Marc Shaw

I just finished another day at RaceCity here in Calgary -- went well.

Problem is, my Pilot Sports rubbed so hard on the oil line and secondary muffler that I got a slow leak that then allowed the tire and bead to separate around turn 4-5 (a fast left-hand sweeper) so I lost ALL tire pressure and almost went agricultural. After I pumped the tire back up, a slow leak was confirmed so I rushed out to buy new tires so as to not lose the rest of the day (I bought MPSC's as that was all I could find locally in a hurry)

but....

When I went back on track, I could tell immediately the right rear tire was still rubbing on hard left cornering.

So, how do I fix it or where is the problem??

The specs:
1. I just got an alignment (RS spec with -2.5 and - 2 camber) with a CB.
2. I have MPSC's 255/40/17's on the rear
3. I run 17" Boxster Twist wheels as track rims (8.5" with ET 50 rear)
4. I have the H&R street performance coilover setup (with spring rates of 250-285 front and 265-285 rear).
5. I also have TRG sways -- 21 mm (I think) rear set at medium.

I run with the red group (fastest students) so I drive pretty hard and fast.

Any ideas??

Are the offsets too low and would a spacer help (but the fenders are not rolled and I suspect the tire would rub on the fender)?

Are the rear tires too wide or do I need stiffer springs that are not progressive??

I need to fix this before the end of June (next track day) so any help appreciated.

Marc

Larry Herman

Marc, I don't think that stiffer springs are the answer, as you are getting deflection in the trailing arm bushings which allow the wheel to move inward under cornering load, and then rub on the oil line. If you have the room, run a small spacer to move the wheel out as far as possible. I'm sure that you are considering this. If you get too close to the fender, you may then need to up the spring rates to keep them from rubbing on the outside under compression, but now you will have opened Pandora's Box. Of course, the best answer is to install monoballs on the rear arms.

Chris M.

Do you have the flat oil line? Do you get any rubbing on your control arms? You can always ditch the secondary.

Marc Shaw

Larry - I can see what you are saying and it makes sense but I am also getting some rubbing on the trailing arm itself - would monoballs help fix this too?

Chris - yes, I have the flat oil line but it is about where it is flattened that it rubs. I already ditched the primary and have a 100 cell cat. so I wanted to try to keep the secondary.

Thanks for the help, guys.

Marc

Mark in Baltimore

Rolling the fenders might help if you use spacers.

Gary R.

http://www.eastwoodco.com/jump.jsp?i...rID=232&KICKER

Larry Herman

The hub is fixed w.r.t. the trailing arm, and so any rubbing is due to a small amount of flex in that unit, and some deflection of the tire that has not re-aligned itself as it comes around. Monoballs will not help with that. So if you are rubbing on the trailing arm, then you have to space the wheels out a little. I have about 8~10 mm of clearance and I still polish the trailing arms a little.

Marc Shaw

Oh yeah, I had the Stealer check the wheel bearings and the left front was loose so it was replaced so it can't be a very loose bearing.

Okay - I guess I need some spacers (maybe longer studs, I'll test fit with the open steel lug nuts) and perhaps some fender rolling.

...hmm....maybe I can justify that JIC Cross suspension with higher spring rates sooner than I think.....

Thanks again for all the ideas and help.

Marc

Marc Shaw

p.s. On a more positive note, I did get signed off to drive solo so I guess that counts as another 180 - 200 lbs of weight loss towards my car weight loss reduction program.

Marc

bobt993

Marc, Had the same issue on my 993. I ran a small spacer and rolled the fenders. Adding monoballs to the rear links allowed me to not run the spacers anymore. Have the alignments checked also.

Chris M.

Marc I'm dealing with the same issue and have already started trying to remedy things. I bought some 5mm spacers and steel lug nuts but after installing the nuts it's clear I'll need longer studs. Here is a thread Kenny started about replacing them.

Marc Shaw

Chris - thanks, I went back and read that one already.

I have some H&R 7 mm spacers that come with longer (52 m) spacers at home so I will fit those. I also ordered the fender rolling tool referenced by Gary above (you can borrow it if you need it).

If I stil get some rub at the top oil lines then I'll have the swap the H&R suspension for some stiffer JIC's. Darn.....

Marc