Does anybody have any info on the use of the GTM as a race car. I was curious as to what level of modification is needed. For example, will the cage meet NASA or SCCA specs. I am looking to build a car for NASA super unlimited or SCCA SPO. Since it is a tube frame car it looks like it would be easy to add more extensive door bars, some more roll structure, and adjustable chassis pickup points. Do you think the chassis could handle an 800 HP LS 7 race motor and emco transaxle?
Well for starters you are going to have to replace the gas tanks with a Fuel Safe fuel cell, seat belts would need to be changed to 5 point which means a brace is needed in the floor for the anti-submarine belt, fire extinguisher set up in engine bay and cockpit, master electric shut off, inspection holes drilled in frame to check wall thickness.
As far as HP goes 800 HP is way over the top. You will be spending more time trying to keep the back end settled and will be on and off the throttle with that much power. It would probably be enough at 450 HP realistically and you would be able to use the entire power band and generally the car would be more manageable.
......what level of modification is needed. For the cage meet NASA or SCCA specs. I am looking to build a car for NASA super unlimited or SCCA SPO......... .
Joseph, I'm going down this path. The cage doesn't meet either NASA or SCCA specs but it can be modified to do so. FFR uses the correct .120 wall 1-1/2" tubing and welds are good quality on my car. Specific areas than need to be moded are:
-The front down tubes terminate at the dash bar and need to be continued down to the frame. This can be added on as the only bars that need to be one continuous piece of tubing are the main hoop and the rear down tubes (with no bends on the latter).
-Round tube door bars. NASA needs two drivers bars and one passenger, SCCA says two on both sides. I just replaced the square tube with round on both sides as it was a in a legal configuration just not round seamless tubing. I'm waiting on upper door bars until I have seats in to ensure it doesn't end up seriously impeding egress or be where my elbow gets anoyed by it.
-There are no diagonal or harness bars. The diagonal (by the book) needs to be in the same plane as the main hoop and the engine is in the way. I chose to make a new main hoop about 5" forward of the 'stock' one. This puts the diagonal forward of the block but still interferes with the water pump. A remote electric pump solved this for me. The diagonal also precludes the use of the passenger side fuel tank which is the side I'd want my fuel on so I wedged a 10 gal fuel cell up front where the A/C package would be. Moving the main hoop forward raised it up a few inches, without doing so, your helmet is above the main hoop. I'm also going to place an X in the middle to get some bars above my head level.
-I needed new rear down tubes since they need to reach from my new main hoop to the frame or chassis in one piece with no bends. I attended an SCCA race at Sonoma Raceway and asked a few officials there if the FFR upper shock mount is considered the chassis or frame and showed them a picture. They said that it is a legal attachment point and I found several cars that day with that configuration. The down bars meet all the angle requirements as well.
I'm sure the chassis can handle the power structurally. How you put it to the ground, as I assume you know, is what racing is all about.
Thats the jist of it, I may have left out some details. Best to spend some time in the rule books. There are other ways to do it and there are stories of alternative compliance measures to get around the mid engine / diagonal issue, I just chose to build to the letter of the rules. Hope this helps.
Hey Joseph, I forgot to say welcome to the forum, so welcome!
I was thinking of starting a thread collecting the details of a track oriented build but here is as good as place as any. There are several of us looking to track our GTM's in competition and only one doing it, as far as I know. Check out their website here:
'Crash' is one of the drivers for the team and makes some oustanding parts for the GTM as well as being a big contributor to the knowledge on this forum. His alignment slugs are a must have for a track build and his stub axles would help hooking up that box to the Corvette uprights.
Thanks for your helpful hints and pictures. I have a few specific questions.
Are you planning on doing wheel to wheel racing and if so, what class?
Why such a small a small fuel cell? It is possible to fit a bigger one if you had a custom made cell. I figure you need at least a 15 gallon cell for a SCCA regional race.
I saw pictures of another GTM with center seating. Would it be possible to remove the center frame structure and add extra door bars for strength. I would also build a rear bulkhead to tie the door bars together and give a platform to mount the roll bar on.
