I would like to open a discussion about something that has bothered me for
sometime about the aftermarket automobile industry in general and the GMC
aftermarket industry in particular. What's my beef? Lack of credible
checking of claims of increased hp/torque/economy/efficiency/braking
improvements if product x is purchased and added to your vehicle.
Extravagant (or even modest) claims are not a big issue for most of the GMC
add-ons. Or are they? Few would argue that adding the Alcoa wheels is not a
significant improvement to the handling of the GMC. Or would they? How
about sway bars? Disk brakes? Fuel injection? New final drive gears? Most
coach owners will swear by the improvement in the handling/power/pleasure
of adding these things to the GMC. But how much of an improvement are they
really? None of us really know. I made the Jim Anstett modifications to my
brakes. It fundamentally changed my comfort in driving the GMC. Yet what
was the real world improvement? I have no idea because I never did any
testing of my brakes beforehand. I was talking with Leigh Harrison a few
weeks ago about his fuel injection system. He was explaining to me how he
had put it through a chassis dynamometer afterwards and it reaches 550
ft/lbs of torque. Wonderful, I said, but what was the reading before you
installed the fuel injection system? And the answer was: I don't know
because I never checked it. I was bothered by this because although I don't
doubt that it improved the torque, I have no way of making a reasonable
cost/benefit analysis (before I spent $3600), without this information.
Given the nature and background of a number of the contributors to the
GMCnet, I assume that I'm not the only person with such concerns. I also
believe a good number of us modify our GMC's not because it necessarily
makes a lot of economic sense but that we find it a challenge to improve
the damn thing. Such is the nature of our obsession with this beauty (or is
it beast?).
So where is this going?
I would like to know if I really am improving my vehicle and by how much.
Therefore, I ask the members of this forum to begin testing in a more
scientific fashion (where reasonable) the before and after effects of their
modifications and sharing this information on the GMCnet. I realize that
such testing will never be up to the standards of Consumer Reports but I'm
sure that it could provide all of us with valuable results. For example,
there is now on the market for $130, a very simple device that measures
horsepower, 0-60, 60-0 and a few other things. If six of us chipped in $25
each, we could purchase this and pass it around. I could easily have
checked my braking beforehand with this. Heinz is thinking about changing
his rear disk brakes from one aftermarket product to another. How about
doing a bit of testing before making the change Heinz. Another example: I'm
going to make muffler and engine modifications over the next few years. My
intention is to have the Transmode checked on a chassis dynamometer each
time. Yes, it will cost me some money (probably $60 per test) but at least
I will really know (and be able to share) the results of the changes. I
would like to see 3 GMC's tested: one with a well adjusted set of classic
brakes, one with the JA system, and one with full disk brakes. I know that
such a test will not be conclusive (if only because the weights of the
coaches will vary) but it will give me some indication of the merits of
each system.
I'm sure that simple testing/measurement procedures could be drawn up by
one of the more analytical engineering types who regular overwhelm me with
their analysis of what goes on inside a bearing (or brake or motor) on the
GMC.
Any takers on this?
Vic Marks
Vancouver BC
75 transmode
sometime about the aftermarket automobile industry in general and the GMC
aftermarket industry in particular. What's my beef? Lack of credible
checking of claims of increased hp/torque/economy/efficiency/braking
improvements if product x is purchased and added to your vehicle.
Extravagant (or even modest) claims are not a big issue for most of the GMC
add-ons. Or are they? Few would argue that adding the Alcoa wheels is not a
significant improvement to the handling of the GMC. Or would they? How
about sway bars? Disk brakes? Fuel injection? New final drive gears? Most
coach owners will swear by the improvement in the handling/power/pleasure
of adding these things to the GMC. But how much of an improvement are they
really? None of us really know. I made the Jim Anstett modifications to my
brakes. It fundamentally changed my comfort in driving the GMC. Yet what
was the real world improvement? I have no idea because I never did any
testing of my brakes beforehand. I was talking with Leigh Harrison a few
weeks ago about his fuel injection system. He was explaining to me how he
had put it through a chassis dynamometer afterwards and it reaches 550
ft/lbs of torque. Wonderful, I said, but what was the reading before you
installed the fuel injection system? And the answer was: I don't know
because I never checked it. I was bothered by this because although I don't
doubt that it improved the torque, I have no way of making a reasonable
cost/benefit analysis (before I spent $3600), without this information.
Given the nature and background of a number of the contributors to the
GMCnet, I assume that I'm not the only person with such concerns. I also
believe a good number of us modify our GMC's not because it necessarily
makes a lot of economic sense but that we find it a challenge to improve
the damn thing. Such is the nature of our obsession with this beauty (or is
it beast?).
So where is this going?
I would like to know if I really am improving my vehicle and by how much.
Therefore, I ask the members of this forum to begin testing in a more
scientific fashion (where reasonable) the before and after effects of their
modifications and sharing this information on the GMCnet. I realize that
such testing will never be up to the standards of Consumer Reports but I'm
sure that it could provide all of us with valuable results. For example,
there is now on the market for $130, a very simple device that measures
horsepower, 0-60, 60-0 and a few other things. If six of us chipped in $25
each, we could purchase this and pass it around. I could easily have
checked my braking beforehand with this. Heinz is thinking about changing
his rear disk brakes from one aftermarket product to another. How about
doing a bit of testing before making the change Heinz. Another example: I'm
going to make muffler and engine modifications over the next few years. My
intention is to have the Transmode checked on a chassis dynamometer each
time. Yes, it will cost me some money (probably $60 per test) but at least
I will really know (and be able to share) the results of the changes. I
would like to see 3 GMC's tested: one with a well adjusted set of classic
brakes, one with the JA system, and one with full disk brakes. I know that
such a test will not be conclusive (if only because the weights of the
coaches will vary) but it will give me some indication of the merits of
each system.
I'm sure that simple testing/measurement procedures could be drawn up by
one of the more analytical engineering types who regular overwhelm me with
their analysis of what goes on inside a bearing (or brake or motor) on the
GMC.
Any takers on this?
Vic Marks
Vancouver BC
75 transmode
