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i went to the track, and my buddy Justin Ross, https://www.facebook.com/p/Magic-Developed-100085564065220/had an FD out, and since um its the same as this one i thought i'd share.
super simple combination, stock REW, 8374 IWG kit, Greddy IC, haltech, Sakebomb Ohlins.... AP brakes. muffler is an RB twin tip, car is basically silent
2900lbs with driver, 360rwhp
on the same tires as the Spec E46's (225/??/17) uses it was way faster, its running Time Trials, but its on the #1 Grid spot... i think he said it was running 1:43's at Sonoma
our S2000 is the next car on grid, and i think its like 1:48's? 1:50?
Justin builds a nice race car, my friend was one of the drivers in the 2019 25 hour
Hey all,
figured some of you might appreciate one of my so called economical or ghetto measures (this conclusion is contingent upon your persuasion )
I was able to find a driveshaft from a NASCAR that had the correct slip yoke (it needed to be hardened due to the roller bearings in the tail housing and have 32 splines) I was able to get the entire driveshaft for $105 and can shorten it to fit (and then balance) which will probably run me around $100 or less. A new slip yoke of this specification would have been over $300 and while I do not mind spending the capital if necessary, I can stretch my funds further if I can prioritize what extra attention should be directed to. I also did not feel like paying $700-800 for the rest of the drive shaft as it is a (very strong) piece of mild steel with some yokes welded onto the end and balanced. It can handle rpms and torque levels that I probably won't ever hit on this engine so I think we will be alright.
The goaltenders in here might appreciate the leg pads in the photo below
Ever seen a 4" dia. driveshaft? I still need to get the "ford style" front bearing retainer for the transmission.
I am planning on implementing a parking brake on the rear subframe that interfaces with a rotor that affixes to the differential pinion flange. I will need to go to an 8.8 to do this as I don't believe the OE assembly will work as well for something like that and I want to be able to go down to a 3.73 final drive now that I no longer have an overdrive.
Went to a local gathering yesterday with Aarkaah. Lots of interesting cars there and cool folks but I only ended up taking pictures of a few. If I can find some that other folks took and they're alright with me posting them here I will add them later.
Fun fact: there are 3 20B powered cars in this photo!
Got to see gmonsen's third gen. I think this might be the most refined modified example out there.
Main hoop went in today. We (myself and the person doing the fabrication) are quite pleased with how well everything has fit up so far.
In other news, I may or may not have a set of (used) air jacks on the way that got pulled from an Audi RS3 LMS TCR. I am planning on setting them up something like this. The third jack is either going to go on the rear subframe or in-between the rear bumper and the chassis like on diyman25's old third gen that was campaigned in Super Taikyu.
Looks like there's space for them here. I like this better than inside the car due to plumbing and not being able to hit them with my leg or ankle in a collision. Photo of the WW2 ST3 third gen from way back in the day.
I have grown tired of jacking low ground clearance vehicles (I think it's super annoying having to mess around with ramps and boards) No more need to lug a floor jack around (we are floor space challenged in my garage) and in addition to taking up less floor space, a nitrogen cylinder will allow me to fill tires instead of using a compressor (another thing that I don't have space for) and can run a pneumatic impact off of instead of lugging around a generator, though battery powered impacts have gotten to be really nice, I haven't gotten one yet and would need more space for battery chargers.
side note: Ingersoll Rand and Dino Paoli make some very nice pneumatic impacts that look to be cost-conscious.
I also did something that might be a bit controversial but increases the safety factor of the vehicle significantly whilst decreasing the polar moment of inertia of the chassis.
I decided to go to a fuel cell, and to put it right where the passenger seat would have been. (with a bulkhead, of course)
Every sanctioning body that I wish to eventually run in permits it, and I am able to increase the fuel capacity to 26 gallons. I could probably get 1 hour and 20 minutes of run time between stops running at around 420 wheel (but we will detune for endurance events when the time comes. I hear that 330-350 wheel is 6mpg so about 1 hour and 37 minutes. The lower BSFC of naturally aspirated 2 and 3 rotors is appealing but it also cost monies, so maybe later)
This was the photo that inspired me to consider this. An S2000 that is used for endurance racing. Note how the door is used as part of the bulkhead.
In true RX-7 build fashion, I have opened up another can of worms, the most recent of which being:
1. I now need to figure out a solution for isolating the fuel (hardline) with a bulkhead of some sort. I have some ideas but they're a bit crude. (remember that we are going for a specific look here) I'm going to try to use the "pseudo-returnless" setup I made reference to a while back so I only have to worry about one feed line going through the car.
It also further simplifies fuel filter maintenance and other fuel system related tasks.
2. I now have nowhere for an instructor to sit. This can be mitigated by coaching through data and video, but it looks like I will either be renting or borrowing something with two seats for a while or will try a race school of some sort. We will see. I suppose it comes with the territory of attempting to do 997 GT3R stuff with an rx-7 budget . (I really should have just gotten one of those tube chassis GT3 third gens or something )
Another thing that I think we should always try to keep in mind when feeding into these rx-7 related compulsions/obsessions/addictions is that every modification or alteration that you do should be to mitigate a specific issue (both perceived or actual) that you might have.