I quess your on the west coast, I would love to get a forst hand look at your build, but unfortunately I am in Alabama. Do you know anybody on the east coast building a GTM racer.
Keep me updated on your build. Good luck and thanks!
Here are some of the more race oriented threads that may be useful for a track car. Alot of this is hard to find through the search function. Once again, list off the top of my head, there is much more, please add.
Thanks for your helpful hints and pictures. I have a few specific questions.
Are you planning on doing wheel to wheel racing and if so, what class?
Why such a small a small fuel cell? It is possible to fit a bigger one if you had a custom made cell. I figure you need at least a 15 gallon cell for a SCCA regional race.
I saw pictures of another GTM with center seating. Would it be possible to remove the center frame structure and add extra door bars for strength. I would also build a rear bulkhead to tie the door bars together and give a platform to mount the roll bar on.
I quess your on the west coast, I would love to get a forst hand look at your build, but unfortunately I am in Alabama. Do you know anybody on the east coast building a GTM racer.
Keep me updated on your build. Good luck and thanks!
Great questions Joseph.
Planning on getting started with NASA. The GTM fits in Super Unlimited as well as STR1 and STR2 which are lb/hp based. There doesn't appear to be a whole bunch of participation in STR here but there are a few SU cars out regularly and I think the GTM will be very competative without a bunch of horsepower. The car may fit another class or two, it just has not been homologated into any other NASA or SCCA class.
Fuel. 10 gallons is all I could get up front without going to a custom fuel cell, but even then I used almost all the available space beween the steering rack, lower frame, footwells, tunnel and sway bar. A transfer pump sends the fuel back to a one gallon surge tank/swirl pot behind the driver for a total of 11 gal (nevermind the tank in the picture above, its an oil tank I ended up not using). I have aranged the orientation and the pickups of the tanks so nearly every drop of fuel is useable.
I gauged fuel burn rate off of the FFR PGD teams' endurance use of approximately 15 gal/hr. They had just over 400 rwhp in the car last year and I don't figure I'll have much more than that. I beleive most sprint races are under 30 minutes so I think I'll have a gallon or three left at the end of a race. Not ideal, but nearly everything on this car is some sort of compromise.
If I decide to go endurance racing, the passenger side can accomodate a massive fuel cell, It would just need to be sheeted in to seal off the cockpit.
Yes, the tunnel can be removed and two door bars on each side should take care of the torsional rigidity just fine. I moved the lower frame bars in almost 5", there was no way that seat was going to fit in without doing so. In the original position, my head was touching the side 'halo' bar. Moving the seat inboard also gives more headroom above which was essential for my relatively 'upright' seat. See link above on seats.
If you're ever out here, look me up. I learned a ton spending some time with the PDG team and they invited me to be part of the pit crew for the 25hrs of Thunderhill. Awesome experience, Thanks again Richard and Yvonne!
your car looks great. I am not sure a 10 gal cell will make through an entire race. I run in TTU and instruct for NASA and go through just about a gallon per lap at VIR with 400ish rwhp in a cobra style car. Time trial is only 3-4 laps. All the AI mustang guys have 15 gal. cells. I have a 12 gal. ATL. Even with the ATL black box my car sputters with less than 3 gallons left.
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your car looks great. I am not sure a 10 gal cell will make through an entire race. I run in TTU and instruct for NASA and go through just about a gallon per lap at VIR with 400ish rwhp in a cobra style car. Time trial is only 3-4 laps. All the AI mustang guys have 15 gal. cells. I have a 12 gal. ATL. Even with the ATL black box my car sputters with less than 3 gallons left.
Thanks for the good information Trevor, that helps.
I sifted through NASA and SCCA's websites and GCR/CCR's and there is little info on race length other than 'it can vary'. The best info I could find was looking at the race results. Most total race times for NASA and SCCA were in the 25-27 minute range. I'm guessing they generally drop the checkered flag for the lead car to cross the line after 25 minutes, although there were a few shorter races 20-24 minutes. I didn't see anything through the season over 27:xx minutes. I know there is staging and a warmup lap or two but these shouldn't eat up too much fuel with a relatively mild camshaft I would think. I've got room to add a small cell behind the driver if needed.
