suspension linkages absorb some of pitch moments created in acceleration and the car would lift less and also transfer weight to the rear faster. The weight transferred would still be approximately the same, but the car would lift less and transfer weight faster, giving traction to the rear tires faster.

What do you guys think?

-Joel


sorry it took so long for me to get back, just got the laptop back today



i think you would incorporate the anti geometry directly into the 4 link suspension setup. if you have the instaneous centers of the links at the CG, that would totally eliminate weight transfer. if you take a sheet of paper, draw a scale drawing of the four link with the mounting points and where your cars CG is, you could visualize differing angles and where that would put you in relation to weight transfer. now whether or not you put the instantaneous center below or above the CG im not sure. Im leaning toward below visualizing the links in my head really quick to be the opposite of anti squat (Joel correct me if im wrong, i dont have a book close to me), which obviously is the exact opposite to what we want in this case.


now how much load transfer we want of course is all dependent on what springs and shocks we have, rolling resistance of drag tires (minimal, but still there), controllability on launch, straightness of launch, so forth and so on.

its because of this debate there is no perfect, everyone has differing ideas on suspension setup and thats what makes it so interesting

[senor honda]

Blue2, you express yourself well, and have a good understanding.

Most people never get past the "bolt-on" stage, and if they can't bolt it on, they ridicule people who know more than they do, and have the ability to fabricate..........................that's why some people
who can't measure suspension geometry ignore the evidence that
cut coil springs don't have to flop around loose, don't have to beat the car , and don't have to destroy shocks.

Thanks for posting the info-Bob

[Enigma97]

As far as the front wheel drive cars, you could use anti-geometry to actually make the front squat when you accelerate. I don't know how this would affect load transfer (and braking would be scary) but it sure would draw attention.

[BLUE2KSS]

Blue2, you express yourself well, and have a good understanding.

Most people never get past the "bolt-on" stage, and if they can't bolt it on, they ridicule people who know more than they do, and have the ability to fabricate..........................that's why some people
who can't measure suspension geometry ignore the evidence that
cut coil springs don't have to flop around loose, don't have to beat the car , and don't have to destroy shocks.

Thanks for posting the info-Bob


Bob,

thanks for the compliment

i have the fabrication down, but im still learning a whole lot about suspension. knowing the fact that there is sooooo much to be had from a properly setup suspension, moreso than engine output 90% of the time, im absorbing all that i can.

being able to do all this hands on is what really helps, building and talking with people who know (Joel can setup a Formula SAE suspension and design it like its his job) is helping immensley

Dustin

[BLUE2KSS]

As far as the front wheel drive cars, you could use anti-geometry to actually make the front squat when you accelerate. I don't know how this would affect load transfer (and braking would be scary) but it sure would draw attention.



well i would imagine that the FWD that would try a setup like this would have skinnies in the back, so it probably wouldn't be anymore scary (maybe less so) than the fact that RWD drag cars have little weight and no front contact patch on the front of the car!

[norachelhere]

sorry i lost track of this thread guys... my subscription disappeared...
anyway

I know the norm for FWD is to do skinnies.. or at least as small as possible in the back. The problem with fwd set ups is it is very easy to loose your drivabiltly, especially when you do slicks in the front and skinnies in the back... Thats why most street going fwd cars just have really stiff springs and what not to avoid any body motion. There has to be a better set up...
Just to show how much I know about drag racing, I didn't even take into account the gyocopic movements... I was just thinking traction on the back tires due to weight transfer...

what do you guys mean by anti geometry?

When I started this thread, I was hoping to compile alot of very easy to understand information. So, if you would be so kind as to dumb it down, still go in depth and all that good stuff, but dumb down the "technical terms" I'll try and ask all of the dumb questions so its easier to understand, which will be easy for me, cuz i really don't know. my knowledge is limited to fwd gets super stiff and slicks in the front. RWD gets softer in the rear, lots of squat, and slicks in the rear...

[Enigma97]

Anti-geometry refers to anti-dive or, in this case, anti-squat geometry that basically takes a portion of the forward acceleration forces off of the springs and into the suspension linkages. You can design the suspension so that part or all of the force from the acceleration is absorbed by the chassis and doesn't cause the springs to compress. For example, if you have 75% anti-squat geometry, only 25% of the acceleration force for go into the springs and (for linear wheels rates) the car will "squat" only 25% as much as it would with 0% anti-squat. Anti-squat doesn't reduce the amount of weight transferred, but it does reduce the time it takes for the weight to transfer and the car to reach its steady-state condition. However, the more anti-geometry you add to the suspension, the more jerky or harsh the accelerations become, due to the suspension not use the springs and dampers to soften the acceleration. Many vehicles come with anti-geometry in order to have a soft ride but not have the car dive excessively under braking.

In order to get a lot of traction on a RWD, the car doesn't need to squat a lot, it just needs the weight transfer.