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Discussion Starter · #1 ·
Here's the setup:

K20A2 Motor/Tranny
Camp1320 Axles
KW V3 Coilovers (lowered a good bit but I don't know how much)
15" Rota Circuit 8's
225/50/15 BFG Radials (front)
205/50/15 BFG G-Force Sport (rear)
Gutted from the front seats back

Did a couple 1-3 gear pulls last night and once I got to 90mph the car felt like it was going to lift off the ground a fly a couple hundred yards so I had to shut down. Also felt like it could have been blown off the road by the wind at any second.

Any ideas as to why or what I can do to fix it?
 

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Did you get an alignment done? Try playing with your dampening settings a little more. Sometimes, the stiffest isn't the best way on a normal street.
 

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What PSI are you running in your tires? Make sure they are even throughout the two fronts and two rears...Maybe the two different tire types are playing a roll in it, namely the Radials on the front?
Other than that, I would only think it's either the dampers or alignment...

Check the tire PSI, then alignment, then if not fixed - seriously consider those damper specs being the culprit.
Bouncy tires with an overly stiff suspension means that the only real suspension is the flex in the tires - and tires dont have struts to manage the movement so that will create nervousness and wandering at higher speeds.
 

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Going off experiences i've had with a similar problem, i agree with dulluthkid_19 that tire pressure might be a factor, if over or under inflation, centrifical force makes the tires bow out in the center in-effect, lessening contact with the road. Also, you mention the car is lowered, how negative is your camber? I had a similar problem, i run -2 camber in front, -1.6 in back for increased cornering responce, but high speeds it can seem a little more unstable. Higher negative or posstive camber decreases surface area contact with the road which is amplified by high speed. Also, the biggest control factor at high speeds is your CASTER angle. If set incorrectly, your car will be extremely sensative and even unstable at high speeds. My advice is get an alignment at a shop with a full lazer align system (SEARS is cheap and good). Tell the tech that you want the caster set to specs set so it is more stable at high speeds. If they don't know what your talking about, you don't want an alignment from them anyways. The down side to caster angle is you can't have your cake and eat it too, higher stability at high speeds means turning at lower speeds is harder if you don't have power steering.
 

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shit guys.... i have this problem as well. im on stock suspension with BFG drag radials 225/50/15 front and some cheap tire 195/50/15. my next move is to work on the suspension. ive taken my car to 140 and was pretty damn nervous. i think the unstability is a combination of a light car, inadequate suspension, lack of downforce. my tire pressures match from side to side.
 

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Considering the post above this and the thread creator's post as well there seems to be a common possible issue. You two are both running two sets of different tires! Do you think that's a great possibility? I think so...
You both have BFG drag radials up front - coinsidence? Drag tires have weak sidewalls, the radials imply that it is ok for street driving. But for high speed stability I would bet my life that the softer sidewalls from the drag radials are allowing the contact patch structure to stick to the road while the sidewalls sway from side to side and thus making the car itself sway and ultimately causing an instable feeling at high speed.
I think maybe this was a slight reiteration from sevndustn, but I think its a pretty good theory.
 

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Discussion Starter · #7 ·
dulluthkid_19 said:
Considering the post above this and the thread creator's post as well there seems to be a common possible issue. You two are both running two sets of different tires! Do you think that's a great possibility? I think so...
You both have BFG drag radials up front - coinsidence? Drag tires have weak sidewalls, the radials imply that it is ok for street driving. But for high speed stability I would bet my life that the softer sidewalls from the drag radials are allowing the contact patch structure to stick to the road while the sidewalls sway from side to side and thus making the car itself sway and ultimately causing an instable feeling at high speed.
I think maybe this was a slight reiteration from sevndustn, but I think its a pretty good theory.
I have used mismatched tires on previous cars and never had a problem and drag radials are designed to handle some pretty high speeds. I loosened up the stiffness of the suspension a little and the ride was noticable more stable and controllable. I think the next culprit will be the alignment.
 