As for the sputtering with three gallons left, I was trying to avoid that with the one gallon surge tank. I modified my ATL pickup to get right down low in the lowest corner of the cell, it leans to starboard and aft slightly. Even when it starts sucking air it should should keep splashing into the surge tank for a while. I used a carter transfer pump wich is reported to be fairly durable running dry. The pressure pump from the surge tank is a Bosche '044'. Crash sells them here: Bosch 044 fuel pump
If you want to run the NASA National Championships, you'll need to account for a 45 minute race for fuel capacity planning purposes.
Also, it's very unlikely that with the weight the GTM will be in race trim, that 400-500 HP will make you competitive in Super Unlimited, at least at the national level.
Perhaps STR1 or 2 would be a better choice? Then you could build your engine for the amount of power- and crucially, put the torque curve where you need it- based on the target car weight.
another few mods I forgot to mention. caster adjustment modifiaction and bump steer. Gen 1 has neither and Gen 2 does not have bumpsteer capability fromthe factory
Also, it's very unlikely that with the weight the GTM will be in race trim, that 400-500 HP will make you competitive in Super Unlimited, at least at the national level.
What do you think a competitive HP level would be on the national level? I figure my car only will qualify for Super Unlimited. Just wondering what the field will look like.
It is not that unheard of to put 700-800 hp in a 2500 lb car. I have been building and running SCCA GT-1 and trans-am cars for on and off for 25 years. Right now the norm is an 800 hp SB2 in a 2500 lb car. It is not that difficult to build a 450 Cubic inch LS7 getting 700 to 800 Hp These engines are also very reliable since you only rev them to 6500 rpm. I assum the GTM has a pretty good rear weight bias (55%+) so it would help put down ther power. The extra frame would also add some extra weight. Full slicks would be a must. Traction control is your right foot.
I am attrached to the GTM becaue it is a rear engine car, very different from any thing I have built to date, and down right cool looking. My days of racing SCCA national are over, so for a regional level car in SPO or superunlimited, the car would be very competive. The GTM is the clear choice over the SL-C because of the full tube frame. I would not race an aluminum frame car. They would be very difficult to modify and even more difficult to repair.
What do you think a competitive HP level would be on the national level? I figure my car only will qualify for Super Unlimited. Just wondering what the field will look like.
John
This year the NASA SU National Championship weekend will have cars with anywhere from 200 to 1200 HP. Weights are from under 1000 lbs to a little over 3100.
Assuming your GTM will weigh in at a little over 2700 lbs wet, you'll need around 650-850 HP to be competitive with others around your weight, and to maintain a similar power-to-weight ratio to the top cars.
For example, a very fast Lister on the West coast runs less weight than the GTM is likely to be in race trim, and is reportedly running an 850 HP SBC, with a pro driver and lots of development.
The current national champion in SU (an SLC, BTW) won last year with about 620 HP and about 2650 lbs.
It would be great to see a GTM in SU. But bring plenty of power. IMO, it will be a steep climb for a GTM that is anywhere near stock, as substantial chassis, suspension and brake changes will be necessary to have a hope at a run at the sharp end of the field.
This year in Super Unlimited the entry list shows an ex-GrandAM Daytona Prototype, a Radical SR8, a Norma, the Lister, an SLC with a Ford LMP1 powerplant, a couple of very quick DSR cars, and an ex-IMSA 911 GT2. Think about that when planning the GTM build.
To bring everyone up to speed (including myself) here is the general description of the NASA classes being discussed here.
