FC3s Widebody Spring rates?
 

Hello,

I am building an FC3s widebody and need some advice.
This is the RoninSpeedWorks.com (85mm Front- 80mm Rear).
I will be running 18x11 wheels and 295/30 square set up.
I currently have Tokico Illuminas and stock springs.

With the additional width, how will this effect spring rate?
What spring rate would you recommend for this set up?
Please keep in mind this is strictly a street car.

Also if you have a anti-sway bar recommendation I'd love to hear it.

Thanks a ton,

Joe

Pics of my inspiration car

For a starting point I was thinking 300/225 front/rear..

If you liked how it rode before the conversion, the easiest way would be to calculate the percentage of increase in the track width and increase the spring rate by the same amount. I suspect it will be a relatively small change, and you could probably buy some standard aftermarket springs from the usual suspects (Racing Beat, Mazdatrix, etc) and be pretty satisfied.
If it's purely a street car, like you say, then there is little need to really "dial in" the spring rates with custom numbers.

Ok Good News to hear.

If going for an adjustable ride height spring like Ground Control, should I mimic the rates offered by
the above listed manufactures?

Thanks again,

Joe

most aftermarket lowering springs are far too soft for the amount the lower the car. You end up hitting the bump stops very easily which makes them feel harsh.

This is why some people have claimed they upgrade to a 350/250 or 400/275 setup with good shocks (ie bilsteins or konis) and it actually rides better than a stock car.

with with my widebody the center of the wheel only moved out less than 2", so the motion ratio didn't change a whole lot... the spring increase will be more based upon the increased grip of the larger tires.

I'd recommend getting some ground control coilover sleeves and going 400/275. You'll be much happier with the performance of the car and it'll be much more predictable because it'll stay off the bump stops.

My car has 600/425 springs on it with bilsteins and I'm perfectly fine driving it around on the street.

Oh I see. That makes a ton of sense.

I understand that some struts have the ability to ride at a lower height.
How are the Illuminas in this regard. Am I going to hit the strut body at 1.25-1.5" drop?

The reason I ask is the cost of GC compared to a actual coil over.
If I could justify the cost difference of 600 bucks or so for the camber plates, better adjustments,
and lower strut body.

I am kinda entertaining the idea of the Allstar Performance coilover sleeves and some qa1 springs in the rates suggested.
Allstar Performance - racing and high performance car parts, accessories and specialty tools.
This would be about $300 for all 4 corners. It would allow me to get through for a while and regroup after the huge initial cost of going wide body.

Also I was thinking of -1-1.5* Front camber and -1* rear. Am I even close? (295/30r18 on all 4)
Hoping for better turn in.

Thanks,

Joe

$1000 coilovers are all total garbage, they have crap dampers (worse than your illuminas which are OK) that will ride crappy which is why everyone thinks high spring rates are too harsh.

The cheapest complete coilovers I get would be this:
Ground Control - 86-92 RX-7 Super Street Kit

or something like this:
https://www.rx7club.com/suspension-w...thread-955929/

I'm not sure about the strut body length, I've never used stock style struts, but it's pretty easy to measure. you can take the dust boot off your strut and just look to see how much bump travel you have before you hit the bump stop when the car is on the ground. If there isn't enough you can always cut the bump stops to make the shorter to increase travel. some camber plates also increase travel by making the top mount thinner.

I ran allstars on my old custom coilovers and they're fine, but you might have to do some work to get them to fit around your stock struts well. GC has already done that work for you. you'll also need a top mount for the different sized spring (which GC already has). QA1 springs are also not as high quality as the GC eibach springs.... if you ask me the GC kit is probably worth the extra $150.

I would run more camber up front, strut cars love camber, and contrary to what most people will tell you, camber does not wear tires all that fast, it's having toe be largely out of wack from adjusting camber and not realigning the car. I would try to run at least -2* if not -2.5* on the front. I run -3.5* on my street/race car

If you don't have the money to invest in decent coilovers... I would just get some racingbeat springs for the time being and put them on your illuminas. a lot of people seem to like them, they'll probably be fine.

Ok.
I'll measure the strut travel remaining and get an alignment and see if I can get enough (-) camber out of the front. I also have rear camber adjusters in the mail.
next I need to make sure I have room from the inside of the front tire and the spring.
This will all direct me to my decision of aftermarket lowering springs or the GC setup.

Thank you guys for your help. I think I have a better understanding of what I'm expecting
from my new project. A harsh ride just isn't it. I'd be happy with less performance and
a more enjoyable commute. (Oh and my wife would appreciate it too!)

Thanks again,

Joe

happy to help.

Just a heads up, camber isn't adjustable stock so in the front you'll need either camber plates or eccentric strut mount bolts (I suggest camber plates)

Do you know much camber do you get from rotating the top strut hat to the other bolt hole locations?
I was under the impression there was "some" camber adjustment in this manner.

As a side note: The previous owner modified the bolt holes in the strut tower to
slide the strut bolts over about 1/2" towards center line of the vehicle.
Then he used the bolt hole configuration that pushed the camber farthest back out to 0*

I could not tell you why he did this, but maybe he just did not understand how to adjust camber in the manner mentioned above. Or maybe I'm way off base.

If it's in the right stock place (dot is forward and towards the engine bay) you shouldn't get any additional camber, by rotating it backwards (so the dot is towards the engine bay and backwards) you gain possitive caster (which is good)

just make the dots face inside and backwards and max out the adjustment the PO added into the bolt holes and it should be fine until you get camber plates...

Fantastic.
as soon as I receive my rear camber adjusters I'll get it in to the alignment shop.
When I bought the car I bought the lifetime alignment. I do for every car I get. Best deal ever.
I'll keep you posted on the progress.
Probably next week.
I cannot thank you enough for your help.

Cheers

Joe

Ended up with Tanabe GF210. Specs said 1.5" lower. This is more then I needed but took a gamble
that my 27yr. old rusty springs had some sag to them. Well the net result was a whopping 3/8".
I'm sure they'll settle in a bit, and that's fine, but I'm really happy the gamble didn't put me on the floor.
The springs are (f)3.0k or 237lb/in (r)2.5k or 198lb/in. kinda stiff for the wife but should be a good compromise.

Thank you guys.
 

Just wanted to say thank you to everyone for your input.
The car rides exceptionally well. My Illuminas were shot but Tokico warrantied them.
The car has much less body roll and the ride feels very tight and very much in control.
Any more stiffer on the spring rate and I would have been disappointed.

Got the alignment the other day and ended up with 1.8* of - camber and 5* of caster.
Factory in the rear.

Anyways, Thanks again.

Cheers,

Joe