Setting Up Coil-overs For Drag

[l_uk3y]

Hey guys.

Just in the process of gettin the new coilovers put in. Now before i get the comments about the coil overs not being suited to drag. I relise this. Not totally sure how to adjust settings. (other then the height). They are Jap spec Tein Super streets

Generally the car will be set up for street/with a hint of circuit. But when it comes to getting the car on the track it will be 90% drag days over circuit days.

As far as setting up the suspension to suit the drag days (as best as the equipment will let me). What should I be setting front and rear at to help traction. Working with a guesstimate of 180rwkw and stock wheels/tyres. Should i only need wheel alignments for height adjustments or would i need them for any adjustment?

(Once i get new wheels id be looking at getting slicks for the stockies to help traction out) But that will be a while away.

cheers for any guidance.

Luke

[Swiper the Fox]

Hey guys.

Just in the process of gettin the new coilovers put in. Now before i get the comments about the coil overs not being suited to drag. I relise this. Not totally sure how to adjust settings. (other then the height). They are Jap spec Tein Super streets

Generally the car will be set up for street/with a hint of circuit. But when it comes to getting the car on the track it will be 90% drag days over circuit days.

As far as setting up the suspension to suit the drag days (as best as the equipment will let me). What should I be setting front and rear at to help traction. Working with a guesstimate of 180rwkw and stock wheels/tyres. Should i only need wheel alignments for height adjustments or would i need them for any adjustment?

(Once i get new wheels id be looking at getting slicks for the stockies to help traction out) But that will be a while away.

cheers for any guidance.

Luke

I run HKS circuit coilovers on our drag car and am 60'ing 2nd fastest in the country on radials....took us about 1 hour of testing to get them right and havent touched them since. You want soft bump on the rear with hard rebound...and opposite on the front...this allows the car to weight transfer on launch and hook up. Also bring the ride height up to allow more suspension travel. Hope this helps.

Edited April 16, 2008 by DiRTgarage

[NYTSKY]

I run HKS circuit coilovers on our drag car and am 60'ing 2nd fastest in the country on radials....took us about 1 hour of testing to get them right and havent touched them since. You want soft bump on the rear with hard rebound...and opposite on the front...this allows the car to weight transfer on launch and hook up. Also bring the ride height up to allow more suspension travel. Hope this helps.

Dont listen to this guy he has no idea what he is on about

[Swiper the Fox]

Dont listen to this guy he has no idea what he is on about

ive just forgotten how to build your engine

[NYTSKY]

ive just forgotten how to build your engine

SNAP!

[NYTSKY]

But in all seriousness your stock rear suspension will be better for drag than a set of Super streets.

[Swiper the Fox]

But in all seriousness your stock rear suspension will be better for drag than a set of Super streets.

i used to use 90/10 revalved stockers and all they did was make the front wheels come off the deck on launch. Very spectacular yes...good for my 60' times no. Put the HKS items back in and instantly picked up a 10th of a sec.to the 60' mark.

Id try what i said about adjusting the Teins...then try your stockers...see what works best...easy

Edited April 16, 2008 by DiRTgarage

[r33cruiser]

ive recently seen a 1000hp supra on youtube run down the drag. the thing farkin squats. it just pivots straight back with the front wheels barely on the ground... are u saying this is good because it keeps traction......where as harder setups would cause wheelspin????

just clarafying. im getting into drag too with bilstien coilovers. and they offered some squat...i thought this was bad in the rear?????

plz part with some knowledge

Edited April 16, 2008 by r33cruiser

[Sydneykid]

All due respect to Twoogle, setting up a 4wd drag car and a 2wd drag car are quite different. In a 2wd Skyline we care very much about maximising the rear traction. If we sacrifice more front traction achieving that it doesn't matter. In a drag GTR we have all 4 wheels to provide the traction, so we can't afford to sacrifice too much front traction in order to achieve some more rear traction. Hence what works in 4wd environment (highish spring rates and minimum rear squat) simply doesn't work in a 2wd situation.

