Re: 1.5 rockers and MPG

From: Quintin (sauerquint@gci.net)
Date: Sat May 14 2005 - 22:29:15 EDT


""Ray Block"" <bpracing@worldnet.att.net> wrote in message
news:200505142244.j4EMiAV25734@bent.twistedbits.net...
:
<edit>:
:
: Well Quintin, I did take a look at that article and what I saw was they
were
: testing a chevy engine that was designed to use a 1.5 rocker. They
: reported that most stock chevy rockers were closer to 1.46 and they gained
: power when switched to a true 1.5. Then they tried 1.6 rockers and lost
: power. That's a totally different scenario than switching a factory 1.6
: rocker to a 1.5.

I understand the differences, the thing that intrigued me the most was the
differences in that motors performance with 1.6's and 1.5's. The changes the
switch brought about in the same engine are what set my mental wheels
turning. For my own part, I would gladly sacrifice upper end horsepower for
more low end torque. I rarely get my engine above 3000 rpm for anything,
even passing on the highway. A separate article I read sometime ago pointed
that this very diffenence in tuning can noticably increase MPG. Of course I
can't remember where I read that one now, but that is what sent me down this
path.

: Then, the other thing you may not realize is to change rocker ratios on
your
: engine would require a conversion kit to utilize adjustable rockers. Add
up
: the price of the kit plus the rockers and you may find you'll have to
drive
: a whole lot of miles to ever recover the expense....assuming you actually
: achieved an improvement in mileage.

My understanding is that I could make the switch to 1.5's in the old
reliable stamped rocker form with minimal fuss. Something like what I was
looking at here:
http://store.summitracing.com/default.asp?target=egnsearch.asp&N=300415&autoview=sku

: IMHO, you will benefit most (and immediately) from modifications that
don't
: cost you anything. A good place to start is with a Google search on
: something like "fuel mileage tips" which will cover most of the basic,
well
: known methods....just to refresh one's memory.
:
: One such site is.. http://www.fueleconomy.gov/feg/drive.shtml

While these tips are interesting I am looking more toward some sort of
tuning mod. I can practice these tips anytime, and I do for the most part. I
am just a 40 year old guy, not a 20 something racer wannabe. Not that there
is anything wrong with that, it's just not my style. I'm too old for that
stuff.

: I will offer you a few suggestions you may not have thought of. Since
you
: have a '92 (as do I) you should use the factory air cleaner and air duct
to
: the radiator support. Use any brand name filter but keep it clean.
Leave
: the IAT sensor in the intake (reads hotter temps and leans the air/fuel
: mixture) and either a stock 195 thermostat or a Premium version of a 180
TS
: (I use a digital water temp gauge and the premium 180 versions have always
: run around 186 degrees. I use a standard 180 TS and it never goes above
: 183). When you are due for a tune up consider using Autolite 3924 spark
: plugs (stock heat range but last longer than Champions). Use the stock
gap
: for your slower driving. When it's time to change fluids, use the
factory
: recommended viscosities but switch to synthetic in your engine and rear
end.
: You can safely run the engine a half quart low (keeps the oil away from
the
: crank for less drag). Don't overfill anything.

I've not done much for performance mods, like the IAT or high flow Intake.
I've just done the underdrive pulley and flexi fan to lighten the load on
the motor, and it has helped.

: If you need to replace your exhaust system, make sure the cat is good and
: you might consider a Gibson cat back system as they not only sound good
: (yes, even on a V6) but make good torque as well as horsepower.

I don't really think I need to do anything with the exhaust as I am not
seeking to hot rod it.

: Use the lowest octane fuel you can without pinging. There's more power
here

I agree, I run 87 octane. Any higher on a mostly stock engine is just a
waste.

: than most people believe. We race all our vehicles and have found
through
: testing that higher octane than is needed has always resulted in poorer
: performance. Even with all my mods to my Dak I only use 92 octane. I've
: tried 94 and ran slower. The other vehicles are stock daily drivers and
: run best at the track on 87. If you do experience pinging on 87 or
: 89...then try relocating the IAT to the air cleaner snorkel and using a
180
: TS. If it should still ping you would probably want to have the intake
: plenum gasket changed.
:
: I have several other tips regarding your brakes but in case I've already
: lost your attention I'm not going to relate them here. Write me directly
: if you really want to know.

My brakes can increase the economy? Please post what you know here, I
promise to read every word.

: Ray Block
: 1992 Dakota Sport, RC, 2WD, 5.2L
: See Drag-Truk link for mods...
: http://www.dragtruk.com/ENTRIES/20KM1FD2KWBP.html
:
:



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