View Single Post
Unread 08-20-2013, 04:01 PM
Fair!'s Avatar
Fair! Fair! is offline
I blame the internet
Join Date: Jul 2004
Posts: 6,079
Default Re: Vorshlag BRZ Project Build Thread

Project Update for August 20, 2013: It looks like we had a huge delay since our last project build thread update on the BRZ Project; it hasn't been discussed since December of 2012. There were some lengthy delays waiting on shocks that were a bit out of our control, which we will explain below. We also got very busy with other projects and racing in other cars. But in the past few months a lot has happened behind the scenes with our in-house 2013 BRZ and we've finally installed proper monotube adjustable coilovers that actually fit these cars at lowered ride heights. We put these to good use at an autocross recently with surprisingly good results. Read more below...

What a difference a year makes! Left is bone stock, right is last week on MCS TT1 shocks, 17x9" Enkei RPF1's and 255 BFG Rivals.

One more thing. Starting in early 2013, all of the pictures in my forum posts can be clicked for higher resolution versions, unless they are posted in-line with BIG format pictures. This takes more time and makes the character count of my posts longer, but we feel it is worth the extra effort to split up posts into multiple sections. With a professional photographer on staff, we WANT you to see our images in higher detail. As always, these watermarked pictures are all copyrighted by Vorshlag, so we ask other shops NOT to steal them (yes, it happens). Anyway, if you see something you like, click that pic!

Where Were We? Waiting On Coilovers...

At the end of my last post (What's Next?) in December we had mapped out future suspension mods. Coilovers were the obvious next modification slated, but that didn't quite pan out as we had expected. There were some early coilover shock options for the FT86, most of which were straight off of the Subaru Impreza that this FT86 chassis was loosely based on. But as we saw, many of those early kits were compromised in some way - namely in the fact that the front struts were not utilizing the room under the spindle for extra travel. Unlike the AWD Impreza, the RWD-only FT86 has several extra inches that could be exploited up front for more strut travel, using the area that the AWD Impreza front half shafts would have been. None of the rushed-to-market coilover solutions used that room. The rest of the kits we saw were all twin tube shocks, which we are not fans of.

This picture was made for a photo shoot last year with stock shocks/springs/sway bars. Handling was pretty awful.

Without proper coilovers to install we weren't about to try to autocross or track this car seriously, either. Sure, the production Swift lowering springs arrived and they looked good, but with the stock length struts and shocks there just wasn't a ton of compression travel to be had. And no lowering spring is going to be significantly stiffer than the OEM bits, not enough to matter for performance handling. Sorry, that's just the truth. Lowering springs are 90% for looks and 10% help handling by lowering the CG. When we see folks arguing one brand of lowering spring over another regarding performance, or one model of OEM spring vs another (BRZ vs FR-S), we have to bite our tongues... because we know it is completely pointless internet talk.

Real coilovers geared towards competition use can work with substantial increases in spring rates. Not 0-30% stiffer, like most lowering springs add, but 100-500% stiffer spring rates. Spring rate changes like this cuts way down on chassis roll/heave/dive, and that's where we've seen the biggest gains over the years with suspension changes - spring rate. And no, the spring rates I'm talking about do no automatically mean "bone crushing ride", not if used with proper monotube shocks. The relatively massive pistons in monotube shocks (relative to twin tube shocks, like the OEM bits) make for a massive increase in low speed sensitivity to movement, so they react more quickly to bumps than any twin tube shock ever could, no matter how stiffly valved. And the large range of adjustment in most aftermarket monotube adjustable shocks means they can work with much stiffer rates and still provide a good ride when the valving (knob) is turned down for street use. These reasons are why Vorshlag ONLY sells monotube shocks - we've seen the glaring limitations of twin tube shocks and just don't want to be a part of that "solution". Sure, Twin Tubes shocks are cheap to make and they have their share of budget-oriented fans, but they don't belong on a car that will be used in competition, and are never going to be something we recommend or sell. Yes, some folks call us shock snobs - but we have our reasons.

