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E Production SCCA Runoffs Build
Been a member of this club for a while now but I think this is just my second new thread. I have never owned a street legal RX7 but have raced/tracked First-gens for about 17 years. I have used this site as a source for parts and a great resource for info on all things rx7. I have been lucky enough to know J9fd3s, Fungus Mungus and have solicited and received immeasurable assistance from mustanghammer thru this site. I have gain a lot of knowledge from those of you who contribute regularly and figure its about time I post something. I’m not really expecting viewers to learn anything really new, but you at least you see another ground up race car build. Two first-gen builds really motivated me to start my project. First, Scott Peterson’s(mustanghammer) extensive SCCA STU build that have probably inspired many of you who might be reading this. I straight-up copied Scott on many components of his build or used a variation of his details or some of the other cars that were in the shop he shares. The other inspiration is Jesse Prather’s immaculate E Production FB. He doesn’t have a build thread here but posted pictures on his Facebook site. My previous car is a 1984 GSL that I built and raced for years in NASA’s popular Pro7 series in NorCal. When the numbers dwindled, they dropped the class and I upgraded the car to SCCA ITA rules with crossover to the NASA PTE class. I did quite well with that car for years. But the Miatas evolved and became faster and my chassis started sowing its age and injuries from many track contacts. My enthusiasm dwindled for racing this car as I couldn’t get it to pace it once had. In the mean time, I picked up a 99 NB miata for my sons to run in HPDE. I started tracking that car myself in NASA time trials while I tried to figure how I would deal with my racing habit. I was considering building the Miata to SM or STL spec’s. But I really liked having a street legal car that could be driven to the track. I considered ChumpCar or Lucky Dog racing with my blue FB but kinda wanted to keep that car ITA legal and didn’t see that as working well in those series. And then there was this 1980 SA chassis that had been buried in my shop for years. About 8 or 9 years ago, I was looking for parts for my brother’s pro7 car and came across an ad posted by a member here (wolfpkn) on the NASA forum. Eric and his other brother Erik had started an EP build but gave up for one reason or another and instead built a second gen PTD car. They sold off parts to their build and by the time I ran into the ad, all that was left was the caged chassis with a very rough Mariah wide body kit. They listed this for $500 and for no real reason other than I thought it was a good deal, I bought it. I stripped the chassis and built the cage on my blue car and know how much work that is. A year ago or so, I ran into the videos from the 2017 SCCA Runoffs at Indy. Mustanghammer had wrote inspirational posts of his journey and experiences from his efforts to participate in this event. I watched all the Production and GT races as well as the SM race. As the rotary cars pretty much only run in EP and GT3, that is what I watched first. The EP race had a crap load of first gens, a few FC’s and Aaron Downey’s rocket RX3. Here is a link: https://www.scca.com/videos/2033593. At least three first-gen rx7s in the top 10 of the largest Runoffs in history left an impression. Watching the 2017 SCCA video of the EP race showed me that there is a class where the first-gen Rx7 can still be competitive. Somewhere in one of the broadcasts, they reported that the 2018 Runoffs would move to the west coast to one of my home tracks, Sonoma Raceway(I still refer to it as Sears Point). This info plus watching Jesse Prather, John Mueller and more being racey at such an event got the racing itch re-started. I started to seriously think about the dusty chassis that has been taking up space in my warehouse. Here’s the that chassis buried in my warehouse for 8+ years. https://cimg4.ibsrv.net/gimg/www.rx7...dd8561887.jpeg https://cimg9.ibsrv.net/gimg/www.rx7...2881fad4e.jpeg |
