Can New School Tech Tame Old School Iron: L46 on Pump gas?

[NewbVetteGuy]

Thought experiment: Can modern engine technology help to make an iron headed 11:1 CR L46 SBC run on 93 octane pump gas, and if, so what would it take?


Run the thing with a really tight squish.
Add an oil cooler and piston oil squirters.
Cold air, of course
Holley Sniper EFI with timing and knock control and the ability to run it fat around the areas where it's most likely to knock.


How close can this get you?


Water + meth injection as the last resort?


Adam

[Lizardracing]

Well, OEMS are faster, safer, more efficient and last longer with less maintaince in every way so I'd say technology whoops old anything any day.

[SchmidtMotorWorks]

Sounds like a way to spend a lot of time and money to be disappointed.

[PackardV8]

New School Tech - The current generation of GM V8 direct injection, computer ignition and the eight-speed automatic should be enough. Of course, for the cost to convert that to an L46, one could by the Corvette it comes with.

[rustbucket79]

Why not just bolt on a set of aluminum heads and reuse everything else you own?

[F-BIRD'88]

Why not just lower the CR on a L46 just enough.... Just enough to run well on good 93 octane gas?
The heads will need hardened exhaust seats also.

10.5..... 10.7.....?

[tenxal]

Thought experiment: Can modern engine technology help to make an iron headed 11:1 CR L46 SBC run on 93 octane pump gas, and if, so what would it take?

Well, to start with.....though advertised as 11:1, the actual compression ratio never approached this.

[rebelyell]

where you been ?

ECM
VVT
EFI (direct in concert w/ port)
GDCI (gasoline direct-injection compression ignition)
HCCI (homogeneous charge compression ignition)

[ClassAct]

I’m not sure why running 11:1 on pump gas on “old school” iron stuff is hard?

[stealth]

I’m not sure why running 11:1 on pump gas on “old school” iron stuff is hard?

Agreed.... if a little on the edge water injection is easy too...

[jeff swisher]

Some numbers to chew on for you and some reading on my results with high compression on pump gas. 91 and 93 octane.

1969 300 hp 350 was given to me that had 100,000 miles and no ring ridge year was 1992.
I stuck flat tops (USA 345NP) into it with Moly faced rings (E251K) and spent 80 hours each porting the 186 casting heads.
I left the 1.94-1.50 valves and uncle did a 3 angle valve job on them No hardened seats.

I roughed up the intake runners and pushed the pushrod pinch open and raised the intake runners .100" and exhaust runners polished and raised .100"

Headers were raised to be larger than the exhaust port..Get some anti reversion there.

Rough Rough intake runners I used a hard stone for that. Get great atomization of the fuel that way.

I decked the block .025" and this left the pistons .013" down the hole 5cc reliefs in the pistons.
I had the heads milled and finished chamber size was 54cc.

I picked the comp magnum 270H cam which is 224@ .050 and .470" lift I ran stock rockers and stock pushrods 110 seat pressure springs.
Engine pulled super hard to 6900rpm where I shifted it for best ET.

Do the math and you will see compression was high. First head gasket used was the .015" steel shim.
This left me with .028" piston to head clearance and 245PSI cranking pressure.
Single point distributor lit it off with a Ford coil from a 1982 inline 6 Mustang.
It liked 41 total timing with 93 octane and 91 octane liked 38 total and I ran 22 initial timing.

I used this as a daily driver in a 78 Nova and I pulled my boat and loaded car trailers with it. No pinging issues.
35,000 miles and I loaned it to a buddy to allow him toi move from his apartment into a house. Trailer in tow.

He gave it back full of gasoline but I found out he stuck in 87 octane..It ran fine until I got on it and busted a ring land and cracked a cylinder wall.

2 days later it is back together with New pistons and sleeved hole and this time I tried the .039" head gasket.

Cranking pressure went down a bit but the performance was not changed.
It ran the same ET and MPH.

Only difference was when outside temps got to 95+ I did not need to change the tune. I did not need to pull timing back 2 degrees.

I still run that block today and it has had a few different sets of heads on it over 400,000 miles on it and not ever ben bored and crank never turned.

My compression now is 10.78 and I have ran the 268H at that compression for years and now run the 280H.
It has been in my 1947 dodge truck for many years and in my 1957 Chevy more door for 6+ years.

Always hammering on it and it just keep going. I have ported 601 heads on it today and run 91 octane it has always been carbureted.

Intake runners are always roughed up. Chambers are always kicked out on the intake side of the chamber near the spark plug like newer heads.
Chambers make a huge difference in the power and RPM capability and fuel octane tolerance.

Like Class Act stated it's not hard to do.

Keep coolant temps in check if you plan on flogging it.
I pulled my 20 foot Pontoon boat from OKC to Texoma lake in August last year 100+ temps I pulled 2 degrees timing and added a lighter step up spring in the 1407 carb for my boat pulling tune.
AC on and windows up the car got 11.5 MPG with boat in tow.
My sons 2013 5.3 chevy truck got less than 10 mpg pulling the boat.
My buddies 2018 Ford 3.5 twin turbo truck got 12.1 pulling it. He has a 10 speed transmission.

I have A TH350. and a Loose 2500 stall converter. Bad choice in converters for boat pulling.

I never hurt the seats in an leaded head car and I have had many of those 60's cars.
Again coolant temps stay in check and no pinging allowed.