Garage Prep I

My solution for body shell storage is to hoist the back 2/3 portion of the shell to the top of my garage. I asked Factory Five technical support for dimensions and weight requirements.

1. 14 - 15 feet long
2. 74 inches wide
3. 150 - 175 pounds

I had our handyman Ted install angle iron across 2 joists for strength.

He installed 4 three foot lengths with a width of 7 feet and a length of 10 feet. The idea is to lift by the wheel wells and door openings in the shell.

Next, I went  to Lowes and purchased a swivel eye pulley plus hanger. Each are rated to 400 pounds.

I attached the pulley to the hanger, then used two 200 pound rated cable ties to attach the hangers to the angle iron.

Just add rope and tie offs, and we have pullet lift more than capable of handling body shell for storage. It is probably a bit over built, but I really don't want to wake up some morning and find it resting on the garage floor.

The Great Parts Round Up Begins

At my birthday party last night, the guys from my small group asked me what I was up to. I mentioned that I was planning to do a GTM build. It was very reassuring to hear Don give his stamp of approval to Factory Five and the quality of their products. Don is a gear head from way back. Most of the guys were wondering if they could come over and turn some bolts. Certainly! One of the things this kind of project needs is friends.

Don asked if there was much welding. I don't think there is, but he has a spot welder I can use if it comes to that. Again, it is good to know there are friends there to help when (not if) I get into trouble.

I purchased the first real parts for the build: Porsche 930 CV Joints. Porsche OEMs are still making these parts even though they appeared in the 1979 Porsche 911 Turbo (model 930). The Mendeola SDR transmission requires these parts to hook the back wheels into the gear box. These aren't the biggest piece of the car, but it has to start somewhere. Besides the love of my life told me I had to make sure the wheels stayed on the chassis.

Synergy

I'm zooming down I94 in the Boxster (freshly liberated from storage at the Barn), thinking about integrating GPS into an 11 year old car. I have a very nice Garmin Nuvi on a pedestal mount that I use in the van and the Boxster. Unfortunately the pedestal mount tends to land in the passenger seat on tight turns at speed.

Somewhere north of St. Cloud, it hit me. The Escort SmartMirror is the solution. All I need is power to make the SmartMirror to work, and there is power 2 inches from the mirror mount. The research for my previous post After Market Goodies gave me the answer.

Myrtle Beach Garage

Maple Grove Cave

Another preparatory step is getting the garage ready for the build. The idea of being on the back under a car on a concrete floor in the midst of a Minnesota Winter just doesn't do it for me. I plan to install a non-skid Swisstrax floor. I already know that it works. I have installed this floor in Myrtle Beach garage and the Maple Grove cave. I have had the Corvette on jack stands multiple times. There is no skids, slips. Each tile is rated to 6000 lbs. Neither floor took more than 4 hours to put down.

If you go with a Swisstrax floor, list Traci as your sales agent. She has done super job on my orders!

GTM Body Shell

Part of the prebuild planning stage is to figure out how to store the GTM body shell.

One solution is to build a body buck (click for plans). If I had the room to do this, I think this is the best solution. Originally, I thought I could build the body buck and store it under the deck. Since I had that thought, my HOA has gone after the little kiddie pools and slides stored under my neighbor's decks. They would probably blow a bolt if I stored the body shell there.

My next idea was to store the body shell off site. This creates logistic problems. I plan to have the kit delivered by Stewart Transportation. These folks are going to show up, off load everything, pat me on the head, wish me luck and drive off. Now how do I get the body shell to my off site storage location - not very easily.

So we come back to on site storage. The body shell consists of 2 doors, rear hatch, front hood (it opens like Corvette C4) and the rear 2/3s of the body. Over all length is between 14 and 15 feet. Width is 74 inches and overall weight is 150 pounds. I believe I can remove the doors and the front hood. I estimate that should reduce the length down to around 10 feet and over all weight to about 100 pounds.

Two sets of Racor Bike Lifts should be sufficient to suspend the major body shell component from the garage ceiling. The rest of the kit build can be stored down stairs in the mechanical room.

The Budget

The base, no frills GTM is advertised as $20,000 plus a donor C5. This is a true statement as far as it goes. However, very few of the builders are doing the base GTM. Most are opting for something newer than the LS1 engine found in the basic C5. The performance of the LS1 (e.g. 345 to 350 HP, depending on the year of the C5) can be substantially improved to the 420 HP with simple things like a larger intake manifold, cold air intake, iridium plugs, better exhaust system.