There are four Super Touring classes—Super Touring 1 (ST1), Super Touring 2(ST2), Super Touring R1 (STR1), and Super Touring R2 (STR2)—with STR1 and ST1 being the higher performance level classes of the four. Super Unlimited (SU) is an unrestricted class for any closed wheel/fendered vehicle that complies with the safety requirements in the NASA CCR. An “Adjusted” Weight/Power ratio (section 7.4), modified based on body type, transmission, drivetrain, tires, and overall weight, is used to equalize cars in each of the Super Touring classes, although there are some additional restrictions placed on all vehicles in Super Touring classes (sections 7.2 & 7.3). STR1 and STR2 are for closed wheel/fendered monocoque sports racers, tube-frame, tube-frame conversion, partial tube-frame, and other production and non-production four wheel vehicles.
Super Touring R1 (STR1) = “Adjusted” Wt/Hp Ratio equal to, or greater than, 5.50:1
Super Touring R2 (STR2) = “Adjusted” Wt/Hp Ratio equal to, or greater than, 8.70:1
The best I can tell with a 2600 lb competition weight, on DOT tires, with a manual transmission there is a 0.3 modification factor resulting in 5.8/9.0 lb/hp = 448/288 peak RWHP for the respective classes.
I seriously considered a an aluminum 5.3 or a turbo 3-rotor rotary and tune for as flat a HP curve I could and go for STR2. I ended up getting a good deal on a LS376/480 from a guy bailing out on a build and that sealed my decision. With long tube headers I think I should be solidly over 400 rwhp so yes, STR1 looks like a good place for me, just as 'Boost' suggests.
Here is the link to where you can download the latest NASA CCR and complete class rules:
As for competing at a national level, I'm far from that. This will be a hobby level sport for me. I love competition and the peace that comes from a clear mind while focused on the track and machine. I also really enjoy the quality of people in racing, that speak the same language, and are as obsessive as I am at striving to do it better.
I have been building and running SCCA GT-1 and trans-am cars for on and off for 25 years........The GTM is the clear choice....because of the full tube frame.
Joseph, I welcome your experience here and hope you find the GTM community as helpful as I have. This kit is fairly unrefined but I'm finding it much easier to make into a race car than fussing over fit and finish for a street car, but that's just me. I must admit I have alterior motives in assembling a collection of knowledge here- I want to see some more GTM's on the track!
If the GTM fits into your plans, I'm sure we can all benefit from your experience and hope you will continue to participate with us in the refining of this kit into a fine race car.
So, onward with some track mods. The front suspension mounts need altered (even on gen2) to get over -2.5 degrees camber and 3+ degrees caster together.
The bulk of this inprovement can be obtained by moving the front upper A-arm mounts- this was the first frame mod I tackled. I didn't like the horizontal plane tabs that you must slot to even get decent street alignment numbers. Even before slotting I had play in the bolt holes and figured any disassembly would end up in a different position once reassembled. I went with the Pfadt bushings and found a 7/16-20 thread fits nice and snug through their upper crosses, so I made these new upper mounts out of 1" x 3/4" bar and placed them 1/2" back from original and they pull the upper A-arm 1/4" inboard. There is more detail in the thread I linked to above about 'roll center'.
The rest of the improvement is easily achieved from another essential item for a track car- Crash's alignment shims (link above as well). They allow more adjustment than the cam bolts and, once again, provide complete repeatability.
Some others have done some beautiful work in this area, mine is a little cruder but it can probably be completed in a day once the materials are on hand:
It is not that unheard of to put 700-800 hp in a 2500 lb car. I have been building and running SCCA GT-1 and trans-am cars for on and off for 25 years. Right now the norm is an 800 hp SB2 in a 2500 lb car. It is not that difficult to build a 450 Cubic inch LS7 getting 700 to 800 Hp These engines are also very reliable since you only rev them to 6500 rpm. I assum the GTM has a pretty good rear weight bias (55%+) so it would help put down ther power. The extra frame would also add some extra weight. Full slicks would be a must. Traction control is your right foot.
I am attrached to the GTM becaue it is a rear engine car, very different from any thing I have built to date, and down right cool looking. My days of racing SCCA national are over, so for a regional level car in SPO or superunlimited, the car would be very competive. The GTM is the clear choice over the SL-C because of the full tube frame. I would not race an aluminum frame car. They would be very difficult to modify and even more difficult to repair.
