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Old 05-11-2021, 02:30 PM   #44
ZDan
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Quote:
Originally Posted by RotARy15 View Post
How bad is the loss of bump stroke? I'm installing Raceseng plates on Sachs dampers and stock springs this week and I plan on staying with those components for at least the fall track day season.
You're probably fine with that setup. I ran Swift lowering springs that lowered the car ~1.5" front and 1.25" rear, and it was a disaster with the Raceseng plates. I cut the bump stops down from 60mm to ~22mm, and also had 6mm (1/4" maybe?) spring spacers fabbed to gain back some front bump travel. Those improved things *a lot*, but still almost undriveable on the street. Smallest bump = BAM! You should have on the order of an inch more bump travel than I did though, which I think will be fine.

Quote:
I thought I saw that someone measured a 1mm rise in ride height with the Raceseng plates but there was no mention of whether the upper spring perch and upper damper rod mounting point were independently relocated.
If anything, it seems to me the Raceseng plates with stock-diameter perches *lowered* my front end, something on the order of 1/8" to 1/4". vs. what I expected with the Swift springs. I think the relative damper rod and spring perch heights are the same *at the spring*, but in the middle of the spring perch there's a radial bearing that takes up ~15-25mm of bump travel.

Ultimately I replaced the sachs dampers with Bilstein B8s, and they apparently have a ton more bump travel, it's no problem at all now even at -1.25"! In retrospect I would have gone with RCE Yellows or Tarmacs at slightly higher ride height to have more bump travel. As it is I'm running lower than my time-trial competition's same-year 86, at his preferred height on adjustable Ohlins coilovers!
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