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MG MGB Technical - Know about custom air cleaner SU conversion?

I'm in the midst of an SU conversion on my '79 and have been looking in the archives on the air filter issue.

I've seen some mentions of 'custom air cleaners', sort of tubes with air filters at one end. Has anyone out there got photos or a description of such?

I thought about the 'ram air' setup Chrysler had in the 70's and wondered if that principle could work here. Trouble is, I know nothing of flow dynamics, etc., etc.

Could you just fabricate a suitable tube with filter and be OK??

I really hate to spend well over $100 for those cone-shaped K&N filters and that not be that great. I'm not trying to 'squeeze' every ounce of performance out of my car, just getting to run a little better.

Thanks for any input !
Dave
David Steverson

The entire concept of "ram air" is ineffective until the car is over 100mph, so that shouldn't be a concern. You may want to check the archives for info on this, but I remember someone was fabricating a "fresh air" box several months ago and was considering selling them. Otherwise sheck Ebay for stock SU aircleaners?
Jeff Schlemmer

Dave. The standard set up for this conversion is the conical K&N air filters, needed to clear the brake booster and master cylinder.

Unless you have a very radically altered engine, these should do quite well for you. Much information in the archives, including part number information. Moss Motors sells these as a catalog item. Les
Les Bengtson

Rememebr the K&Ns will last a lifetime, making the cost a little more reasonable. If you are not looking to increase performance (and anyway the gains would be fairly marginal on a standard engine) your best option is to stay simple and original.
Steve Postins

At 100 mph, there is a 3% increase in pressure if you slow the air down to a dead stop (ref Bernoulli's equation. Assumes a streamline and no height change from the air inlet to the carb inlet- and by height difference we're talking in terms of hundreds of feet, not a few inches. Equation is: (air pressure) + (1/2 air density times the square of the speed) + (density times gravity times height) equals a constant along a streamline. If you have a pressure and a velocity, and you pull all the velocity out, with no other change, it results in a small increase in pressure)

Makes much more sense to just grab outside air that is colder, and more dense, if you're looking to stuff greater air weight in.
greg fast

I would suggest using the K&N cone filters in the original filter housings, and then running hose from the two inlets on those out to in front of the radiator, which will be a fairly effective cold air system.
dave

Mike Brown of the Seven Shop in Oregon designed a cold air intake system for dual SU carbs for Barry Kindig out of New Jersey who used to post frequently on this site.(there was a thread once on either this site or the MGB experience that someone thought he had passed away but I can not confirm this). Also Daniel Wong out of Ca who also occasionally posts here also designed a cold air intake system for his B. Excellent reading on this subject(cold air intake) can be had in David Vizard outstanding text on Tuning the A series engine. This book is well worth what ever you pay for it.
Frank

I purchased my copy of Tuning the A-Series Engine from WalMart online for $24.26 plus tax and shipping. I agree with Frank, it is one of the best performance books you can buy. Clifton
http://www.walmart.com/catalog/product.gsp?product_id=677153
Clifton Gordon

I been running the K&N conical filters w/HIF's conversion on my '79 with no problems. Little British has them on sale:
KNN56-9320
CONICAL (TAPERED) FILTER FOR SU 1.5 INCH HS4/HIF4 (SAME AS 222-985)
K&N
Retail $65.95 Our Price $56.00


GM Chohaney

This thread was discussed between 10/11/2004 and 11/11/2004

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