Quote:
Originally Posted by 949 Racing
I'd bump to the OEM or GR rear bar before dropping front spring rate. Going lower in front only increases the risk of blowing through the travel and spending too much time on the stops. The same problem you had with your out of the box set up. That would actually increase understeer. Unless you are too low in front or not running enough camber, you should have plenty of front grip with your current set up. You above 130mm front and at least -5°?
Regarding sensitivity to set up, you are right in that higher spring rates, all else equal, make the set up more sensitive. Higher rates also make the car more sensitive to driver inputs. So smoother, slower inputs are required to extract the extra speed potential. Sway bars are springs too so adding more bar has the same downsides of more spring; additional sensitivity to set up and driver input. Agreed though, when we wen to 616/616 (11kg) rates on Blub, it was definitely a tad harder to drive than 500/500, but also quicker.
Let us know what ends up working for you.
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I'll give swapping bars before springs a try - I've got the Karcepts rear on the car, a 14mm OEM, and a 15mm OEM here to play with now. Blowing through the travel was my worry with going down to 450lb up front for sure. The idea I had in my head is that dropping to 450 would move the overall balance enough that I could run the rear bar in the middle and then adjust from there, but that could have been misguided.
By setup/tire dependent I mean that the car can go from right on balance wise to too tight depending on the track and tire heat cycles.
For example, at Arizona Motorsports Park on sticker RC1s the balance was pretty good. When I went to Podium Club with 5HC on the tires and an incredibly rubbered / abrasive surface the car was tight mid corner, which cascaded to the expected higher front tire temps and accelerated wear.
I ended up going out and measuring everything this afternoon.
Current relevant parts:
500/600 Rates w/ Roll Center Correction
22mm Perrin front full soft / Karcepts rear, prior was a Mann on full stiff
17x9.5 +40, 5mm spacer up front to keep the tire out of the dust boot
OSGiken Diff
I can add the rest of the front camber plate (it is one hash mark on the plate), the rear I need to find a thin jamb nut for and it'll give me -3.3*.