Strut tower slotting rule change proposal

#1

Sorry to overstep my bounds as a newbie but I’d like to figure out a legal way to get -3.5 camber before I go to comp school in April. I would be surprised if it helps very much but why not be able to slot the strut tower holes in any direction we want. Maybe I can get a combination of enough caster and camber to work effectively. Its fine the way it is on 225/45/17 but I anticipate a lot more tire rollover running the spec size.

9.3.8.1.2. Any adjustable or fixed camber/caster plates are allowed, unless specified in
these regulations.
a) They must be installed in the location intended by the manufacturer, per their
instructions.
b) The three front strut mounting holes may be slotted laterally, only to enable more
range of camber adjustment.

“b) The three front strut mounting holes may be slotted.” is all that b) needs to say. My offset fcabs move the whole strut a little bit forward. If I could move the top back a little it may help stop my top spring perches from rubbing. At the very least it will increase caster which decreases the need for camber adjustment. Why it says they can only be slotted laterally makes no sense to me. The rule already allows slotting so doing so longitudinally has no effect on cost.

yeah or neigh?

#2

What camber/caster plates are you using? The Ground Control plates designed specifically for Spec E30 work well and allow max camber provided your struts aren’t bent. They provide enough travel to cause rubbing in both directions. Slotting won’t really help and the current rule is fine. Perhaps an alignment shop can straighten your struts.

#3

I don’t see that proposal flying and it’s not necessary.

Using the ground control plates will allow you to get over -3.5 degrees, but the limiting factor is when the top spring hat hits the inner strut tower. I have seen SE30’s that have a hard time staying less that -3.5 degrees due to the chassis moving.

#4

I’m using the IE plates. Top perches are hitting at -2.7 degrees.

#5

I’m on my second car and using GC Spec E30 camber plates. On neither car have I been able to get more than 2.8deg of camber w/o the upper perches rubbing on the strut tower. Looking at the rub marks I don’t think that moving the plates rearward would help.

#6

I have the GC SE30 plates from Bimmerworld on my car. They aren’t even maxed out at 3.5. I can almost get 4 probably.

#7

I know there there are supposedly some frames with strut towers 980mm apart and some 1002mm apart. Both my 87 and 89 fit are the 1002mm variety. I’m wondering if the short bar variety is blessed with more camber. Assuming everything else is the same it would be.

#8

Great question, does anyone have the answer?

#9

Great question, does anyone have the answer?[/quote]Realoem says the front clip changed 9/87-on. It shows one subframe for the whole run of 325s, so the camber change isn’t happening at the bottom.

#10

I’m thinking of sending my struts to IE to have them bent. Seams like the more body contact people have had the more negative camber they can get. If its legal to have your front suspension bent out of shape I should be able to legally have my struts bent.

#11

I understand your frustration, but I doubt it’s legal:

9.3.8.4. MacPherson strut inserts.
9.3.8.4.1. Bilstein Sport insert - part number P36-0335 or P30-0334 shall be used.
9.3.8.4.2. Other than rebuilding by Bilstein, no modifications of any kind are permitted.

#12

I think that it’s IE’s site that says that. I don’t know that it’s true tho. It’s almost a full inch of difference, and I don’t see anyone else offering two flavors of strut bar.

22mm of difference would catch a person’s eye pretty easily.

I don’t think that the OEM alignment specs varied early to late. That would indicate, near as I can figure, that if the front subframe didn’t change than the relationship between strut top and front hub didn’t change either.

#13

If you slot the holes, who is checking for the straightness of the slots. I can bend the shock towers in and slot the holes front to rear and get extra caster and camber gain, which means I need less static camber…which helps.

Just sayin…