MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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hirot
Ian Hart
Ashbourne UK
(88 posts)

Registered:
06/01/2011 05:15AM

Main British Car:
1971 MGB GT (conversion) Rover 3947 R380 gearbox

authors avatar
4" K&N style Air Filter Housing
Posted by: hirot
Date: July 28, 2014 11:49AM

I am currently using an Eddelbrock 2" drop base air filter which I have taken around 1/2" off its base so that it all fits under the hood. Having seen many pictures of Eddelbrocks with a small filter top that leads to a 4" pipe conneted to a K&N tube shape filter, I was wondering if it works any better and secondly can you buy the filter top.

Looking at my current set up I can see that th drop base restricts the air as the gap between the filter top and drop base is small, however, whether it allows less air past than the 4" tube version is not clear. I can see that if I used a 4" tube I can at least try and suck in cooler air from nearer the front of the car or even suck it through from the passenger side near the glove box, which may not be a good idea.

In some recent builds I noticed that the heater box has been removed and air is then sucked from in front of the screen, which probably works very well as it is probably forced in. However, over here in winter the heater is kind of handy. Although when the fans come on the hot air gets blown straight through the hood louvres, gets sucked straight down the screen vent and feet get toasted.

The question is should I try and fix some thing that isn't broke and in the finish worse off ?

Regards Ian
Regards Ian


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 4" K&N style Air Filter Housing
Posted by: Moderator
Date: July 28, 2014 03:16PM

Well... if you haven't seen this old article, I think you might enjoy it: MGB Cold Air Induction, Etc.

"Should I try and fix some thing that isn't broke?" is obviously a loaded question. Pretty much anything can be improved. If you finish worse off, you're doing it wrong. Happily, most mods are reversible. Take your time and do your best, and you'll probably be happy with the results.

I was pleased with my old cowl induction system, for carburetor. It worked just fine. After ~20 years, when I finally got around to installing EFI, maintaining that feature was important to me. The MG heater is something I've never missed.


Addicted
Mike Hagadorn
Warren PA
(132 posts)

Registered:
09/27/2013 03:46PM

Main British Car:
1976 TR7 Victory Edition Ford 302

Re: 4" K&N style Air Filter Housing
Posted by: Addicted
Date: July 28, 2014 10:10PM

I pieced together a Spectre Performance brand inline filter setup for my TR7 project. It seems like really nice stuff to me. They have two different sizes of inline 4" filters. I used the smaller diameter version, # 9832. The plenum I used (part on top of the carb) is 98499. They have several different sizes and styles, and best of all, they have drawings with basic dimensions. On their website, look under air intake systems, and then under components.

http://i302.photobucket.com/albums/nn89/74jawa/TR7/Capturee_zpsf4695199.jpg



Edited 2 time(s). Last edit at 07/28/2014 10:20PM by Addicted.


hirot
Ian Hart
Ashbourne UK
(88 posts)

Registered:
06/01/2011 05:15AM

Main British Car:
1971 MGB GT (conversion) Rover 3947 R380 gearbox

authors avatar
Re: 4" K&N style Air Filter Housing
Posted by: hirot
Date: July 29, 2014 12:19PM

Curtis what an amazing article and I think I understood most of it, however, I now have a headache.

It all makes sense and it was kind of the conclusion I had come to in that above 25/30 mph the engine temperature drops to 78/80 very quickly and runs smoothly. As I get into traffic the temperature rises to 85 and the engine just feels slightly lumpy not bad but you can feel it. I had guessed that it was because the under bonnet temperature air was less dense and caused the engine to run a little richer. Whilst my twin fans keep the temperature at 85 when stationary I could see that the under hood air was probably just too warm.

I do have RV8 style headers which I have wrapped and they do seem to help keep the temperature down and from your results if there is a negative pressure under the wheel arches then maybe some heat gets sucked out and blown out when the fans come on.

I like Kellys piped inlet which is the same essentially as Mikes that is a flat plenum with a 4" pipe which I should be able to feed passed the radiator on the passenger side to the grill. However, with the rain we get here maybe it should not point straight forward. Again Mikes TR7 looks like he doesn't feed the 4" pipe straight forward.

I noticed that Bill had a small fan in his pipe, is this a fan to ram the air or just a spinning propeller to atomise any water ?

What I have noticed with the hood louvres near the screen is that they work well when the fans are blowing and I understand that whilst moving they at best suck a little air in.

As the plenum from spectre costs around $133 plus shipping I think I shall try and fabricate a prototype and then buy one if it appears to make a difference.

