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Unread 07-23-2012, 08:21 PM
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Join Date: Jul 2004
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Default Re: Brianne Corn's Pike's Peak Subaru STi

Project Update for July 23, 2012: A lot of hours and late nights have gone into this project in the past 7 days. Plumbing, flares, suspension, and more. Let's get everyone caught up on the last week of Vorshlag work on Brianne's Corn's hill climb Subaru (including Brianne, who is also watching our work progress online) by the crews here at Vorshlag joined by our hose and fitting experts.


Major Plumbing Upgrade Work

The crew from Pirtek Plano South have burned a couple of nights and most of last Saturday at Vorshlag getting the complete plumbing upgrade of the car knocked out. This is a big job happening on a compressed schedule. First they worked with our crew to get every device mounted, then mapped and planned the hoses, got the AN fittings ordered. Once the fittings arrived (including some they custom built for this application, to reduce adapters) each dedicated hose end fitting (+ adapter, if needed) was installed on each device. With these in place the individual hose lengths can be measured, then the complete hoses were built at the Pirtek shop, then the hose + fitting assembly was installed on the car at Vorshlag. This is normally a multi-thousand dollar plumbing upgrade - luckily Pirtek is a sponsor to Brianne's race effort.



The fuel filler tube hole is covered with a Hurst boot - yes, a manual shifter boot - and it works like a charm. The custom double-mount for the two fuel filters (pre- and post-surge tank pump) has rubber sheeting on both sides for vibration protection and bolts to a threaded fitting TIG-welded to the chassis (called a "weld nut"). The surge tank is mounted to the unibody through poly isolators as well.



Vorshlag's fabricator Ryan and assistant Cameron re-worked the initial shape of the strut tower brace (aka: the dual oil cooler mount) with larger 3/4" square tubes for the forward section. Pre-drilled brackets were tack-welded in place, the coolers were bolted to these, and the AN fittings were pre-installed for hose routing. Ed from Pirtek is shown laying out some hoses under the hood - he will be traveling with Ryan and Jason from Vorshlag to help support the Brianne Corn Racing effort during the week of the PPIHC event and will be joined by 4 more Vorshlag employees around race day as well as tuners from AWD Tuning. If it "takes a village to raise a child", it takes a crew of experts in their respective fields to help make a car capable of winning at PPIHC. It goes without mention that it also requires an awesome driver and navigator, too! We know that formula is there, with Brianne Corn and Jeremy Rowland. We are all so excited to see this driver, navigator and this car attack the mountain again!



With all of the fittings and hoses in hand, they got to work properly routing and plumbing it all. The RedHorse AN fittings look great, the hoses are all secured, the routing tweaked, and any hose that can rub against anything else will have some abrasion protective sleeve added.



I will show more of the under hood work after the new coolant expansion tank is added and the new coolant lines are plumbed. That's happening in the next few days. At the moment the entire fuel system and oiling lines are all upgraded and completed. We still have heat management issues we want to address, but that's a job for next week.


Suspension Upgrade Shaping Up

With only a couple of weeks notice before the event, and a tighter than normal budget, AST-USA worked with Vorshlag and Brianne to come up with a custom set of inverted AST dampers that will suit this unique Tarmac Rally setup for this car. A mix of track worthy AST 5100 inverted front struts (45mm shaft) was paired up with some inverted AST 6100 Rally (50mm shaft) rear struts, for a combination that has the proper bump travel and extreme droop travel necessary when attacking the one of a kind Pikes Peak asphalt course (and again, this year is unlike any other before, with a fully paved course). The old front struts had almost zero droop travel, which is obvious when you look at the comparison picture of the old TEINs, the AST 5100s, 4100s and 5100 Rally struts. More travel = mo better! There were many corners last year where the car had 6" of air under a rear tire. Not conducive to good corner exit acceleration when you have a driven tire in the air.

We tested with four different front struts on the car and ended up picking the off-the-shelf GD 5100 front struts after we found that they had the perfect amount of bump and droop travel. Ryan tweaked the mounting holes in the lower half-brackets on the strut bodies for maximum tire clearance. Then Erik and Stuart at AST-USA checked out and went though all of the struts in short order, and got them to us from start, to testing, to finished in under two days. It sure is handy being located next door to their shop! These struts look great and should be strong as hell on this car. Our standard Vorshlag GD front and rear camber plates will be on top of each strut, of course. To gain an extra 5mm of room for spring length our single row race radial bearingsare used in the front set - which we do on a lot of race cars. The GD rear plates/perches always use the single row radial bearings.



One way to pick custom damper and spring lengths is by checking the travel on the car. We start by removing the springs and installing the strut (or shock) + the final top mount onto the car while suspended on a lift. Then we lower the car onto the tires and allow the suspension to compress down and touch the bump stops, then raise it up to check maximum droop (we check for fender flare clearance the same way, too!)



We did this testing on both ends of the car with several dampers. Since we already had the wide body front flares completed in steel at this point, the front wheels we used were the custom-Vorshlag-run of 18x10" D-Force units, while the skinny stock wheels were tested inside the not-yet-flared rear fenders.

