3.5 ID Shorty Air filter
 

Is there such a think as a shorty 3.5 inch filter? With the turblown IWG manifold, and the greddy vmount, there is all of about 3.5-4inches of clearance from the Upper radiator hose to the turbocharger inlet. It's a small Sxe200 series with a 3.5 inch inlet. Right now I have a 45 on it to clear a larger air filter, but the polished 45degree aluminum tube is making contact slightly with the upper radiator hose and I'm worried about it eventually wearing through. It's much better than direct contact with the air filter however. Just looking for ideas.

you mean like this?

https://www.knfilters.com/ru-4410-un...-on-air-filter

On the K and N website you have filtering options for all the critical dimensions and it gives you your options

i had a similar problem with both my t78 manifold and the gleaseman BIG R while using the hks Vmount .
instead of getting a smaller filter I highly suggest to fabricate an elbow that will clear from all the surrounding components and use a bigger filter. The small filter will restrict your flow

Like R-R-Rx7 said, you will be far better off by making piping to locate a larger filter where there is space. A small filter will potentially cause a restriction in the intake that can hamper your turbo's efficiency.

it’s been discussed here by one or two members before; most people have zero idea how much filter is actually required and that even the largest 4” ID K&N filter is too small. You really need two of them to avoid restricting the compressor inlet imo.

Think of it as intake-induced emap, because in reality insufficient filter area is limiting boost pressure relative to manifold pressure.

the easy way to find out is to run and log a test with no air filter, just an open velocity stack air horn inlet.
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Summit has a huge catalog of filters searchable by size. Start there, and get the biggest one you can fit

You can measure the restriction of the air filter by putting a pressure sensor in the compressor inlet that can precisely read vacuum (think pressure transducer, or 1 bar MAP) sensor. The more restriction, the lower the absolute pressure (more vacuum) measured. This changes the pressure ratio across the compressor, which corresponds to the Y axis on a compressor map.

The pressure ratio on a compressor map is the relationship between the compressor outlet pressure and compressor inlet pressure (amplified by inlet restriction).

Garretts equation for correcting the actual air flow to corrected flow has 0.5psi as an example value, less is better, but its probably a realistic value
i set up a spreadsheet to do the calculations, if i can do it, its easy

https://cimg3.ibsrv.net/gimg/www.rx7...907bc436de.jpg

per that example, 46.3 lb/min is ~671 cfm

which is only ~350 rxhp

if you go back to my prior post, a short 3.5” ID filter to meet that doesn’t exist. Which means you won’t actually be getting to even 350 rxhp with said filter within the parameters used for the calculation.
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