[87Fox5.0]

MM kmember, Griggs spindle adapters, SN95 spindles, upper control arms from Summit, MM SN95 lower control arms. Fabricated upper shock mount. Zero scrub using 18x11 rims.

 

[somanycorners]

Holy necro bump…

I need to make this upgrade eventually, so, subscribing lol

 

[Patrick Olsen]

MM kmember, Griggs spindle adapters, SN95 spindles, upper control arms from Summit, MM SN95 lower control arms. Fabricated upper shock mount. Zero scrub using 18x12 rims.

Very cool. Where did you source the Penskes from? Had you been running the car with a normal strut setup (presumably with the MM K-member and A-arms) before going to the SLA?

 

[87Fox5.0]

Very cool. Where did you source the Penskes from? Had you been running the car with a normal strut setup (presumably with the MM K-member and A-arms) before going to the SLA?

Hi, yep this was a strut car that was mostly for street use. I autocrossed it once with the struts and it sucked big time, even with the K-member and A-arms. It wasn't until the SLA that it became a truly competitive autocross car. It's literally a night-and-day difference - so much grip, so solid. The shocks I got directly from Penske Racing with custom valving - these too made a major difference, particularly in quick transitions like slaloms - so much control it's unreal.

 

[seijirou]

Yeah it really is night and day; a completely different car.

 

[jw98lx]

MM kmember, Griggs spindle adapters, SN95 spindles, upper control arms from Summit, MM SN95 lower control arms. Fabricated upper shock mount. Zero scrub using 18x11 rims.

Would you mind sharing a part number for the summit upper arms?

 

[CDW6212R]

Very nice.I loved to see a list of the parts for that, minus the fabricated UCA mounts. From top of my head guesses, I have looked at the Grigg's parts a few times. It sounds like the cost of the shocks/springs/UCA's, and the spindle adapters, plus the UCA mounts.

 

[87Fox5.0]

Would you mind sharing a part number for the summit upper arms?

SPC 92142 for the upper control arms. Use with the Chrysler type ball joints Moog K772.

FYI the Griggs spindle adapters took about 9 months to arrive. Another option is the Whitby Motor Cars spindle adapters https://www.whitbymotorcars.com/product/sai-mod-kit/ but they have a greater steering axis inclination (9 degrees advertised).

 

[Patrick Olsen]

Hi, yep this was a strut car that was mostly for street use. I autocrossed it once with the struts and it sucked big time, even with the K-member and A-arms. It wasn't until the SLA that it became a truly competitive autocross car. It's literally a night-and-day difference - so much grip, so solid. The shocks I got directly from Penske Racing with custom valving - these too made a major difference, particularly in quick transitions like slaloms - so much control it's unreal.

Thanks for the details. How does the process work with Penske? I know jack squat about how to spec custom valving, wouldn't even know where to start. Did you have to tell them what you want, or did you contact them and say, "I have a custom SLA. I need a shock that is X" long and is suited for road racing and auto-x use," and then they spec'd everything for you?

 

[Peter92lx]

Thanks for the details. How does the process work with Penske? I know jack squat about how to spec custom valving, wouldn't even know where to start. Did you have to tell them what you want, or did you contact them and say, "I have a custom SLA. I need a shock that is X" long and is suited for road racing and auto-x use," and then they spec'd everything for you?

When I had MCS change the valving in my shocks I told them the weight of the car corner weights, spring rates, tire type and what kind of suspension. Then they came up with the valving for the shocks. It worked the shocks were far better after the rebuild.

 

[87Fox5.0]

Yeah you just tell them what your spring rates are, weight of the car, and what the car will be used for. It helps if you can include corner weights. Emphasize it will be used for autocross where you need superior control in quick transitions, e.g. abrupt turning and braking. It took some trial and error. They nailed the front shocks the first try, but I had to send back the rears for revalving - they were a bit too stiff initially. IIRC I don't think they charged me for the rear revalving, and their turn around time was really quick, within a week. Penske Racing as you would expect was very professional.