These tests + lots of calculations dictated the proper spring lengths and rates for the unique dual spring set-up Jason is developing for each corner of this car. The front flare is made to allow the wheel outboard enough so that a 10-12" long spring assembly can be used. In the rear, it is set up to use 11-12" of spring stack, all placed above the tire. One of Vorshlag's spring vendors, Swift Springs USA, stepped up and sponsored Brianne's PPIHC race effort this year with free set of eight springs! That was very cool and much appreciated. Jason ordered those + another twelve springs from Swift for tuning purposes next week as well as during the week of the Pikes Peak event.




Wide Body Flares - Part 1

I didn't show much flare work in my last post, but it was already well underway (we began on Day 1). I have been posting teaser pics on the Vorshlag Facebook page, which if you "like" will show you spoilers of most of our projects before they are formally written up in our various build threads (as well as new products, long-term project cars we are selling, and other news). Let's take a step-by-step look at how we're making this custom fabricated set of steel fender flares for this car. As usual, we show more behind the scenes steps than most folks are willing to share, and hold back nothing.


The factory box flares look great, but they have trouble covering more than a 255mm tire. Not good enough for Pike's Peak!

The factory 2005 Subaru STi fenders already have a modest little box flare, and instead of lopping those off and taking a short cut by welding on a new rounded flare section from a donor BMW fender flare section (like we have done on non-STI Subarus in the past), the VoMo team instead opted for an exaggerated factory box flare. This is an old fabricator's trick where you take an existing flare section or bodyline, slice open the upper section, and extend it. Seems easy, but the proper execution of this method is time consuming and tricky. We're burning 1.5 man days per corner, just in fab work.



Even though this process takes longer to do than the rounded flare transplant, or slapping-on some composite flares, we went with it for aesthetic reasons (it just plain looks right!), but also because it makes for a stronger, more durable finished unit. Steel flares can take a bit of a beating (smacking autocross cones, gravel hits, etc) that will normally crack fiberglass flares. Show me a real race car with fiberglass flares and I'll show you the cracks. We were also short on time for finding the right kind of widebody kit, such as ordering fiberglass fenders + overflares (which are usually built to order and almost never just sitting in stock). We could start making the steel flares in-house on day 1, which we did, using our past steel flare experience and the skills of our in-house fabricator Ryan. Sticking with steel worked for this tire size package, this car, this crew, and this timetable. Luckily the car owner Brianne left it up to us, as we were the ones that talked her into the 285mm tires.



We looked at another similar project's work (Kevin Byrd's beautiful LS3 widebody E30 M3, of Two Guys Garage TV fame), followed his example, and modified this proven method to fit this Subaru's boxy body lines. The total amount of room added is about 2" per side, with a sliced/and-filled pie section only about 1-1.5"" wide at the top of the flare and a re-shaping of the radius where the flare meets the body. The front inner fender lip was also rolled once it was pieced back together. These flares will cover not only the 18x10" wheel and 285/30/18 Hoosier, but an even larger 18x10.5" wheel and wider 295 tire - in case Brianne wants to go wider in the future.



A TIG welder was used with a very specific rod that can take a lot of heat without blowing out, and a very steady hand. These pictures show the cutting, slicing, patching, and re-shaping necessary to make a wide body flare in steel. What you don't see is the hammer and dolly work, the tweaked contours of the bumper covers to match, and the hours and hours spent getting the metal shaped and re-shaped to the final contours. There are a lot of radii built into the Subaru box flare, surprisingly! Overall, all I can say is: "It's a lot harder than it looks".



We still have all hands on deck attacking these flares, trying not to let this push anyone's deadline back. In fact, last week we pushed up our own the deadline to get the car to the tuner half a week sooner than originally planned.

Two of my racing buddies and I volunteered our bodywork talent (of which we have very little!) last Saturday to try to make these look "race car good" before the vinyl wrap. I came back on Sunday and did some more filler, did another round today, and I will keep attacking the bodywork every night to keep from dusting up the shop during the day - when they are cutting, welding, and wrenching on this car. I think I've ingested enough body filler dust to make a 1/25th scale, sand castle replica of Windsor Palace.



So far we are on target to get the rolling chassis back over to AWDTuning on Thursday night or Friday, fully plumbed and on the big wheels/tires, for their tuning work. The flares won't likely be 100% done by then, but they should be clearanced and the 285mm tires functional. Hopefully the tuning can be wrapped up Friday and then that gives us all weekend to swap in the new Swift dual-spring set-up, corner balance and align the car, and work on more flare stuff. Hopefully we can sneak out of work for a few hours to do some track-side testing early next week as well. After the test (and any subsequent changes), we can vinyl wrap the car and add sponsor decals and number graphics.

I will show one teaser pic of the rear flare work, then describe it in more detail in "Flares Part 2" - just know that the fronts were EASY to widen compared to the rear, which also encompass the rear doors as well as the fuel filler door:



Nice, fat back end shaping up. See why we moved the fuel filler to the trunk? That fender will be seamless when its completed. Again, more pics of the rear flares next time...

Stay tuned!

Last edited by Fair!; 07-27-2012 at 04:53 PM.
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