With all the bits now here I could look into planning out where and how it would all fit into the engine bay.

More research convinced me to mount the rotrex oil cooler in the LHS front fender in front of the wheel, and relocate my current engine oil cooler from in front of the radiator into the RHS fender well area.
like this; (image blatantly stolen from Lokiel)


Two suitable holes in each side of the front bumper (cos racecar) along with some matching ducting would feed both of these coolers nicely.

This also meant that (since I had no aircon either - again cos racecar), there was plenty of room in front of the radiator for the intercooler.

I also liked the look of the over the radiator intercoolers, with their straight shots out of the blower and into the intake manifold.
This removed the need to create any highly complicated cobra snake shaped intercooler pipes, and cut down the number of connections that could possibly leak.

Some thing like this




rather than something like this..

more bends than a yoga class!!


Another long research process for intercooler core sizes, pipe diameters, etc, lead me to choose a suitable intercooler from Cooling Pro, a local supplier here in OZ.
I settled on a 11" X 12" X 3" intercooler with top mount 2.5" outlets .




This would allow me to run a 2" pipe off the Rotrex to keep up the velocity through a 2" inlet 2.5" outlet 90deg silicon bend which joined onto the intercooler.
Then a 2.5" silicon bend off the intercooler straight into the 2.5" inlet manifold.
In here will also be a 2.5" T piece to feed the BPV.

So just three bends in the whole blower-to-intake manifold system, and only a handful of hose clamps reqd, reducing the likelihood of leaks.


so time for some backyard manufacturing to mount it up.

 

The rotrex unit was mounted using the provided brackets. I clocked the rotrex from factory to make it a shorter path over the top of the bracket.
Clearance is tight around the power steering but nothing does or can rub.



It uses a fixed idler underneath, and an auto tensioner on top.
This setup makes it almost impossible to get the belt tension wrong, and provide plenty of wrap (over 200deg) so the belts shouldn't slip.

Now the planning for the radiator/intercooler was undertaken.


Some rough measurements proved that the over the radiator mount wasnt going to work with my current radiator/mount setup, unless I wanted to drive around with no bonnet(!) so an alternative option was needed.

Further measuring showed that I only needed to find about 30mm (1 1/4" for you imperial guys) to make it all work.
I couldn't just re-drill the existing mounts lower and fit rivnuts, as I had the large Goodwin Racing heavy duty sway bar mounts,


which occupied the same space as I'd need to use, so some new lowered radiator mounts were fabbed using aircraft quality, military spec materials.
Ok so I just used garden variety 3mm thick steel strips from Bunnings (Oz version of HomeDepot))


Though I added some triangulation to the mounts and they were plenty strong enough.


Then bent up some new alloy brackets on top to hold the radiator in the new lower position



The below shows how tight it is between rotrex crank pulley, sway bar, and radiator fan



With the radiator now sorted, I set about plumbing in the intercooler.

 

Initial mockup showed that whilst there was plenty of room in front of the radiator for the intercooler itself, (having moved the previous oil cooler out of the way, and no air con), there was not enough room for the hoses to feed the intercooler from above.
This was fixed with the trusty angle grinder, removing enough metal to allow the pipes to fit through, and some judicious filing and then split rubber hose on the edge to protect the cooler pipes.






As can be seen in above pic, it also gave me juuust enough room to fit the original fan back in, so it doesnt overheat in the pits. (there is barely 1/8" between fan mount and auto tensioner)

Also you can see the straight shot to the throttle body..


On to mounting both the oil coolers.

 

Some simple metal brackets bent to shape (again from Bunnings Motorsport depot) held the coolers in the correct spot, and tied in to all 4 corners. This ensured they didnt move at all.
Routed the Rotrex cooler lines through the front behind the headlight to the compressor, and rubber hose offcuts strategically ziptied to ensure they wouldn't rub on the chassis.

The oil cooler hoses are stainless braided so extra care to ensure they didn't saw through anything in their path, which they are notorious for.

below shows the coolers in place minus the radiator


And below is all 4 heat exchangers in their final positions.


