When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have just recently gotten my 82 Pr-7 car sorted and on the track and I'm going to start racing with gusto next year! In the meantime I've been (obsessively) thinking over what I want my next project to be. Since it'll take several years to build up both a faster car and the skill to drive it (not to mention the money I'll need!) I've decided that I'd like to build a tube frame FC! Because of that I've been searching doggedly for any info I can find on Mazda's 1990-1991 IMSA GTO RX7. I have plenty of pics of the car in the paddock with bodywork off, and some screenshots from taped IMSA races from the 90s found on youtube and that sort of stuff, hell I even know a guy who worked on the 89 Roush team with Pete Halsmer and if I ask him nicely he'll go talk to Pete about the car for me, but I can't find any info or pics or blueprints of the frame! Does anyone have any info on it? Anyone have any blueprints or pics of knowledge that I could have? All I really know is its a bespoke tube frame designed by Lee Dykstra.
All that begging aside, if anyone has any tube frame pics or knowledge they'd be willing to share for either an FB or FC specifically, or about tube frames in general please chime in! I'm just resuming school for my engineering degree and I find it all fascinating! Also I hope to one day build a fast racer too
you might see if you can find any blueprint from any car Lee Dykstra built, its probably somewhat similar.
having seen the car in person a bunch, i can tell you the only stock parts are the roof panel and taillights.
you might see if you can find any blueprint from any car Lee Dykstra built, its probably somewhat similar.
having seen the car in person a bunch, i can tell you the only stock parts are the roof panel and taillights.
You have a point with that: the designer's hallmark are probably in his other work as well. I'll have to see if I can find any blueprint for engineering drawings of his and see how he designs his frames. I've seen it at Laguna Seca every year I've gone! Just like the Dekon Monzas and Greenwood Corvettes the only stock body parts are the roofs and tail lights!
Originally Posted by gracer7-rx7
Dude… after you start taking hits of the racing crack pipe next season, you’ll forget about building and just want to skip to the racing.
GT classes are usually tube frame cars but they are often $50-100k builds.
Theres a decent tube frame build in the first gen section as a starter
Oh I've been around racing for most oof my life and I'm already completely hooked; a total track junkie! My uncle races vintage trans-am and IMSA AAGT with SVRA and HMSA. Most years I work the Monterey reunion weekend, which is why ice seen the Mazda GTO RX& and GTU MX6 more times than I can count, but I'm always working the races so I seldom get to actually look at them closely!! Tube frame cars are dan expensive, but I'll do all the work after I clock out at the shop where we maintain my uncle's IMSA monsters and have the family help me with the making of the bespoke body and getting the tubing cut and tack welded together for the frame, cage and other needed crap. Hell the project may take me a decade, but I've decided its gone happen, so its gonna happen!!
I can't wait to get racing properly, but I don't want to take the Pro-7 car to full tube frame. That car may get Group C or IMSA GTU bodywork and some small suspension upgrades, but I plan on keeping it 12a powered and low stress. I may have lofty aspirations here, but I'm totally committed to this silly idea.
I'll check out the 1st gen section for that tube frame build tonight after work.
Does anyone know if the current owners of any IMSA GT series chassis is active on the forums? I know there was a GTU 1st gen for sale years back in SD by me, and I know the Team Highball RCX7 was for sale a while ago too.
Well I'll definitely have to look at that! The only problem is that I'm in SoCal but the library is in NY
I guess I'll have to email the library and see if I can access the blueprints or designs online or be sent a copy.
Well I'll definitely have to look at that! The only problem is that I'm in SoCal but the library is in NY
I guess I'll have to email the library and see if I can access the blueprints or designs online or be sent a copy.
or just ask Mazda if you can look at the car and bring your tape measure
also, fyi, there's a decent discussion in the GT3 group on FB about tube frame 'blueprints'. The context of the discussion is that the participation trends have been decreasing due to the expense of fab'ing a new chassis and people just aren't racing them as frequently as other classes presumably due to cost.
Judging by what I see turn up at regional races, the lower cost race cars are raced far more frequently and in greater numbers.
also, fyi, there's a decent discussion in the GT3 group on FB about tube frame 'blueprints'. The context of the discussion is that the participation trends have been decreasing due to the expense of fab'ing a new chassis and people just aren't racing them as frequently as other classes presumably due to cost.
Judging by what I see turn up at regional races, the lower cost race cars are raced far more frequently and in greater numbers.
it seems like the trend is just to get track time, more than competing. some of my friends and i ran Lemons this year, and its a ton of track time, but its not a race, nobody wins...
or just ask Mazda if you can look at the car and bring your tape measure
Well I wish it were that easy! I don't believe it's so simple as driving up to Irvine and knocking on Mazda's door. I'm not aware whether or not random, non-press-associated laypeople are allowed to just wander into the Heritage Collection and crawl all over the priceless historic race cars. But that's an email I'm going to send right after I email the library and see if they have any of Dykstra's RX7 notes or blueprints!