Hey Joe,
I agree its pretty easy to get an LS7 up to 750/ 800hp . Its not easy to get a transaxle that will live at those power levels for long. An Emco will do it, but the jump in cost is very high. The Ricardo will do it, but that also has complications.
I decided to keep the motor down to 630 and use mendiola transaxle. The Mendiola is geared well and for the money I could have 2 or 3 transaxles in the trailer just in case when you compare the cost to the Emco or Ricardo. Of course the emco is in a different league but im not racing for money or on a national level.
I agree with you on the GTM vs SL-C. Aluminum is cool, but a steel tube frame that is easy to repair and modify as well as suspension parts and a corvette parts bin that can sourced anywhere in the country are a huge plus.
The PDG team have blazed the trail. Mark and I are both working on versions of a GTM race car. There are also threads on The Factory Five Forum . com (remove the spaces) on the the things we needed to do in order to build the GTM for NASA and SCCA.
I hope you decide to build a GTM for racing. The more guys building and sharing ideas the better all our cars will turn out.
To bring everyone up to speed (including myself) here is the general description of the NASA classes being discussed here.
There are four Super Touring classes—Super Touring 1 (ST1), Super Touring 2(ST2), Super Touring R1 (STR1), and Super Touring R2 (STR2)—with STR1 and ST1 being the higher performance level classes of the four. Super Unlimited (SU) is an unrestricted class for any closed wheel/fendered vehicle that complies with the safety requirements in the NASA CCR. An “Adjusted” Weight/Power ratio (section 7.4), modified based on body type, transmission, drivetrain, tires, and overall weight, is used to equalize cars in each of the Super Touring classes, although there are some additional restrictions placed on all vehicles in Super Touring classes (sections 7.2 & 7.3). STR1 and STR2 are for closed wheel/fendered monocoque sports racers, tube-frame, tube-frame conversion, partial tube-frame, and other production and non-production four wheel vehicles.
Super Touring R1 (STR1) = “Adjusted” Wt/Hp Ratio equal to, or greater than, 5.50:1
Super Touring R2 (STR2) = “Adjusted” Wt/Hp Ratio equal to, or greater than, 8.70:1
The best I can tell with a 2600 lb competition weight, on DOT tires, with a manual transmission there is a 0.3 modification factor resulting in 5.8/9.0 lb/hp = 448/288 peak RWHP for the respective classes.
I seriously considered a an aluminum 5.3 or a turbo 3-rotor rotary and tune for as flat a HP curve I could and go for STR2. I ended up getting a good deal on a LS376/480 from a guy bailing out on a build and that sealed my decision. With long tube headers I think I should be solidly over 400 rwhp so yes, STR1 looks like a good place for me, just as 'Boost' suggests.
Here is the link to where you can download the latest NASA CCR and complete class rules:
As for competing at a national level, I'm far from that. This will be a hobby level sport for me. I love competition and the peace that comes from a clear mind while focused on the track and machine. I also really enjoy the quality of people in racing, that speak the same language, and are as obsessive as I am at striving to do it better.
Mark
The "competition" weight for STR classes includes the driver. Assuming you weigh 200 lbs all kitted out with suit, shoes, helmet, HANS, etc., and you are planning for a 2600 lbs car as you mention, your car needs to be 2400 lbs wet. That weight seems very unlikely to me for a race-prepped GTM with the necessary chassis mods, adequate fuel cell, sway bars, heavier (than race) DOT tires, etc.
Also, assuming you'll want to use the max size tire, you'll have an additional penalty, and so need to account for that- which is an additional .3, if I recall the rules correctly.
I have attached a link to my lastest build. It is a 600 hp 71 camaro, front half tube frame, fiberglass body, and c-5 suspension and brakes, 18X 12 inch wide wheels all around.
I have no skin in the game, but if you are really looking to build a race car, you might try looking at Superlite cars. They are coming out with an aluminum tub version of the Cadillac LeMans race car. It will not be drivable on the street, but for racing it might be just the ticket. Also, it uses a Corvette transmission, which can be suitably modified to hold the kind of power you are contemplating, without completely breaking the bank as an EMCO would do.
been there, done that, got the T-shirt.
