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MG MGB GT V8 Factory Originals Technical - Air Dam

Hi Everyone,

I noticed at the MG 2006 that many of you had air dams on the front. In your opinion, does it make a difference in cooling, stability or just style?

Kelly Combes

While the air dams or spoilers have little effect at low speeds, they will aid cooling over 40+- MPH.

Where they really shine is the stability they add at high speeds. Over 80 mph they will really nail the front end to the ground. In my opinion, regardless of how straight & deserted the road is, the MGB in roadster or GT form in not safe to drive over 110 MPH without a good spoiler, but can be very stable with one at speeds over 125 mph.

Not that I have ever driven that fast on a public road.....
Jim Stuart


It makes a big difference in all 3 areas.
In my opinion it definitely enhances the looks of the front end of the car.
The ST Air dam along with ducting used to force air through the lower part of the radiator and vents to get the hot air out of the engine bay are the way to go IMHO.
As far as stability. With the original front valance, I feel it tended to lift the front end at higher speeds. The LE type spoiler although better does not come close to the ST Air dam. 120MPH and the car was very stable.


Bruce Mills

My front spoiler is an LE replacement from Moss. I think it is a different material from original. It is quite stiff. Makes a huge difference at high speed. Like stated above: no spoiler feels like the front wheels are barely touching the pavement, with spoiler (or air dam) = high speed stability.
Carl Floyd

Okay, I have to ask since I'm struggling with the decision. My plans have been all along to cut and finish some intake openings into my stock '68 valence, along with rad ducting for cooling. But, in quest of stability, I'm tempted to buy an ST or LE dam from Moss or VB, but am loath to pay 135 bucks to VB, or get the cheaper and probably fragile fiberglass ST item from MOss. The alternative that I'm considering is, in addition to openings for cooling, converting my stock valance to an air dam by pop riveting a shaped aluminum lip to the lower edge, like they used to do on Trans-am racers. Any opinions on if this would work? Anyone done this and have any comments or suggestions? Best, Joe
Joe Ullman

Hi Joe
To me, with the V8, it is all about stability at higher speeds and cooling. As I mentioned in an earlier posting, I feel the stock valance actually lifts the front end rather than forces the front end onto the road.
I have a Fiberglass ST Air dam and the only problem I have is paint chips caused by rocks etc thrown up in front of the vehicle from the road. I think it is 135 bucks well spent for stability and cooling.
I think your idea will certainly help with cooling, getting cooler air forced through the lower rad, but I can't see it helping any with stability.
I just completed a 4000 mile trip which involved sitting at the Canadian/US border for 1 1/2 hours in 90 degree heat. The temperature gauge got up to about 3/4 but as soon as I started moving it went right back down.
Ford Falcon/Mustang rad
3000 CFM fan
Buick Water Pump
ST Air Dam to lower rad
Duct Work
@10 % antifreeze (just enough to lubricate the pump)
And louvers high up on the inner fender side panels open to the low pressure wheel wells.
It was the addition of the louvers/vents that really solved my cooling problems


Bruce Mills

Hi Joe,

I just got done with duct work for my MG. It makes a big difference. I use a standard valence panel with the 2 oval shaped openings fully ducted into the radiator. I'm still running a 3.9:1 rear end so getting above 80mph is hard reving, when I get my 3.08:1 rear I may add a front spoiler. Even a 80 the car dithers on the road a bit.

M Mallaby

Guys, thanks for your comments. It still seems to me that about a four inch lip off the valance at a 45 degree angle or so would act as a front spoiler. I'm not too worried at this point about cooling, as I'm confident that with my fenderwell header openings, ducting, and a proper radiator, that "shouldn't" be a problem. I guess I could just try my modified valence, but if it doesn't do anything for stability then it's lotsa wasted work, after doing the openings and all.
I'm wondering what's the difference between Moss's $90 fiberglass ST air dam, and the one from VB for $170. Maybe the material?
Just have to decide what's more valuable to me, time or money at this point. Joe
Joe Ullman

Thanks for all the comments. I have not had any cooling problems but a little extra air flow never hurts. I am thinking about putting a oil cooler on and the ST duct would point right at it. Too much?
I have a ST air dam that's been sitting in the garage so I guess I'll give it a try and see how it works.

Kelly Combes


In our climate, our cars don't really need oil coolers. If you don't use one with an oil temp. thermostat you run the risk of not getting the oil up to proper operating temperature.
Carl Floyd

Thanks Carl, The oil cooler was another one of those things hanging out in the garage too. All I needed was to make the hoses. I was thinking I would have to cover it for half the year anyway. Just gotta tinker you know.

Kelly Combes

This thread was discussed between 15/09/2006 and 16/09/2006

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