-----Original Message-----
From: Bridges, Bruce <bbridges@alarismed.com>
To: 'dakota-truck@buffnet.net' <dakota-truck@buffnet.net>
Date: Thursday, February 25, 1999 6:07 PM
Subject: DML: RE: RE:part II Re-post Mileage Drop
>James,
>forgot to mentionthat both exhaust shops I talked too were very reluctant
to
>put a "straight thru" muffler on my truck unitl they saw the stock
Ultraflow
>unit. They said that the dodges dont like low back pressure UNLESS its an
>R/T (different computer?? I cant verify, but thats what they "surmised")
>Sams '95 seemed to go the same way as your truck, He put a high flow 3"
cat
>on his truck with the exisitng straight thru muffler (ultraflo??) and lost
>power and mileage! Changed his muffler out to a huge Ultraflow something
or
>other and it "fixed" the problem. Your shop didnt say anything?? Sam, can
>you verify and add to this??
>BKB
You are correct sir! My '95 took a serious low end power hit, and mileage
suffered
2-3 mpg (I religiously document all of my fill ups, and always get a full
tank of gas).
My off the line power was way down, but anything above 3000 RPM was a kick
in the pants (but short lived to only 4500 RPM, then the 'truck' cam took
over and
the party was over too).
Took my truck back to Ed Hanson's, and went from an Ultra FLO (round)
to a Super Turbo (oval) and mileage improved to a solid 15.0 (city/hwy)
and did a dyno run and gained 6 hp, and 30 FT. lbs. over original setup.
The Ultra FLO wasn't the problem, but adding a high Flo CAT, and 3"
pipe ahead of it caused a big decrease in back pressure, and the muffler
was the easiest thing to replace (to gain back pressure).
My '99 RT has been running with a DUAL 2.25" setup, and the same darn
ULTRA-FLO (round) setup that I had in my '95. Sound is great, and mileage
seems to have picked up .5-.75 mpg (you read right, 3/4 mpg). In my first
month of driving the RT, mileage has averaged 13.35 for the first 2100
miles,
with a high of 13.9, and a low of 11.5 (gee what day was that.... Carlsbad,
then the SCCA Solo II day at the Stadium... oh yeah).
I have all mileage figures from my wife's RT as well, and will put them all
together
to map out a expected MPG over the break in of the RT for other drivers.
Having
2, and knowing the conditions that they drive in, I should have a pretty
good
baseline for other people. My wife's RT is bone stock (except for a Quick D
K&N),
and will stay that way. My RT has dual exhaust, and will eventually have a
stage I
H&B throttle body, a Mopar Performance SBEC (YES I AM HOLDING MY BREATH),
and possibly JBA headers/headpipes (still undecided).
I've got a cool spreadsheet in Excel for anyone who wants it (makes neato
graphs to
see how well/not so well you are doing mileage wise). Accurate enough, that
I was
able to detect a mileage drop trend, that had led to a plug change (which
cured the
problem). Statistics don't lie.
Sam '99 RT
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