04' STi Front Strut Slotting, alignment spec ?'s

[skid542]

Basically where I'm at is this week I will be milling out my front struts and wanted to make sure I'm seeing this right. I'm an aero guy and am admittably a little dense on what should be a very simple mechanical system. Pardon the very crude Solidworks drawing but this is how I am understanding what I need to mill out - http://filebox.vt.edu/users/lskidmor/Pu ... 0strut.jpg . The cross hatched circle is the current existing hole and the lines represent the line to which I will mill out to. It is not to scale.

I'm not looking for a super aggressive alignment as I still do a lot of highway/interstate travel with my car and don't want to ruin the tires from having a nice cornering alignment and then not running corners. So I'm thinking about 1.5* up front and about 1* in the back, leaving toe in/out as standard stock spec. Again, I really am not very knowledgable on alignment specs but do like the current/stock setup with regards to it's ability to induce rotation, both from off-throttle effects and appropriate use of hard braking coming into very tight corners. I do Auto-X a couple times a month and also go off road some though I don't really push the car off road. I plan on doing some Rally-X this winter though. I enjoy the ability to swing the back out because it helps keep my RPM's and load up with the auto tranny coming out of the tight 180's and back to back L-Boxes, and I simply enjoy sliding the car around some. If you have any other recommendations, I'm am open. My springs are 245lb front and back so not soft but not the high 300-400+ lbs range track rates.

So that said, I believe I will be moving the holes approximately 1mm and using the current/stock camber bolts but having them really torqued down. I will be putting aftermarket camber bolts in the back - going to call Rallispec today.

Any advice from those running this setup or any other general comments would be appreciated.

Thank you,

Lee

[skid542]

After more searching around over on Nabisco, I will only be slotting out the bottom holes. So I will be slotting them towards the center of the car.

[jamal]

no you slot the bottom holes away from the car. So that the lower bolt and bottom of the tire are farther out. I need to replace my steering rack before I can get the car on an alignment rack, but it looks like I have well over 2* negative camber in the front. Which should be expected since they're slotted about 2.5mm. Each mm of slotting works out to about 0.9 degrees added.

In the rear I'm just running aftermarket bolts. There should be between -1 and -2 degrees of camber.

[skid542]

*hangs head*, yeah, away from the car. Thanks.

Also thanks for the ratio of slotting to camber gain. I spent hours and hours yesterday and last night searching and reading up on Auto-X and track setups and have determined I'm going to go a little more aggressive and try to get 2* up front and 1.5* in the rear. I think it will be a good balance as I still want high speed capability without the back end rotating too much and only have a few Auto-X's left this season.

I'm ordering some Oakos bolts this morning for the rears.

Thanks again for all the input Jamal.

[jamal]

Sorry for the delay; I haven't really been on the internets much lately.

I would slot the struts more than 1mm. That's really only going to get you back to stock adjustment, which isn't enough camber to make the car grip well, especially for auto-x. Those guys run like 4+ degrees of negative camber. You should really shoot for over 2 degress, and if you decide it's too much you can just bring in the top bolts a bit.

[skid542]

Thanks Jamal. I ended up taking them into the shop at work and one of the machinists help me put in a nice 0.100" slot. I'm might file on it a little more though. Right now I'm shooting for 2.25* up front and 1.75* in the back. That should give me a decent bite, still running all-seasons, and not have wear issues driving a lot of interstate/highway miles.

I'll be installing the fronts tomorrow along with some fender braces and put the backs in Tuesday hopefully. I'll take it down for an alignment by Friday and see.