As I'm assembling my front suspension, I noticed that the FFR supplied yellow Konis (82-2598) only have an available stroke of 3". They are mounted at a slight angle, so maybe total suspension travel may be a bit more, but I doubt it will be over 4". I've got the coupe, and I'm not planning to race it. Our roads get a lot of potholes, and our parking lots have speed bumps. None of which are suspension-friendly features. On my last project car, I set it up for a 5" ride height and I had a solid 5 inches of suspension travel. I found that acceptable for daily driving, as long as I was reasonably careful. I believe I set it up to allow for 3" compression and 2" rebound (in other words, at rest it could be compressed 3" before bottoming out). I was not planning to use an anti-sway bar: I drove my last project car with and without it and I could not see a difference. My center of gravity was so low it didn't really seem to help. I've been told the "quick and snappy" high speed lane change is the telling maneuver, but I saw no difference.
Has anyone played with the suspension for increased travel? I just need my front ball joints and I'll be able to see what happens if I increase travel. It looks like I could use QA1 coilovers and they have one that would give me over 5" of travel with the same nominal length, with a simple knob adjustment for shock damping. Same 2.5" diameter springs, 10 or 12" length I think. I'm assuming the 5" nominal ride height would help, and I've read that a number of people have gone with a 5" ride height. I'm sure the tires rubbing would become an issue at some point.
Thoughts?
Last edited by 67 Car Guy; 01-03-2021 at 10:10 AM.
Reason: corrected "anti-sway bar"
Hi 67 Car Guy, I am going to add my comment in RED
As I'm assembling my front suspension, I noticed that the FFR supplied yellow Konis (82-2598) only have an available stroke of 3". Stroke is 4", but there is a rubber bump stop that reduces that travel. They are mounted at a slight angle, so maybe total suspension travel may be a bit more, but I doubt it will be over 4". I've got the coupe, and I'm not planning to race it. Our roads get a lot of potholes, and our parking lots have speed bumps. None of which are suspension-friendly features. On my last project car, I set it up for a 5" ride height and I had a solid 5 inches of suspension travel. The FFR 818 design for the street is 4.5" ride height. I found that acceptable for daily driving, as long as I was reasonably careful. I believe I set it up to allow for 3" compression and 2" rebound (in other words, at rest it could be compressed 3" before bottoming out). I was not planning to use an anti-sway bar: I drove my last project car with and without it and I could not see a difference. My center of gravity was so low it didn't really seem to help. I've been told the "quick and snappy" high speed lane change is the telling maneuver, but I saw no difference. My car had a lot of body roll and front tire rub that I solved by increasing my rear springs from 270# to 500#.
Has anyone played with the suspension for increased travel? I did not increase shock travel, But I did lengthen my shock hat 1". I just need my front ball joints and I'll be able to see what happens if I increase travel. It looks like I could use QA1 coilovers and they have one that would give me over 5" of travel with the same nominal length, with a simple knob adjustment for shock damping. Same 2.5" diameter springs, 10 or 12" length I think. 818 uses 2.5x8" springs I'm assuming the 5" nominal ride height would help, and I've read that a number of people have gone with a 5" ride height. I'm sure the tires rubbing would become an issue at some point. Yes, front tire rub on the gen 1 nose is a problem. It is better on the gen 2 nose.
WOW! That's impressive! I don't think I'm going to have any issues with a 5" ride height-
Is that with the 500lb springs in the rear? And I think I've seen you comment that you don't use an anti-sway bar?
Has anyone used 10" springs with the Koni shocks? I measured them and it looks like they would just barely fit with no pre-compression. With the same spring rate that should put the resting point more in the middle of the adjustment travel.
WOW! That's impressive! I don't think I'm going to have any issues with a 5" ride height-
Is that with the 500lb springs in the rear? And I think I've seen you comment that you don't use an anti-sway bar?
Has anyone used 10" springs with the Koni shocks? I measured them and it looks like they would just barely fit with no pre-compression. With the same spring rate that should put the resting point more in the middle of the adjustment travel.
1.0g on Toyo R888 235F 255R street Legal tires with no aero on the car. Yes,500 springs in the rear. Below is my shock setup when I had 600# in the rear. I'm not sure 10" springs would fit. I also added tender springs on the rear.
You also have to take the motion ratio, due to where on the arm the coil-over is mounted, into account to find the true total suspension travel. The total travel ends up being close to twice the shock shaft travel when you calculate it, so at the tire it is around 7 inches including some compression of the bump stops.
Thanks Jim; So I guess the shock will be further inboard of the wheel than I expected. Good to know! I guess that means the springs will see close to twice the force of the corner weight?
I took a closer look at my shock assembly, it looks like I could fit a 10" spring on it if I need the extra adjustment range. I'm going to have something like an extra 400 lbs of battery up front, maybe 200lbs per wheel. I guess I'll also need stiffer springs as well. Although with the extra adjustment range of a 10 inch spring, I might be able to accomodate the extra loading. I'd wind up with a softer ride, which may be OK for a street car. I think I need to get further along in the build before I start worrying about the springs.... Looks like the Koni's will work fine though.
More questions on spring rates...
Bob-n-Cincy’s explanations make sense and being backed up with experience on the track is persuasive.
I just wonder how FFR got to 350# fronts and 275# rear on the S, with this much rear weight bias? Has anyone seen or heard an explanation of this?
I’m building an R, manual says 300# front and 500# rear, when using aero. And reversed for street use; 500# front, 300# rear! I don’t get it but I’ve got to have some faith in the FFR development right?
Bob’s experience of 500# on the rear makes sense to me. I know my Cayman has stiffer rear springs. And I’m coming to understand not needing a sway bar with such high spring rates. I thought I might source 400# for the rear and use the 300# front, since I won’t start with a bunch of aero.
I’d appreciate any further discussion or experience anyone wants to share.
Hey I talk to Wayne and he ran 500 front and 600 rear on the FFR car they took to VIR. He was on full slick and full aero.
I tried that setup on my S with out slicks and found it to be to stiff for street tires.
I have settled in with 425 front and 500 rear. The 350 front was to soft and I was dragging the front splitter under heavy braking.
No need for the sway bar for sure with the stiffer springs. It just made my car tight so I took it off.
Good tires make as big a difference to the cars handling as anything. With a harder tire the car just doesn’t turn as good and then you can’t put the power down either. I have had best luck with under 200 tread wear tires at the track. Car is light so soft tires and good brake balance makes the car fun.
taco20, thanks for the response. I found another thread that discusses the 818 and other rear weighted cars and how they have heavier springs in front. This included explanation by Jim Schenck.
It just seems like such a dramatic difference; F/R= 350#/275# on the S and F/R= 300#/500# on the R. Since I may start my R going without aero, I might try a half step; like F/R= 400#/300# and/or 300#/400#.
Thanks: 
Likes: 
Reply With Quote
Originally Posted by 67 Car Guy