About mid February last year I had enough equipment out of the way to roll out the car. It’s an 1980 SA without sunroof. I went thru all my spares to get suspension and wheels on so I could get it on a trailer and bring it home. https://cimg5.ibsrv.net/gimg/www.rx7...a39b3b4ee.jpeg Basically good starting point but missing lots of bits. https://cimg9.ibsrv.net/gimg/www.rx7...6278a0192.jpeg Been so long since I had looked up close to this car I kind of forgot what I was working with. |
https://cimg6.ibsrv.net/gimg/www.rx7...a715f06f1.jpeg Car looks jacked up on stock suspension and no weight https://cimg7.ibsrv.net/gimg/www.rx7...332fb21ed.jpeg There was no way I would’ve gotten anything done I’d I tres to work on this car at my shop like I did with my other first gen. Needed to get suspension and wheels on so I could trailer it home. |
Got the car home and strip everything off. There was a lot of surface rust as previous owners must have left it outside. Required a lot of wire wheel and hand sanding. I built a 4 wheel cart that can be broken down. Garage not that big but could spin 360 degrees. Height was also adjustable. It really worked out great. https://cimg0.ibsrv.net/gimg/www.rx7...3a8480d0f.jpeg I decided to focus on the rear first. Cut out the rear well. Wasn’t positive yet about whether I was going to have the fuel cell removable from above and cut out more of the rear deck. I tapered back the the rear latch brackets in case I went that route. https://cimg2.ibsrv.net/gimg/www.rx7...6b8818c27.jpeg Fuel cell needed to be a min.6” above the ground. Was trying to get all of the cell and protective cage below the rear deck, if possible. Most of the other first gens seemed to have sheet metal enclosures above the deck. Not sure if for larger fuel cells. I purchased a 12 gal ATL aluminum unit which is pretty small. However did not know my ride height was without any suspension bits in place. Ultimately had to guesstimate. Pic below, I am trying to find out how low the bottom of cell will be with just minimal clearance for hose fittings. I had just installed the panhard rod mount and brace. https://cimg4.ibsrv.net/gimg/www.rx7...76f412416.jpeg Proppimg up the beginnings of the fuel cell cage trying to figure how to mount, but also so it is easy to remove. The cage is made out of 1” sq tubing and front side mounts on a 1.25” steel angle welded just behind panhard brace. Back side bar rests on removable angle bars. Thought I had a pic of the assembly outside of the car but could not find one. Straps are holding the rear axle at my best guess of static car ride height. The upper bars are just squeezed in there. They were spread apart to fit the cell. https://cimg8.ibsrv.net/gimg/www.rx7...417ee5032.jpeg |
Good luck on the build! I honestly think it can be a pretty competitive car in EProd - I'd be working on one too except I'm tired of messing with unibodies.
You will need a suspension package to run at the front at the Runoffs - Aaron Downey is using stuff from JRI, I know some others are on Dynamic shocks, etc. My impulse was to try to work something out with Feal suspension and basically adapt AE86 struts to our knuckles. I meant to write a letter to find out if it's legal to switch to alternate bolt patterns as 4x100 has some great inexpensive 15x7 wheel options, while 4x4.5 or 4x110 in 15x7 means custom wheels for good lightweight stuff. What're you planning for driveline option? In 2019 I wouldn't build anything other than a Weber fed 13B unless you have a pile of good 12A parts. I was thinking hard about an RX-8 trans with 1st ground down and a Paco Motorsports 5.38:1 ring and pinion as that should get 5 usable track gears but there's a lot of options. Just, most of them are really expensive. |
Cool Beans! I have been waiting to see the details of this build. This will be a great story to follow. Thanks for the kind words.
And yeah at Indy in 2017 you couldn't swing a dead cat without hitting a 1st gen RX7 in the paddock area around the Mazda tent. |
Originally Posted by mustanghammer
(Post 12325712)
Cool Beans! I have been waiting to see the details of this build. This will be a great story to follow. Thanks for the kind words.
And yeah at Indy in 2017 you couldn't swing a dead cat without hitting a 1st gen RX7 in the paddock area around the Mazda tent. |
Originally Posted by Kenku
(Post 12325651)
Good luck on the build! I honestly think it can be a pretty competitive car in EProd - I'd be working on one too except I'm tired of messing with unibodies.