This approach does produce a sporty, fun car to drive. The LS1 engine is no slouch, and mounted in a chassis weighing around 2400 pounds, it would be fast. Not 200 mph fast, but sneaky fast.

If I were just interested in going through the exercise of building a car, I might go this route. However, I'm interested in building a super car that has an astonishing performance envelope.

To my mind, this means new engine, new transmission, big wheels, big brakes, enhanced electronics and upgraded interior that leaves the fellow in the dust asking, "Who was dat guy?"

So there is an X factor not reflected in this budget. The X factor are those things that do not have to be part of the initial build, but can be added over time.

Built to order GTMs start around $110,000 and go up from there. Yes, there are GTM builders, and they have found a market. Dave Smith (Factory Five's President) says that he has people asking to buy completed GTMs. His answer is you can't buy it, you can only build it. A builder that produced between 5 to 10 of these per year would have a pretty decent income.

There is another benefit. Factory Five kit cars seem to hold their value. I think this is because they aren't just an exotic body shape glued to a rusting VW or Fiero chassis. These are real cars that people want.

Item	Estimate
brakes	2000
donor	11000
wheels	3200
Kit	25000
engine	9500
harness	1500
transmission	9000
Paint	3000
electronics suite	4000
Total	68200

For round numbers, let's peg it at $70k spread over three years, with the middle year incurring the greatest expenditure.

I realize budgets aren't much fun to figure out, but they are a necessary part of the pre-build. The GTM project is not simply an engineering and mechanical puzzle, there is a financial component that needs to be faced up front. If you don't have the financial wherewithal to finish the job, then don't start.

The budget doesn't reflect tool rental, shop supplies or incidentals. I plan to keep shipping costs separate. Items like powder coating parts, ceramic coating, windshield install that need to be sent out will be covered under miscellaneous expenses. My goal is to provide anyone following this build journal a good idea of where and when costs are incurred.

Tool List

I finished acquiring the tools on the required tool list.

• Storage shelves for kit and running gear parts
• Body storage area (can be outside)
• SAE and metric socket set, a 52-piece set that includes an 18mm is a good choice
• Deep sockets for some common sizes are helpful.
• SAE Combination wrench set (3/8” – 15/16”)
• Metric combination wrench set (10mm – 18mm)
• Full set of standard and Phillips head screwdrivers
• Standard Hex key set
• Long nose pliers, 4.5”
• Snap ring pliers
• Pop rivet tool with 1/8” and 3/16” heads
• Drill
• Drill bits (3/32”, 1/8”, 9/64”, 3/16”, 7/32”, 5/16 ”, 7/16”, ½”)
• Caulk gun
• 24 oz. Plastic Dead Blow hammer
• Razor knife
• Wire stripper/crimping tool
• ⅞”, 1¼” and 2¼” hole saws (Body cut outs)
• Bench top vise
• Tape measure or straight edge ruler/T-square
• Hydraulic floor jack
• Work Bench or 2 Saw horses with 4’x 8’ ¾” Plywood Top
• Engine hoist
• 6’ 5/16” chain (to lift engine)
• 4 Jack stands
• Hack saw (metal blade)
• ¼” & 5/16”Fuel/brake line bender (hand held)
• Jig saw (Body cut outs)
• Torque wrench (Click style, ⅜” drive)
• Eye protection
• Gloves
• The thing between your ears

Body storage is listed in red. I haven't figured this one out yet. Most likely the body will have to be stored off site, then retrieved for painting and body work when I get to that part of the build (probably in 2013).

Engine hoist and chain is listed in green. These can be rented from Highway 55 Rental, which is just down the road from the house at the intersection of Highway 55 and 101. The actual dropping the engine into the car and securing it to the mounts shouldn't take more than a couple of hours. This will probably be towards the end of 2012.

So many of the things discussed in the build manual and the jobs that need to be done would have made perfect sense to my dad. I know I am going to struggle on some of these issues. The entire point of going through the build manual and breaking it down into a 142 tasks is to help simplify the build in my mind. Not one task was beyond my abilities. I think if I keep that in mind then the build becomes a doable project that results in unique car.

Finally, I know I have some friends who will help, and eight grand-kids to turn a bolt or two.

After Market Goodies

The GTM has been around long enough to spur an after market. Rather than wait for the car to be fully finished before deciding on enhancements, I intend to add enhancements into the initial build.

Sway Bars:
Quick Racing Products makes a sway bar kit for the front suspension.

