To get the best possible performance out of your
1. CHANGE THE CATALYTIC CONVERTER. Makes a HUGE
difference on throttle response, and also acceleration,
clogged or not. Meineke is a good place to
get it done, or any place that does it cheaper.
Magnaflow seems to be a good brand. If the
original converter is left on, it can rob the car of
30-40 precious horsepower as well as throttle
response. If it has the original converter and over
80-90,000 miles, you almost certainly don't need it
tested--just replace it. Complain of low throttle
response, and difficulty attaining high speeds even
though the engine revs at high rpms. Can also cause
rough idle and difficulty starting, if the rest of the
ignition system is in decent working order.
2. Make sure your oxygen sensor is working (can make
a low growling sound when accelerating and cruising
over 30). This can affect idle, minor surging, and
cruising speeds. You can also check this with onboard
diagnostics (make sure it reads rich/lean at fast
3. Using performance ignition components can make a
BIG difference on responsiveness, horsepower, and EASE
OF STARTING. After significant and extensive
research, I've singled out Denso Iridium spark plugs
(other Iridiums plugs may also be good), Magnecor
spark plug wires (www.magnecor.com), and Accel
performance components (ignition coil, ignition
module, distributor cap, and rotor--all available
through kragen, and sometimes autozone.) The ignition
module and coil together, both from Accel, can make
your HT4100 start in half a crank. No kidding.
4. Have a good air filter in there -- the best one
I've found for performance and good filtration is
Amsoil, available at www.amsoil.com. I wouldn't use
K&N paper filters since they can lose efficiency over
time and aren't as good for the engine.
5. Advance the timing 2 or so degrees if you want to
squeak out a few more horses. I haven't done it yet,
but it can make a pretty decent difference.
I've had this setup for two years and 15,000 miles,
and have been extremely pleased with the performance
of this HT4100. It may not necessarily be the
swiftest car on the road, but it has certainly made
this beauty an even greater pleasure to drive.
If one performs all these modifications (listed in
order of significance above), it will probably feel
like a hotrod compared to stock. Although, it may not
quite be ready for a drag race. Now mind you it'll
finish the race easy enough, just not ahead of any
other cars--unless, of course, there's another HT4100
on the track. In this setup, the components seem to
hold up very well, though if there's any ignition
symptoms in the future, check the coil--as it's
usually the first culprit to go out (coils can cause
varied ignition symptoms like rough idle, no start,
and even backfiring through the throttle body--similar
to a clogged catalytic conveter.)
Hope these comments help, and if anyone's tried these
modifications, please post and let us know your
results! My experience with my '82 Eldorado has been excellent.
As a luxury car, it's comfort and elegance is to be enjoyed
the most. But if you want a 'few' extra horses, these
mods will get them.