Since they were invented in the 19th century and many a HAMB era car ran them, I'll assume they are HAMB friendly. If not feel free to delete this thread. The engine for the 51 has a mixture problem there to keep the car pump gas friendly and still be able to make power, it runs lean. We made 640 but were turning in 14s and 15s on the AFR. Since I prefer to have it be correct the discussion became how to fix it, EFI was mentioned and will fix it. Boost has been brought up and blowers and those hair drier turbos have been brought up as a way to fix the mixture and gain a little extra. If I go boost, does anyone have any pros or cons about using a centrifugal super charger like the Torqstorm? Different heads are also an option as they flow too well (not enough air velocity but plenty of flow) for the cubic inches we have.
Runs lean = not enough fuel mixed in with the air that is being pumped into the engine. Question is why and then what is the solution to fix it. The why could be the carbs being used or the jetting of the carbs. It could be that the carbs are running out of fuel on a hard pull due to restrictions in the fuel system. Had that happen on a 327 with dual fours.
Ran 10 pulls on the dyno. Started with a BG 830 - might have been too small. Switched to a 1050 cfm Holley. Still ran way lean even after going up 6 jet sizes. Went all in with my 1475 dominator. Still ran lean but was only pulling 1000 cfm of air. That told us, the heads are too big and even though they are moving the air, they aren't creating enough venturi effect to mix the fuel with the air. Heads are too big for the engine. But at 8.5:1 it still made 640. The blower could fix the mixture and take it up to 800 ish.
AFAIK centrifugal blowers have the downside that the amount of air pumped goes up with the square(?) of the rpm, meaning double the rpm, four times the air - or something along those lines. I have a feeling if you combine an engine with heads way too "big" for working well at low rpm with a blower that works poorly at low rpm and perhaps works too well at high rpm you may get an engine with a very unpleasant character. Something along the lines of a high performance twostroke bike - first you get nothing, then you get nothing, then more nothing, until suddenly you find yourself on your back on the ground, wondering where the bike went.
What are the engine specs? Some of the things you've stated don't make sense. Keeping things "pump gas friendly" but it only has 8.5:1 compression, for example. That's plenty low for pump gas. On blown motors, that's typically where we start, with a final compression ratio of roughly 10-11:1 with 6-8 pounds of boost. Here are dyno pulls on two engines we've built using Torq Storm blowers. Very satisfied with the results. The first was a crate LS327 in a '68 C10 at the wheels and the second, a SBC 383ci on the engine dyno. The cars drive like stock until you push them into the revs. Very user friendly. The '68 we ran through an air-to-air intercooler while the 383 went directly into the throttle body, so it suffers from higher intake temps but doesn't seem to care. .
Thank you. I’m hoping the slight boost at low rpms will be enough to pick up the fuel as the system and carb is more than capable of providing enough fuel, the air just isn’t moving fast enough to pick up the fuel in the carb, or at least that is what they are saying. Also with the blow through, I should be able to keep the 830 and still provide enough air and fuel to make it all work right. If not, I also thought about switching to my Crower stack injection setup, but that traditionally doesn’t have good around town manners. In my mind there is never a down side to adding more HP with boost. Well at least there isn’t until I get in trouble with it. It is a 505 BBC. .100 over 454 with a 4.25 stroke. SRP 18cc domed pistons. Heads are FloTek 360 heads with the 133 chambers. They were ported and had a fair amount of work done to them. They flow 430. Dominator Intake that was ported and port matched to the heads. It is a Comp cam with solid roller lifters. 648 lift on 110 center
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