Raising Spindles, what about that taper?

Matt-Man · 09-04-2006, 05:30 PM

I know the subject has been beat to death, but I haven't seen a direct response to the problem of the Boge struts being almost 2mm bigger around right above the spindles current location. Looks like it would be no big deal to move the spindle down out of the way and turn the outer diameter of the strut housing down to size, but I am a little concerned about the tubing then being too thin as it appears to be swedged to the larger size. Looks like the best way would be to remove the spindle completely and step bore the inside of the spindle to accommodate the larger tube size, but that would require turning off most of the weld where the ball joint mount attaches to the tube. How do most people accomplish this, as I am sure people are doing more than just Bilsteins. Am I overlooking something obvious?

Thanks, Matt

jpnovak · 09-04-2006, 06:21 PM

This mod is Bilstein only. It will not work with Boge or Koni strut housings due to the taper you describe.

Eagledriver · 09-04-2006, 07:35 PM

You have discovered why Bilsteins are more expensive than Boge or Koni. Your idea of step boring the spindel may have merit. I think that is your only chance. You have to judge if the spindle will still be strong enough.

-Andy

TimT · 09-04-2006, 07:52 PM

You could always have an F prod champ modify your struts

http://www.tangerineracing.com/images/Suspension&Brakes/FrontStrutMod.JPG

TimT · 09-04-2006, 07:57 PM

here is more of a link

http://www.tangerineracing.com/suspension.htm

Tyson Schmidt · 09-04-2006, 08:19 PM

You can raise Koni's about 17mm before you hit the taper.

Matt-Man · 09-05-2006, 11:24 AM

Thanks to all!
Tyson, I was just looking at that possibility after I bead blasted the struts having noticed the clearance between the strut tube and the spindle bore. Looks like the would be some room to move and I was speculating on just how deep the existing step might be. I was only looking for 17 or 18mm anyway as I am not super low up front now (24 1/2), but I want to restore some of my lost travel and the other problem being that I am unable to get any closer to zero camber than about -1.5 degree. I think 17mm should do me just fine.
Since I have your attention I have another question; I will be bending my steering arms, should I remove my current bump steer spacers or leave them in and just raise my steering arms the same amount that I raise my spindles? I know the blanket answer might be get the ERP kit, but I am getting ready to drop close to a Grand in the front end now, so P dollars are getting thin again.

Thanks in advance, Matt

Eagledriver · 09-05-2006, 04:03 PM

I bent my arms. If you don't bend them then you can make up some of the space with your rack spacers but it won't be as good as bent arms or the extensions like the ERP kit.

They are not that hard to bend. I put a bolt and washers in the tie rod end hole to keep from damaging the ends. Heat up the arm bright red with an oxy acetalyne torch and then hammer away. I bent them down as close to the spindle as I could and then back to level down by the tie rod hole. I dropped them the same amount that I raised the spindle (18mm). I heated them in the two spots that I wanted to bend separately. Let them cool slowly so they don't get brittle.

I like this solution better than adding extensions that can break. It does change your akerman but I don't think it's that much. I also believe this is how Porsche did it on the RSR but I don't know for sure.

-Andy

Tyson Schmidt · 09-05-2006, 09:36 PM

Matt, leave the rack spacers in and also bend the arms down the same amount you raise the spindles.

You could go even further and still not eliminate all the bump steer. But you will be getting it in the factory range, and maybe a little better.

Like Eagle Driver posted, it will change Ackerman by effectively shortening the arms, but that is a non-sissue, since reducing the designed-in bump steer also reduces the designed in Ackerman that was a side effect of bump-steer. (Toe-out from compression)

Matt-Man · 09-06-2006, 11:41 AM

And quicken the steering ratio a bit, right! Thanks to all, for the input. I noticed quite a bit of interest in this thread, I can take a few pictures to post here when I get started if anyone would like to see?

Matt