Originally Posted by j9fd3s
it seems like the trend is just to get track time, more than competing. some of my friends and i ran Lemons this year, and its a ton of track time, but its not a race, nobody wins...
"nobody wins..." that's so funny because its true! You guys have both summed it up pretty well amongst your replies. My 82 racer won't be getting more than either E-prod or vintage ATCC Group C modifications, which are just upgrades to systems built on the unibody tub. That's the kind of car I want to race with in SCCA or NASA or VARA myself and with my dad and car friends in Chumpcar or Lucky Dog type races. A tube frame car is my next project and one I'd like to move onto when the time comes as I become both a better driver and fabricator. I'm gonna need years to build the skill to drive a tube frame racer, let alone the skill too build and money too fund one! I'm extremely passionate about researching these old racers so I'm trying together this project started in any way I can
Hmmm "nobody wins"... A good day at the track with good friends is always a win in my book
You might be surprised by how much time, effort, learning is required to run up front in these competitive classes. It can get pretty intense. At least in Spec Miata.
Hmmm "nobody wins"... A good day at the track with good friends is always a win in my book
oh for sure
You might be surprised by how much time, effort, learning is required to run up front in these competitive classes. It can get pretty intense. At least in Spec Miata.
so two things, Spec Miata is racing, there is a winner, and a championship, and if you win that (and you're good at the PR stuff) you can move up.
second i have a couple of friends who have built front running Lemons cars (our Rx7 https://www.rx7club.com/build-thread...s-car-1150848/ needs better drivers, come drive it), and the work it takes to have a front running Lemons car is on par with a cheater Spec Miata. not only do you need to find a 77 fairmont, but you need to swap a 5.0 mustang under it, for $500 and then come up with costumes
Edit, its just like the GTO Rx7, because um they both raced at Sears Point? sorry about the off topic stuff....
Hmmm "nobody wins"... A good day at the track with good friends is always a win in my book
You might be surprised by how much time, effort, learning is required to run up front in these competitive classes. It can get pretty intense. At least in Spec Miata.
I've heard tell that it really is time and expense intensive. If it's anything like the historic racers who want to be at the front then I understand the huge delta between being ok running mid-pack Vs. at the front! I'm in my mid-20s and just getting started so I'm planning on having at least 30, if not 40 more years to hone my skills so I'm not dissuaded! I do understand it will be a quite long term project, potentially spanning decades.
Originally Posted by j9fd3s;12499190
so two things, Spec Miata is racing, there is a winner, and a championship, and if you win that (and you're good at the PR stuff) you can move up.
second i have a couple of friends who have built front running Lemons cars (our Rx7 [url
https://www.rx7club.com/build-threads-293/lemons-car-1150848/[/url] needs better drivers, come drive it), and the work it takes to have a front running Lemons car is on par with a cheater Spec Miata. not only do you need to find a 77 fairmont, but you need to swap a 5.0 mustang under it, for $500 and then come up with costumes
Edit, its just like the GTO Rx7, because um they both raced at Sears Point? sorry about the off topic stuff....
An RX7 needs driving? I'll grab my gear sign me up! My plans for my current race car are to get it racing in ITA or similar and move that car up to E-prod maybe, but LeMons or Lucky Dog for the seat time and team fun are definitely in the cards! Getting to race regularly in any SCCA class for points is something I can't wait todo but I'm not quite there yet
i'm probably being too pessimistic about Lemons, if you wanted to work on your racecraft or just get lots of seat time in a car or track its probably great. with 150 cars on track, you have way more traffic to manage
I've been told by Carl and Michael that Lucky Dog is actually a really good way to get a lot of seat time per weekend given that they're endurance races. I've heard that Lemons is less serious about the racing, but that it's still a fun time if you get a good team together. Frankly I'm just looking forward to getting on track as much and I can! I understand its definitely a good stepping stone, and I hope one day tp be able to move up to being able to build and race a gnarly tube frame race car.
@j9fd3s We need to meet next season. I have probably walked by you multiple times at events over the last 10 years...
I'm not the biggest fan of LeMons. I've attended a few where friends were racing and needed someone to drink their beer but I've only raced one leMons event 12 years ago.
@IMSAaspirations LD and Champ are definitely more racing oriented that LeMons. Better quality of drivers and cars usually in attendance.
The tube frame build that gracer7-rx7 referred to may be mine : Tube Frame SA turbo 13B autoX/track car. There is a complete log on the LocostUSA forum in the non-traditional build log section. Since the Lotus 7 clones are all tube frame, it's a good source for the design and construction of any tube frame you can dream up.
