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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.
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.
|thanks Paul, sadly it seems K&N only start at 3" depth.|
|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|
|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.
|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. |
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
|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...
|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.|
|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..
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.
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.
This thread was discussed between 07/06/2001 and 11/06/2001
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