First I might add, the NASA nationals would be no place for the GTM. 1: it is not fast enough in many ways to compete against a NORMA, Radical, or any sports racers for that matter. I thought the winning SLC had a stock LS3 when competing last year?(525 hp). SPO in SCCA, at 381 HP PDG logged 14 podium finishes in 16 races against a range of cars from 381- 800+ HP. The PDG car focused on reliability and corner handling and not HP. HOWEVER, it is not a sprint race car. It is designed and built for endurance racing. It gets about 7.8 to 8.5 miles to the gallon. Let's not forget it runs on DOT tires and Stock C5 rims and stock C5 brakes. Nothing fancy here. Safety concerns at the time of construction, prompted us to move the driver to the center of the car. This car carries 44 gallons of well balanced fuel. This car has been racing competitively for 5 years now.
The "competition" weight for STR classes includes the driver. Assuming you weigh 200 lbs all kitted out with suit, shoes, helmet, HANS, etc., and you are planning for a 2600 lbs car as you mention, your car needs to be 2400 lbs wet. That weight seems very unlikely to me for a race-prepped GTM with the necessary chassis mods, adequate fuel cell, sway bars, heavier (than race) DOT tires, etc.
Also, assuming you'll want to use the max size tire, you'll have an additional penalty, and so need to account for that- which is an additional .3, if I recall the rules correctly.
Good points Boost. There is no penalty for DOT tires though, if I'm reading the rules correctly. In fact, if you wanted to, you get some back if you run 275 or smaller DOT tires.
I've had an eye on weight from the start of the build and netted only 22 more feet of tubing to bring the cage within the rules. I'll add seven more feet for an X in the roof, so 29 feet at 1.8 lb/ft = +52 lbs. The dry sump system will be adding an estimated 30 lb. Fire ex and other safety equipment will add a little more. Ted's front sway bar adds 8 lbs.
A bit of weight will be saved in other areas though:
No side windows, actuators, dooor frames, door panels - 35 lb
Lexan pin-on rear window, eliminates hinges and brackets -~20 lb
No e-brakes
Replaced steering column with straight shaft and QR -10 lb
My 930 transaxle is only 120 lb wet with clutch and slave. -~30lb
Custom motor mounts ~ 5 lb
Aluminum toe links
Carbon Kevlar seat
Etc.........
I've been trimming and smoothing parts all over the car too. It's an obsession.
Richard has proven you don't need giant (heavy) brakes so I am going with the C5 front calipers all around on Z51 caliper brackets. The Z51 rotors are 1/2" bigger than the base C5/C6 rotors (12.9" vs 13.4") and will get me started without 'braking' the bank. The brackets are about $50 each and the rotors cost the same so this is a no-brainer upgrade. They may not fit 17" front rims though.
2400 lbs, I think I can make it under that. We'll see.
Mark, I hope you can make it for the 25 this year.....IT WILL BE A HISTORIC MOMENT IN KIT CAR AND FACTORY FIVE HISTORY and road race history in itself! I will only give you a hint of drivers for this year
initials: MH, DR. EF ZA. (more to come later) WE will be a featured car exhibit at SEMA this year on the main floor for BAJADESIGN/(FACTORYFIVE as well),
Joseph: WE opted to sit out this year on the WERC and completely rebuilt the car. A few of the upgrades as the 25 is drawing more and more pro teams. We are still a low budget team but remain innovative and competitive at the same time. Here are a few of 2012 25 hour upgrades: air jacks, traction control, electronic shift management, sway bar development, suspension development, new shock development package(testing this week), new light system including tail, head, driving, new wing development(less drag, more downforce) different engine set up.
Our nest test session is with our new driver this year Sept 22-23 at Thunderhill. It is a Hooked on Driving event and all are more than welcome to come and help out and be a part of history in the making!
