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Thought I’d share some of the build info as I prep the car for NASA’s ST4/TT4 classes. This year I’ll mainly run in Time Trial as I get used to the car and dial it in. Last year I got little more than two hours of driving in before the engine blew, so the car is still very new to me.
Originally built as a Pirelli World Challenge TC/TCA car, there wasn’t much done to it beyond the basics for a dedicated track-car (full cage, lighten panels, etc.). Frankly, a bunch of that wasn’t really done as it should’ve been done, so I’m slowly undoing stuff as I come across it. In the meantime, the car looks like hell. The PWC hosts its fair share of cowboy drivers, and car-on-car contact is common. So I have a bunch of body work in the pipeline, and I managed to score a bunch of spare panels for a song – always good to have spare body panels on hand for a wheel-to-wheel car.
as delivered, RA
There was no aero on the car, and the ST4/TT4 classes allow a modest package. Mine is pretty simple in conception: a front splitter, a modest rear wing, and a deep-draw vented hood.
Loading the car onto the trailer is hard enough with just the lowered stance and (now removed) chin-valance, so I designed the splitter to be quickly removed along with the entire front fascia as a single piece. Four camloc fasteners do the job (along with the four clevis pins securing the splitter struts to the blade).
Small brackets were required on the sides to receive the camlocs (one bolted to the fender structure and another replacing the side-markers). I got lucky and was able to use existing mounting spots on top to remove the upper fascia brace quickly.
camloc brackets
camloc brackets - inside fender
The front splitter is built up to the class legal limits (4” from bumper and no further than front axle centerline). Rules dictate it has to be flat and horizontal, so no funny business. Damn.
Here’s a preliminary mock-up:
mock-up w/nose and blade
The construction is designed as a two-part splitter, a main frame and a sacrificial blade (all in a single plane so as to form a single piece mounted horizontally). The idea is that splitters get abused in racing/track use, so the front of it is meant to take the beating and be easily replaced. Hopefully, this also reduces the expense of replacing the damage. The blade is quick to make and cheap as all get-out (1/2” MDF board, soon to be covered in a couple layers of fiberglass cloth).
Here’s a shot of the support with splitter frame/blade mounted to it:
frame/blade mock-up (frame unskinned)
To secure it to the car, the chassis wasn’t exactly helping much, so I had to make a sub-frame to properly take the load. Simply bolting it to the front fascia is a waste of opportunity. You’ll split the air and thus benefit from having less air go under the car and such, but with all the flexing the nose allows you won’t gain much from the low pressure zone under it. For that you need a rigid structure that can take the aero load and transmit it directly to the chassis. The sub-frame also serves double duty of easing the removal of the nose. The splitter frame slides on/off the mounting hooks built into the frame.
The sub-frame came in at only 5.5 lbs., so not too bad. Add in another ½ pound for the pair of upper braces to secure the outboard support struts, and we’re looking at 6 lbs. total for sub-structures.
Here’s the outboard support for the blade struts:
outboard supports
Here’s a shot of the blade struts (mounts made from aluminum square tube, 5/16” clevis pins are mil-spec items…mmm…mil-spec hardware…yummy!):
blade struts
The struts themselves are put together from off-the-shelf Speedway stuff. The usual splitter supports you see online weren’t long enough, so I mocked up my own. I didn’t need to use the QA1 rod ends (there are much cheaper options), but good-god they’re gorgeous! Here’s the parts list for the curious:
· QA1 AML5 A Series Rod End, Alum., 5/16-24 LH, 5/16 in. Bore (Part # 721AML5): $24 ($6 ea.)
· QA1 AMR5 A Series Rod End, Alum., 5/16-24 RH, 5/16 in. Bore (Part # 721AMR5): $24 ($6 ea.)
The blade is 7 lbs., and the splitter frame is another 11 lbs. (3.5 lbs. of which is the aluminum skin; heavier than I expected!). So all told I put about 24 lbs on the nose…and now the 40 lb battery is going in the trunk. =)
Everything is now painted silver, so it looks pretty. I triangulated everything so when it’s mounted to the chassis it forms a very rigid platform. You can put a lot of weight on the blade and it doesn’t flex – I haven’t tried to stand on it yet though.