Determining the goal is the easiest part of the exercise. Figuring how to get there and what you will need to do it is the more challenging aspect. Fortunately, if you've got some perseverance and too much time on your hands, you can do just about anything. (irrespective of whether you should )
Thanks for reading.
Last edited by SETaylor; Aug 21, 2024 at 05:32 PM.
I also did something that might be a bit controversial but increases the safety factor of the vehicle significantly whilst decreasing the polar moment of inertia of the chassis.
I decided to go to a fuel cell, and to put it right where the passenger seat would have been. (with a bulkhead, of course)
This was the photo that inspired me to consider this. An S2000 that is used for endurance racing. Note how the door is used as part of the bulkhead.
Small world! I know this endurance S2000 very well - that was my friend's Paddy and Pete McParlands
Jason filling it up during a driver swap with me holding the fire extinguisher
Such a great car - you get used to the crazy amount of fuel sitting next to you
Especially after building some confidence from the wheel to wheel bang ups the boys brought back in - realize that bulkhead and cage was very well built
Let me know if you want me to get you in contact with them for some insights and other considerations on the fuel cell
All very cool and inspirational Simon - keep at it!
I was going to say—if you still need instruction/development, maybe hold on that or maybe think about saddle bag tanks for the bin area if you're really itching to change it. Having a right seat for a while could be really helpful.
Hey @j9fd3s and @ptrhahn, I hear you guys regarding the tank placement. Instruction is priceless and I imagine that you all could run me down on with a mobility scooter or shopping cart if so inclined . I would like to keep the right seat and I was really only considering it at this stage for packaging of other components and the fact that it makes it a whole lot harder to damage. One thing that gave me pause about using the OE location was the need to seal off the entire hatch section of the vehicle with a firewall, and then entirely sealing it off is a bit challenging.
Photo courtesy of gnx7
I recently saw some photos of a time attack third gen in Australia that has something that I might be able to make work. It looks like they have the cell in the OE position but the access cover is raised to clear the components as seen in the photo below. I would want to have the fuel filler outside of the car so isolating it with sheet metal could be done but it (specifically the fuel filler) might be rather intricate to do and be removable.
I imagine it could be an additional piece that goes over the main cover that I already have and is retained by bolts and captive nuts welded to the bottom?
This car has a tiny tank due to its application but it looks like I could just lower the cell a bit to allow for the secondary bulkhead to be lower? Would need to see what the minimum ground clearance rules for cells are and account for the metal cage it is held in.
Like this but using either the OE filler location, but I don't think I'm ever going to fit a dry break receptacle in there. I'm getting into the weeds here but it will cost more monies to alter later. I could do what some folks have done and just have a receptacle just below where the rear hatch key cylinder is like on KenSpeC's car.
The other reason I had considered it was that it would allow me a ton of space to fit mufflers where they could easily be accessed, like on the grand am rx-8's and other purpose built contraptions.
Again, I'm really getting into the weeds here with this and it might not be the greatest idea but it would allow for me to exit exhaust gasses through a diffuser and fixture a blown diffuser with a flat floor (it decreases lift and drag at the same time with more surface area than a wing or splitter alone ever would). Not ready for that stuff yet but I would like to make the transition easier when I am.
The other thing I would need to figure out is how much space I would have left down there for the fuel filter, pressure regulator and air jacks. I might be able to fit it off the back of the frame and it has an OD of 2" so it really shouldn't be hard to do as I have seen it done before on diyman25's old car but I don't remember what capacity and dimesions his cell had.
I need to figure out where I'm going to put my electronics (I am thinking near the passenger footwell affixed to the dash bar?) and fire suppression system (probably passenger footwell?)
@ZumSpeedRX-7 Thanks for the photos! I've seen Pete's in the comments section of posts on the Professional Awesome Tech Forum facebook group. He's got a lot of good insights and his stuff is really informative. I had been wondering how he had addressed venting of the cell. If you all are at Palmer on the 18-19 or the 25th-26th of October, let me know. I will be in the area for some non-rx-7 related stuff.
I love this thread. I'm glad to see the project continuing to move along.
Appreciate the kind words!
I hope people will be able to find something in this that they can apply to whatever they're trying to do, and am very interested to see how this will end up working out on track with a competent driver behind the wheel.
The car that J9 posted photos of a couple posts up is running some insane lap times (think a few seconds quicker than 997 cup with a sequential gearbox and michelin slicks and the like and faster than most people are taking 991 gt3's around Sonoma) with not much more preparation than what most people with modified third gens have. It's pretty nuts if you think about it.
Last edited by SETaylor; Aug 22, 2024 at 02:31 PM.
What components need to stick up that high in the trunk? Surge tank? I admit, I'm always shocked when I see a surge and lines open in a trunk. but sheet metalling them in like that seems way preferable to an interior bulkhead, or no passenger seat.