LED Lighting:
Quick racing Products makes some interior LED lighting strips ready to plug into the electrical system.

Big Brakes:
West Coast Corvettes sells the big brake upgrade for C5/C6. This does require the 18 inch wheels.

Instrument Panel:
I'm still thinking about this one. The kit currently comes with these Auto Meter gauges. They look kind of ugly. The gauge set sits on a beautiful carbon fiber panel, and white clunky looking gauges just don't make the grade. One problem I have run across is that many gauge sets have speedometers that only go 160 mph. The Revenge Design folks produce a luxury GTM starting at $145K, and they appear to be using a Dakota Digital display.

Exhaust System:

Vraptor Speed Works offers a stainless steel cross over pipe exhaust system that looks way better than the H pipe supplied in the kit. All I can say is, "Now that's an X pipe!" Regardless, which exhaust makes into the initial build, I am going to have a ceramic heat coating applied to the pipes.

LED Exterior Lights:
There are a couple of places that do a great job with Corvette replacement of bulb with LEDs. I am considering contacting them about a core replacement on the kit supplied lights.

Fuzz Buster:
The Passport 9500ci is an integrated system built into the car. The build seems like the perfect time to get this installed.

GPS/BT/Backup Camera:
Escort also makes a product called Smart Mirror. This replaces the donor rear view mirror with a unit that has GPS, Blue Tooth and an integrated backup camera. I am pretty sure the GTM does not offer the best sight picture. It will definitely need a backup camera, especially since all of my sports cars are backed into their parking spots.

HUD Display and Home-Link:
I really like the HUD in my Corvette. The after market HUDs that I have looked at to date are very primitive in execution. Although, Pioneer and Microvision are working on some things due out in 2012 that look quite interesting. For Home-Link, I think the easiest thing is to have it integrated into the driver's side sun visor.

Powder Coating:
As I understand it, there 34 sheet metal pieces that are visible on the GTM. Several builders have powder coated these black. This is mostly for aesthetics. Powder Coating Technologies is just down the road. I'll probably use them for the ceramic heating coating on the exhausts as well.

AM/FM/XM/MP3 Player:
I though that I would need something that integrated all the functionality of the smart mirror into this unit. Now I have the option to simplify this aspect of the build. I think I'll still go with some 2 DIN unit just so I have allocated space for a 7 inch screen. Who knows my passenger might want to watch a movie or something.

Old vs. New: Engine

For me this is a no brainer. You certainly can save significant money going with a donor engine (e.g. LS1, LS6). The GTM achieved the its extreme performance numbers with a LS7 hooked to a Porsche G50 transmission, and 0 - 60 in 3.0 seconds flat is something everyone should sit up and take notice. If we take the nominal GTM curb weight of 2400, then the power-to-weight ratio for the demo car 0.210416 HP/lbs.

The curb weight for Corvette Z06 is 3180 pounds. The LS7 is the base engine for the Z06 and this has a p-t-w ratio of 0.158805 HP/lbs.

My 2003 C5 (as currently configured) has a curb weight 3214 pounds. It has a modified LS1 engine and it has a p-t-w ration of 0.124455 HP/lbs.

The base LS3 engine produces 430 HP. In a GTM, the p-t-w ratio is 0.17916 HP/lbs. This is already higher than the Z06, which has a published top end speed of 198 mph.

For emission conscious locales. GM provides green E-Rod engine with the same p-t-w ratio. I only include this engine for completeness. It is not on the list for engines in my GTM.

For close to the same money as the base LS3, there is a more powerful version called the LS376 engine that produces 480 HP. In a GTM, the p-t-w ratio is 0.2 HP/lbs. This engine set up approaches the powerful LS7 used for the demo car. Now we're talking! The MSRP is $8,075. If you shop around, this engine can be found for as little as $6,100.

Granted horsepower isn't everything, but it is the heart of the beast.

Donor Parts vs. New Parts

It is much cheaper to go the donor car/parts route. I asked Factory Five Tech Support about going the C6 route with a donor car. Factory Five said the donor car has to be a C5. This basically ended my idea of going with a C6 as a donor car and salvaging a LS3 engine.

The other issue I have wrestled with is a new car build with is used car parts. Do I really want to put used parts on a new car? I think I have come up with a reasonable compromise on this issue. I will probably go with a donor parts kit from Fparts for the suspension, cooling system, e-brake, full delivery and miscellaneous parts. Anything that seems really hacked up will get replaced with new. I have also inquired with Fparts about the possibility of getting the telescoping steering column and the newest version of the fuel tanks as part of the donor parts kit.