For the rear, I originally planned on fabricating a NASCAR-esque spoiler out of lexan. Simple and cheap – and time-consuming (at the rate I work). So I bought my way out of the rear. I opted for an APR GTC-200 wing. Nice unit, nothing crazy, but it works and should match the front nicely. Here’s the preliminary fit:
APR GTC-200 on car
The trunk was previously gutted for weight savings, so it’s hopelessly weak to support aero load. This wing isn’t a monster, on its best day producing no more than 200 lbs of downforce. That’s more than the trunk can currently support, so I need to mock up some reinforcement inside the lid, nothing fancy just enough to distribute the load to the strong parts of what’s left of the trunk lid. The lid itself is plenty strong enough (I’ve put my full weight on just one side and it was solid); I just need to tie into the parts with structural integrity.
I’ll catch up with ya’ll in a couple weeks when that’s done and the hood is tackled. The hood is soooo Men’s Warehouse – “you’re gonna like the way you look.” =)
Jake!! Good to see you here. To everyone else here: Jake and I have history together - he almost ran my slow-butt over during our comp school. =)
I'll get a few shots of the interior - or try at least. The previous owner had it shot in black...all black, everywhere. Bad idea. A race car's interior should be white, light grey, or silver...that's it. I can barely see a damn thing inside the car (working on wiring is oh-so-much-fun when everything recedes into a dark abyss).
Anyway, the cage is pretty standard, nothing fancy. 6-point cage, NASCAR bars on the driver side, X-bar on the passenger. The cage is one of the few things I think the previous owner did well on the car.
Thoughts on TT builds:
My rendition of this car makes for a very good TT4 car. Lightened as it is, she sits with a competition weight around 2820 lbs (i.e. me in it and on fumes). With a healthy free-breathing NA-rotary, the power-to-weight is very good for TT4 (with modifiers - you get that 4-door bonus!). I'm coming in around 12.15 with adjusters (11.75 raw) using peak figures, so I'm getting a bit of wiggle room from the new "average hp" rules, and that should keep me safe from breaking out of the class.
Going up to TT3 would mean more power squeezed out of this (still think I could get close with a NA rotary), big slicks (damn the fenders), and a very different (very aggressive) aero package. That's a lot of investment to go play with the Corvettes, and this is supposed to be my "in-between" car while I continue to work on the 818R.
I hope to run this car this year and maybe next. I'll likely sell it after that, but we'll see where I'm at with the other car.
Comp school was fun, that's for sure! I don't know about the whole running you over part, a bit of an exaggeration! I mean my old H2 car only had 158whp! Wish I was able to get back out there with my new civic and contest for the national championship. Lol! However it's taking forever getting it finished.
I purchased 2 RX8s over the past two years. A really clean 2004 GT in red which will remain oem, and this 2005 white sport model which was too good of a deal to pass up, blown engine. I may just rebuild the engine if it's not too messed up.
Other option is to REW swap it. We shall see! But fully agree with you on choice of interior paint! Can't wait to see this thing done and out on track!
Last edited by JakeKaminskisRacing; 03-29-2017 at 04:18 PM.
How much does your car weigh? TT4 is where I want to go but w/p being 12.0, I am having a hard time finding lightness.
Edit: Never mind. I just noticed you posted a weight of 2,820 lbs. Still not sure how you'd get to w/p of 12.0. My comp weight is 2,850 (starting with a full tank of gas, measured after a session). I'd need to be in the neighborhood of 2,500s to be competitive (even without using OEM aero +0.4)
I may have more power to the wheels than your car. Lightly ported, tune, and race intake with very free-flowing headers, 3" exhaust and a joke for a "muffler" the car laid down around 240 rwhp. The new engine is a beast.