What components need to stick up that high in the trunk? Surge tank? I admit, I'm always shocked when I see a surge and lines open in a trunk. but sheet metalling them in like that seems way preferable to an interior bulkhead, or no passenger seat.
I too am less than thrilled with exposed fuel lines in the passenger compartment, especially on street driven cars where the driver more than likely isn't wearing a fire suit.
The big thing is the fuel filler neck. From a packaging standpoint, the easiest thing for me to would be to run the fill neck tube to the back. Keeping the filler in the trunk was something I saw done on a lot of the earlier race converted third gens and does seem to work fine but it looks like it would be really annoying to have to lug a fuel jug into the trunk and invert it without spilling anything.
I think I could use a fill neck set up like on this car and just sheet metal over it. The other thing would be the venting and discriminator (rollover) valve, but I don't think that it will be too difficult to fit. See the picture below of a forum member's car for the fill neck I was referring to having covered with aluminum.
I might end up losing the trunk latch doing this, but the hood/trunk pins found on the 996-current generation cup cars look like they could work very well, though I'll try not to get rid of it. Probably going to use them on the stock hood I'll be messing with later.
Looks like a template for the filler neck bulkhead could easily be made with the power of cardboard aided design.
Don't you (or someone else here) have a differential cooler on your car? Trying to figure out where to put the pump. I'll be running a water to oil heat exchanger off of that microtube radiator so I won't need to duct air to it. I just need a pump.
I need to figure out if I have enough space between the cell and rear subframe for the third air jack so it will package well whenever I end up throwing a flat floor and diffuser on. Time to go dig up more fd photos!
The trunk location still seems favorable versus contending with all of that sitting right next to you, and losing the seat in the bargain. I'd just sheet metal it in the trunk.
I don't have either a diff or trans cooler, but if I did I'd hang the pump off the subframe (for diff), or off the trans (for trans), and maybe put the cooler behind a vented panel where the license plate is/was, hanging from the bumper support. Costas has been working on them, but he mounted the cooler up front.
i helped build an enduro miata with the tank in the passenger seat, it does work for what you want to do.
i don't recall any fancy plumbing to do it either. i did the wiring, so different set of pipes.
i helped build an enduro miata with the tank in the passenger seat, it does work for what you want to do.
i don't recall any fancy plumbing to do it either. i did the wiring, so different set of pipes.
can you run the stock tank for a while? or does it need to be a fuel cell right away?
Hey J9,
I personally don't have any issue with retaining it. The only metaphorical wrench in this plan was PHA (Penna. Hillclimb Assoc.) recently requiring cells for the classes this car would otherwise be eligible for given that it has a roll cage among other things. They used to permit something like this to retain the stock tank in their ITE class, but I think they moved everything of that nature to their "Street Modified Extreme" iirc or "SMX" in an effort to cut down on underpopulated classes.
I don't believe NASA cares, but it does appear that other sanctioning bodies that used to not require them are beginning to. Might have more to do with their insurance than anything. I do find some humor considering that a lot of the factory-built race vehicles offered not so long ago had stock fuel tanks (eg 996-7 cup) and were professionally raced with them not all that long ago.
I could just not do those events until I got around to adding one. Might be the best option at this stage. I'll try to hit some autox events with it but as you know vehicle setup for this application is different enough that it might require some messing about (eg gearing and the like. Looks like I am going to be very good at swapping ring and pinions in the future...).
The air jacks showed up today. Should be easy enough to plumb and fit given that they're very compact and don't weigh much of anything. I think I could actually fit this between the stock fuel tank and rear bumper, which is pretty cool. Still need to get jam nuts to retain them at the top but that's about it aside from fabrication.
Trying to determine if I should put the connector valve for the air lance on the back of the car or near the base of the hood, as they seem to be the most common areas. Not super important at the moment but it doesn't hurt to plan I suppose.
Krontec LL-24-230 air jacks and LL-16 connector valve
I could just not do those events until I got around to adding one. Might be the best option at this stage. I'll try to hit some autox events with it but as you know vehicle setup for this application is different enough that it might require some messing about (eg gearing and the like. Looks like I am going to be very good at swapping ring and pinions in the future...).
where are you in the driver process? i ask cause i'm thinking of digging up my 1st gen to run in TT5 (ha!). i would need to run through the HPDE schools,
so even if the car was ready today, it would be 2026 before it needed to meet the rules, lol that sounds like a really long time
so basically car doesn't need to meet the rules right away, which is good cause it doesn't. and my driver suit says Camaro on it, so i need to grow a mustache and find some medallion to wear.
i'm about ready to rebuild the differential in my FC, check this out, he makes it look so easy i think i can do it too!
really though, ive never done a differential, so i think i should on principal
This is becoming one of my favorite builds to follow.
Some really crazy stuff going into this car.
Penske dampers, F1 radiators, NASCAR gearbox, 3D scanned cage, air jacks!
Between your school and this car you are basically already a full time engineer lol
I just hope everything will fit and assemble together properly to bring this car to life.
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