Just assembled my koni/gc's and the ride is rough. I'm thinking I did something wrong but i'd like some help to just make sure. It takes bumps really hard and I feel almost everything. This was my first time assembling these so any help would be cool.


Parts I got:
(4) koni yellow shocks
(4) gc sleeves (560/450)
(4) oem tophats
(2) Insulator bushings for tophats
A crap load of washers, bolts, ect.

Steps I did for rear:
Koni shock body
slid the sleeve on to it
Set the spring on top of the sleeve
put on cut bump stops
set washer on top provided by ground control
installed the black Insulator bushing for the tophat provided by GC
Installed tophats

Steps for front:
Same as above but since I only had 2 insulator bushings I used my oem ones and thats what I'm thinking is causing the bounce.

I was given only 2 of the rubber pieces from gc (Left), and used the oem (top ones) for the fronts.



Question is if I missed a step or something causing it to bounce. Any help would be appreciated. I'll be ordering extended top hats this weekend if that'll help.

 

450lb rear springs can ride rough.

How low are you?

 

This is your problem.
(4) gc sleeves (560/450)
WHy did you buy such stiff springs?

 

Im all the way down in the front and about an inch left in the back.
I got high rates cause my old f&f was an 8k 6k and was way too soft so i read that 560/450 would equal about a 10k 8k. And it would be going as low as possible so i wanted somethinh that could handle it.

 

Because of your spring rates and you must be slammed.

Gotta pay the price to ride like that.

 

Im low for an ef but its barely tucking. Do you thibk the off the shelf rates will mke it better?

 

Yes, softer rates mainly the rears effect ride quality. However what setting do you have the koni's on?

 

You're slammed with high spring rates, this is why your ride is bad.

Make it better? Sure, but you will be creating bigger issuses. Such as, front UCA's slamming into the shocks towers.

 

I have them a little of the soft side but close to middle.

Makes sense, the ride right now is just ridiculous for a koni/gc setup. I know a lot of people are running them slammed but it doesnt seem to be affecting them really bad. Im barely tucking tire.

 

I was tucking over half an inch in my teg up front with top hats, raised it a inch and it handles so much better now. It doesnt look as good but it is way more functional on corners!

 

With those rates, stock top hats and being that low, you're probably riding your bump stops..

The '91 Si I race has Koni/GC/Hypercoil with 450F/550R and stock top hats and sits with about a finger gap all around. The car actually rides relatively smooth and doesn't bottom out. I used to have Koni/GC 450/550 on my '95 coupe and the ride comfort in that was worse than the '91 with the same spring rates and shocks. I'd say the weight difference and also that the front of the '91 coilovers are slighty preloaded helps in comfort. Handles amazingly well and won me a few championships last season..

 

That was helpful, and kinda what i was looking for. I'll be ordering extended tophats all around this Friday. Do you think that and trimming my bump stops a little more will help? Sorry, noob question.

 

How much are they trimmed right now?

 

GC extended upper shock mounts come with new bumpstops that you should not trim.

 

You don't need top hats in the rear. They're simple for show at that point.

 

Yea, but i found some online for cheap and since tophats all do the same thing I was just gonna try to save some money.

only one was trimmed cause it was way bigger than the rest. All the others sat fine on the strut.

I found a set of 4 for cheap is the only reason. I'm gonna look at reviews on them but if they're bad i'll only be ordering 2 fronts from GC.

 

If you want to do it correctly (and most won't bother), you should first install the shocks without springs or bumpstops and fully compress the suspension until it bottoms out, which will probably be the UCA hitting in the front but could be the tire hitting instead, and measure the remaining exposed shock shaft. With that measurement, cut the bumpstops until they're 1mm longer than the exposed shaft at full compression (full compression is important here, and difficult to both achieve and measure once it is there). This will preserve the absolute maximum amount of suspension travel while still allowing the bumpstop to do it's job of protecting parts from hard impacts.

For the rear, since the shock is likely to bottom out before any other parts, you want the smallest amount of bumpstop that still prevents the shock from bottoming out internally once the bumpstop has reached full compression.

 

Dang, I havent even heard of that. I dont wanna do anything wrong though so I might put theef back on jack stands and do this. But do you think the extended top hats and setting it to soft will make a noticeable difference?

 

The extended top hats will give back some compression travel for the slammed ride height which should ride a bit better. But do as TunerN00b says measure the travel.

 

Are you sure this a good idea? If the UCA or the tire is the limiting factor, then you render the bump-stop useless by cutting it so short. Bumpstops are a relatively soft material that have a very progressive effect on spring rate. How progressive depends on their total length vs their compressed length vs their durometer. If you only have 1mm of bump-stop compression before something else in the suspension bottoms out, there be almost zero effective rate & protection produced by the bump-stop.

Maybe I read that wrong or something.

 

Let me try and summarize better (because yes, you are misinterpreting what I was trying to convey).

You want the bumpstops to fully compress and prevent any further suspension movement right before anything else would bottom out (whether that "anything else" is the tire, UCA, or shock internals).

1mm of remaining travel at full compression of the bumpstop, not 1mm of bumpstop compression before contact.

And this is being posted by a guy who didn't bother to measure once, blindly threw a set of GC extended upper mounts on the car, and now has dented shock towers from the UCAs slamming into them. I post this to let others learn from my mistake. Do it right the first time, always measure things first, never just assume the parts intended for your car were actually designed correctly.

 

Ah okay. I'm dumb. Reading > Me.

 

Ok, so i just ordered extended tophats and ots spring rates. Hopefully this will give me that really good ride i hear from koni gc.

 

Those springs will be pretty soft, and might not be able to support that ride height.
You could begin to bottom the shocks out, smack the UCA's into the shock towers.

 

This is the height.

And the guy said it was 450 375 if thats ots. And I got them for 50 dollars so I wont hurt to try them out lol.