What spring rates?

So I am about to order a set of Ground Control coilovers for my 93 Civic that are going to be used with Koni Sports. I am trying to decide on a good spring rate for a fun weekend driver/ Street Modified autocross car. Aiming for around 2100lbs. Anyone have suggestions? Running a Type R rear bar and stock front.

For a similar weight Miata, 500 F/ 350 R is the recipe for what you seek.  Not sure how the Civic chassis differs in terms of front/rear balance.

Based on my experience with koni sports, no more than about double the stock rate if you want it to ride at all decently on the street.

93EXCivic said:

So I am about to order a set of Ground Control coilovers for my 93 Civic that are going to be used with Koni Sports. I am trying to decide on a good spring rate for a fun weekend driver/ Street Modified autocross car. Aiming for around 2100lbs. Anyone have suggestions? Running a Type R rear bar and stock front.

Give the guys at Ground Control a call, they will be able to point you in the right direction based on your setup goals and tires you'll be running.

Comparing spring rates between different vehicles is meaningless - they use different suspension motion ratios and angles and everything, and between Miata and Civic: different weight distribution.

I did a wack of measurements and calculations on 88-91 and 92-95 Civics, and I recommend 700lbs all the way around.  You'll need the Koni race-valved shocks, and I highly recommend short body shocks. 

You may also find next to nobody runs these spring rates, but a number of relatively local guys have tried this, and have found them VERY successful. YMMV.

I have a Corolla FX16 which will be different because McStrut.  However, the weight distribution is similar.  The FX has 440# front and 750# rear.  There is anecdotal evidence that Koni Sports do not like springs rates much above 500#.  There may be some truth to that.  One thing I would do is run stiffer rates in the rear than the front.  This will give you rotation.  I was advised on the opposite and with that setup the car would not turn.  It is used for autocross and some mountain curve fun.

Guessing a ballpark of 400#f/500#r.  

I'm sure there are some ST Civic drivers here that can get you closer.

You might end up losing that front bar too!  Testing will confirm.

dps214 said:

Based on my experience with koni sports, no more than about double the stock rate if you want it to ride at all decently on the street.

Ground Control can valve the Koni's to work with the springs.  Just call them.

Yeah, motion ratios different between chassis means that comparing rates is useless. Never mind the weight distribution difference. 

Nothing else to contribute here other than to say dont use miata rates :D 

LF:600, RF: 550, LR:550, RR:500

z31maniac said:

93EXCivic said:

So I am about to order a set of Ground Control coilovers for my 93 Civic that are going to be used with Koni Sports. I am trying to decide on a good spring rate for a fun weekend driver/ Street Modified autocross car. Aiming for around 2100lbs. Anyone have suggestions? Running a Type R rear bar and stock front.

Give the guys at Ground Control a call, they will be able to point you in the right direction based on your setup goals and tires you'll be running.

+100!!!

When I bought the setup for our chumpcar (93 Civic hatch) I gave them a call and had a great conversation with the tech guy.  He asked lots of questions about how the car was built and recommended 450 front and 550 lb rear.  We are all very happy with how neutral it handles. 

In reply to Stefan (Forum Supporter) :

I could be wrong but I don't think they have the ability to custom build them, probably just choose between sport and race valving. (and if they can custom valve them they won't have the ability to put gas in them which isn't great for a street car). For race valving the rate limit is probably around 3x stock, maybe a touch more depending on your tolerance for bounciness over bumps on the street and how smooth your autocross/track venues are.

For an application as popular and common as this one the people at GC probably do know what they're doing and whatever they suggest will probably be decent. But I've had experience with less popular applications where their advice and the setup they put together was very much not up to the task.

Alright I reached out to Ground Control and will see what they say.

Fwiw I run a 350lb/250lb on my 1780ish lb 2nd gen CRX with no/light sways for street, da integra/ST 3/4 sways for sticky rubber. Seems to work well for me. A bit rough on the street, but lets me use my range of travel. Ymmv. 

Other possibly relevant info:

Still running the tokico illumina (white, 1-way adjustable) shocks with noname coilover sleeves and the lighter chromoly qa1 springs. I do not recommend the illuminas for competition, but they have held up unexpectedly on the street besides the chipping paint that seems to plague all non-anodized brands. I do recommend QA1 products all day for reasonably priced springs. GC are also generally great.