Ground Control Spring Rate for EK Hatch
07-Nov-2010, 08:47 PM
#1
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Ground Control Spring Rate for EK Hatch
I want to throw some Ground Control Springs on my 96 hatch, I was wondering if anyone could tell me what a good spring rate for my car would be?
I plan on doing some autocrossing occasionally but its mainly a daily driver except during the winter its stored. I have 17 inch wheels for daily driving and just picked up some 15 inch aluminum rims that I will put slicks on and use for the track. Going to be running integra brakes all around with all upgraded brake components and id like to set it at about 2-2.5 drop and pretty much leave it like that. I just don't really know what factors into choosing a spring rate..
I know that spring rate plays a big part in ride quality and performance though so is there any setup that would put me somewhere in the middle? They come 380F/280R but you can choose your spring rate for $40 bucks, any info would be much appreciated.
I plan on doing some autocrossing occasionally but its mainly a daily driver except during the winter its stored. I have 17 inch wheels for daily driving and just picked up some 15 inch aluminum rims that I will put slicks on and use for the track. Going to be running integra brakes all around with all upgraded brake components and id like to set it at about 2-2.5 drop and pretty much leave it like that. I just don't really know what factors into choosing a spring rate..
I know that spring rate plays a big part in ride quality and performance though so is there any setup that would put me somewhere in the middle? They come 380F/280R but you can choose your spring rate for $40 bucks, any info would be much appreciated.
07-Nov-2010, 10:10 PM
#3
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Check out this link to see how the spring rates relate to your vehicle's dynamics.
http://www.torontocivics.com/f58/rac...ormula-167975/
I'll do some calculations for ya tomorrow and help you find a good setup starting point.
Don't lower the car too much. Proper spring rate and suspension geometry is more important than a slightly lower center of gravity.
http://www.torontocivics.com/f58/rac...ormula-167975/
I'll do some calculations for ya tomorrow and help you find a good setup starting point.
Don't lower the car too much. Proper spring rate and suspension geometry is more important than a slightly lower center of gravity.
07-Nov-2010, 10:48 PM
#4
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If you wouldnt mind doing that id appreciate it a lot.
To be honest most of the article is to advanced for me but its frustrating cause i can tell there is some good info there, looks like i have some research to do...
To be honest most of the article is to advanced for me but its frustrating cause i can tell there is some good info there, looks like i have some research to do...
10-Nov-2010, 11:09 AM
#6
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The whole premise of this formula is to load the front and rear outside tires evenly while cornering allowing the vehicle to maintain maximum mechanical grip. You can read about it in more detail in the link I posted earlier. I’ve had several years experience with this. It’s extremely effective and really does work very well.
Ok. If you want a great handling setup but maintain comfort for the road, you’ll need a spring and sway bar combo that will match your car’s weight and weight distribution.
Knowing the sway bar rate will really help determine what spring rates to use. That being said, sway bars can be changed easier than springs.
I based my Initial calculations on a vehicle weight of approx 2200lbs and weight distribution of 60/40 (f/r). The optimal wheel-rates come out to around 350in/lbs front and 530in/lbs rear.
For an all out, no compromised optimal race setup with NO sway bars, I’d recommend starting with spring rates of 700in/lbs front & 1050in/lbs rear. This is also based on the use of full race slicks. If you’re going to be using a street tire like the toyo RA1, you should go a little softer.
That being said, this isn’t an all out race car and you want to drive this on the street. 700 and 1000in/lb springs will be very stiff and you’ll have back problems after the first day…lol.
What we then must do is combine softer spring rates with sway bars so that if you add the spring rate and the sway bar rate, that equals the calculated optimal spring rate.
For example, let’s say your front sway bar has a rate of 150in/lbs. You’d take 700 – 150 = 550in/lbs. for the spring rate. Make sense? 550spring rate + 150bar rate = 700total equivalent spring rate, during cornering.
The problem is it’s difficult to find out the rate of the sway bar. You don’t want to go too stiff with the spring and end up with the sway bar adding too much stiffness, as that will cause under steer. For a fwd car, staying a bit on the soft side for the front end is usually a better option as it’s easier to adjust the rear sway bar to compensate and adjust for proper balance.
If your car doesn’t already have a front sway bar, you may want to add one from a 99-00 SiR or integra Type R. With either of those I’d then start with a front spring rate of about 400 to 450in/lbs up front. In the rear, to maintain driving comfort, I’d go with about the same as the front or even a bit softer, 350-400in/lbs and use a large adjustable rear sway bar to compensate for the lower rate. These rates I would recommend if you're using a tire like the toyo RA1 or softer. For a stickier tire, I'd suggest going a bit stiffer by 50-100in/lbs, front and rear.
