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Recommend me a short air filter
matt_gsxr - 16/1/11 at 10:26 PM

Hi there, an air filter question.

I am putting a turbocharger onto my gsxr1100 (slave to fashion).

I plan to attach the filter to the front of the turbo, and duct some air to that area. It is all getting a bit busy in the underbonnet area as you may have guessed.

Anyway, I have about 3inches of space from the front of the turbo to a panel. I have loads of space in the other directions so need an air filter that is short and wide, which flows without significant loses for 250bhp (planned capacity). Turbo inlet has a 60mm interface.

I looked at mushroom filters, which are popular on japanese (think fast and furious) cars. But I read a review that found these to be poor at filtering( http://www.australianauto.com.au/HTML/Images/Air%20Filter%20Shoot%20Out.pdf ). Most of the air filters that support the power from the usual suspects (K&N, Pipercross) are too long.

Any thoughts?

Matt

tul214 - 16/1/11 at 10:54 PM

Search the k&n filter model RU 0690

RazMan - 16/1/11 at 11:15 PM

How about a T junction the same bore as the turbo and TWO filters?

matt_gsxr - 16/1/11 at 11:30 PM

Cool. thanks for that suggestion that looks like it should pretty much fit.

Area of filter element is about 2.7x5.5*3.14 = 46sq inch (2.7 because some area lost to flange)

Area of previous KN filter on GSXR (stock for carbs) is 6x6 = 36sq inch.

So not too far off and should do the job. I guess I need to measure the space really carefully. That K&N range is a good one I had forgotten about their clever calculator.

Thanks,

Matt

matt_gsxr - 16/1/11 at 11:35 PM

quote:
Originally posted by RazMan
How about a T junction the same bore as the turbo and TWO filters?


2 filters = 2x the price

Which doesn't fit with my super-budget mentality.


Actually I don't really know what the rules are for turbo filters. With NA engines any restriction is a killer, but with a turbo I guess you just end up working the turbo in a different place on its map at the top end. The guys who fit these on bike have loads of space and fit massive long filters, which started me worrying.

I think I need to worry less.

Matt

tul214 - 16/1/11 at 11:46 PM

Info taken from here

K&N Filter RU-0690

Price: £32.93 (£39.52 Including VAT at 20%)

K&N Filter RU-0690. Flange Inside Dia.(F) 57mm Outside Dia.( D ) 140mm Length (L) 89mm Top Style Rubber Flange Length (FL) 16mm Flange Angle (FA) 0 Degrees Flange Offset 0mm Approx BHP rating (Add 80% to this figure if fitted to a turbo engine ) 174Bhp

matt_gsxr - 16/1/11 at 11:48 PM

This is what worried me about the K&N filters.

sorry about the column formatting

Neck Internal Diameter (mm) Neck Type Filter Outer Diameter (mm) Filter Length (mm) Capacity (BHP)
57 Centred 114 127 210
70 Offset 140 127 255
76 Centred 178 152 400

This is from the Demon Tweeks site. It suggests that for 255bhp, it needs an area of 140-20mm x 127mm x 3.14 = 74sq inch

(the -20mm is to account for the filter area being less than the total height).

matt_gsxr - 16/1/11 at 11:51 PM

quote:
Originally posted by tul214
Info taken from here

K&N Filter RU-0690

Price: £32.93 (£39.52 Including VAT at 20%)

K&N Filter RU-0690. Flange Inside Dia.(F) 57mm Outside Dia.( D ) 140mm Length (L) 89mm Top Style Rubber Flange Length (FL) 16mm Flange Angle (FA) 0 Degrees Flange Offset 0mm Approx BHP rating (Add 80% to this figure if fitted to a turbo engine ) 174Bhp


That is perfect. So the formula of add 80% for turbo engine, is the bit that I didn't understand.

Awesome. Thanks. Good link that.

I will now sleep well

Matt