In regard to setting up a 2wd drag Skyline, I posted this recently (that's why the Search button is so handly);

You want no more then 3 kg/mm rear springs, around 2.5 kg/, is better. You want rear shocks with very little low frequency bump valving but a large amount of low frequency rebound damping. If the shocks are a decent brand then you can leave the high frequency valving alone. The soft spring rate allows the rear to squat and absorb the torque hit, the large amount of low frequency rebound damping holds the rear down for maximum weight transfer onto the rear tyres. The problem is you get a lot of dynamic negative camber when you get enough squat, so you need to set the static rear camber slightly positive (around 0.5 deggres). A rear subframe alignment kit installed in the "Maximum Traction" positions is also a must.

Around 3.5 to 4.0 kg/mm front springs are OK (hardly "hard"). You want front shocks with a large amount of low frequency bump valving but with very little low frequency rebound damping. Similarly to the rear, if the shocks are a decent brand then you can leave the high frequency valving alone. The limited amount of low frequency rebound damping allows the front suspension to extend therebye reducing the weight over the front and hence more effective weight transfer to the rear. The reasonable front spring rate helps to hold the front tyres onto the track, you may need to steer at some point. The front suspension geometry is pretty much irrelevant, just make sure the wheels are pointed straight ahead (zero toe) so they don't provide too much drag.

In a general sense the average Japanese aftermarket coil over kits are not suitable for drag racing and the standard suspension is better. But (there is always a "but") the problem with the rear standard shocks is that they don't have anywhere near enough rebound damping. That's when they are new, let alone 15 or so years old. So you get bad axle tramp, the kind that breaks drive shafts. The more power the car has, the worse this problem becomes. In a standard'ish Skyline (boost up, FMIC, exhaust etc) you might just get away with it (standard shocks) on street tyres. But drag radials or slicks and decent power don't mix well with poor rebound control. You will spend more money/time replacing drive shafts than you will spending the extra on buying the right shock spring combo.

Cheers

Gary

[Swiper the Fox]

All due respect to Twoogle, setting up a 4wd drag car and a 2wd drag car are quite different. In a 2wd Skyline we care very much about maximising the rear traction. If we sacrifice more front traction achieving that it doesn't matter. In a drag GTR we have all 4 wheels to provide the traction, so we can't afford to sacrifice too much front traction in order to achieve some more rear traction. Hence what works in 4wd environment (highish spring rates and minimum rear squat) simply doesn't work in a 2wd situation.

In regard to setting up a 2wd drag Skyline, I posted this recently (that's why the Search button is so handly);

Cheers

Gary

i gave him the set-up for a 2WD car....don't you read anything...you really are not as clever as you think you are

i said " YOU want soft bump on the rear with hard rebound...and opposite on the front...this allows the car to WEIGHT TRANSFER on launch and hook up. Also bring the ride height up to allow more suspension travel."

As i looked and saw he had a GT-t so i gave him the correct information to set it up with the suspension he mentioned and also gave him an alternative. Ive driven a GTS-t with stock suspension axle tramping down the strip so id say his coilovers would probably be a better option if they were not re-valved.

My knowledge of why a RWD set-up does not work on a GTR was stated here.."i used to use 90/10 revalved stockers and all they did was make the front wheels come off the deck on launch. Very spectacular yes...good for my 60' times no. Put the HKS items back in and instantly picked up a 10th of a sec.to the 60' mark"

I pretty much stated what was in your text box but did it in simple laymans terms so as not to confuse/bamboozle him.

All due respect eh...my respect for you is very quickly diminishing

Edited April 16, 2008 by DiRTgarage

[beersandwich]

i gave him the set-up for a 2WD car....don't you read anything...you really are not as clever as you think you are

i said " YOU want soft bump on the rear with hard rebound...and opposite on the front...this allows the car to WEIGHT TRANSFER on launch and hook up. Also bring the ride height up to allow more suspension travel."