Note class regs prohibit me from cutting the radiator support panel to provide better flow to the radiator/intercooler, which would be a much better option.

 

Breaking out the CAD skills, (Cardboard Aided Design) I fabbed up various examples of ducting to the fender mounted coolers.
Iteration #346 seemed to work well and would seal up against the bumper when it was refitted.






And as appears to be typical, I don't have any photos of this piece actually fitted behind the bumper.

 

I hope the slower updates mean you've been out enjoying the car! Thanks for the great documentation as I'm hoping to replicate your path to FI track miata fun soon.

 

I was hoping to catch if you finished the project with the rotrex and the ITBs. Sorry for the necro bump but this is a path I am highly considering as well.

 

This is/was a great build. I'd love to see an update too!

 

Hey guys, still here, just time isn’t what it used to be to keep this updated…

l’ve got three years of updates to do to bring this thread up to date…

summary of what has happened since my last post, which hopefully I can post more details off to keep the thread happening.


- realised Oz vendor supplied version of rotrex kit is rubbish, predominantly their mounting solution.
- caused Multiple belt shredding and my crank pulley shearing off at 110mph on track.. (not fun hearing large metal object bouncing around engine bay at full noise)

- ended up speaking to Gary at TDR to obtain just the mounting portion of their kit, which they were happy to provide. Excellent service here and would (and have) thoroughly recommend them to anyone doing a rotrex setup.
In hindsight I should have stuck to my heart and gone there first and to hell with the exchange rates/shipping. It ended up being more expensive and much more stressful doing it twice..

- removed horrible prior mounting kit with their stupid big third pulley that hangs off the front of the crank putting undue stress on the pulley and ultimately caused my high speed pulley failure. Also the non braced mount was the reason for the belt shredding as it flexxed each time you revved it..

- refitted rotrex with standard TDR mount kit and can happily say that have had zero problems since that day. Even still using the same belt since three years ago and it doesn’t even look like needing to be changed.
- moved oil cooler to rhf fender to (kinda) match the rotrex cooler in the lhf fender.

20 track days since and it hasn’t missed a beat. Car is super reliable and requires only a fluid and spanner check prior to each event.

- car is currently up on the hoist to get a suspension refresh after 15 years and 20,000 miles of service from the previous setup.
new coilovers, 863 bronze bushing kit, new adjustment pins, new ELBJs.

oh and most exciting of all, finally fitted the correct size rotrex pulley to return to the 8psi it originally made with the previous non TDR kit.
dynoed just last week at 220hp unrestricted on a stock rebuilt motor (just forged rods/pistons for safety) and then the tuner tweaked the tune to make 184.6hp which is what I need to run in my class (185hp limit)

first track meet is in three weeks so very much looking forward to seeing how all the new improvements go. Should be fun..

 

Are you running ITBs with the supercharger?! Don't tell anybody, but I've plotted forcing air through my borla ITBs more than a couple of times...the trick is finding someone to build a boost capable airbox.

What pistons did you or are you running on the built engine?

Anyways, looking forward to some pictures or videos of your car soon.

 

I took the ITBs off when I went down a class, and just added the rotrex when I went back up a class. Its running on the standard NB1 inlet manifold.
Pretty sure there's more than a few guys running 300+hp through the std inlet manifold so not sure of the benefit of going ITBs other than because of a want, rather than a need..
ITBs sound cool, but enclosing them in an airbox as you'd need to for forced induction kills that sound and kinda removes the only real bonus of them. imho.

Pistons I believe are supertech 9.5:1. and manley rods.

 

That's more sensible. I agree the only reason to do boosted ITBs is for the novelty. A boosted ITB Miata is likely the closest I can get to a Ferrari F40

Good to know. Are you happy with the Supertechs?

 

Yeah, they seem to do what it says on the packet…
They aren’t noisy at startup or warmup and appear to keep the explosions inside the chamber to help the rods push the crank around as required..
not much else to report given they are otherwise an unseen item (hopefully for a while yet….)