I'm actually using 2800 as my declared weight (bringing the number even closer to maxing the class ratio), so I can absorb some scale variation and not get DQ'd for being under weight. Also, with the new average hp rules, the final numbers will be a bit higher. Not exactly "spot on" for the class (I'm giving up a little power), but not horrifically off either, pretty close actually. Where we're horrifically off is in torque, but we can't do anything about that aside from an LS swap. =)
Whether or not I'll be competitive is a whole different matter than the numbers...
Oh, say it isn't so, GG makes another random B.S. arbitrary judgment against a car because...he doesn't like car...
I figured someone might object to taking the modifier for that, which is why I was trying to err on the conservative side. Looks like I'll need the average-HP rule now and probably declare my true min. weight.
Out of curiosity, did GG make the call over email or is there a thread in the NASA forums I can respond to? I'd like to give him **** over it. >=)
At the very least, we should have a full rationale for the decision to deny a car with four doors from taking the 4-door points.
I'd be interested in that thread as well. You can't deny that the car is carrying more weight due to it's pair of suicide doors.
As for the lack of torque, just have to ensure you're able to maintain inertia everywhere on the track. Which is one of the main reasons I chose the RX8 over any other RWD chassis. To me it's the civic of RWD, and in that regard an awesome training tool for me to learn the skills needed for making a RWD fast.
John are you planning on carrying the splitter surface further back to the centerline of the front hubs? I only ask because it looks like the frame of the splitter doesn't carry further back than the front of the tire.
Last edited by JakeKaminskisRacing; 04-01-2017 at 12:45 AM.
Yep, the pics don't show it ('cause I haven't built it yet), but the center portion of the splitter will extend back another 10" or so to the front wheel centerline. That portion will remain on the car.
The frame section you see here is the part of the splitter that stays attached to the front bumper fascia, and you're correct that it only goes as far back as the front of the tires. The whole nose assembly (fascia, splitter, & inlet ducts) are all designed to release as one piece for unloading/loading onto the trailer.
Funny you should mention the relation between momentum car and training tool - I had the exact same thought. I usually tell folks that a Miata is the best first car to track, because it punishes you so badly for botching the corner and rewards so well for getting it right. They're the best training cars because they don't let you hide behind the "sensation" of going fast that you get from high-hp cars. You have to drive them well. So part of my attraction to the RX-8 is in the same vein.
Yep, the pics don't show it ('cause I haven't built it yet), but the center portion of the splitter will extend back another 10" or so to the front wheel centerline. That portion will remain on the car.
The frame section you see here is the part of the splitter that stays attached to the front bumper fascia, and you're correct that it only goes as far back as the front of the tires. The whole nose assembly (fascia, splitter, & inlet ducts) are all designed to release as one piece for unloading/loading onto the trailer.
Funny you should mention the relation between momentum car and training tool - I had the exact same thought. I usually tell folks that a Miata is the best first car to track, because it punishes you so badly for botching the corner and rewards so well for getting it right. They're the best training cars because they don't let you hide behind the "sensation" of going fast that you get from high-hp cars. You have to drive them well. So part of my attraction to the RX-8 is in the same vein.
Best,
-j
Can't wait to see this the splitter in person. I love my quick release on the civic and want to figure out a means of fabricating one for the RX8.
I own the sister car to yours. If yours is anything like the shape mine was in, you have my sympathy. I am building mine for STL class in SCCA. I'm completely redoing the car but eventually it is going to be respectable. Below is a pic of it when I was at a Road Atlanta test day (normally I race Spec Miata).
Oh no! I was truly hoping nobody got the other car from TechSport. I feel for you Adax, I totally know what you're going through. Like:
"Hey, look at this, this on-board fire bottle is not wired correctly..."
Ugh!
I'm pretty much repairing/redoing just about everything I put my hands on with the car. I don't think a single system on the car hasn't been addressed in the short time I've had the car. The worst is the junk engine that was in the car and died after about 2 hours of track time. I mentioned some of this in the New Member forum.
I got a decent deal on the car and extras that came with it, but I've put a ton of time and money into it already, so I wouldn't say I got a good deal. I hold out hope that it'll be a very good car when I'm done.
Yeah, my car is basically junk. I'm embarased to go into detail regarding the extent to which I am restoring this car. Drivetrain and shocks were good. That's about it.
