Foreword: Due to rules and regulations, here in Denmark, you can't just slap a supercharger on your engine and go get it inspected. You have to have the right papers/forms etc., so basically the only option is taking it to someone who already has those - or paying out the bottom to have someone do a custom job on it. I went with the first.

Apparently, they've started doing a low install, and while I appreciate the advantage with regards to weight distribution, it also limits you quite a bit with regards to air filter unless you start making some crazy piping - for which I have to time right now. Nürburgring on Friday.

Picture of the low mount:


I'm a suspenders and belt kinda guy, so that they decided to just go with a fine mesh instead of said filter has been bugging me no end - so I decided to see how much filter much I could fit below the flat top (with no brace) without having to resort to extensive surgery. I decided on the K&N RD-0720 which fits and has almost the same flange size as the input on the C30-74 (64 inside vs. 60 outside) - then whipped up this in Fusion and printed it in carbon infused PETG:



With filter: (compared to a can of brake cleaner)




Will this completely strangle the engine - and will I break anything when it was mapped with just this:




A bit worried but what the hell - it's only money (said the guy who emptied the MX5 account for 2024)


[Edit:] Installed. Fits... just :|

 

That is totally fine and will support 250hp without a problem

 

Give it a shot, it looks good for sure.

f in doubt, grab a cheap vacuum gauge and connect it to your 3d printed pipe and measure the pressure. I did this long ago with a big whipple SC setup I had, and I did find that some filters were more restrictive than others and bigger helped. But I was running 30 psi boost so that setup was a more senstive to intake restriction than typical SC setups. My testing picked up some power once I found a better filter.

Intake filters are less of a problem on turbo's, but still when you're going maximum effort, they do matter.

 

Thank you <3

 

That filter looks big. Is your PETG intake going to hold up to vibrations?

I'm not familiar with Rotrex installs, what's that Rotrex part that looks like a fuel filter?

 

It's an oil filter.

The printed pipe goes from 3 to 4mm in thickness and the assembly, pipe + filter weighs around 420g so I don't think it's going to be a problem. My switch panel is hanging from 2 printed parts and they've shown no sign of stress cracks yet.



Excuse the old picture - even worse at the moment This was my first attempt at shaving everything not needed from a loom and it's getting redone. As mentioned, just got it back with the supercharger and ME442 and that means e.g. the immobilizer can go as that does nothing anymore. I'm not allowed to as long as it has a function. Same with the airbag controller - also going away.

 

Ah, interesting. Does the rotrex have it's own oil and pump, or is it filtering the oil beyond what the engine oil filter filters?

Sounds good, I didn't know your switch panel is bolted to your hot and vibrating rotrex.

Wait a minute...harmonic mystics over here in the new world said to screw something to the end of the filter so it's not cantilevered out there like a tuning fork. Does the rotrex say well below 74°C, the temp at which PETG-CF gets squishy??

It'll be fine. If not, wrap that bitch is carbon fiber or something.

 

Pump is built into the supercharger. Has a complete setup with filter, cooler and reservoir.

Everything gets rattled to f* in this car. I was thinking about two thin'ish prints holding a myriad of gizmos with no signs of stress around screw holes etc.

If it fails it fails. I can always put the mesh back on if needs be.

 

Thank you for that info, I had no idea they had a built in oil pump, fancy.

 

I've seen examples of printed intake plastic pipes (even ASA) deforming from the clamps. Despite the increased wall thickness, I'm skeptical PETG-CF is enough with engine bay heat to withstand typical clamp tension. I'd ideally stick in and epoxy/glue an aluminum pipe internally to support wherever a clamp is. Or design a THICC bead to seal and use very little clamp tension. Most clamps don't apply a perfectly uniform tension, in my experience there is a high point where the screw is and tends to crush it there.

 

I agree with the others that I dont think that intake tube will last. I can't for certain say that PETG-CF will be temp resistant enough or not, but my instinct is no. Mainly I would be worried about it structurally failing. With the filter cantilevered on the end plus any rocking or vibrating of the engine, all of your bending loads are inline with your layer lines which is where the print is the weakest. I personally think the tube will probably crack and break right between two layer lines as its printed now. If possible I would try to print the part at a 45* angle to offset the layer lines from the load while keeping support to a minimum, and if you can find someone with nylon printing capability I would make it out of a PA6/PA12 CF like Onyx. One of my coworkers has velocity stacks made out of Onyx on his Triumph and they have not warped or melted on his car.

 

Update time I figure.

Good part is - the printed filter tube lasted as long as my Nürburgring trackday adventure which was all of 2 sighting laps. Then an injector decided I shouldn't have any more fun and filled the cylinders and intake manifold with fuel. Good thing SWMBO had convinced me to upgrade the daily to something capable of hauling a trailer with a Miata on it. That was a loooong drive home : (

Anyway - the printed part was never meant as a permanent solution but a fix to a here-and-now problem. So a lof of headscratching, printing and buying a couple of now surplus silocone hoses - I ended up with this:



60mm 60 degree silicone bend on supercharger:



With filter mounted:




Quite pleased with this. Now if only Postnord could find it in themselves to deliver the hose for the coolant reroute - of course removing something again turned into a "While I'm in here"...

 

Nice! Keep an eye on it for a while though, as it is chassis-mounted, and I am not sure that the silicone coupler is flexible enough to accommodate for engine movement. I would also suggest a metallic sleeve/compression limiter in the moulting bolt hole, as plastic parts tend to creep quite a bit.

 

Thank you. You do make a very very good point there. Even though I run Innovative Mounts engine mounts, the engine does move a tiny bit. Wondering if I should replace the silicone part with something like this: Flexible pipe PVC 60mm | 18,30 € | races-shop.com

Never ending story with this filter

 

Sorry for quoting you twice Harry. I've been giving what you said it a lot of thought, can't help it, and might, prematurely, have ordered a piece of flexible hose. When I was fundling (fnarr) the 60 degree silicone bend, there's not much longitudal movement - on that we agree. But then it dawned on me - with Innovative Mounts engine mounts and poly bushings in the back, there engine has basically no longitudal movement. There's a tiny bit of lateral movement - but since the supercharger sits below when engine mount and the filter bracket just above it, it can't me more than a few mm tops - and there is, as you know, a bit of flex in that direction in the silicone hose. I'm thinking I'm going to be ok with this.

A clip of how much lateral movement there is with the Innovative Mounts:

 

Fair point, and most likely you may be right, but cannot be too careful. Just keep an eye on it periodically, and see if it survives; worst case, if it cracks, you can print another