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zotex said:
I have used mismatched tires on previous cars and never had a problem and drag radials are designed to handle some pretty high speeds. I loosened up the stiffness of the suspension a little and the ride was noticable more stable and controllable. I think the next culprit will be the alignment.
Having just finished an extensive test programme to solve this would indicate the following
King Pin inclination is incorrect a line from the top of the shock mount through the bottom ball joint should intersect the wheel contact width on the outside 50%, Install camber plates to move to the centre the top shock mount inwards.

Check toe to insure the car is slightly toed in

Reduce rim width to max 7" rim and tire to 215- wide rims and tyres will enhance problem.

Get to know someone who owns a wheel aligner- it will take a fair bit of time to solve

Glen
 

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Discussion Starter · #9 ·
As soon as I figure out what ride height I want I am going in for an alignment. Thanks for the helpful comments.

Anyone know why my car would sway to one side and feel a little weightless under moderately hard braking at speeds around 80mph and up? I braked last night after a run and thought I was going to float to one side and then I corrected and expected to spin out because of how it felt. Got lucky...
 

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Bionichonda said:
Having just finished an extensive test programme to solve this would indicate the following
King Pin inclination is incorrect a line from the top of the shock mount through the bottom ball joint should intersect the wheel contact width on the outside 50%, Install camber plates to move to the centre the top shock mount inwards.

Check toe to insure the car is slightly toed in

Reduce rim width to max 7" rim and tire to 215- wide rims and tyres will enhance problem.

Get to know someone who owns a wheel aligner- it will take a fair bit of time to solve

Glen


hondas dont have king pins.you probably ment SAI (stearing axis inclination). which is usually for mcpherson strut vehicles

make sure the rear toe is 0 or centered and the fronts are slightly toed in. also check all the bushing in the lower control arms and the upper arms.
 

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Reguarding your unstable breaking question. First instict is uneaven tire pressure or tire size/age. Second, uneven clamp power to one side via worn rotors/pads. But, I had a similar problem, even after installing all new brembo parts on my '91 civic attempting to fix it. While trying to find answers to my problem, i read a post about someone buying a late 60's mustang from a guy for dirt cheap because the guy couldn't figure out what was wrong with the braking system (same problem). After buying it, he realized the bushings were shot and replaced all of them with the Energy Suspension master kit, problem solved. I did the same a few weeks ago, posted about it on the k20a suspension forum actually. It fixed this problem along with a few others i had. basically this is just a long post validating what [email protected] just said about the bushings in the lower control arms. Check them out on your car, especially if you car is over 5+ years old. If the stock rubber bushings sag with the weight of your car on them (don't examine while on jack stands) you might consider replacing them. Its a kickarse upgrade either way, but i think this may be the answer to more than one problem your having.
 

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Yeah I've had a few of these problems in other cars heh. Usually a pull at high speed breaking = bad allignment, plugged break line, 1 tire with better traction than the other.

I would also have your steering rack checked to make sure it doesn't need to be replaced, not just realigned. Just make sure nothing is bent and as they said above, check your bushings, your brakes and tires also.
 

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I also have this problem. I swapped out my azenis for bfg drag radial and it is definitely a washy at high speeds. only thing i could do was bump up the tire pressures a bit to lessen the sidewall flex when i know im going to be hitting the freeway or taking long drives. but around town, i drive around on 20 psi :p
 

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B16B said:
I also have this problem. I swapped out my azenis for bfg drag radial and it is definitely a washy at high speeds. only thing i could do was bump up the tire pressures a bit to lessen the sidewall flex when i know im going to be hitting the freeway or taking long drives. but around town, i drive around on 20 psi :p
you should check out this link seems they got progress to put together a kit to lower your car with a k swap and improve driveability all at the same time

http://www.k20a.org/forum/showthread.php?t=7118
 

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I would suggest checking all the bushings, ball joints, wheel bearings for play and ultimatly check the alignment. Until you have done this don't take any unnecessary risks. Stop driving fast until its fixed. lol.
 
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