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Unread 08-20-2013, 04:02 PM
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Fair! Fair! is offline
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Join Date: Jul 2004
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Default Re: Vorshlag BRZ Project Build Thread

continued from above

We got our first FT86 set in and they looked absolutely beautiful. We could see they already had a lot problems we saw in other brands solved. The included strut bracketry was made to fit the hoses and lines on the BRZ perfectly. They had a nice solution for the slotted holes found in many struts using precision CNC machined fixed offset insert slugs. The coilover perches were all metal (not plastic) and 2-piece, that clamped in place with spanner wrenches (not bolted) and one of the Vorshlag pinned spanners we've made for other brands of coilovers fit perfectly.

Testing the strut and shock lengths on the first set of MCS singles - almost there...

Sure enough, as the MCS folks expected, their "C Stock" length singles were too long to work at the lowered ride heights we wanted to run this BRZ at. And they should have been, as they were initially intended to be SCCA Stock class legal (it is nearly impossible to make anything legal for Stock class work at properly lowered ride heights - without some major compromise somewhere). You see, we had been looking at NASA Time Trial and SCCA STX to run in, and in those classes we could lower the ride height and use true coilover springs in any rate we wanted - a novel idea that almost any competitor would want.

That day we went through the same battery of measurement exercises with the MCS singles as we always do on any new set of shocks we test. We re-spec'ed them with our desired ride heights, then measuring bump and droop travel at the wheels, with and without springs installed. We sent along our wish list of drawings and measurements and shipped this first set of coilover shocks back to MCS, hoping they would make us a set of housings, shafts and lengths that would work.

Lo and behold, they delivered a new set built to our specs in less than 2 weeks. We were floored, as this turn-around time was much quicker than we had even hoped for. We took the 2nd set and tested these on the BRZ again, going through our full sweep of tests with and without springs once again. By now we had burned about 4 days of shock testing on this poor car over the previous few months and hadn't driven one mile on anything but the stock shocks. Luckily the third time was a charm, and the 2nd MCS set was a winner. They fit with the lowered ride heights we wanted and now offered real usable bump and rebound travel at both ends. Hot damn!

Left: New Vorshlag tender spring. Right: The MCS TT1 shock worked with the stock rear top mount, Hyperco spring & our tender.

This may seem like a trivial thing to some of your readers, but getting these MCS "TT1" shocks built correctly and onto this car, with real spring rates and usable travel in both bump and rebound directions, was a long time coming. Big thanks to Lex and the folks at MCS for getting these re-made so quickly and for working with us and our needs. So now we needed to know - how do these dampers RIDE and HANDLE?

The ride aspect was easy - let's go drive it. With the initial set of springs we went with a 450 #/in spring at both ends. If you look at the charts below of the OEM and lowering spring rates, which we measured here at Vorshlag, you will see that we nearly tripled the front rates and doubled the rear rates. That's usually a good starting point for us, and we also based the 450F/450R rates on our years of Subaru GD chassis shock sales, testing and racing. To keep the rear spring seated at full droop we added our new Vorshlag 60mm ID tender springs (shown above) on the rear shocks, too.

Left: Stock 2013 Subaru BRZ spring rates, front and rear. Middle: Stock 2013 FR-S rates. Right: Swift BRZ progressive rate lowering springs

A few drives on our 2 mile "shock test loop", a couple of rebound knob changes, and we had the ride set to "Amazing". Yes, with triple the front spring rate it was handling bumps better than the stock shocks did with lowering springs, which often bottomed out. It was firmer but not at all jarring, and we quickly knew this would be a big seller.

Note: We have renamed MCS' line of shocks with actual model names that are easier to type and remember. We began referring to the non-remote single adjustable shock as the "TT1". This refers to the fact that in many forms of Time Trial racing you get dinged points for remote reservoirs, so these non-remotes are better for that sport, hence TT. The "1" refers to the number of valving adjustments. There are TT1 and TT2 models for most MCS applications - yes, the elusive double adjustable monotube without remotes does exist. We've already sold several sets of TT2s from MCS. And the RR2 and RR3 are "Remote Reservoir" 2 or 3-ways. Get it?

Of course we used our Vorshlag camber plate solution, mated to our custom built 60mm radial bearing upper spring perches. These worked perfectly, giving the car an extra .75 degrees of positive caster over stock (by moving the strut pin backwards). The camber setting range is huge, and at this lowered height we were able to get a max reading of -3.4 camber in the front and -2.6 rear (with the stock rear arms). Our technicians corner balanced the car and the final ride heights at 13" front and rear, approximately 2 inches lower than stock. And yes, it clears the big 255/40/17 BFG Rivals with ease.

Now, when could we find a competition event to run this in?? There was a Texas Region SCCA autocross (Aug 18th, 2013) only a few days away, so Matt and I signed up...

What's Next?

Well this forum update has already run far too long, and I barely covered the MCS TT1 install. Sorry - it was such a long wait getting proper coilovers on this car, you have no idea. I am going to cut it short and cover the rest in another installment in about a week, before we head off to the NASA National Championship event to compete in our TT3 Mustang (we're thrashing to finish up some front aero work on that car in our shop this week) and visit with other customers there.

Left: The BRZ with MCS shocks was surprisingly fast at its first autocross. Right: MCS RR2 remote doubles being installed onto an FR-S at Vorshlag

In our next BRZ Project Thread update I will show details of another set of 17x9" wheels we tested, how a set of 255/40/17 BFG Rivals felt, cover an autocross event we ran in the BRZ with 2 drivers, and show off some MCS RR2 shocks we're installing onto a customer's BRZ track car this week. We have several more autocross and track events planned in the car this year as well.

Thanks for reading,

Last edited by Fair!; 08-20-2013 at 04:27 PM.
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