I got it at a decent price but I'm not too upset about it. The cost of the car is pretty minimal when you look at the cost of a season of racing. Car is in paint as we speak and I'll eventually post some pics of how a race car should be built. Hint, it doesn't include spraying the entire interior with bed liner material, or using wheel weights as spacers in mounting the seat, or stereo cable for criticial wiring, I could go on.
I think I'm intentionally starting to forget about a bunch of stuff - the list is long indeed, as long as it is just stupid/careless/wtf? I actually want to like the car, so selective memory is becoming my friend.
You got me on the bed liner though, mine was only black rattle can, which is easier to address. If our paths ever cross, first beers on me.
Looking forward to your finished car! I'm going with wrap - never done it before, so the adventure continues. I figure, it's a race car!, so if you're going to experiment with wrap, may as well be on a something you're not overly picky about. NASA (and I imagine SCCA as well) has a 50/50 rule: car has to look presentable from 50' away at 50mph. Not exactly your concourse standard.
Ok, small update. I'm hoping to have enough buttoned up on the car to take it out to Mid-Ohio in a couple weeks. Mission: break-in the new engine, make sure nothing falls off the thing...
Front end is mostly done. Brake ducts aren't fabb'd, but I won't be pushing hard enough to really need them for this event.
Here's what I have been working with...
Old Radiator Intake: Pro-race team radiator inlet (no, that's not a typo)
"Slapped together out of multiple scrap pieces" is how I'd describe it. The mesh was on the nose, but it was thrashed and had to be replaced immediately after getting the car. Hard to see in that shot, but the angles don't even match.
This is how I roll...
New Radiator Intake: Garagista radiator inlet w/mesh
Here's a preliminary shot of how it's coming together:
I run with a few organizations, but I spend most of my time with the NASA Great Lakes region. Despite our regional name, we go as far as Pittsburgh Raceway, NCM in KY, and Mid-Ohio. Most of our events are in IL, WI, and MI. Every year we do a couple of events at the Autobahn Country Club, Gingerman, and occasionally hit Road America.
Check us out! Hope to see folks out there. If you're thinking about it, shoot me a PM.
Nasaforums has a post on "rx8 and the sedan allowance.". GG was very adamant the rx8 is a four door coupe.
Thanks for pointing this out - I found the thread. For those here who don't want to follow up on the NASA forum, and to clarify what hufflepuff pointed out, GG was adamant that the RX-8 is NOT allowed the 4-door sedan points - on [b.s.] grounds that it's a "coupe" rather than "sedan."
It's now a moot point for me. NASA requires 2-wheel drive cars to be tested on a Dynojet, so I had to re-dyno the car. Oddly enough, my "official" chassis dyno results came in much lower, and that has opened the door to a TTC build (with a little ballast to make the numbers work). Bottom line: I won't need the 4-door sedan points.
And all that is now a moot point as well, since I need to fix a fuel leak (thanks again Kevin! ) before I follow up on that unusually low dyno pull...which may throw all this back to square one.
On a positive note, the engine bay mods are coming to a close - hopefully soon I'll have something "cool" to share with folks.
Get it...something "cool"...
[Look, at this point I either laugh at anything I can get my hands on or I start drinking heavily.]
BTW, the shake-down run at Mid-O seems to have been a success. Kept the revs under 6K, so just puttering around the track. Hardly had to use the brakes at all! Still fun.
Nothing fell off the car - that's nice. The quick-release nose worked perfectly; whole thing comes off/on the car in under 2 minutes. Makes loading/unloading the car on the trailer a breeze.
Also realized that the alignment is probably off - you know, because why would a pro-race team not properly align the f'n car? Oh, I know, because it's TechSport! Should've looked into it anyway, and definitely after finding all the stuff I found. More to do.
That splitter and wing should really help. I had a smaller splitter with same wing and was surprised how much it improved my RX8 just for lower speed autox use. Unfortunately they banned aero mods for the prep class a year or two later.
03-28-2017, 06:50 PM
) before I follow up on that unusually low dyno pull...which may throw all this back to square one. 
