Order Kit

Order Kit:

I ordered the kit in April of 2012. This is after about 10 months of planning and preparation for the car. So it was a big day to sit down at my computer, pull up the Factory Five order screen and actually start entering the information for the car and delivery. I'm bouncing up and down, because I was really doing the steps to order my GTM Supercar Kit. Did I know how hard it was going to be? Did I know I would really enjoy so much of what the next years would entail? Did I have a good handle on everything that needed to be done?

No.

How did I get here?

Some time in 2011, I sat down and evaluated my sports car collection. Actually, the collection only has 2 cars: a 2003 Millennium Yellow Corvette Convertible, and a 2000 Metallic Arena Red Porsche Boxster. I had a laundry list of things to do on both of these cars. I knew I wanted a third car to round things out, but what?

I tracked Ferrari 355 Ebay sales. At one point, I'm pretty sure I knew every 355 up for sale in the country. I ultimately decided against the Ferrari, not due to initial cost, but the maintenance tail. I wasn't sure I could keep it running.

Simultaneously, I watched Porsche 928. I remember going to the Minneapolis Auto Show with my dad the year this car came out. I was a junior in college. They had an engine under glass on a turn table. I loved the lines, the power, everything about the car. Of course, there was no way I could afford that car. I was having a hard time affording my Chevy Vega. I didn't know I would go another 33 years before I finally got to own a Porsche. I decided not to pursue this car, because of the nagging issues for cars that had low mileage and had just been left to rot in garages for 20 years. 

I stumbled (as so often happens) across the GTM. This car had the subtle sleek lines I love in the Ferrari. It had was based around a Corvette C5, and I figured I had the same generation Corvette in the Southern Man Cave, so there was a familiarity. It used a Porsche G50 transaxle. Gee, it has Porsche parts, so I liked that idea. It used a Corvette engine. Okay, something that is cheaper to maintain than a Ferrari power plant.

I didn't know at the time, I would build my GTM around a LS376/525 6.2 L power plant, or that I would jump at the chance to upgrade the transaxle to the 991 7 speed Porsche Transaxle straight from the factory. Of course, there was the little catch about having to build the car.

Hmmm, can I build a car?

I guess the jury is still out on that question. I think I can, and failure is not an option.

Tire Decision

The kit is due to be shipped from Factory Five in about six days. One of the first elements of the build is to get the chassis up on wheels so that it can be moved around. The goal is to have it mobile by the end of July. I believe that is doable (and I could be a 100% wrong!).

This means the tires need to be purchased sometime in the next six weeks. As of this writing it is June 3, I probably need to get tires ordered by June 17. This is where previous build decisions have an impact on the tire decision. The stock tire sizes for a C5 Corvette are 245/45 - 17 (front) and 275/40 - 18 (rear). If I were going with the stock donor, then I would use the donor wheels and purchase matching tire sizes.

One of my decisions early on is based on the whoa and go concept. The GTM (regardless of the engine) has plenty of go. It is fast. It is sleek. It will rumble and growl. It looks like it is breaking the speed limit sitting still. I have an LS1 in my C5 (albeit, with a Hurricane cold air intake, Corsa Pace Car Sport Exhaust with Tiger Shark Tips and a cross over pipe) and she pops, rumbles and growls. There is plenty of power for the C5. A GTM at 800 to 1000 pounds lighter will be that much quicker. However, my buddy Brian pointed out that while I had the Go figured out, what about the Whoa? The Whoa comes in the form of the Big brake Upgrade.


The big brake upgrade requires 18 inch wheels front and rear. This is a departure from the stock C5 configuration. To accommodate the big brakes, I needed to purchase bigger wheels. I purchased Forgestar F14 wheels. These are the same wheels featured in the Factory Five catalog. These changes are within spec for the GTM. The monster LS7 power car that Factory Five built and that was featured in Car & Driver had the big brake upgrade and the larger wheels.


Tire sizes jump to 245/40 - 18 (front) and all the way to monster 335/30 - 18 (rear). The rear tires are a street legal drag radial. An alternate size for the rear tires is 295/35 - 18. Selection for the largest tire size is extremely limited and cost is quite high. The intent for my GTM is street use (granted I'll be the leanest, meanest on the block - Dodge Vipers beware!) When I drop down from the 335 to the 295 width, my tire selection goes up and my costs come down.

The OEM tire for C5 Corvettes is the Goodyear F1 Eagle run flats. These are noisy tires. They tend to drone on long trips. I would be hard pressed to point out a C5 in the Myrtle Beach Corvette Club that hasn't upgraded/replaced the Goodyear tires. Most people migrate to the Michelin Pilot Sport PS2 or PS3. This seems a safe and popular choice. I bounced this off my buddy Brian and heard quite the horror story about his Michelin Tires. The approximate cost for these tires is $1510 ($320 for front, $435 for rear).