I also recommend koni yellow adjustable dampers. They have a large range of adjustability for their price and should work well with this combination.
If you find it’s under steering excessively, try a larger rear sway bar, or softer front sway bar. And try the opposite if you have excessive over steer. In autocross you can afford to be a little more extreme with setting it up to induce lift-off over steer as it doesn’t matter if you don’t catch it right away and spin out in a parking lot. The most you will hit is a cone…lol. It’s ok to have the car more neutral while you are learning and getting used to it, but generally, you’ll find the faster you get, the more “on-edge” you’ll want the setup and it’ll teach you to have quicker reflexes.
Anyways, I’ll shut up now…haha.
Any questions, feel free to ask.
Good luck and keep us updated. J
Ok. If you want a great handling setup but maintain comfort for the road, you’ll need a spring and sway bar combo that will match your car’s weight and weight distribution.
Knowing the sway bar rate will really help determine what spring rates to use. That being said, sway bars can be changed easier than springs.
I based my Initial calculations on a vehicle weight of approx 2200lbs and weight distribution of 60/40 (f/r). The optimal wheel-rates come out to around 350in/lbs front and 530in/lbs rear.
For an all out, no compromised optimal race setup with NO sway bars, I’d recommend starting with spring rates of 700in/lbs front & 1050in/lbs rear. This is also based on the use of full race slicks. If you’re going to be using a street tire like the toyo RA1, you should go a little softer.
That being said, this isn’t an all out race car and you want to drive this on the street. 700 and 1000in/lb springs will be very stiff and you’ll have back problems after the first day…lol.
What we then must do is combine softer spring rates with sway bars so that if you add the spring rate and the sway bar rate, that equals the calculated optimal spring rate.
For example, let’s say your front sway bar has a rate of 150in/lbs. You’d take 700 – 150 = 550in/lbs. for the spring rate. Make sense? 550spring rate + 150bar rate = 700total equivalent spring rate, during cornering.
The problem is it’s difficult to find out the rate of the sway bar. You don’t want to go too stiff with the spring and end up with the sway bar adding too much stiffness, as that will cause under steer. For a fwd car, staying a bit on the soft side for the front end is usually a better option as it’s easier to adjust the rear sway bar to compensate and adjust for proper balance.
If your car doesn’t already have a front sway bar, you may want to add one from a 99-00 SiR or integra Type R. With either of those I’d then start with a front spring rate of about 400 to 450in/lbs up front. In the rear, to maintain driving comfort, I’d go with about the same as the front or even a bit softer, 350-400in/lbs and use a large adjustable rear sway bar to compensate for the lower rate. These rates I would recommend if you're using a tire like the toyo RA1 or softer. For a stickier tire, I'd suggest going a bit stiffer by 50-100in/lbs, front and rear.
I also recommend koni yellow adjustable dampers. They have a large range of adjustability for their price and should work well with this combination.
If you find it’s under steering excessively, try a larger rear sway bar, or softer front sway bar. And try the opposite if you have excessive over steer. In autocross you can afford to be a little more extreme with setting it up to induce lift-off over steer as it doesn’t matter if you don’t catch it right away and spin out in a parking lot. The most you will hit is a cone…lol. It’s ok to have the car more neutral while you are learning and getting used to it, but generally, you’ll find the faster you get, the more “on-edge” you’ll want the setup and it’ll teach you to have quicker reflexes.
Anyways, I’ll shut up now…haha.
Any questions, feel free to ask.
Good luck and keep us updated. J
13-Nov-2010, 11:54 AM
#7
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Join Date: Aug 2010
Location: London, ON
Posts: 31
Okay sorry i havent replied sooner but I managed to find out that my 96 cx/dx hatch has a stock 13mm rear sway bar..
I want to upgrade my stock brake to 94-01 teg brakes to match the back so what would I need to install a front sway bar at at the same time? Im pretty sure my car doesnt come with a front sway bar.
Basically sway bars allow you to handle better with softer springs rates right? I was doing a little reading about front sway bars and people said they gave them a lot of understeer, im thinking they didnt put much thought into the spring rates though.
