Project Update for May 18, 2012: We've made some additional changes to the car and had an autocross since my last update after the TWS NASA Time Trial event. After we received the new Vorshlag camber-caster plates and the re-valved Moton Club Sports, we scheduled time to install all of it onto the Mustang, then went looking for an event to test the new set-up at...
New Parts for our Mustang
The newly revised Vorshlag camber-caster plates were finally complete at the electro-plater a week ago and after we fulfilled customer back-orders, we built a set for our own S197 Mustang (shown below).
I was looking forward to the much easier camber adjustment these new plates would allow us. Plus we could potentially use the added range of positive caster, if we felt the need to add more than the +6.4° the car came with stock. The next bits that were finally ready to install were the Moton Club Sport 2-way coilover shocks. The AST 4150 prototype coilovers had served us very well the past year, but we were really pushing the envelope on grip levels in an S197 Mustang with 315mm R compounds at all 4 corners. Adding compression adjustment would be a tuning improvement and the additional fluid from the remote reservoirs would also help stabilize performance on longer track stints.
These Motons had been purchased a while ago and were a bit unique in that they were built before the Moton acquisition and were an old design. The front struts had lower mounting flanges with massively slotted upper holes, which are not part of the current Moton S197 spec. I'm not a fan of slotted mounting holes as it reduces wheel/to-strut clearance and can allow the lower setting to slip under hard cornering. So after test fitting the front struts and new VM plates to check the available camber range (more camber travel than before), Ryan filled in the slotted holes.
There was enough range in the camber plates and strut tower opening that we could actually use the stock sized upper strut mounting hole on the Moton struts, so the slot was filled with a steel "slug", fully welded, then ground smooth (on all four slotted holes). Again, this isn't something that needs to be performed on this S197 strut any longer. Moton-USA also installed custom valving and their new DDP digressive pistons for some extra rebound force at low speeds.
Click to see the full sized dyno plots for these. Left = front struts, right = rear shocks
Well, if you know much about dyno plots, those actually make a LOT of extra rebound force at low shaft speeds! That area from 0-2 in/sec shaft velocity is crucial in both autocross & track use, and being able to alter those numbers to this extent with the turn of a knob makes for better racing performance and a much more comfortable street ride after rebound is turned down. These DDP pistons are evil - we had them in the AST 4150s on this car before and loved them! Now with these double adjustables we can adjust low speed compression as well, for more tuning ability.
Vorshlag's Step-By-Step Moton S197 Install Gallery -
http://vorshlag.smugmug.com/Instruct...stall-Mustang/
Installing the Motons and their accompanying remote reservoirs, then aligning and corner balancing the Mustang, took the better part of ten hours. About two hours of that was the fabrication work Ryan had to do on the slots, but that's still eight solid hours of install and set-up work. These were far from a "just take it out of the box and bolt them on" affair - just like all remote reservoir shocks, which add their own mounting complications.
The front strut installation was relatively straightforward and didn't require any cutting or surgery since the hoses were long enough to route under the frame rail next to the brake hard lines. This allowed the remotes to mount right up into the engine bay with no fuss. The struts were bolted up to the Vorshlag plates with stiffer 550 #/in Hyperco springs (up from 450 #/in) and went in fairly quickly. Of course we fabricated custom front and rear reservoir mounts, like we've done
on some other installs here recently. These brackets bolt to existing factory holes and keep the remote reservoirs away from engine heat, but keep the compression knobs accessible.
The rear shock on this Moton kit is a standard for race cars - an "eye-to-eye" shock. That means it has a spherical eye mount on both ends, unlike the stock shock which used an eye lower and pin upper mount. To make it fit the S197 chassis without modifying the upper mounting hole, we found some "eye-to-pin" adapter mounts made for the S197 from Ford Racing. These mounts bolt to the upper eye mount, along with some bushing adapters from Moton, and then slide into the hole in the stock sheet metal. The lower eye mount also has bushing adapters (included in the Moton kit) to fit the stock lower hole.
We had several options for routing and mounting the rear shocks' reservoirs. I wanted them away from exhaust heat/rocks/rain/debris and since there is no spare tire with this car, I decided we should mount them in the spare tire well inside the trunk. We routed the hoses through sheet metal, so there was some cutting involved with the rear reservoir pass-through hole. This is the first cutting or drilling we've had to do to the chassis, so we took great care (Amy does not want us cutting or drilling on her street car!). We like using these 2-piece "Seals-It" brand grommets for reservoir mounting. They can be unbolted and the entire reservoir can pass through the hole in the chassis when removing the shocks, without having to discharge the nitrogen and remove a hose. Even with "quick connects" (a very costly option) you still have to discharge the nitrogen in a monotube shock with remotes. If installed the way we did them, you don't ever have to discharge the pressure and potentially lose fluid when removing the rear shocks. We tested the fit of these seals at the autocross in the rain and not a drop made it into the trunk. Perfection.
Other New Bits Coming?
While we were doing this Moton CS install, AST Holland was posting Facebook pics of the new and improved but much-delayed AST 4150 coilover strut housing for the S197 Mustang. They let the cat out of the bag (or the wooden shoe out of the closet?), so I am going to repost at least one picture. Now we
could be seeing the first 4150 test sets for this S197 chassis, the BMW E36, BMW E46, and the Subaru BRZ at Vorshlag before too long. We will be contacting local Dallas/Ft. Worth testers (so we can install them here, to verify that everything fits perfectly) for all of these cars when we have the first 4150 shocks on hand. Once we've verified these fitments, AST-USA can have AST Holland proceed with full scale production. Don't hold me to any dates, because so far I've been failing miserably on ETAs for these shock models.
Speaking of overshot ETAs on new products, we finally have a gaggle of D-Force 18x10's for the S197 chassis now in hand. There have been a dozen sets sold and shipped so far and I've been seeing pictures on social networks of them on cars - very cool. We only have a few Flat Black sets and plenty of Silver sets in stock - give us a buzz if you are interested. They were 19.5 lbs exactly when weighed here, just as predicted.
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