MK-4 Roadster > What Spring Rates Are You All Running > 3 & 4 Link Set Ups Onlyl

[GoDadGo]

My car came with 500-LBS springs up front and 350-LBS out back.
Have any of you messed with the factory rates?
I am specifically interested in the rear springs.

[Jeff Kleiner]

What is it you're trying to do Dad?

I run 750 front and 500 rear on a 3 link because my car gets tons of autocross and track time. Most would consider that harsh for street use; I don't but am more hard core than most ;) Going to a softer spring in the rear (or stiffer in front) without a corresponding change to the other end of the car will cause it to understeer more (the natural tendency with the factory 500/350) while doing the opposite (higher rear rate/lower front) will promote oversteer.

So again, what is it you want to accomplish by making a change?

Cheers,
Jeff

[CraigS]

Back in the day FFR shipped 450F/250R. There were quite a few people who went to 200 in the rear for a better ride. This was using the old ProShocks. When FFR went to their specifically valved Konis, they started shipping w/ 350 rears. I don't have those shocks myself but have ridden in a couple of FFRs w/ them. Personally I think the 350 is on the firm side and, if I had the Konis, I would go for 300 to get a better ride. I find that the rears affect the ride a lot more than the fronts.

[ram_g]

GDG, are you on the other forum at all? Because this topic has been discussed extensively there...

[GoDadGo]

What is it you're trying to do Dad?

I run 750 front and 500 rear on a 3 link because my car gets tons of autocross and track time. Most would consider that harsh for street use; I don't but am more hard core than most ;) Going to a softer spring in the rear (or stiffer in front) without a corresponding change to the other end of the car will cause it to understeer more (the natural tendency with the factory 500/350) while doing the opposite (higher rear rate/lower front) will promote oversteer.

So again, what is it you want to accomplish by making a change?

Cheers,
Jeff

Since I put an all iron SBC and ZF-6 Speed in this thing, the driveline had to move forward about 6" and about 1" to the left.
The good news is my drive shaft is perfectly straight & 12".

This had to happen to get the distributor to clear and to get the shifter in the right place, plus it's so wide I've got it as far back as possible.
I've got .75" sway bar up front so I've likely will have created some understeer and because of the change in the C/G (52F/48R).
You can see where the engine is located in the attached YOUTUBE:

https://youtu.be/UJwM5godh88

Not sure if my rear is too stiff, but man it has very little deflections when I sit on this thing.

What-Cha-Think?

[GoDadGo]

GDG, are you on the other forum at all? Because this topic has been discussed extensively there...

No, only this one.

[Jeff Kleiner]

What-Cha-Think?

Leave it alone until you get it on the road. Any changes you'd make now would be strictly hypothetical.

No, you won't get much deflection by sitting/pushing on a corner. These cars are stiff; if they weren't they'd do this:

http://i269.photobucket.com/albums/jj43/jkleiner/citroen-ami6-in-curva.jpg

:D

Jeff

[edwardb]

Leave it alone until you get it on the road. Any changes you'd make now would be strictly hypothetical.

No, you won't get much deflection by sitting/pushing on a corner. These cars are stiff; if they weren't they'd do this:

http://i269.photobucket.com/albums/jj43/jkleiner/citroen-ami6-in-curva.jpg

:D

Jeff

Hmmm... I vaguely remember someone else giving similar advice. :confused:

[Desert Cobra]

I put 300 on the rear and 450 front. Street use only. Lower rates seems to reduce the initial shock felt with small bumps. Not as "jarring". Wife likes it more as well. I agree that you should drive it some first, then see what you think of the ride quality and how you want to adjust it, rather than merely adopting what others may have done. After all its your butt that will feel the difference, not theirs.

[GoDadGo]

Thanks Gentlemen!

I was afraid that since my drive line has been moved forward that the rear was unusually stiff.
I've now lowered the car down to ride height and used the "Tie Wrap Method" to keep the rear springs from dropping down if the car is being jacked.
Please know that I will leave it alone until after I get some Go-Karting miles on it.

Thanks Again!

Steve

[frankeeski]

There are many things that can affect your suspensions rate, tire side wall height and stiffness is one very few think about. The biggest one thing you can do as far as springs go is to change to a better spring. The rates of the supplied springs can be questionable. I ended up going with Eibach springs with the FFR Konis with #425 in the front and #250 in the rear. I do run a front anti-sway bar in the front and Gordon's 5-link in the rear. If you're thinking of only changing 50 lbs. of spring rate, I don't think I would bother. I do agree with Jeff that you should wait until you get a bit of seat time before making a change. But I would also add that you HAVE TO make sure you have absolutely no bind in both the front and rear of the car. I have seen too many of these cars assembled without grease installed on all of the bushings and sleeves during initial assembly. You can't just try and pump grease in after everything is together and call it good. My advise to all first time builders, or any builder for that matter, is to pull the coil over out on the front and raise and lower the front assembly and make sure it moves freely with no bind. If you can't move it up and down by hand then something isn't right (see note above about grease).

[frankeeski]

The good news is my drive shaft is perfectly straight & 12".


This kind of bothers me. Your drive shaft should not be perfectly straight from the tail-shaft to the yoke of the rear-end. You want a small amount of offset so that the needle bearings in the u-joints don't wear funny and then fail. FFR purposely offsets the engine and trans in the car so that this is accomplished.

[GoDadGo]

This kind of bothers me. Your drive shaft should not be perfectly straight from the tail-shaft to the yoke of the rear-end. You want a small amount of offset so that the needle bearings in the u-joints don't wear funny and then fail. FFR purposely offsets the engine and trans in the car so that this is accomplished.

Let me clarify this.

The drive shaft is straight in reference from a front to back alignment standpoint. Basically, the pinion flange is in line with the plane of the engine and transmission so the driveline is about 1.125" offset to the right side of the car.

Please know that the car does have a slight angle downward so that the needle bearing will cycle.

Thanks for your thoughts regarding this issue.