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had a student of mine been helping me try to make something. I'm wanting to make an adapter to fit the stock air filter box to a BNR upgraded turbo. I have in the past used an O'Reilly special, just a silicone elbow with some metal pipe in it to go from the turbo to the upper elbow. It looked crappy and took a good amount of RTV to get to be airtight but it worked. Drove this way for many years. I'm wanting to make this adapter to provide a stock-like appearance as well as a direct fit. Here is a picture of the silicone elbow I was using, as well as the initial model for the adapter in green, and the current iteration of the adapter in white. The white one fits well. I just need a couple of small feature adjustments. The question I have is how could we make one? What material is suitable?
If you guys have any ideas on how to make something like this, please let me know. I know its a small amount of people who would be interested, but I think it would be a cool contribution. On a separate note, does anybody have a spare of the ring that goes in between the upper and lower elbow? We moved last year and my engine bay was apart and I cannot find that thing for the life of me.
If you need flex, TPU is great if you dial in your printer for it - I've prototyped numerous things that are still in use using Overture TPU including gaskets that see more than their fair share of petroleum products and heat, also a few air box adapters.
If you don't need flex you can both A. get rid of those ribs (unless its for aesthetics) and B. use something like CF Nylon. I've built a few throttle body adapters from Polymaker PA612. Again, your printer will have to be set up to use it properly.
It does need a little bit of flex. The three baffles in the middle are to give the inlet duct some flexture since the engine moves in its mounts independent of the chassis. It's that way on the stock elbow as well. It also helps compensate for inconsistencies in manufacturing. I can try printing a TPU version. How do they hold up with the heat and time?
I have been trying to identify the material the stock elbow is made of, but I can't find any markings on mine that would tell what it is. If I knew that, that would get me quite a ways. I do know that it is about 90 durometer Shore A. That and the ribs give it quite a bit of stiffness so the turbo can't collapse it, but it still has some flex. I asked the FD guys if they had any markings on their turbo inlets and they came up with P-TE as the identifier. https://www.rx7club.com/3rd-generati...ation-1167607/. I have yet to match a material to this identifier.
The stock elbows look like they were molded from sheets of rubber squished in a die. The lower elbow has two halves joined at a seam, while the upper elbow appears to have three sections that are seamed together. Buna-N and Neoprene are sold in sheets and could be material candidates.
HKS made an RS Intake, which won't work, because the casting is 60mm. i wish they would have made the casting 70mm (or whatever) and had a boot to make it fit the stock turbo. the big end is 100mm
3d print out of whatever works in an engine bay
and then this is what Knighsports gave you, maybe its not as simple as it could be
Again, Overture TPU will do what you want if you can print it. It's 95 Shore A and if layer adhesion is dialed it lasts in an engine bay as well as resists petroleum products. That said you do still have the option of just piecing together hard pipes and silicone couplers.
10-03-24, 01:09 PM
