Welcome to our Site for MG, Triumph and Austin-Healey Car Information.
MG MGB GT V8 Factory Originals Technical - Coefficient of drag
|Does onyone know the coefficennt of drag of an MGBGT, I have been putting figures into a car performance program and it is one of the parameters I need to check.|
|as relative to the pocketbook, off the chart. apologies to the humorless.|
|In Colin Campbell's book The Sports Car, he states|
that a MGBGT v8 has a cd of .39
|On the technical thread there was a discussion re the benefits of an air dam and I believe the drag cf was somewhat lower -- for a chrome bumper gt.|
|I will go with 0.39 and see hows it goes.|
The original BL ST tuning leaflets (1977ish)included with the STR 0189 front spoiler kit said that the MGB Cd was .42 with the original front valance, which reduced to .38 with the front spoiler. The further addition of the ST rear GT spolier (STR 0190) reduced the GT ratio to .37. (MIRA wind tunnel was mentioned)
It never said what the .42 base line referred to, whether this was a Roadster or GT, but as we all know the GT's better aerodynamic performance always showed up in contemporary road test top speed measurments. That is when the vast 'production tolerance' differences were filtered out!
what does the rear GT spoiler look like? Are there aftermarket spoilers that are similiar? I just purchased a front spoiler from J.C. Whitney for $89 (98 list with 10% sale discount). It looks pretty good. It replaces the sheetmetal under bumper piece (this is chrome bumper stuff). It wraps around to the wheel opening of the front fender. a 4" piece of flexible plastic pop rivets/screws to the bottom of the fiberglass spoiler/air dam. The fiberglass piece is the same depth as the original front valance, however it is vertical. with the addition of the flexible bottom piece the air dam gets withing 2 - 3 inches of the road surface.
Lastly, are those cd figures for the rubber bumper or chrome bumper configuration. It would seem to me the cd for the CB configuration would be less because of reduced ground clearance and less underbody drag.
|I'm sure Roger will correct my if I'm wrong,|
The ST rear spoiler as fitted to a full race V8 from the Moss championship in the UK, plucked from the image gallery of Cambridge MGOC on this site.
I have the same fitted on my own GT.
This thread was discussed between 31/10/1999 and 03/11/1999
This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now