I really like your intake from the screen vent but I have my wife and dog to consider in the winter months.

Again many thanks....Ian


hirot
Ian Hart
Ashbourne UK
(88 posts)

Registered:
06/01/2011 05:15AM

Main British Car:
1971 MGB GT (conversion) Rover 3947 R380 gearbox

authors avatar
Re: 4" K&N style Air Filter Housing
Posted by: hirot
Date: July 30, 2014 12:42PM

Curtis the more I think about your findings it would seem reasonable/sensible to take air from the screen vent.

A couple of questions:- do you just use an inline air filter and do you still draw air into the cockpit through the face vents/flap vent.

I will keep thinking about my next step as I might consider putting a heater matrix above the passenger footwell and maybe draw air from a 3" tube from infront of the radiator powered from a spare boat engine compartment blower I have. Kind of like the 4" K&N solution but for hot air to clear the screen on those damp days as opposed to feeding the carb.

Needs a lot of thought and mock ups before holes are cut and heater boxes pulled apart.

Regards Ian


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 4" K&N style Air Filter Housing
Posted by: Moderator
Date: July 30, 2014 07:01PM

I removed the cabin vents. That might not be a good option for you, but it suited me fine. When I originally installed my Buick 215, I went to a local auto parts store and looked at every filter in stock. I chose a filter from a first generation Ford Probe (a.k.a. Mazda MX-6). Those cars had particularly nice panel filters with oiled gauze media bonded into a steel frame. Filter area measures ~6" by ~9.5". That suits an MGB firewall, but more filter area might be a good thing. (Ford evidently judged these filters sufficient for their 3.0L V6.)
OldPhotoOfPanelFilter.jpg

Have a look at these too:

Link: Bill Jacobson uses a Smiths heater box as an engine air cleaner.
http://www.britishv8.org/articles/Images-V15-2/BillJacobson-FA.jpg

Link: Scott Wooley fabricated a nifty engine air cleaner too.
http://www.britishv8.org/MG/ScottWooley/ScottWooley-BF.jpg


jblanchard@hcpg.net
Jeb Blanchard
Collierville, TN
(52 posts)

Registered:
12/07/2007 01:01PM

Main British Car:
1961 MGA Chevy 4.3 Vortec V-6

authors avatar
Re: 4" K&N style Air Filter Housing
Posted by: jblanchard@hcpg.net
Date: July 31, 2014 03:35PM

Ian,

I had a problem with air flow and hood clearance on my MGA. I solved the problem with a carb bonnet. Here are some on eBay.

www.ebay.com/itm/Blow-Through-Carb-or-Throttle-Body-Hat-Turbo-Bonnet-Performance-Techniques-/400749477160?

www.ebay.com/itm/Blow-Through-Carb-or-Throttle-Body-Hat-Turbo-Bonnet-Performance-Techniques-/400749477160?pt=Motors_Car_Truck_Parts_Accessories&hash=item5d4e87bd28&vxp=mtr

www.ebay.com/itm/Blow-Through-Carb-or-Throttle-Body-Hat-Turbo-Bonnet-Performance-Turbocharger-/400749476859?pt=Motors_Car_Truck_Parts_Accessories&hash=item5d4e87bbfb&vxp=mtr

I simply placed an air filter near the front grill and connected two 2" flexible hoses to two tubes fashioned from muffler pipe. Plenty of cool air flows: This solved the air cleaner/hood clearance problem. The vent hose on the passenger side was to bring air to the heater box. I covered the inlet to the heater (at the heater) and cut rectangles in the hose to bring cool air to the motor. If I want to use the heater in the winter the covering to the inlet is removed and a flexible vent pipe with no holes cut is connected.

Hope this helps...

Jeb


revised motor 2.jpg
Revised motor side view left.jpg
Revised motor side view.jpg



hirot
Ian Hart
Ashbourne UK
(88 posts)

Registered:
06/01/2011 05:15AM

Main British Car:
1971 MGB GT (conversion) Rover 3947 R380 gearbox

authors avatar
Re: 4" K&N style Air Filter Housing
Posted by: hirot
Date: March 18, 2015 11:56AM

Well its taken a while but I finally reworked the the heater to free up the hole in the firewall and bashed (I think the technical term is panel beating) a piece of aluminium into a filter top.

It seems to run smoother but I need to sit in heavy traffic on a warm day to be sure.

I originally got a top like Scotts but it would not fit under the hood without serious cutting, so I ended up making a test one. Now I know it works I will attempt to beat out a neater one an polish it up.

The side effect of the mod. is that the heater now actually blows.

AirBox.JPG


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