Fuel economy of 7.4L (454) powered 3/4 ton suburban

[Daox]

I may have missed it, but how many miles are on the engine?

[Daox]

Also, there are diy ceramic coating and dry film lube kits available. Price is about $100 for materials to do an engine.

Welcome to Techline Coatings

[oil pan 4]

I have some ceramic coatings. I coated the turbochargers on my diesel and the cast iron turbo manifold.

This engine has 150,000 miles. Problem is it has 4.10 gears and the top gear in the 3 speed transmission is 1:1 so the engine screams anything faster than 70mph. Which wears them out faster.

This engine will get a 4 speed over drive transmission with lockup converter and 3:1 or 3.25:1 rearend gears behind it eventually.
That will bring the final drive line ratio from about 4.5:1 with non lockup converter and 4.10 gears to about 2.1:1 with an over drive transmission, lockup converter and 3:1 rear gears.

With an engine that can make upwards of 500hp and 600 torque there is no reason to run final drive gear ratios anywhere near 4:1.

[oil pan 4]

Hopefully I can file fit the rings today.
This is the plan.

The engine has been bored to 4.28 inches.
This chart says I should do a 0.015'' gap on top and 0.016'' gap on the 2nd ring and 0.015'' on the oil ring.
That sounds about right because on my diesel I did 0.014'' top and 0.015'' on the second and its still running great. Although I should have ran the wider "nitrous, turbo, supercharger" ring gap. I gave my diesel about a 15,000 mile break in before I even thought about sticking a the turbo on there.

[oil pan 4]

I got the rings file fitted. The guy at the machine shop thought I was crazy for wanting to run that gap. They said I should run 0.028'' minimum. So I put them at 0.024''.

[oil pan 4]

The bow tie aluminum heads I am putting on there (GM P/N 12363390) weigh 41 pounds each the cast iron lead sled heads weigh 77lb each (GM casting 14081045).
The only difference between the heads is the cast iron still have the rocker arms on them.
So both heads stripped down to the same configuration likely weighs about 75lb.
That is a 34lb per head difference.
So the heads plus intake manifold saves almost 100lb of weight.
I have not bothered to figure the difference between the cast iron manifolds.
I know the iron manifolds are about 20lb each. If I remember correctly both headers weigh about 25lb but I didn't weigh them.

[oil pan 4]

I was reading a hotrod magazine article the other day.
They switched from a flat tappet to an identical roller cam and picked up 16 foot pounds of torque through the entire RPM range.
That means it will take 5 to 8 less horsepower to drive down the road at cruse RPM.

[oil pan 4]

I eventually did take apart my old cylinder heads, mainly I wanted to pull the exhaust valves to see if they were burned.
The exhaust valves showed no signs of burning.
So my lean burn cruise tune was safe.

[oil pan 4]

The last major hangups have been over come.
Getting the second cylinder head and the correct longer head bolts. I found out the hard way that these aluminum perdormance heads need longer bolts.
Now it's back at the machine shop getting fitted for the correct push rods. With a $300 cam, $450 roller conversion lifters and $320 full roller rockers, all made by comp camps I don't want to screw something up with something stupid like incorrect push rod length.

[gumby79]

I had an idea on a carb mod for your lean burn setup.

Tuning the fuel to air ratio for peak efficiency with an EGT Probe
From the peak EGT, either increasing or decreasing the fuel to air ratio causes a change in Exhaust gas temperature. Richer EGT cooling occurs because there is excess fuel cooling the exhaust stream via less than optimum burning, and leaner , heating occurs because there is excess air (oxygen) making for a hotter burn. So you must have a base line of where you are starting from regarding cylinder exhaust gas temperatures and a rich or lean condition of the fuel / air delivery system.
Peaking exhaust gas temperature (EGT) with a carbureted engine is frequently a vague point because of less efficient atomization compared to electronic fuel injection to the individual cylinders. As a result, carbureted engines tend to operate smoother at +25 degree +50 degree F on the rich side of peak exhaust gas temperature (EGT).
Fuel injected engines typically provide a more precise peak exhaust gas temperature, therefore the EGT system is likewise a more precise method of performance tuning with fuel injection.
A simple definition of peak EGT is the chemically correct mixture of fuel and air, which gives something close to 100% utilization of all the fuel and all the air delivered to the cylinder.
EGT Probes LVDT Position Sensors Pyrometers Signal Conditioners Electronics H.G. Schaevitz Ind.

Add a screw to the step up spring cover. To push ithe plunger/metering rod down leaning the motor .hook a twist type cable to the screws (have to figure out a spliter, 2 metering rods.) Run into the cab then when cruising down the highway twist to tune. As there is some taper between the needle steps.
This could be automated with a servo controler and this signal amplifier and a fast response probes at 125ns run one for each bank.
Add a vac switch to shut system down in power mode to alow full enrichment.
Dreem big chisel down to reality