I just picked up my ITR about 2 weeks ago and I wanted to get some thoughs on swapping the springs on the JIC FLT-A2s that came with it. Front rate is 550 lb/in and the rear is 385 lb/in, but coming from an RSX with odd wheel rates, I'm used to having 375 lb/in fronts and 650 lb/in rears. So, I wanted to get the thoughts of the masses on doing a spring swap and running the higher rate in the rear.

Questions:

-Will it be unstable in high speed cornering? I do a lot of autocrossing and plan to hit up a few track days next year. I don't want it to be unstable at high speeds. The RSX has a hint of this.
-Will the dampers be able to handle the change? I wouldn't think the change would be too drastic for OTS coilovers, since its probably the same damper on all 4 corners, but someone may know better than I do.

Any suggestions would be appreciated. TIA.

 

Don't the FLTA2's have adjustable body length? I only have my fronts off right now so I can't compare, but as long as you can get the lengths the same, can you just swap mounts and readjust the lengths?

I run the same shock; 900lb front 1000lb rear with 225/45/15 and stock front/rear bar (ITR). I likes.

So your F/R ratio would be a little smaller then mine, so I would try just swapping first and then add more rear bar if you need to.

 

That's a good thought. Instead of swapping springs, I could just swap the entire body. I'll check it out tomorrow.

 

Do you think your front and rear sprung and unsprung weights are the same? And do you think the front and rear shocks are valved the same?

 

Sorry am I missing something here? He is talking about an ITR, a fwd honda.. Why would his f/r sprung weight be the same?

We are assuming that JIC valved the dampers to match the springs that are on them. Personally, I think that is a heavy assumption. But ideally if they had, he could keep the valving matched to the shock.

 

Yes it sounds like you've missed the point, which had nothing to do with the car's drive layout. The weight distribution is definitely different front to rear, as is the wheel rate, as is the valving (probably). All of which mean that flipping the shocks around is not a good idea, performance-wise, even if the shock body length's were compatible.

 

I pointed out the drive layout because no fwd car is going to have a f/r weight distribution that is the same. So I don't understand why you would ask him if it was. Maybe you were being rhetorical? I think the point is that advice in the form of rhetoric that is based on partial understanding of suspension design is not very helpful.

The wheel rate is what he is trying to change, via changing the spring rate . The wheel rate will change any time you change the spring rate, by definition. Perhaps you are thinking about the difference between f/r motion ratio? It's ~10% on his chassis, much less than the proposed spring rate change.

Mr. Mike- If you can match the lengths, it wont hurt to try, and its free. Try it out at an autocross, see how you like it, and go from there.

 

I believe I'll try it and find out. The worst that could happen is that the rear of the car will be unsettled and I'll end up backwards.

I checked the shock bodies and they do seem to be compatible. JIC has FH, FR, RH,and RR marked on the coilovers. I find it odd that they would mark each corner differently.

I don't think the lengths will be difficult to match, either.

 

They mark them for you when you take them off, so you dont get them mixed up

I think you'll like it this way.

 

Car tried rotating on me today at about 60 MPH on an on-ramp. Not so sure about those higher rear rates now. Hmmm...

 

lol.

Well sounds perfect for autocross

So maybe you went too far and have more oversteer than you want. So go somewhere in the middle, buy a pair of 550lb's and put those on the front, and have the same spring all the way around.

Or disconnect the rear sway bar for street driving and see how that goes.

 

Oh no, this was on stock suspension. I haven't even put the coilovers on yet. Probably won't bother until spring time.