Factory Five recommends Toyo Proxes 1. From everything I read on these tires, they are real good, a tad bit noisy and tread life seems a bit short. There is a real shortage of dealers selling these tires. The lack of a good dealer network is a deal killer. The approximate cost for these tires is  $1272 ($255 for front, $381 for rear).

About a year and a half ago, I replaced the tires on my Boxster with Continental Extreme Contact DW. What a difference these tires made! They were quiet. The grip the road. In the Boxster this is important, because I like to take sharp turns (testing the strut braces and Eibach performance sway bars - you know. Especially on Troy Lane!). These tires live up to their billing. I really like these tires and I have experience with them. The problem is availability in the rear tire size. The approximate cost for these tires is  $? ($195 for front, $? for rear).

This winter I replaced the tires on the Corvette. I wanted to go with Nitto Invo, but I could not find them in the Myrtle Beach area, so I went with the NT555. These are good tires. They are quiet. They have a long tread life. They hold the road (and some of the roads along the Grand Strand leave a lot to be desired). The Invo is an asymmetrical tire (like the Continental Extreme Contact DW) and it is available in the sizes I need. The approximate cost for these tires is  $886 ($188 for front, $255 for rear).


I based my cost estimates at Tirerack. 


I am going with the Nitto Invo. I am impressed at the ride quality I get in the Corvette. I like the way she handles. The Invo is Nitto's premier performance tire.

Parking Assist

I ordered the parking assist sensors last month. I decided to go with a 4 sensor set up for front and rear for a total of 8 sensors. Basically, you end up purchasing two 4 sensor kits. The purpose of parking sensors is to assist the driver with an audio/visual notification of obstructions within 5 feet of the front or rear bumpers.

This is one of the kits.

I already know that parking a car on the lift or under the lift will be a close thing. It is easy to park a car under the lift. It is harder to park a car going up the ramps and keep everything straight. I can park the Camry and Boxster without any problems. The minivan fits on the lift if you remove the side mirrors, so there are limitations to what I can park on the lift. The driver's rear view and perception in the GTM is minimal.

They sent me 2 sets of sensors. This is the basic set.

The sensors are  position inside the bumper fascia. This means it will be inside the fiberglass shell. Forward sensors are connected to the brake light. Rear sensors are connected to the reverse lights. You might think forward sensors are overkill, but I have discovered that parking the Corvette and/or the Boxster (with its new front end) can be a challenge as you just don't have a great sense for the distance between the front end and the curb.

This is the second set of sensirs that have double sided 3M auto motive tape.

The sensors connect to a control box. The control box is wired to a power source. Most likely with wire taps. This is very low power system. I will be employing LED lamps through out the GTM, so tapping these sensors into those circuits should be a minimal load.

Control box, power leads, buzzer and buzzer interface wire.

The control box has outlets for buzzer and display. I plan to only use a buzzer system. I will augment the parking assist sensors with forward and rear cameras wired into the stereo/Mp3/BlueTooth/GPS system on the center console. One of this year's projects is to upgrade the Boxster's electronics. I plan to add a camera to that project. I will use the Boxster as a camera test bed.

Control box with inputs for power, left sensor, left center sensor, right center sensor and ring sensor. Outputs for display and buzzer.

This set changes the ISIS wiring setup. At the time, I reasoned the parking assist required a separate circuit. Since this system is designed to piggyback on lighting circuits, there is no need for a separate ISIS circuit. The other change to the ISIS wiring diagrams is the elimination of a separate circuit for HomeLink. Since I am going with a GPS Navigation system on the center console, I can move HomeLink functionality to the rear view mirror.

Are you crazy or something?

I didn't go to bed one night and wake up the next day with the dumb idea that I am going to build a car. This is one of those year long conversations that results in waking up and saying, "Yeah, I think I can build a Factory Five GTM super car."

Build a car or buy a car? Of course, it is much easier to buy a car. I had my eye on a Ferrari 355 Spyder. I could probably swing the purchase price, somewhere between $45,000 and $65,000. I did not have qualms about purchasing a used sports car. I already had purchased a Corvette C5 Convertible and a Porsche Boxster 986. The prospect of digging into the car and mapping out modifications did not daunt me. However, the idea of a $10,000 engine out service every 3 years gave me pause.

I can come up with space for one more sports car. My preference is a Ferrari, however, my wallet is not quite up to the task of Ferrari maintenance. So if not a Ferrari, what kind of car compliments a Corvette and a Boxster. It has to handle like a Boxster, roar like the Corvette and have the Ferrari's wow factor. The performance specs for the GTM are as follows:

• 0 - 60 in 3.0 seconds
• 0 - 100 in 6.6 seconds
• 1/4 mile in 11.0 seconds @ 132 mph
• Curb weight 2350 lbs
• Corvette suspension
• LS Series engines
• Either a Porsche G50 or Mendeola transaxle
• 245/40/18 front tires
• 335/30/18 rear tires
• Z06 Big Brakes
• Koni coil over shocks

The GTM looks fast and drives fast. It is exotic and fits the current definition for a super car.

So it begins.