You will need a suspension package to run at the front at the Runoffs - Aaron Downey is using stuff from JRI, I know some others are on Dynamic shocks, etc. My impulse was to try to work something out with Feal suspension and basically adapt AE86 struts to our knuckles. I meant to write a letter to find out if it's legal to switch to alternate bolt patterns as 4x100 has some great inexpensive 15x7 wheel options, while 4x4.5 or 4x110 in 15x7 means custom wheels for good lightweight stuff. What're you planning for driveline option? In 2019 I wouldn't build anything other than a Weber fed 13B unless you have a pile of good 12A parts. I was thinking hard about an RX-8 trans with 1st ground down and a Paco Motorsports 5.38:1 ring and pinion as that should get 5 usable track gears but there's a lot of options. Just, most of them are really expensive. |
I stripped down the rear axle and removed all the weldments that weren’t necessary. Extended down the lower arm link and added he panhard mount. Straight up copied mustanghammer’s axle design but with the steel stock I had around. This is a big bearing GSL axle, not a GSL-SE. I think the are the same but I am using GSL axles, rotors and brakes. Cuz it’s what I had and I want crossover of parts btwn my ITA car. https://cimg2.ibsrv.net/gimg/www.rx7...8891580c1.jpeg The factory spring perches are still present in the photo above. I originally planned on ordering adjustable sleeves that floated on top of the spring. Could not find any that fit over the tapered cone at the chassis mount. I ended up cutting out the stock axle perches and welding on threaded sleeve with adjustable collar in its place. For various reasons, I decided to stay with a four link rear suspension instead of the more common three- link. I liked the setup that mustanghammer pictured on his build thread of another eprod car that was in his shop. Literally copied as best as I could what was in those pic’s. See mustanghammer’s thread: https://www.rx7club.com/build-thread...-build-992966/ post #13. https://cimg8.ibsrv.net/gimg/www.rx7...d00d9bb71.jpeg https://cimg0.ibsrv.net/gimg/www.rx7...8b69e4ade.jpeg I ordered tie-rods and rod-ends from Summit racing. I used 1/2” rod ends at my the new mounting points and 5/8” for where I was using the existing mounts. At the axle upper mount I drilled out the 14mm hole to 5/8”. At the lower arm mount at the chassis, due to time constraints, I used the factory hardware but used strips from an aluminum can. I wrap the strip until it was a snug fit. Worked great but ultimately will have a sleeve milled. The tie-rods are not equal length but way better than factory. https://cimg3.ibsrv.net/gimg/www.rx7...144bf87fb.jpeg |
Here’s a closer shot of axle. Lower control arm mounts were lowered but kept stock shock and upper mounts. https://cimg9.ibsrv.net/gimg/www.rx7...d780f07da.jpeg i am using double adjustable Koni rear shocks and I can just reach the adjustment knob. |
For the front suspension, I was going to copy mustanghammer’s set-up. After some PM’s with Scott, he sold me on getting the Techno Toy Tuning kit. I did get one custom addition, again at Scott’s recommendation, I ordered them with double adjustable Koni inserts. This kit, though pricey, is very well made and incredibly adjustable. I am so glad I went this route. Spring rate is 450#. I felt this would be pretty neutral for starters. Out of the box: https://cimg2.ibsrv.net/gimg/www.rx7...743f8df01.jpeg Here’s the suspension installed. Those are GSL discs with adapters to fit my spare set of miata wheels. I wasn’t sure what wheel off-set I was going to use so I used those wheels and adapters for most of the build. Figured I may use them on my other car if I go ChumpCar racing. I also eventually ordered the KC Raceware front hub and disc kit once I sourced some SE calipers and mounts. That’s a spare Pro7 sway bar. https://cimg0.ibsrv.net/gimg/www.rx7...f7009e1f6.jpeg |
Running 12A rear brakes is pretty normal with the lack of availability of the GSL-SE parts. Redrilling the axles and rotors isn't that hard.
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Kenko, you’re not kidding about SE parts. I ultimately kept the stock calipers and bolt pattern. Mainly because it was because it is what I had, I have more spares, I wanted crossover parts between both my cars and didn’t think it was the weak link. Also, as I will descriibe later, I didn’t have a lot of time. |
Kurt, i'm glad you're finally building this thing!
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Originally Posted by j9fd3s
(Post 12325963)
Kurt, i'm glad you're finally building this thing!
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Once the suspension and fuel cell fab was done, my focus was to work on anything that needed to be done before the car was sent to paint. My plan was to send the car on the cart so could be painted inside and out, at the same time, one color. Seat mount and tie-back were next on the list. As this was a “budget” build, I decided to reuse a spare Kirkey seat I had. https://cimg1.ibsrv.net/gimg/www.rx7...151c3eb46.jpeg We are all jealous of mustanghammer’s work space but you can still get things done at home. Here’s my welding table. Costco folding table and some scrap plywood shelves. Stitch welding the front cross member https://cimg4.ibsrv.net/gimg/www.rx7...d2c1bb74a.jpeg Then began the long process of prepping for paint. Not that it should take long but there was quite a bit of work to do. Gut the doors down to almost nothing and fill holes from mirrors, key lock etc plus minor bodywork. The Mariah Mode 1 kit that came with the car was very rough with cracks, dings and a previous paint that was bubbled like acne all over it. Spent way to much early time on this prep that it cost me. https://cimg3.ibsrv.net/gimg/www.rx7...5219c9675.jpeg Freshly installed front tow hook https://cimg4.ibsrv.net/gimg/www.rx7...28317ba20.jpeg If you look close you can see all pitted paint on the fiberglass nose. |
Great work so far, I'm looking forward to how it turns out.
