I've often asked for this, and here it is.
David Vizard bench flows a BBD 2bbl
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HankRearden
Well-Known Member
Very interesting. I wonder how the bigger 2v from the 360 would flow.
This also confirms a bunch of the stuff we did when I was a kid. Holley economaster was tiny but about double the flow of this. The bigger 2v from the 360 has to be an improvement. 500 edelbrock worked great on stock 318.
This also confirms a bunch of the stuff we did when I was a kid. Holley economaster was tiny but about double the flow of this. The bigger 2v from the 360 has to be an improvement. 500 edelbrock worked great on stock 318.
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Interesting video. I was really looking forward to this series, mainly to see what kind of ways he'd show to free up parasitic HP losses. If they end up stroking the crankshaft by offset grinding (as he mentioned they "might") then I've lost all interest. At that point it's no longer a 318, more like a 318 with a 360 stroke.
PRH
Well-Known Member
In the discussion about the pistons they mentioned “if we can get a light enough piston”.
Of course, they’re supposed to be using only stock replacement type parts.
There aren’t going to be any “light weight” stock replacement pistons.
They should all weigh about the same as the factory piece.
He should have better explained why he was testing the carb “as a 4bbl”.
4bbls are rated at 1.5”hg test pressure.
2bbls are rated at 3.0”hg test pressure.
I agree with them using the 4bbl test pressure, so the flow number for that 2bbl is directly comparable to a 4bbl(the numbers most are familiar with).
Keep in mind the number they got is “dry flow”.
Typically, the wet flow of a carb will be about 92% of the dry flow.
Of course, they’re supposed to be using only stock replacement type parts.
There aren’t going to be any “light weight” stock replacement pistons.
They should all weigh about the same as the factory piece.
He should have better explained why he was testing the carb “as a 4bbl”.
4bbls are rated at 1.5”hg test pressure.
2bbls are rated at 3.0”hg test pressure.
I agree with them using the 4bbl test pressure, so the flow number for that 2bbl is directly comparable to a 4bbl(the numbers most are familiar with).
Keep in mind the number they got is “dry flow”.
Typically, the wet flow of a carb will be about 92% of the dry flow.
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MomsDuster
Well-Known Member
Vizard is definitely one of the great minds in the industry. I just find him incredibly hard to watch.
Rat Bastid
Dunamis Metron
And that test was mostly a guess. They were holding the carb down by hand. With duct tape for a gasket.
Was it sealed? No. They pretty much guessed at the leakage.
Were the butterflies centered over the bores in the carb plate? I doubt it, but how do you know for sure?
Why not drill the plate for the carb and bolt it down with a gasket?
Again, I will never understand why Vizard and Wood wanted to hook their names and reputation to something like this turd.
And yeah, offset grinding the crank and “lightweight“ pistons are already diverging from the original claims.
Does anyone actually think that maybe they shot off their mouths and are trying to unscrew what they claimed?
And, when you start knife edging counterweights you can get into some serious balancing issues.
The clusterfrick has begun.
Was it sealed? No. They pretty much guessed at the leakage.
Were the butterflies centered over the bores in the carb plate? I doubt it, but how do you know for sure?
Why not drill the plate for the carb and bolt it down with a gasket?
Again, I will never understand why Vizard and Wood wanted to hook their names and reputation to something like this turd.
And yeah, offset grinding the crank and “lightweight“ pistons are already diverging from the original claims.
Does anyone actually think that maybe they shot off their mouths and are trying to unscrew what they claimed?
And, when you start knife edging counterweights you can get into some serious balancing issues.
The clusterfrick has begun.
yeah, I thought in the beginning they were going to use a "stock 318 2bbl" and see what they could get. Jetting, timing, degreeing the cam, etc. Still will be a cool build, but if we are stroking, regrinding the cam, better pistons..... at that point I'm not sure "mission impossible" fits.
2bbl, who cares. lol what a waste of time.
well, it mattered because the goal was to get 318 hp from a 318 2bbl. Sounds like now it will have a bunch of mod parts with a 2bbl on top
No matter how many times I point out the obvious on the using 1.5"Hg std to test or converted to compare, the same members will jump on to declare it "doesn't matter & it becomes whatever the engine wants". Proving they have mental mice running in circles butt-F'ing each other,.....
