Re: Mileage issues.. (long)

From: Sam Parthemer (samp@cts.com)
Date: Wed Jun 04 1997 - 19:15:54 EDT


Bruce-

        On my truck I keep it below 5000 rpm... 4400 rpm is my hp peak, which
only drops off after 4800 rpm... My torque peak is at 3800 rpm, but is
nearly
a flat line from 1600-3800 rpm (it rises ever so slightly from 1600 to
3800), then
starts to drop off, then falls after 4400 rpm...

        If I wanted to run higher rpm, then the heavier valve springs from Mopar
(p/n xxx - Call Jules @ Magnum Performance :)... But I can't see doing that

with the stock cam... Only a blower / nitrous is going to make any more
major
hp out of the configuration (other than the minor hp increases from MSD
ignitions,
pullies, etc.)

        I currently have Doug Thorley headers, Mopar Perf. SBEC, K&N FIPK
open air filter, and a 3" CAT back exhaust system (Ultra Flo-Stainless).
Without
the headers I lost low end (due to the exhaust system, and also when I run
the
MP SBEC). The FIPK may/may not of made a difference in performance, but
has
changed my driving style (WHAAAAA!)

        Once I put the headers on, my low-end torque came back in a big way,
and my mid-range was great!! (4th gear pulls 1600-4500 rpm). When I tow,
I use the stock SBEC to avoid the 92 octane fuel, and so that I get even
more
torque..(the MP SBEC generates more hp/less torque than the stock unit, and
isn't recommended for towing). On a recent trip to the Colorado river, I
towed a
4500# boat/trailer combo from San Diego - 175 mi. to river, and back... I
did the
same trip last year minus the headers & K&N... Results = 3 mpg better with
same load, same conditions. Speed = averaged 67 mph entire trip vs. 60,
and
pulled the toughest grade 5 mph better... I pull my friends boat better
than his
F250 w/460V8, and get better mileage (I do better pulling than he does
driving hwy
not towing! : 13.5 mpg vs. 11 mpg!!!)

        Again, all towing is done with stock SBEC... It only takes 5 minutes to
change...I've gotten so good at it, that when I get a full tank of gas, I
check the oil-
change the SBEC-- usually with 20/21 gallons used...And I'm done!
        
        I've got a picture of the boat and my truck, I'll post it up the web page.
(nice boat, wish it were mine!)

        Sam '95 SLT

 



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