Richard you bet I'll be there, glad to participate in any way I can. I wouldn't miss a chance to part of history! That's quite a list of upgrades, I've got to get over to see you soon and check it out.
I've got some good news for those that are looking to comply with SCCA rules.
SCCA GCR 9.4.2.a states:
Main hoops shall incorporate a diagonal brace. The brace
shall either be in the plane of the main hoop, or extend
from the top of one rear brace (described in 9.4.B.2.c) to
the bottom of the opposite rear brace.
9.4.2.c
Cars must have 2 braces extending to the rear from the
main hoop and attaching to the frame or chassis. Braces
must be attached as near as possible to the top of the
main hoop (not more than 6 inches below the top), and at
an included angle of at least 30 degrees.
I dismissed this detail before because I was looking for a solution to comply with both NASA and SCCA (NASA diagonal must be in the plane of the main hoop). I further dismissed this rear brace diagonal allowance because at original engine height, the intake manifold slighly interferes with a diagonal in the plane of the rear braces.
Late last week I was measuring for dry sump pump clearance and removed my motor mounts and set my engine down on the front crossmember, lowering it an inch. Driving home today this just hit me, I got back to my shop and tried to fit a diagonal and it now clears the manifold perfectly between the fuel rail and throttle body. More good news from the GCR as well, it can be removeable.
BTW, that >30 degree included angle I got some clarification on, it's the angle between the plane of the main hoop and the plane of the rear braces. At less than 30 degrees, they don't help the main hoop stand up too well.
If I'm interpreting these rules correctly, this may greatly simplify SCCA compliance while retaining the FFR main hoop and rear braces. To summarize:
Dry sump your engine and lower it 1-3". Add a diagonal to the rear braces (about 44" of 1.5" .120 wall seamless tubing)
A horizontal harness bar needs to be added (can be removeable as well) but doesn't need to be in the plane of the main hoop so it can come forward from the main hoop into the cockpit, accross, and back to the main hoop. (~5 ft)
The FFR forward down tubes terminate at the dash bar but need to continue down to the frame. Two bars can be added to drop from the forward down down tubes to the frame. (~4 ft)
Two door bars on each side. The FFR square bar can be replaced with round for one of them as it is close to a legal configuration, just needs to tie into the front hoop possibly with a short jumper. (~16 ft)
This should take care of the legalities with about 30 feet of tubing but....
The main hoop is below helmet level and I don't feel this is safe. The GCR has a few references to helmet clearances with repect to the cage but each of these paragraphs opens with "on open cars...."
It does state this though:
"On all closed cars, the main hoop must be as close as
possible to the roof and “B” pillars."
The FFR main hoop does seem to meet this criteria, but the roof is sloping downward fairly steeply behind your head. I would highly recommend some sort of diagonal or X-brace following the roof as high as possible.
This is where I should attach some sort disclaimer. This is my interpretation of the rules. If you are heading down this path, download and study the latest GCR from here: The Sports Car Club of America - Club Racing
It is also advisable to seek out a scrutineer for advice and guidance. I have heard stories of some having their own interpretations of the GCR and some having additional 'unwritten' rules in their heads. I have no experience with SCCA, mostly NHRA and I have done very well by being fairly familiar with the written rules and having the latest copy of them with me at tech. I have passed tech quite a few times even though a tech was picking on something. I just very nicely tell them I'm a little confused because I don't remember understanding it that way from the rulebook. Can you show me here? More often than not they let you slide because the written word is vague and open to interpretation. Results may vary.
If you find something wrong with this info, please post and lets get it right! I've been doing my homework but it's not graded yet.
SCCA is very strict to their written rules. If it is not written, you can't do it. PERIOD. I went around and around over a window net in the GTM. the state having a roof requires a window net for arm protection...UH the GTTM is center seat and the driver can't possibly have his arms out the window. My argument was also that it compromised fire egress having to do four separate functions to get out. They didn't care it was not in the book that way and had to put a window net on the car. Which side you say? We tried to convince them it was English and wanted to put it on the least compromising side. NO it had to be on the drivers side. So there you go.
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