Nearly 8 months after we ordered the first prototypes we finally got a set of coilovers from a monotube company to test. We tested their set-up on Matt's BRZ several times over 2 days, with and without springs, and we found several issues. These included brackets that didn't fit the mating hoses, mounting holes drilled the wrong sizes, and strut and shock lengths that were completely wrong. There was no easy fix for the strut length problems, either, other than running them at stock ride heights - which we weren't about to settle for. These tests were a real set-back and we knew this would turn into another huge delay. Still, we had hope, so we spec'd out the proper front strut and rear shock lengths and waited to hear back about a new set that could actually work at a lower ride height.

More months of waiting turned up nothing. It was a problem with the supplier, who was unwilling to make any changes - even if every issue we noted was true. Nobody involved came out ahead on this one. We wasted months waiting for a fix that never came and lost a lot of time in the FT86 suspension market. Matt's BRZ was just tooling around on nice wheels, good bushings, and lowering springs - all dressed up but not race worthy. After seeing how this car fared on track with the stock shocks and soft springs, we knew it would be better suited to proper coilover spring rates and dampers, and really wanted to move to the next step.

I cannot fully put my frustration into words, but I'm not throwing any names around. I'm just going to leave it at that. So after we ran out of patience waiting we broke down and looked at other vendors making quality monotube coilovers for the FT86.

Monotube Coilover Solution Found in the MCS TT1

A relatively new shock company we've been eyeing for a while was Motion Control Suspension (aka "MCS"). This is an American company started in 2011 that has the same principles that formerly ran Moton for 12 years. We had seen that they had made their new MCS non-reservoir single adjustable monotube coilovers for the FR-S/BRZ and the SCCA C Stock guys seemed to love them. This run of FT86 coilovers were made explicitly for this class's unusual shock rules: where OEM spring must be used and the shock length can be no more than 1" different from stock.

Left: Moton 2-Way Dampers we built for SCCA Stock Class BMW 135i. Right: Custom perches for F Stock use on S197 Mustang

The MCS solution for this class was sold with adapters to convert them from adjustable height coilovers normally holding 60mm springs over to fixed height struts that worked with the OEM springs. As crazy as that sounds, we have built shocks like this with other shock companies in the past. It is a very small, niche market of a few dozen racers a year that buy shocks for SCCA Stock class. They can easily cost upwards of five thousand of dollars for custom built double adjustable, remote reservoir shocks that work within the narrow confines of the SCCA Stock classes, and they do find performance benefits in a few loopholes... but nothing like a set of proper coilover springs would give them if they weren't saddled with that class' oddball shock/spring rules.

We loved the quality and durability we've seen in Motons, and I run Moton Doubles with remotes on my personal NASA-TT3 Mustang. But while Moton never offered a single adjustable shock, the folks at MCS did, releasing their non-remote single adjustables in early 2013. A Single adjustable non-remote reservoir monotube coilover is one of the areas we at Vorshlag really excel in. This type of shock has a big chunk of the performance benefits of a 2 or 3-way remote reservoir monotube (that can costs $4500-8000+) but at about half the cost of "remote doubles", and without the hassles of mounting reservoirs/hoses. Monotube Singles are a great solution for 80% of the coilover users out there, and we really needed this "internal single monotube" coilover if we were going to play in the FT86 market.

Since stock springs and stock length struts and shocks aren't what 99% of the FT86 crowd wants, we saw a glimmer of hope in MCS, and wanted to give them a try. We talked to MCS, set-up Vorshlag as a dealer, and ordered one of these FT86 sets in our initial stocking order. We knew they might not be the right length but were willing to test them and see, and they said they'd be willing to customize them to our specs.

Left: MCS TT1 singles for FT86, kit priced as shown is $2750. Right: Vorshlag pinned spanner fits the ride height perches perfectly.

continued below

Last edited by Fair!; 08-20-2013 at 05:49 PM.
Reply With Quote