I recently had the opportunity to dyno my Impala at Lee's Performance
Dynojet shop near my Brother's place in Charlotte, NC. It was quite an
experience straping that 2-ton behemouth down and winding it out in
third gear 7 times. I did several runs with the hypertech tuning
installed and then a couple of stock runs. Below is a composite graph of
the HP and torque curves for
two hypertech and one stock pull, along with some of the data I recorded during the runs
with Scott Knight's Diacom software. You can also see detailed graphs
of the O2 sensor, the
MAF and injector pulse widths , and the
spark advance.
As you can see from the curves, the HPP+ is worth some power. This
amounts to around 8 HP at the low end of the rpm range and 4 HP at the
top end. One thing I found interesting was the stock rev limiter kicking
in at only 5100 rpm. I adjusted that to 5500 for the two hypertech runs
shown below. When I programmed the Hypertech with the stock
rev limiter set, it also limited at 5100 rpm. Based on the analysis, it is
pretty clear that the power improvements from the
hypertech come exclusively from
a 2-3 degree timing advance. I will be updating this page as I get feed
back from my fellow Impalers on this data.
--Mike