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Unread 06-09-2014, 05:39 PM
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Default Re: Vorshlag Scion FR-S LSx Alpha Project

continued from above


Our 2nd set of motor mounts and new drivetrain location required removing these 3 spot welded brackets

Above you can see the U-shaped brace that was removed, as it no longer served any purpose and was just in the way. At right are two little funky, angled, bent steel pieces were barely attached to the steel front subframe welded assembly and after a couple of spot welds they were gone.


Left: Our first set of mounts had weird bends. Right: After removing two stamped steel bits our motor mounts will fit a LOT better

Removing these slotted black brackets removed a big angled protrusion from both spots on the subframe where we wanted to land our mounts. The first mounts we built had weird bends to try to go around the factory bits (above left), but now with a nice square section of crossmember to mount to (above right) the new lower portion of the motor mounts will sit flush against this vertical wall of steel - and still bolt into factory drilled holes. This makes our new LSx motor mounts (version 2.0) a little easier to make, but it will now have an additional hole to secure them to the subframe and sit more securely there. Removing these 2 brackets was super easy - 2 spot welds per side and they popped right off.



Here is the U-shaped transmission tunnel structure that was interfering with the big Tremec Magnum XL 6-speed manual, so after some spot welds were cut it was removed. There were a decent number of spot welds, but it came off in about 30 minutes. See my quick write-up for Spot Weld Removal tips below - its fairly easy and takes no special skills, just a $5 spot weld cutter and a drill.



Olof made the new Tremec Maxnum XL specific crossmember fabrication (above) that squeezed into the tunnel nicely. Two side plates will bolt to and key off of the chassis, then have 4 holes per side that are drilled into the transmission tunnel (see them bolted in place, two rows above). Then our new U-shaped transmission crossmember will bolt to those side plates, which have some bolt-together attachment points integrated into them. One of our Vorshlag bolt-through 95A polyurethane T56 mounting bushings will go between the transmission crossmember and the Tremec 6-speed.



These brackets and mounts have since been finished welded, templates were made and reverse engineered from each piece, and CAD drawings produced for laser cut production runs of these mounts and crossmembers. I'm happy where the drivetrain ended up, as this gained us more room at the throttle body/hood and moved the weight back even more towards the rear.



Here are the semi-finished prototype motor mounts and transmission crossmember pieces that we will use for the LSx V8 and Tremec Magnum XL. Unlike some shops that never show off their swap parts, we're showing the unfinished prototypes. I'm sure some of you arm chair engineers will want to comment, but remember: 1) these are prototype parts and 2) we have made 100+ V8 swap kits over the past 8 years and have had zero failures. We still have a few more gussets to add to the transmission crossmember mounting pad, then these welded parts will be painted, assembled with the correct poly bushings and hardware, and installed back in the car next week. They are light and strong, and we will road/track test them before going into production for anything.

Cutting Spot Welds Is Easy

This V8 swap kit installation is going to require a little bit more work than some of our swaps we developed in the past, but it is nothing insurmountable by any able bodied person with a drill. There are 5 factory stamped sheet metal pieces we have removed - three from the tunnel and two from the factory engine crossmember. These are attached with simple spot welds. It is unfortunate that we need these removed for the kit to work well, but it is worth it for a better engine placement.

In this section I will show the process for removing two pieces of sheet metal parts that are spot welded together. I did an entire roof panel removal in my home garage, which had hundreds of spot welds, and it took less than half a day. These 5 pieces on the FR-S will take even less work.


This "roof swap" wasn't much fun, but all of the hard work was in the welding. Removal of the old skin was easy

Several years ago I owned a BMW 330 Coupe that had a sunroof and full interior, which I raced in an SCCA class (DSP) that didn't allow for gutting the interior or adding a sunroof delete panel (there are carbon fiber panels you can bolt or bond in place of the sunroof cassette). I couldn't sit in the car upright without my head in the roof panel, so I converted the BMW to the factory non-sunroof structure for more headroom. This conversion included a new roof skin, an addition of one more roof bow, and a new headliner. We started by removing the entire roof skin that was both bonded and spot welded to the surrounding structure in about 200 places around the perimeter. Some of these spot welds were hard to get to, as we had to remove the front and rear glass and all of the interior to even see them. But once we had access, we had the roof skin off in a couple of hours using a drill, a spot weld cutter and some elbow grease.


Left: Typical spot weld cutting tool (small hole saw with a spring loaded centering pin). Right: Spring loaded center punch marks the spot

A spot weld cutter is essential a tiny hole saw with a spring-loaded alignment pin. The goal is make a small dimple in the middle of the spot weld, align the pin in this dimple, then use the tool to cut around the spot weld. This releases the top layer of steel from the base layer. If you do it correctly only the outer layer has a (1/4" diameter) hole in it - and this is the layer we want to discard - while the base layer ends up with the little "bump" of extra weld material left. This bump is the weld and steel from the outer metal layer, which can be ground smooth or in this case, ignored.

On the FR-S, we're just removing some things that are no longer needed to make room for the new transmission or engine mounts. Luckily we don't have to weld anything in place of these removed parts, or even grind the remaining bumps smooth (that's optional - and we did that for better aesthetics). These stamped steel parts are spot welded together without any bonding agent and come off with relative ease. Sure, the joints have a bit of seam sealer smeared over the edges, to prevent water from getting underneath them, but with a little coercion they still come right off once ALL of the spot welds are gone. The spot welds are easy to see - each one leaves a small round blemish in the outer layer of steel.


The spot weld cutter is simply a tiny hole saw with a guide pin that aligns with the punched dimple you add in the center of the spot weld

The FR-spot welds we were after are all easy to see and easy to access, with the drivetrain out. Only the outer layer of sheet steel needs to be cut with the spot weld cutter - the inner transmission tunnel metal should be left alone. Once the spot welds are gone from the outer section these stamped parts can be pulled off with your hands, but if you get a stubborn spot weld (or don't drill it from the center) a chisel or screw driver can be used to pry the metal apart.


On this car there was a bonding agent in addition to the spot welds, so they had to be pried apart. On the FR-S the panels were only spot welded

Rest assured, this step is not too difficult and you won't be welding things back onto the car once these bits are removed. Just be prepared to spend a few hours with a $5 spot weld cutter and a drill before our production motor mounts and transmission crossmember will have enough room to bolt into place. We will show more of this step after the kit is in production, with some videos.

What's Next?

Right now the FR-S is sitting with the drivetrain temporarily held in place (below) by an engine hanger while the prototype motor mounts and trans crossmember are being welded, painted and assembled. Then we can get the final engine in place and gather the parts needed for the engine accessories (Corvette LS2 or something compact like these). After the engine is fully assembled and the radiator is back in place we can finally begin prototype header construction, a custom 1-piece aluminum driveshaft can be measured and built, and a cold air inlet tube can be design and routed.



In our next installment I'll show these steps listed above and detail the final motor being used for this car. It will likely be an LS1 5.7L with an LS2 intake manifold in this Alpha car, but since many folks doing this swap will opt for the "easy button" 430 hp 6.2L LS3 crate motor from GM (about $6500, with a warranty) and the includes LS3 intake manifold, we will make sure both LS2 and LS3 variants fit. While there are no external differences in any of the LSx V8 family of blocks/heads, these two intake manifolds (LS2 vs LS3) have small changes that we need to design around. The LS1/LS6 intake manifold are very different (and have a mechanical throttle body, which we don't want; this car has an electronic throttle pedal) and push the throttle body way too far forward, but we'll test and show that in the next build thread update.

More soon!

Last edited by Fair!; 06-10-2014 at 08:03 AM.
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