So i guess now i need to know what front sway bar to get to work with a front disc brake swap (sir knuckles with teg calipers) if that that even matters, and also what spring rates to run with that sway bar?
thanks for your help
I want to upgrade my stock brake to 94-01 teg brakes to match the back so what would I need to install a front sway bar at at the same time? Im pretty sure my car doesnt come with a front sway bar.
Basically sway bars allow you to handle better with softer springs rates right? I was doing a little reading about front sway bars and people said they gave them a lot of understeer, im thinking they didnt put much thought into the spring rates though.
So i guess now i need to know what front sway bar to get to work with a front disc brake swap (sir knuckles with teg calipers) if that that even matters, and also what spring rates to run with that sway bar?
thanks for your help
14-Nov-2010, 08:43 PM
#8
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Location: Where my car is.
Posts: 5,460
^Something you should understand about sway bars.
In a street car situation with still relatively soft springs, yes, sway bars can help the car handle better, but to a point. Basically all stock cars have fairly soft springs. I mean REALLY soft springs...lol. This is mainly for ride comfort. The problem with this is evident as soon as you try to turn a corner and the car leans over excessively. To control body-roll, sway bars take the motion of the suspension and effectively change the wheel rate during cornering. While traveling in a straight line, they do nothing. They do not function until the car starts to roll.
The way a sway bar functions is; in a corner, the inside wheel rate is reduced and the outside wheel rate is increased. Where this becomes a problem is it can over-stiffen the outside wheel rate, causing the tire to become overloaded and it also reduces the inside tire loading. The inside tire grip may not be as important, but that extra grip is being reduced.
Also to expand, inside and outside tires should remain independent in their function. What the left side suspension and tires do, should effect the other side. (In an ideal/optimal race suspension setup).
So like I said before, you can set your car up for a pure race setup and it'll be crazy sharp on the track, but super-stiff for daily driving. If you want it to be good on the track but soft enough for daily driving, you'll need to lower the spring rates and combine them with sway bars to achieve a similar level of handling on the track.
In a street car situation with still relatively soft springs, yes, sway bars can help the car handle better, but to a point. Basically all stock cars have fairly soft springs. I mean REALLY soft springs...lol. This is mainly for ride comfort. The problem with this is evident as soon as you try to turn a corner and the car leans over excessively. To control body-roll, sway bars take the motion of the suspension and effectively change the wheel rate during cornering. While traveling in a straight line, they do nothing. They do not function until the car starts to roll.
The way a sway bar functions is; in a corner, the inside wheel rate is reduced and the outside wheel rate is increased. Where this becomes a problem is it can over-stiffen the outside wheel rate, causing the tire to become overloaded and it also reduces the inside tire loading. The inside tire grip may not be as important, but that extra grip is being reduced.
Also to expand, inside and outside tires should remain independent in their function. What the left side suspension and tires do, should effect the other side. (In an ideal/optimal race suspension setup).
So like I said before, you can set your car up for a pure race setup and it'll be crazy sharp on the track, but super-stiff for daily driving. If you want it to be good on the track but soft enough for daily driving, you'll need to lower the spring rates and combine them with sway bars to achieve a similar level of handling on the track.
14-Nov-2010, 09:18 PM
#9
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Location: mississauga
Posts: 68
Wow 700 and 1000lb in the rear would kill anyone on the street, but i can only imagine the cornering speeds in and out. If your going to decide this rought i totally agree with the koni yellow. But anything over 400lb on a stock koni yellow would eventually kill it, they do offer a revalving and shortning of the valve to help prolong life of the shock at a cost of course. Also the yellows i beleive offer lifetlime warrenty.
If your going to do occational track with the car I,ve done koni reds with H&R' sport or race as well as tockico agx with the H&R or nuespeed race springs. All were excellent on the street. Went with a sir front sway with lower control arms, and rear el sway or you can buy a ASR brace and run there bar or a type r bar.
There's so many options with hondas the most important thing to remember is buy quality and best if new. Used it can be hard to tell if a shock is going either by itself or on a full coilover, as i have bought a shock that looked gtreat but died 3 months after install.
If your going to do occational track with the car I,ve done koni reds with H&R' sport or race as well as tockico agx with the H&R or nuespeed race springs. All were excellent on the street. Went with a sir front sway with lower control arms, and rear el sway or you can buy a ASR brace and run there bar or a type r bar.
There's so many options with hondas the most important thing to remember is buy quality and best if new. Used it can be hard to tell if a shock is going either by itself or on a full coilover, as i have bought a shock that looked gtreat but died 3 months after install.
