1996 Silverado K1500 Fresh Meat

[Piotrsko]

Not to be distracting: I am under the inpression that the larger lift was to open the valves sooner with a longer chance to blow the mixture straight out the exhaust during the increased overlap. On a huffed engine, you run smaller lobed cams

[aerohead]

Originally Posted by vteco

Received a call from Black Bear Performance. The guy at the other end didn't seem to understand what I was asking. He basically reiterated what the website said about custom tuning through them -- gains in HP and torque but at most only slight gain in fuel economy.

I said I wasn't interested in HP gain or torque gain per se, I didn't tow heavy loads in summer, didn't do long distances at highway speeds in general, etc. That I was ONLY interested in a custom tune that might increase fuel economy at say an average 40 mph rural driving -- if that was possible. Would shift points be adjusted, etc.?

He just reiterated what he said were the benefits. From that I gathered that it wouldn't be a "custom" tune to favor a set of desired parameters, but probably just a flash of stock firmware. Or maybe he was just a phone salesman and didn't understand what might be possible for the back shop to do. I do know they do true custom performance tunes, and even loan out recording engine monitors to gather data to optimize custom tunes.

Well shucks, anyway, no progress on that front. Too bad.

For the 350, it's displacement, compression ratio, injectors, fuel pump pressure, valve timing, manifolds, spark timing, exhaust system back pressure, shift points, ECU PROM internal look-up tables, etc. , are going to determine the optimum brake specific fuel consumption ( BSFC ) that the engine is capable of producing, which limits fuel economy potential.
If we had an engine 'map' for your truck, we could see where the 'island' of lowest fuel consumption resides, and the rpm 'band-width' associated with that 'island. It could be just a few hundred rpm, until you're out of it.
Today, a CVT, or 10-speed trans allows small enough gear splits during transient operation that, the engine rpm can be kept close to the BSFC 'sweet-spot,' maximizing mpg.
Once an engine is optimized, all we can do is 'load shedding', with either rolling resistance, aero drag, or a combination of both.
And, even if we're successful in reducing load, if we can't get the engine to see a 'comparable load' at the same 'speed' ( 'taller gears ), we can lose a major portion of savings potential ( happiness is a warm chassis dynamometer ).

[vteco]

305 Vortec CFI L30 actually.

I do look forward to seeing what I can do, in both ecm tune and aero mods with this truck.

Probably have to construct an "engine map" using the tuner/programmer -- it has an ancient interface -- Intel 486 era, apparently it'll even run on a 286. Should be interesting!

It will save a file for the old ECM firmware -- be interesting to explore that file format.

Wonder if it will run in WINE??

[aerohead]

Member AeroStealth bracketed runs in his 2014 F-150 EcoBoost, V-6 at 5-mph increments back in the day.
The truck was good for 22-mpg at 62-mph constant.
32-mpg @ 35-mph constant.
35-mph used to be considered the velocity of highest mpg, but that was before variable valve timing, Atkinson cycle, turbos, CVTs/ 10-speeds, and gasoline direct injection.
40-mph ought to be pretty 'tasty'!

[vteco]

Wow very impressive! I'm getting about 16 mpg average presently on my usual driving routes.

EPA Rating is 13 city, 17 highway, 14 avg. Truck has 250,000 miles on it. No mods whatsoever so far.

First thing to change is adding the mpg meter (Torque app w/dongle).

Then testing to get a baseline.

Then removing that sunshade and seeing what the difference is.

Probably after that will come a half tonneau out of plywood.

And blocking the grill (high temps here are about 35F these days).

I'd like to hear recommendations for fluids like differential, if you think that makes a difference.

The tuner/programmer should be here by then, and I'll have to study up on the many topics that touches on.

Suggestions in general for this truck from anyone interested are greatly appreciated.

[freebeard]

Suggestions ... are greatly appreciated.

Try to resolve the conflict over the half-tonneau. Is a wall to box it in necessary or does the air pressure need to reach the inside of the tail gate as I've seen some claim. Personally, I think the wall and tailgate are rigidly connected.

I wonder about a radius or bevel at the lower front inside the bed.