Techno Duck

What would be the ideal spring setup in the front be? I read somewhere that the 28mm bar is roughly equal to something like 254 lbs / inch. So do i want to match that spring rate exactly in the front with something like 275 or 250lb springs or is it okay to go slightly higher, say something like 300lbs.

Also what are the length and diameter springs i need to buy with the Paragon adjusable spring perches?

I appreciate any info on this.

Here are the bar effective rates from the Jim Pasha article.
23.5 - 126 #/in
24 - 137
25.5 - 175
26 - 189
27 - 220
28 - 254
29 - 292
30 - 335

M758

250lbs springs are a good match.

Bri Bro

What Joe said.

Owain

I have 250s in the front with 28mm tbars in the rear and the handling is very neutral to slight oversteer. I like it.

Techno Duck

Looks like 250's it is... thanks for the suggestions!

arbeitm

Wouldn't you want to go with something like 275's? If the effective rate of the torsion bars is 254, isn't the effective rate of the front springs like 90% of the spring rating. So 275's would put you closer to a 250 effective rate (248 actually).

Bri Bro

Front spring MR is 0.94. The 250# front spring rate with 28/29mm TB has a good history of happy customers. I have that on the silver car and it works well.

Oddjob

Depends on how you want the car to handle and what you are setting it up for (street, auto-x, track). What sway bars, tires, wheel widths, etc.

I ran 300/28 on my old 944S club race car for awhile, with turbo cup sway bars (30mm ft, 21mm rr), and 245/45, 8x16s all around. It was ok. It certainly didnt understeer on full/high speed road courses (like Road America).

If you are setting it up for auto-x'ing, Id go with a lower front spring rate, to get more rotation in the tight turns.

badmofofosho

FYI there is a guy over on the birdie board selling a like new set of Welt 250's with the ride height spacers for cheap ($60-$70), but you probably knew that already.

sandwood

bumping this thread from the depths for some advice.
for a coilover setup (kw v3), front spring rate of approx. 335 lbs, rear 280, what is the appropriate size torsion bar? this is for street/DE usage, m030 sways, 255 front 275 rear tires. I am aiming for slight understeer to neutral.

28 or 29 mm?