15-Nov-2010, 09:55 AM
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^We've been running koni yellows with 600in-lb springs in the front and 350in-lbs in the rear of our MR2 for the past 2-3 years. We actually had to turn the stiffness down on the front as it was ratcheting on us (was over-damped). So I don't necessarily agree with the 400in-lb limit of the koni yellows.
Koni reds are a step down from the yellows. Though they are adjustable, you have to remove them from the vehicle to do so. The yellows are adjustable while on the car, making tweaking between runs a piece of cake. The red's range of adjustability and use are also more limited. They could work well for a street application with the occasional track day, but for ease and range of use, the yellows are worth the extra cash imo.
Koni reds are a step down from the yellows. Though they are adjustable, you have to remove them from the vehicle to do so. The yellows are adjustable while on the car, making tweaking between runs a piece of cake. The red's range of adjustability and use are also more limited. They could work well for a street application with the occasional track day, but for ease and range of use, the yellows are worth the extra cash imo.
15-Nov-2010, 10:21 AM
#11
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Okay if i were to order a brand new SIR front sway bar with lower control arms, and a rear integra type r sway bar, with this setup what spring rate should I run for a daily driver with a somewhat decent ride and track style handling?
I decided to buy a rear camber kit because my stock camber arm bushings were done but do you think I will need a camber kit for the front with a 2-2.5" drop?
Originally because of my budget I was gonna go with the Kyb AGX shox, they would match the springs and my red LCA really well too. Now i think im going to go with the Koni yellows. I want to do this right the first time and wont have my car on the road until the spring so im taking my time and saving up for the right stuff just having a hard time finding what i need lol
thanks guys
I decided to buy a rear camber kit because my stock camber arm bushings were done but do you think I will need a camber kit for the front with a 2-2.5" drop?
Originally because of my budget I was gonna go with the Kyb AGX shox, they would match the springs and my red LCA really well too. Now i think im going to go with the Koni yellows. I want to do this right the first time and wont have my car on the road until the spring so im taking my time and saving up for the right stuff just having a hard time finding what i need lol
thanks guys
15-Nov-2010, 06:11 PM
#12
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I was working on my car on the hoist this afternoon and noticed it has a FAT sway bar up front... Im guessing that it is the SIR because I have an sir engine, dash, cluster, power doors/tweeters and looks like sway bar? All this stuff was done by a previous owner but I guess I should get to know my car better.. lol
Im not 100% sure its the SIR bar but its at least twice as big as the rear 13mm and makes it look tiny.. I will prob post pics to be sure...
Im not 100% sure its the SIR bar but its at least twice as big as the rear 13mm and makes it look tiny.. I will prob post pics to be sure...
16-Nov-2010, 09:12 PM
#14
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It seems hard to find a used type r sway bar and a new one will cost me close to what this will:
Product Name - OBX Racing Sports
You said I might want one a bit larger and this one is 24mm..
Whats the point of a subframe brace? Just flash basically? Does it eliminate a rear lower tie/can you still use one?
Product Name - OBX Racing Sports
You said I might want one a bit larger and this one is 24mm..
Whats the point of a subframe brace? Just flash basically? Does it eliminate a rear lower tie/can you still use one?
17-Nov-2010, 10:26 AM
#17
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using a large rear bar, the best thing would be to add a sube frame brace. The brace is better than a tie bar, and a tie bar is better than nothing...lol.
If you install a brace, a tie bar is unecessary and redundant. Some people run both, but honestly, if you have a good solid brace, the tie bar is useless.
If you can't find an itr rear bar or similar within your price range, you can always grab a smaller 99-00 SiR rear sway bar and go with stiffer rear springs. So like 500in-lb in the rear instead of 400 with an itr bar. The ride will be a bit rougher, but the results will be about the same on the track.
If you install a brace, a tie bar is unecessary and redundant. Some people run both, but honestly, if you have a good solid brace, the tie bar is useless.
If you can't find an itr rear bar or similar within your price range, you can always grab a smaller 99-00 SiR rear sway bar and go with stiffer rear springs. So like 500in-lb in the rear instead of 400 with an itr bar. The ride will be a bit rougher, but the results will be about the same on the track.
17-Nov-2010, 10:59 AM
#18
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Id like it to be as smooth as possible but i kind of like the look of the rear brace and a red one will match to my collection of red suspension components very nicely...
MPR thanks for all the info learning a lot!
MPR thanks for all the info learning a lot!
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