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MG MGB GT V8 Factory Originals Technical - Better Air Filters?

Has anyone gone beyond the usual 14" chrome air filter? A recent spell on the rolling road showed my engine is being starved of air at the top of the rev range. Due to bonnet clearance problems I only have a 2" deep filter element and this is causing the restriction. There's about 0.7" further clearance above that, so a 3" filter won't quite fit. Anyone know if there's a 2.5" filter out there?

Beyond this I have considered drilling holes all over the top panel of the filter and then spraymounting appropriate foam over the top. Conservative calculations show I should be able to increase the effective filter area by 50%. Am I crazy or is it actually a good idea? If so, where can I get the foam

All comments would be very welcome.
Thanks, David.
David

David,

K&N filters are supposed to flow more air, have you considered that option. Alternatively, I have heard that the air filter can be crushed to fit under the bonnet.

Paul
Paul

thanks Paul, sadly it seems K&N only start at 3" depth.
David

David, instead of cutting holes and filling them with foam (yecch), K&N makes a filter lid called an X-Stream which has the top made of filter material. That should increase flow. You can get one from Summit Racing

www.summitracing.com

David

David, NJ, you are the guru! Firstly it looks like a very useful site in itself, secondly the top plate is exactly what I need.

Many thanks for your help.
David.
David

K&N does make a 2" element(overall size 2 1/4 X 14) that flows enough air for at least the warmed over 3.5 - 3.9.

Calculations page:
http://www.knfilters.com/facts.htm#SELECT

The instructions that came with my X-Stream air-flow top said that a clearance of 1 1/2 inches is needed between the carb choke horn and the bottom of the X-Stream. Not going to happen with a 2" element and a drop base cleaner. I only had about 3/4" clearance. K&N said that 3/4" was the absolute minimum. I didn't use it. I think the standard K&N 2 1/4 X 14 element does the job with air flow to spare. Part # KNN-E-3740

Carl
Carl

Yes K&N makes a "small" filter. 2.312" tall. I am bummed to give this secret away, but they also have a new item that will help..

Check for it on www.Summitracing.com

It is called the xtream that combination should flow more air than you will ever need. You WILL have to buy a K&N lower filter, the xtream that I bought did not work with my stock filters...
Larry Embrey

I'm running a stage 2 4.6 litre, the rolling road shows an immediate 25bhp gain when we lifted the air filter. A large surface area such as the X-Stream should certainly be of benefit. Will let you guys know.
David

Yeah, the fact that the x-stream allows air flow while a standard top does not will be a help, even if not optimal..

about the only other way to get better air flor would be to duct the top of the carb and use a cold air induction type set-up with an airbow and filter, heck why not plumb in a supercharger while at it hehe..
Larry Embrey

David,

We appear to be running similar set up, I'm using a Holly and Stump Puller Cam from Real Steel.

I do need to rolling road the car. Which rolling road did you use?

A K&N filter was next on my shopping list (I,ve been delayed because I twisted the halfshafts) so I would be interested in any prices you get. I do know someone who is an authorised K&N supplier and could get a price from him, although may not be as cheap as the big boys.

Paul
Paul

Paul,

I rolling roaded at Wilsher Garages, Wimpole, Cambs, SG8 5QE. Guys name is Peter Baldwin, 01223 207217. Very knowledgeable and is ok for you to be 'hands-on'. Races his own mini 'super 7'. Big enthusiast and knows a lot of useful contacts.

Have gone to stateside suppliers for the 'Airflow top'. www.summitracing.com charging $62 plus $24 handling fee plus shipping. Handling fee seems toppy and I've queried this with them this afternoon. Anyone got experience of this as it's 35% of cost price? Order time up to 2 months but will let you know how it shapes up on the rollers.

Be glad to hear of any problems/solutions you've devised with the 4.6 Paul. Perhaps starting another thread?? It's not a straight engine swap from the 3.5.

Regards, David.
David

This thread was discussed between 07/06/2001 and 11/06/2001

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