If You stroke the stk. crank by offset grinding, then look for the lightest stk. replacement pistons, You optimize displacement/compression/mass balance with the "stock junk". I guess.
I've got an extra 360 crank laying around, thought about turnin' the mains down & tossin' it in, combined with the truck 7:1 compression slugs.......like I have too much time on My hands, lolol.
Always wondered what these carbs flowed just out of curiosity so enjoyed the video.
Most surprised at DV failing to mention an important, & limiting, aspect of raising the rocker for supposedly increasing the ratio. The rocker ratio is generated in two parts, the prod side & the valve side. Raising the rocker to use a longer prod might be detrimental to the overall ratio because it changes the geometry detrimentally on the prod side.
Most surprised at DV failing to mention an important, & limiting, aspect of raising the rocker for supposedly increasing the ratio. The rocker ratio is generated in two parts, the prod side & the valve side. Raising the rocker to use a longer prod might be detrimental to the overall ratio because it changes the geometry detrimentally on the prod side.
The original intent from UT was a 318 maxed out.
Then in there live (I think it was) they moved from the stock 318 cubes to mentioning striking the stock crank.
So anyone that thinks there moving away from the original plan is correct to the point when they discussed it further and opted out of it before it was in stone.
Further videos have them stating there only removing metal for the project and NOT sticking to the 318 only cube build rule.
This was on both channels.
Watch DV’s video on how rockers work. While you are correct in a wrong pushrod length shortening the overall lift because the geometry will lessen the ratio, the opposite is also true.
I didn't say a wrong prod would shorten lift, I said it might change the overall ratio [ & therefore valve lift ]. Lift could be more. could be less. It will depend entirely on the contact points of the particular lifter.
Why it surprised me that DV failed to mention the above is that in his BBC book he has half a page of rocker arm tests, where some rockers delivered a higher ratio than advertised, others a lower ratio.
Why it surprised me that DV failed to mention the above is that in his BBC book he has half a page of rocker arm tests, where some rockers delivered a higher ratio than advertised, others a lower ratio.
My bad! Your right and now your saying what I was trying to get across.
Dartswinger70
Well-Known Member
Vizard basically said they are going to try a 4 barrel. 
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The whole point is to use 318 things, crank, pistons, rods, head, intake and carb.
Can only do addition by subtraction. No aftermarket stuff. Just factory or factory original. It is a cool challenge to try to make 318 hp with such a small carb(flowed 256 cfm).
Can only do addition by subtraction. No aftermarket stuff. Just factory or factory original. It is a cool challenge to try to make 318 hp with such a small carb(flowed 256 cfm).
I agree, it will still be a cool build. I just think a lot of folks were sold at the beginning that this 318 2bbl was going to make 318 hp (or at least try) without all the mods. I think when you stroke the 3.31 crank, use aftermarket lighter pistons, custom grind the cam, port the heads, all of a sudden it is no more "mission impossible", but a cool build.
You can do a lot with just cam, our circle track cars up here can't do much besides cam and have to run a holley 500 cfm two barrel. The stock two barrel can pull the cfm a 318 hp 318 just gonna be very restrictive doing so. It's a weird build but interesting, I like unconventional builds.
superstock64polara
Well-Known Member
When DV mentions 'stroking' the 318 crank I think he's only trying to get the factory piston to zero deck height, that's it (0.030"-0.080").
So, in my mind he'll be using OEM pistons and probably selecting the lightest ones he can find from a pile of shitty cast 318 OEM pistons.
DV's difficult to watch but has an undeniable genius, his guesses (on flow bench leakage) are probably better than most people's hard facts.
I'm tuning in, might actually learn something.
So, in my mind he'll be using OEM pistons and probably selecting the lightest ones he can find from a pile of shitty cast 318 OEM pistons.
DV's difficult to watch but has an undeniable genius, his guesses (on flow bench leakage) are probably better than most people's hard facts.
I'm tuning in, might actually learn something.
What would be fun is when they are done, regardless of the HP it makes, install a 4bbl and see what it makes for HP to see how much that 2bbl hurts a well-prepped 318. Maybe I'll suggest that to Andy
superstock64polara
Well-Known Member
318WR, that's a great idea.
I'm sure I heard Uncle Tony saying the same thing in one of his earlier posts, dyno the 2BBL 318 and then install intake, 4BBL, and headers...
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