All of this talk about performance had gotten me to thinking again (even
though I should know better by now). All of this talk about point bounce
at high rpm, larger plug gaps, filters and headers giving 10% power
increase, FI vs carbs is entertaining but how much does it have to do with
the actual "performance" of our beloved LBC's?
A 9 hp gain is about 10% on an A so the 0-60 time would drop from about 12
to about 11 seconds. I still won't be threatening anything above minivans
in a drag race. As far as high rpm point bounce goes, the A makes more
noise than power above 5000 rpm so I don't think that this will effect
performance. It is a wonderful noise, however.
As far as cornering forces go, I would guess that the A generates a
prodigious .7 G on a skidpad. Again, anything above minivans have little
Yet, on an autocross course, I finished in about the same spot with the A
as I did the year before with the Corv**te (near the bottom) Even though
the performance numbers are low, the performance level of the MGA is quite
high. In the hands of someone who can actually drive, the MGA can show
tail to some of the fastest cars made on a tight course. A slightly
modified MGB often beats all comers in the DSP class. Measured this way,
an MG delivers tremendous performance.
People talk about feeling performance increases when modifications are
made. The feel of acceleration in people is one of comparison, not
ultimate numbers. Unless you ran you car hard through the gears, made
changes in 30 seconds, and did it again in the exact same way, I doubt that
you coud tell the difference. I once spent an entire day changing jets and
needles on my Do*ge Char*er before a drag race to try to "home in" on the
proper setting. It took about ten minutes to change parts on the carb and
get back out onto the deserted stretch of highway that served as our dyno.
In the end, the settings chosen were based more on sound and throttle
response than on the feeling of acceleration. K&N filters and headers are
louder than the stock units that they replace. This probably has as much
to do (along with the need to justify the expenditure) with the feeling of
increase performance as any actual number changes.
Want to increase the performance of your LBC a few hp for minimum expense?
Tune your SU for maximum acceleration. The tried and true method of
lifting the dashpots at low rpm / no load assumes that the needle will
correctly deliver the right amount of fuel under all other conditions.
This is probably not the case. If you want performance, tune for
performance and screw the idle.
Having said all of that, I also admit that the MGA runs K&N filters and
that the Spit**re ran a foam filter and a header. Why? Because I, like
most people, want MORE HORSEPOWER.
61 MGA with a well balanced performance envelope