For several decades I was involved in the design/construction and maintenance of multiple GT2 and GT3 RX7s running on the west coast from Laguna Seca to Seattle Raceway. I'd be happy to provide my two-cents on any tube frame questions that you have. The SA RX7 when it reached roller status. The first of the FD GT2 cars we fielded. Hanging the body.
Super sick Build there.
I raced at buttonwillow last weekend and blew my trans, which turned out to not be such a bad experience. Sevens Only is based at the track so I got to meet Tom the owner who has heeps of knowledge with NA Tube chassis cars. I may look into something like this vs tracking my FD. I think it will save me money in the long run lol.
I think it would be interesting to compare the construction of the 91 Mazda GTO car to the stuff being built and raced now. State of the art in the 90s may not be as good as the stuff being raced now. The level of effort to build a car like this would be the same no matter how it is built. So why build an obsolete car?
As far as GT3 (and GTL) are concerned, what the class needs are racers driving the cars that already exist. Both of these classes received a veiled warning from the SCCA regarding future Runoffs participation. They are included in the 2022 event at VIR but participation numbers need to improve if that is to continue. Currently GT3 is a rotary racers paradise with some interesting engine options in the rule book. Check out the race from Indy this year (it is on Youtube) Rx7s of all generations are represented. If is a spendy class but the cars are REALLY fast. I have first hand knowledge of this because my class shared qualification sessions with them at Indy.
If a person really wants a tube frame car, a GTL build could be very wallet friendly. The SIR (Single Inlet Restrictor) for 12A and 13B engines is so small that guys aren't spinning their rotaries much past 7500RPM. So an engine could last 5-7yrs! With the right chassis and transmission a GTL car would be a really cost effective way to go national racing. Also, the GTL community on FB is really supportive because the elders in the class get it - building participation is key. If I was starting over, younger and wanted to race a tube frame car in the SCCA; GTL is where I would be looking.
Last edited by mustanghammer; 12-27-21 at 10:02 AM.
I agree with what Scott just said about the " state of the art in the 90's". All race car classes are subject to the rules published by the sanctioning body. SCCA Club, SCCA Pro and IMSA rules dictated some specific suspension designs that evolved, sometimes driven by "cost saving" logic. Specifically, rear suspension could only be live axle with 3-link trailing arms. The freedom to design your car with current concepts/parts would be very desirable.
Here are some shots of a tube frame car in our shop. It is a pro-built chassis that has had some success in GTL/3 in the past. Front suspension is double A-arm coil over and the rear is a triangulated 3 link coil over. Fully clothed, it is a Nissan Sentra. I keep trying to talk him into a rotary with a Protege' body but he likes hand grenade piston engines.
Last edited by mustanghammer; 12-31-21 at 10:49 AM.
I really don’t have anything to add but am enjoying following this thread. I also follow the GTL, GT3 & Prod FB pages. Some good humor but also lots of info and sharing. Keeps me motivated.
Scott, wouldn’t mind a JPM-esque shop tour. Just sayin’.
Theres a decent tube frame build in the first gen section as a starter
Originally Posted by gracer7-rx7
also, fyi, there's a decent discussion in the GT3 group on FB about tube frame 'blueprints'. The context of the discussion is that the participation trends have been decreasing due to the expense of fab'ing a new chassis and people just aren't racing them as frequently as other classes presumably due to cost.
Judging by what I see turn up at regional races, the lower cost race cars are raced far more frequently and in greater numbers.
These both may be me; actually poking away at the "cost contained design" this weekend, got a pretty fair idea how I want to structure things. Oh wait Mustanghammer linked my thread. I need to post some updates, but long story short some parenting stuff has been taking time. I'm not too active around here anymore but not dead, and not stopping!
So OK. Let's me kinda more specific... first off the GTO FC relied on a lot of custom parts. Diff housing is custom castings with Hewland internals, gearbox is custom casting with Hewland parts, suspension uprights are fabricated weldments, etc. Almost nothing off the shelf; the chassis is kind of the easy part. Having priced out stuff like centerlock spindles... there's just a whole pile of custom parts where if you add up the costs either you need a huge variety of tools and expertise or you need to spend a lot of money. Plus a 13J, which don't exactly grow on trees. The chassis is just tubing; triangulated tube structures were figured out in aircraft in the 30s or so; people since have done things right or not within various constraints (deciding how much stiffness you're willing to pay for in weight) since then. Lee Dykstra did it right but you don't have the resources he had to get stuff made so it'd be folly to copy him.
Figure out what you actually want and where you'd race it. For example, if you made a 4 rotor fully independent suspension tube car... where would you race it? How will you afford consumables? How do you afford to fix things that break?
I'm more than happy to provide guidance and stuff, just, do you want to dream or do you want to figure out how to build something that can be raced?
12-21-21, 09:32 AM
I'm extremely passionate about researching these old racers so I'm trying together this project started in any way I can