Originally Posted by kurtf
(Post 12325516)
The EP race had a crap load of first gens, a few FC’s and Aaron Downey’s rocket RX3.
Originally Posted by Kenku
(Post 12325651)
In 2019 I wouldn't build anything other than a Weber fed 13B unless you have a pile of good 12A parts.
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Originally Posted by chuyler1
(Post 12326220)
As the Downeys have shown, you can still make good power with the 12a and you don't have the weight penalty. Their motor in a 1st gen Rx7 would have been up at the front. However, you need some good housings to start with which are not easy to come by. 13B is certainly the more economical approach these days.
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I didn't want to say it, but I'm pretty sure that's what all the top teams are doing now, and it's working to their advantage because of the exhaust port size and spark plug placement.
As for rotors, they are easier to salvage off junk motors than the housings. I don't know, I just like the 12a. |
I reached a point where I ran out of good rotors... I might be able to fix some of them but I'm going GT-3 instead.
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Spent some time with Aaron’s dad at the track. He said if they were to build another car they would go first gen. I thought I had more pic’s but there is a bit missing. Below are photo’s sent to me from the paint shop https://cimg1.ibsrv.net/gimg/www.rx7...912defac6.jpeg https://cimg2.ibsrv.net/gimg/www.rx7...97f6cefb8.jpeg It was quite a relief to get it painted finally. It had been pretty rough looking for so long. Getting it back was a little nerve wracking. https://cimg2.ibsrv.net/gimg/www.rx7...a0c3cf420.jpeg Back in the garage and ready for some assembly. https://cimg5.ibsrv.net/gimg/www.rx7...276234cb4.jpeg |
I skipped a bit. I had planned to order a hood and wheels from Mariah Motorsports in Santa Barbara. Unfortunately, I called in March last year and ended up talking with Jim’s wife Only to find out he had just passed away in February and they were shutting down the business. Very sad news. Back in in my enduro karting days, I had done some fiberglass body work fabrication so I decided I could just make my own hood. Kept in line with my budget build concept. Not my smartest move. Wasted quite a few weekends doing body work on a blank, then casting a mold. Had issues with gel coat, and had a lot of ‘alligator’ ripples that needed to be filled and sanded. The wax used for the edges didn’t stick well to the edge boards so lot of filling etc there. https://cimg6.ibsrv.net/gimg/www.rx7...fa9c6057a.jpeg Gel coat over blank. https://cimg3.ibsrv.net/gimg/www.rx7...ad58676db.jpeg Fiberglass for mold. i glued plywood strips to the back with the expanding foam in a spray can from Home Depot to stiffen and reinforce hood. After spending a lot of time making the mold perfect and adding something like 10 wax coats, I stopped. I couldn’t find the right rigid foam for reinforcing the new fiberglass hood. So I moved on figuring I would get back to it, but never did. The mold is in my shop ready to go but I think I would just prefer to buy one. If any one has a source let me know. In the end, I used the hood that I had prepped to make the mold. |
Up to now, I have really only been posting pictures of the build, and not any of the drama. I’m saving that for later but will note this. I lost a lot of time last summer due to work and efforts qualifying for the Runoffs that I almost gave up. I sucked it up and kept going but deep down did not think I would finish in time. Also didn’t have time for pictures so I lot of the build is left out in the middle of the process. But for reference, picture below, with some progress, was taken four weeks before the Runoffs. https://cimg8.ibsrv.net/gimg/www.rx7...7949b6078.jpeg Missing Lexan, drive-train, exhaust and a list too long to fit on one sheet of paper. The next day, I towed the car two hours to Sacramento to my good friend Mike Haag’s shop of Haag Performance. He is a Miata race engine specialist but has his roots in Rx3’s and Rx7’s. Early on in the build, I reached out to him about a motor. I had about four 12a’s laying around including a street port I had gotten