"Eric Luce" <ontheluce@adelphia.net> wrote:
: Hi. I installed a Mopar performance computer in my truck about a month ago,
: and have been very satisfied with it.
: As an experiment, I tried running a few tankfuls of the "medium" grade
: gasoline instead of "premium" due to these wild gas prices. My question is
: ... I see no appreciable difference in the swith-over, and was wondering
: what advantage I would gain in switching back ?? I am getting no knocking
: or rattling from this, so why is the premium so highly recommended ?? It
: seems to like the medium grade just fine. Thanks in advance for your input,
: guys !!!
As Bernd mentioned, its because of the advanced timing in the MP PCM.
The more advanced spark makes the engine more ping or detonation prone,
especially with heavy loads or towing (which is not recommended with the
MP PCM). You are probably being helped out a bit by the 180 t-stat and
the FIPK which are allowing your engine to run cooler than stock. When
I installed the MP PCM in my '96 318, I had very noticeable pinging even
on 93 octane. However, installing a 180 degree t-stat solved the problem.
I did several other mods afterwards, some of which also helped with this
situation, making it even more of a non-issue. In fact, I actually towed
a 6,000lb trailer through the mountains of PA with the MP PCM in place,
and didn't notice any pinging. This was an accident - I forgot that I had
the MP PCM in there, and didn't realize it until I was about 3/4 of the
way home. Once I did realize it, I swapped the computers since I
fortunately had brought the stock one with me.
I agree with Bernd also regarding the pinging - damage could be occuring
even though you don't hear anything. If it were my truck, I'd be inclined
to throw the stock PCM back in there if you aren't going to use the high
octane fuel. (Actually, that's what I'm doing right now with my Dak.) I
was at the pumps today putting some gas in the Ram, and the attendant asked
"fill 'er up?" I told him, "not at these prices!" Yes, I am foolishly
hoping that the price will drop; and the sooner the better! I put $21
in the truck which put the needle *just* over the 1/4 mark; I don't think
I'm emotionally prepared to handle an $80 fillup. ;-)
Anyway, getting back on topic - another option you may want to look
into, assuming that you don't want to stop using the MP PCM is to
use the low or mid-grade gas with an octane booster. You'd have
to check the prices on the booster and do some calculating, but who
knows, the lower octane gas plus booster *might* work out to be less
expensive than the high octane alone. (I doubt it, but hey, it
doesn't cost anything to check.) :-)
--
-Jon-
.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --.
| 1970 Barracuda - 1990 Dakota 'vert - 1992 Ram 4x4 - 1996 Dakota |
| 1996 Intruder 1400 - 1996 Kolb FireFly - 2001 Ram QC 3500 CTD |
`------------------------------------ http://www.jonsteiger.com --'
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