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MGB-GT Have you removed your car's rubber bumpers?

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N

NC Mike

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Guys and gals,

I have two other discussions running about my 74.5 GT and its preparation for a trip to the body shop.

I am not planning a chrome bumper conversion. For that matter, I have a spare pair of rubber bumpers that I will send with the car for paint, so that bumpers match the body, you know, updated look, and all that. (original bumpers held in reserve in case I don't like the look)

My question is this - have you noticed a difference in performance once your rubber bumpers were removed?

Maybe it was just because I haven't driven the car much lately. Maybe it was because the bumpers, spare tire, door glass, quarter windows, side trim, window trim, vent windows, and all of the interior except for the drivers seat and shift knob have been removed for the body work. But WOW!

Even with the car not running up to snuff, due for some plugs, fresh fuel, and maybe some carb tweaking, it provided what seemed to be a much more spirited driving experience. I'm talking seat-of-the-pants noticeably improved, bark the tire on the 1-2 shift without trying hard, kind of improvement.

Has anyone else noticed the same, just by removing bumpers?

I understand I have removed considerable glass weight (haven't put it all on the scale), but I'm curious if any else has noticed a similar change due specifically to bumpers.

Curious,

Mike
 
I haven't....but I really doubt it makes a significant difference. Both bumpers combined weigh less than my wife, and I can't tell any difference in performance when she's not in the car. It is quieter, though, without her screaming "SLOW DOWN!!!!" :smile:
 
Joe Reed said:
I haven't....but I really doubt it makes a significant difference. Both bumpers combined weigh less than my wife, and I can't tell any difference in performance when she's not in the car. It is quieter, though, without her screaming "SLOW DOWN!!!!" :smile:
Click to expand...

Quieter. Ha, ha, ha, ha, ha! :wink-new:
 
Quieter indeed! :D the reality of the rubber bumper generation of cars is that they were pretty seriously detuned to meet smog requirements of the era. So, a GT started in 1962 with 98 horsies and by 1973 was 79 (MGB in 1976 was 62.5 horsepower) so, frankly the weight of the bumpers won't account for much without the rest of the engine getting some serious attention.

stats: ​https://www.mgexp.com/article/performance.html
 
Don't forget that advertised horsepower ratings changed from gross to net in about 1971 or 1972. That accounts for some (but not nearly all) of the reduction in advertised horsepower in the later cars.
 
Horsepower ratings aside, claimed or actual, it was intriguing to be able to feel a difference in the car's performance.

Granted, the bumpers are heavy, but having thought about they are just two of many parts I removed.
Heck, the ro-style spare tire and jack I removed from the back probably weigh as much as one of the bumpers.
For that matter, the glass I removed probably outweighs both bumpers combined.

Horsepower isn't so much an issue in this car anyway. This originally equipped GT will remain so. The second 74.5 GT I have recently acquired is currently without a drive train, but was previously fitted with a 4.3 v6 and automatic. I know a guy with a rover v8 and we're discussing a purchase. That car will be the "Hyde" to my "Jekyll," if I manage to finish both projects. Of course, that car won't be as much about horsepower as it will be about a different kind of fun. :smile:
 
I would think a 72-74 chrome bumper car and a 74.5 rubber bumper car would have the same horsepower. It was not until Jan 1, 1975 that the cars got that single carb setup. Its only a few extra pounds for the bumpers as stated. normally less than a passenger.
 
bob67bgt said:
I would think a 72-74 chrome bumper car and a 74.5 rubber bumper car would have the same horsepower. It was not until Jan 1, 1975 . . . .
Click to expand...

As far as I know, you're right Bob.

The 18V engine was pretty well toasted when I acquired the car. I disassembled it and left the major bits in the capable hands of a local friend who has operated an engine machine shop with great success for decades. That was around 10 years ago, so I don't recall all of the details off the top of my head, but cylinders bored, crank turned, heads rebuilt with new guides, high compression pistons, double row chain, . . . typical stuff. Originally, and currently equipped with the twin carb setup identical to the CB '74 and earlier versions. I still have the air pump mounted (but not connected) "reserving" space for the future installation of an A/C system (hopefully).

When I have the carbs just right, it will idle for me at the 6-700 rpm range.

I'll have it out of the car in the future to install a factory OD I've acquired, but not yet inspected, and while it's out, I'll tend to a few low-performing gaskets, and may consider installing a slightly improved camshaft.

Something about "big boys and their toys. . . ." comes to mind. :smile:
 
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