I intend to spend close to 40% of the build money on a brand new engine, transmission, A/C, big brakes, big wheels and upgrades to the interior, instrumentation, electronics and lighting. If I am going to build a car capable of approaching 200 mph speeds, then I am going to make sure the drive train and power plant are up to the task.

The other reason for going with this approach is the story of Vern and his Miata. He had this beautiful little red Miata for twenty plus years. He knew every bolt, quirk, screw and sound the car made. When the car was totaled in an accident in 2010, Vern was bummed out. I asked him why not pull the new stuff he had just put on the car and get one of the same vintage. Those cars were only running about $5000 to $8000. Vern shook his no, explaining that he wouldn't know what had been done to the car. He knew everything that had been done to his car.

The GTM build is a unique opportunity to know the car right down to the last bolt. So next month, I plan to pull the trigger and purchase the donor parts kit. It will take me a couple of months to get everything cleaned up. Meanwhile, there is the new front end for the Boxster and the Z51 sway bars for the Corvette...

The Donor Car - Part 2

The donor car is a cost effective method for acquiring the parts needed for the build. The donor is a cadaver that will never roar down a twisting country road again. So you have to ask yourself what happened. The car either was the victim of a flood, theft or crash. (Stay away from the fire damaged ones. The reasons become obvious, once you look.) The insurance company deemed it unrepairable, and that means there was in excess of $20,000 damage to the vehicle. This number is based on the current replacement cost for a low end Corvette C5.

The major subsystems provided by the donor are as follows:

• Front suspension
• Engine
• Rear suspension
• Rear CV joints
• Emergency Brake Assembly
• Fuel Delivery
• Cooling system
• A/C 
• Brakes
• Miscellaneous (basically everything else)

Factory Five says the donor needs to be a C5. This is the path of least resistance, but many of these subsystems are common across generations for years 2003 to 2009. There is a substantial financial argument to be made for donor with a working engine.

My perfect donor is as follows:

• 2008/2009
• Larger wheels (18 front / 19 rear) - I'd scavenge these for the Big Yellow Toy.
• Big brake upgrade
• LS3/LS7 engine
• Intact suspension
• Intact instrumentation

This poor thing has too much damage for the GTM project. My first clue was lack of wheels and anything to hold them along the driver's side. The love of my life has already indicated that I need to make sure the wheels stay on the car.

This car on the other hand got hit on the passenger side. There is a substantial mess inside, but the mechanicals look good.

As I said, there is a substantial cost savings going the donor car route. The opportunity to acquire a working LS3 or LS7 engine plus the majority of the parts needed for assembly needs to be considered. Copart and Ebay are the easiest places to look for salvage or unrepairable titled cars.

Old vs. New: Transmission

There are many issues that you need to confront. One of the biggest is old parts versus new parts. Aside from the Factory Five kit most of the rest of the car can be built from used parts, including engine, transmission, brakes and suspension.

Transmission:
The first generation GTMs used a Porsche G50 transmission. The G50 was introduce in 1987 and retired in 1999 or there abouts. I know of 5 variations on this transmission, plus a long and short version of the case. To make the G50 work with an LSX engine, you will need an adaptor plate. In addition, make sure you get the following parts with the G50:

• speedo sender
• pressure plate
• friction plate 
• release forks
• driveshaft adaptors
• slave cylinder
• rear mount beam ("short only")

You probably want to make sure the unit has been rebuilt/refurbished and has documentation. By the time you have all the pieces, the rebuilt transmission, and pay for core exchange (which you don't have to exchange), the bill is anywhere from $6500 to $9000. This is for a very good transmission. But it was built in the last century and you are going to hook this up to your brand new, dyno tuned LS3 engine.

The other option is to go with a new transmission built for Factory Five by Mendeola. This has limited slip differential standard, a torque rating of 475 ft lbs (warranty 400 ft lbs) and a horsepower rating of 525 HP (warranty 450 HP). It costs (with shipping) $8900. It bolts directly to a LSX engine.

Nothing against Porsche. They are fantastic machines (I love my little Boxster). I have had some wild times on empty country roads in North Western Minnesota. However, I can't see bolting a 15 to 20 year old transmission to the back of a new engine. When you get right down to it, the dollars aren't that far apart.

If you go with the Mendeola, remember to order early. There is a minimum three month wait on these units.