from FungusMungus. He convinced me to go 13b and agreed he would build up a new motor. I had already commissioned Mike to build me a tranny with miata guts. Problem was I was way late getting to the point to install the motor and he was similarly delayed. I was heading to Spain for two weeks, something we had planned before I decided to build the car. Mike agreed to tackle the remaining components to the build, specifically installing the drive -train, ignition system, and exhaust system. Here is the car as I left in in his shop. https://cimg0.ibsrv.net/gimg/www.rx7...9085f719d.jpeg Nice shop. That’s Glen McCredie’s (EP pole sitter) second gen behind mine. https://cimg0.ibsrv.net/gimg/www.rx7...baaf464c8.jpeg At least it’s clean. Here is the best part...fresh 13b with S4/S5 core and SE front cover and pan. https://cimg7.ibsrv.net/gimg/www.rx7...e7244c65f.jpeg https://cimg8.ibsrv.net/gimg/www.rx7...509fb706b.jpeg Will upgrade clutch and flywheel later |
Three weeks later, I arrived back to Haag Performance shop to finish ignition wiring and radiator plumbing with Mike’s son Chris. Chris did the bulk of the installation work and I really appreciate the time he put in to help get the car done. But we weren’t quite there yet, one week before the start of the SCCA 2018 Runoffs at Sonoma Raceway. That’s a big radiator. Both mustanghammer and Charlie of KC Raceware advised to get the biggest radiator that would fit. That’s a double bypass 27.5” x 19” x 3” Adco unit. Had to lean in towards the motor to fit btwn the frame rails. Took some head scratching to get the lower hose to fit. BTW, Mustanghammer told me a few times to reach out to Charlie(thanks Scott). I am definitely glad I did. I picked up my Lexan, front hub kit and rear DA Koni shocks from Charlie. Charlie called me to update progress of parts and give suggestions and answer questions. Those Missouri guys sure are nice. https://cimg2.ibsrv.net/gimg/www.rx7...14eb4dfdf.jpeg nice to see that motor in the engine bay https://cimg7.ibsrv.net/gimg/www.rx7...ee718945f.jpeg Lifts rock. Nice pic of the underside with new exhaust. You can see the lower rear links in the back. Suspension hardware is still loose. Had appt later in the week at the alignment shop. I had a fresher oil cooler that was pressure tested by a radiator shop but of course it leaked. That’s an untested spare out of Mike’s “Room of Doom”. |
There was an incident at the muffler shop while I was out of the country. New car had body damage before it had ever been driven. Quite a bummer. https://cimg8.ibsrv.net/gimg/www.rx7...4544d3eee.jpeg At least the Grey vinyl on the fiberglass fender matched. Here is the car back from Sacramento. Drove it for the first time ever on and off the trailer. New panasports rims 15x7 110 bolt pattern, zero offset. Ordered directly from Panasport and received in 10 days. Those are new 225 R7 Hoosiers that I planned on using for first track sessions. Didn’t want to waste heat cycles on the bias slicks while I was breaking in motor and getting up to speed. https://cimg4.ibsrv.net/gimg/www.rx7...1148f95f2.jpeg still needed alignment, vinyl, Lexan windshield and a large punch list of items that now was just barely on one page. And there was a new problem.... we had a water leak. Originally thought it was from intake manifold cuz we could not find correct size freeze plugs in the time we had. But turned out to be a water seal btwn rear housing and rear plate. We tried getting up to temperature and then let cool a few times in the hope it might seal itself, but no luck. Time check: the Sunday before the Runoffs start. More on that later. I scramble that week to get as many of the punch-list items done. Had the alignment shop set up the suspension on Friday morning and then the vinyl on Friday afternoon. Then Saturday, first official day of the event, I instead head to Sacramento to meet Mike and Chris to fix the leak and deal with remaining items. https://cimg2.ibsrv.net/gimg/www.rx7...335709455.jpeg we pulled th motor, Mike repaired the seal, and had it ready to reinstall in a few hours. https://cimg3.ibsrv.net/gimg/www.rx7...e8ae291fb.jpeg https://cimg4.ibsrv.net/gimg/www.rx7...bf96bdc96.jpeg |
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