As i looked and saw he had a GT-t so i gave him the correct information to set it up with the suspension he mentioned and also gave him an alternative. Ive driven a GTS-t with stock suspension axle tramping down the strip so id say his coilovers would probably be a better option if they were not re-valved.

My knowledge of why a RWD set-up does not work on a GTR was stated here.."i used to use 90/10 revalved stockers and all they did was make the front wheels come off the deck on launch. Very spectacular yes...good for my 60' times no. Put the HKS items back in and instantly picked up a 10th of a sec.to the 60' mark"

I pretty much stated what was in your text box but did it in simple laymans terms so as not to confuse/bamboozle him.

All due respect eh...my respect for you is very quickly diminishing

lol e battles make you look cool lol

I pretty much stated what was in your text box but did it in simple laymans terms so as not to confuse/bamboozle him.

what you said is so vague that its not even similar to what he said. you put hks in where? back, front?, what did you have in rear? who said you didnt learn how to drive while changing suspension?

but lets ignore the advice of SK(which is also the advice of every drag racer ive known, but they know nothing) and listen to you. yes coilovers are 'sic' everyone put em in. NOW

to OP - you dont sound that serious so dont really worry. but as you have guessed coilovers are not the idea thing. at least get/make them as soft as possible

[Swiper the Fox]

lol e battles make you look cool lol

what you said is so vague that its not even similar to what he said. you put hks in where? back, front?, what did you have in rear? who said you didnt learn how to drive while changing suspension?

but lets ignore the advice of SK(which is also the advice of every drag racer ive known, but they know nothing) and listen to you. yes coilovers are 'sic' everyone put em in. NOW

to OP - you dont sound that serious so dont really worry. but as you have guessed coilovers are not the idea thing. at least get/make them as soft as possible

not vague at all...changed all the suspension back to HKS...easy.

he's got a set of coilovers and wanted some advice...simple

coilover adjustments = plenty

stock suspension adjustments = none

only a handfull of people in this country have driven a street import down the strip quicker than i have and i have been involved with a couple of cars who top (or close to it) their lists in the world. My ability to run 9 sec passes back to back within a 100th of a second with a manually shifted synchro box is something even the most seasoned drag racers find remarkable. Not blowing my trumpet but...Im a little qualified to make judgement. I know full well Gary's involvement in the drag scene years ago and respect what he has to say. What i stated for a RWD car is simply correct, and is something that his text agrees with.

e battles make you look cool eh...thats why you had to get yourself involved.

Edited April 16, 2008 by DiRTgarage

[r33cruiser]

[Swiper the Fox]

[r33cruiser]

lol got more

[Sydneykid]

not vague at all...changed all the suspension back to HKS...easy.

he's got a set of coilovers and wanted some advice...simple

coilover adjustments = plenty

stock suspension adjustments = none

only a handfull of people in this country have driven a street import down the strip quicker than i have and i have been involved with a couple of cars who top (or close to it) their lists in the world. My ability to run 9 sec passes back to back within a 100th of a second with a manually shifted synchro box is something even the most seasoned drag racers find remarkable. Not blowing my trumpet but...Im a little qualified to make judgement. I know full well Gary's involvement in the drag scene years ago and respect what he has to say. What i stated for a RWD car is simply correct, and is something that his text agrees with.

e battles make you look cool eh...thats why you had to get yourself involved.

I re-read what I posted several times and I don't see where I contradict what you posted. But I appologise if it came accross that way, it was not my intention. I was simply escalating the engineering input, and trying to put some technical space between a 4wd set up and a 2wd set up. Which I have found many inexperienced guys have trouble understanding.

It is always hard to judge the knoweldge base of someone from a single post, so I tend to err on the side of providing a reasonable level of technical response. If it's too heavy reading, they can always come back and ask for clarification. If I go in too soft, the knowledge transfer maybe be misleading, they go off on a tangent and I don't get a second chance.

