Linear Rates for Koni Coilovers

Converting my Koni Coilovers to 60mm Hyperco springs and was curious if anyone with experience in the MKV chassis had some insite into good rates with a 200-300 tread wear tire for sprinted street driving / very rare track day.

Right now I am thinking 350 or 325 front and 250 or 225 rear.

Anyone know what the Koni dampers can take for spring rates before being out of their efficiency range?

:thumbsup:

If you are only very rarely going to do a track day why would you run a linear spring? You'd be faster with progressive springs and a 120 treadware tire. Oh yeah, AND more comfortable on the street.

Because I do not like the mushy turn in and un-predictableness of the Koni progressive rates.

Cumulonimbus said:

Because I do not like the mushy turn in and un-predictableness of the Koni progressive rates.

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And what makes you think it's the spring rates causing this behavior?

You can only increase the spring rates by 10-20% without revalving the damper. If you do anymore than that you will negatively effect the handling and ride. Those spring rates are about 100% stiffer than stock (not sure what the Koni coilovers come valved for) so it's going to be bouncy. That's not what you want for your daily driver. I would actually go much higher than what you suggested. Those are less than what even a PSS10 has and even that is a very mild street suspension with less than spectacular handling. The PSS10 is also a monotube shock so I would expect that the Koni's would ride even smoother with the right valving. I'd also go with a higher spring rate in the rear than the front to balance the F/R spring rate ratio and take advantage of the IRS. There's no reason VW should still be using 90 lbs/in springs on the rear of a Golf after they switched to IRS. You have to remember that the rear suspension has a .6 spring rate ratio because the rear spring is mounted in the control arm. So if you have a 250 lbs/in spring, it's only 150 lbs/in at the wheel. The front suspension doesn't have that. The spring rate from the swaybars also comes into effect here and that changes the wheel rate which is what you need to be tuning the shock for.
I won't comment on the tires because this site is full of tire threads.

Cumulonimbus said:

Because I do not like the mushy turn in and un-predictableness of the Koni progressive rates.

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350 fr, 250 or 300 rear will work fine.

200 - 300 are fine for street only.

GSM is right with the 0.6 ratio.
For street I'd go for slightly higher spring rates on front (opposed to autocross) though.

If you want some linear springs with similar rate have a look at the Sachs Performance springs (new version).
To me they seem to fit the Koni coilover.

the bruce said:

200 - 300 are fine for street only.

GSM is right with the 0.6 ratio.
For street I'd go for slightly higher spring rates on front (opposed to autocross) though.

If you want some linear springs with similar rate have a look at the Sachs Performance springs (new version).
To me they seem to fit the Koni coilover.

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On an R32 I'd suggest higher, for a 3100 lb GTI, 350 fr is a rate that will handle great and still have compliance. At 400 and up, handling will improve at direct cost of ride comfort (obviously also dependent on shock damping). At speed the stiff spring rates are excellent, at low speed you'll feel every micro crack in the pavement. I've run several cars with Dick Shines high spring rate setups, all handled excellently, all had this characteristic. If this was a dedicated track/DE car I'd opt for the stiffer rates. No doubt Sachs can provide an appropriate set of springs. OP said "occasional spirited driving with very rare track day". Let's not forget that a bunch of stiff parts doesn't make a fast car (but does make an uncomfortable one), but a good driver goes miles.

To OP, if you get the Hyperco's (excellent spring BTW), I'd go 350 fr, and 300 rear to suggest a bit more rotation. I use 2.5" ID, with a 7" spring up front, and 8" rears. This gives adjustment range from stock to lowering up to about 2.0". You'll need adapters to use 60mm or 2.5" with the factory upper bearing, conversion is actually pretty simple. I'd also suggest getting helper springs, especially with a stiffer rate spring. The factory 18" Hufs also ride fairly stiff with linear springs, you might want to ditch them (if haven't already) for some lighter wheels.

Spirited driving with a stock Mk6 GTI:

http://www.topgear.com/uk/videos/stig-hillclimb-vw-golf-gti#commentsListTop

bostonaudi:

Thanks for the in-depth reply! I have a fully caged car that I trailer to the track for time attack, so like I say it is very rare this car will be on the track, it is mainly just for fun twisty roads and driving to work

I went with Ground Control camber plates with 60mm spring mounts, I will go with a 50lb split between rates as your comments make sense to me with that low motion ratio.

I am running 22lb wheels right now, still not lightweight but I guess a touch better than the 29lb huffs ha.

Was planning on running a shorter spring than the Koni spring with some helpers to give a better adjustment range on the coils.

Think the Koni's will be able to handle 350lb ok?

Cumulonimbus said:

bostonaudi:

Thanks for the in-depth reply! I have a fully caged car that I trailer to the track for time attack, so like I say it is very rare this car will be on the track, it is mainly just for fun twisty roads and driving to work

I went with Ground Control camber plates with 60mm spring mounts, I will go with a 50lb split between rates as your comments make sense to me with that low motion ratio.

I am running 22lb wheels right now, still not lightweight but I guess a touch better than the 29lb huffs ha.

Was planning on running a shorter spring than the Koni spring with some helpers to give a better adjustment range on the coils.

Think the Koni's will be able to handle 350lb ok?

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I should think so. You can always call TrueChoice (authorized Koni) and run this by them for 2nd (or really 1st) opinion, but I think it will be fine, 350 isn't a radical rate by any means.

http://www.truechoicekoniracingservices.com/