Sub-frame Connectors

[jasocal13]

Got a 95 SHO with MTX conversion that i race for dirt track oval racing. Looking at some upgrades for handling and have read alot about sub frame connectors helping for cornering, but i am assuming everyone is talking about cornering on pavement, asphalt, etc.....what about a clay dirt track for cornering? Would it be too stiff and push the car through the corners or would it stick to the corners like they do on pavement? Or also maybe lift the left side of car up? thanks

 

[luigisho]

That's a good question. They are stiff enough to have the wheels come off the ground in certain circumstances. You may have to be the guinea pig for this. You can always spot weld them on and cut them off if it's too stiff.

 

[Jbeck]

I would think on a dirt track you would want the chassis to twist to keep the wheels all down...I would think anyway, I could be wrong

Maybe make a "bolt-in" set and try both in realtime to decide.

 

[BaySHO Performance]

Yes, I've lifted an outside front wheel off the ground with subframe connectors (and a Quaife LSD) on the track (steering wheel saws back and forth), but on a dirt track I wouldn't think you are going to get enough grip for that to happen. Especially if you don't have an LSD. Don't know if subframe connectors would make any difference.

 

[PaulTAutoX]

I think Nick meant lifted an inside wheel because an outside wheel would be very alarming indeed .

I did all of my SHO autocrossing in a class where the welded SFC's were not allowed, so no direct experience. But strut tower braces and lots of bar and spring worked to keep it reasonably stable. With the camber changes, springs, and bars on top street tires I'd bet the car was pulling 1.0 G peak on asphalt. It always had the inside rear off of the ground.
Since you're trying to plant the fronts, more rear stiffness either from bar or springs would help there of course. SFC's will improve the efficiency of transferring rear stiffness to the front. And likewise as it's a track car, you could try to get all of your front stiffness from springs rather than the sway bar, since a sway tends to lift the opposite side tire directly. When I first started in a stock class you were allowed to take out front bar stiffness and I did so, going to a smaller Taurus wagon bar, to reduce front wheelspin which seemed to help.
For rainy events especially the Quaife was great, pulling the car out of the corners nicely. I always placed higher in the rain, FWD FTW! But planting the inside with the above tips will improve inside traction even without LSD, particularly increasing the rear to front stiffness ratio.
Keep us posted if you do some of this please!

 

[BaySHO Performance]

Duh, yes Paul, the inside wheel. But it was a front wheel, not a rear. I have video of a Porsche 911 doing the same thing at Sears Point.

 

[Toolman]

If you have a cage it won’t make much difference. My track SHO has no SFCs, buts easily the stiffest SHO structure I’ve ever had due to cage.

 

[PaulTAutoX]

Duh, yes Paul, the inside wheel. But it was a front wheel, not a rear. I have video of a Porsche 911 doing the same thing at Sears Point.

Yes, lifting the both inside tires is a little more possible on race tracks which have a lot of race rubber on the surface, as well as higher speeds, corner bumps, and more uneven surfaces. The dynamics of higher speeds and chassis stiffness/frequency make rolling a car easier. Which is part of why autocrosses are supposed to be speed limited to about 65 MPH. Autocross courses are usually flat like airports and parking lots. But I have seen cars at autocrosses lift both insides, generally modded cars with race rubber.

At dirt tracks I see most of the racers (rear wheel drive) lift the inside front under power. So there is, depending on dirt composition, tires, and surface prep, fairly good traction. Weight transfer to the rear favors RWD but like a rain situation the sheer weight on the fronts of the SHO helps forward grip, so the mods I mentioned should help maximize that.

Agreed on Toolman's comment, a cage is likely to stiffen the car more than SFC's.

 

[TimboSHO]

I did all of my SHO autocrossing in a class where the welded SFC's were not allowed

What class were you running?