If it's a beer I owe you, then so be it, my shout when we catch up next.

Cheers

Gary

[Swiper the Fox]

I re-read what I posted several times and I don't see where I contradict what you posted. But I appologise if it came accross that way, it was not my intention. I was simply escalating the engineering input, and trying to put some technical space between a 4wd set up and a 2wd set up. Which I have found many inexperienced guys have trouble understanding.

It is always hard to judge the knoweldge base of someone from a single post, so I tend to err on the side of providing a reasonable level of technical response. If it's too heavy reading, they can always come back and ask for clarification. If I go in too soft, the knowledge transfer maybe be misleading, they go off on a tangent and I don't get a second chance.

If it's a beer I owe you, then so be it, my shout when we catch up next.

Cheers

Gary

hey cool, i think you may have thought i was refering to 4WD which i wasn't. You didnt' contradict what i was trying to say, you actually backed it up albeit on a more indepth manner.

See you at Superlap...watch out for the Red "R" Racing GTR with Luke Searle behind the wheel (this our 1st real go at circuit so will be a good learning curve)

Edited April 17, 2008 by DiRTgarage

[l_uk3y]

Hey guys. Thanks for clarifying that. Albeit in a long drawed out way

Btw Sydneykid. i did search and i have read that post by you before. Very good info but yeah. Bit to "heavy" for someone with my suspension knowledge base. It would make a lot more sence to me if i had a suspension tuning screen like that from gran turismo in front of me to adjust as i read. All i know is i have Height adjustment and Damper adjustment.

So to clarify. Raise height slightly. Stiffen front, loosen rear??? Lol. Pardon for bein such a suspension noob. but hey. You have to start somewhere. I realise that the coil overs im getting arent the best for drag app. But i want the car to be an all rounding street car slightly circuit bias'd.

And yeah. I was struggling with axle tramp with the stock suspension. But in saying that - im also struggling with the stock clutch so lets just say. Conservative launches anyway till im further ahead with the build. On a positive. Will have the car back by end of this week to see how she handles with the suspension and rest of exhaust.

Thanks for the input guys.

Luke

[Sydneykid]

Hey guys. Thanks for clarifying that. Albeit in a long drawed out way

Btw Sydneykid. i did search and i have read that post by you before. Very good info but yeah. Bit to "heavy" for someone with my suspension knowledge base. It would make a lot more sence to me if i had a suspension tuning screen like that from gran turismo in front of me to adjust as i read. All i know is i have Height adjustment and Damper adjustment.

So to clarify. Raise height slightly. Stiffen front, loosen rear??? Lol. Pardon for bein such a suspension noob. but hey. You have to start somewhere. I realise that the coil overs im getting arent the best for drag app. But i want the car to be an all rounding street car slightly circuit bias'd.

And yeah. I was struggling with axle tramp with the stock suspension. But in saying that - im also struggling with the stock clutch so lets just say. Conservative launches anyway till im further ahead with the build. On a positive. Will have the car back by end of this week to see how she handles with the suspension and rest of exhaust.

Thanks for the input guys.

Luke

That's not heavy Luke, it's actually quite simple really. The coil overs you are getting almost guarateed will only have one adjustment, that being rebound. There will be zero (or virtually zero) bump adjustment. So the best that you can do is fact 100% opposite to what you posted above.

1. You want the rear shocks with MORE rebound damping than the fronts. That's what I meant when I said "The soft spring rate allows the rear to squat and absorb the torque hit, the large amount of low frequency rebound damping holds the rear down for maximum weight transfer onto the rear tyres"

2. You want the front shocks with LESS rebound damping than the rearss. That's what I meant when I said "The limited amount of low frequency rebound damping allows the front suspension to extend therebye reducing the weight over the front and hence more effective weight transfer to the rear"

Cheers

Gary