Carb shootout

[mleach72]

I found this on the Internet. I thought it was an interesting read.

 

[41bigdawg]

I found this on the Internet. I thought it was an interesting read.

That guy is awesome!

Sent from my SM-N975U using Tapatalk

 

[liferider]

Won’t download

 

[mleach72]

I'll try posting the link.

 

[knothead]

Good info...

 

[mleach72]

http://neverworld.net/socalnetscum/files/tech/CarbShoot.pdf

 

[Mr. Wright]

Wow, that was some good reading. And his conclusion wasn't any different than the information you would find on here.

 

[awg]

I had to take a nap after reading all that.

 

[mleach72]

Does anyone know what the flow numbers are on our stock S&S heads? @john sachs would probably know.

 

[john sachs]

S&S heads, with 1.940" intake valves stock flow in the high 150's CFM to 160 CFM @ 10". Not earth shattering by any stretch.
I know Bruce Woltz fairly well, and he is pretty much on in terms of his flow #s. It's possible the modified G was 1 of mine.
John

 

[mleach72]

What I found interesting is how much the manifold bunches up the carburetors. The lowest is the super g at 174.7 and highest is the super d at 191. 16.3 cfm is not a lot in the grand scheme of things. It's even less if you toss out the super d, which isn't really considered a street carb. With this in mind, it stands to reason that the carb with the smallest venturi would produce the most low-mid range torque and best throttle response. That would be the super g. The g is a very good carb, but the butterfly does create manifold turbulence which can lead to some tuning issues occasionally. Next in line is the 45 mikuni. Granted, I have a bias towards the 45 because it's what I have on my pitbull, but this seems to confirm everything that I have been told by the experts. The 45 can move enough air to feed a big inch engine, yet it is small enough to produce big bottom end power and FI-like throttle response.

 

[john sachs]

The manifold is the restriction. S&S originally had a sand cast intake manifold that was really bad. They finally came out with an investment casting, which is a huge improvement. Most Big Dogs have the good one.

 

[mleach72]

The manifold is the restriction. S&S originally had a sand cast intake manifold that was really bad. They finally came out with an investment casting, which is a huge improvement. Most Big Dogs have the good one.

John, I have my 45 mounted to a SE 44mm manifold. Do you think that is a good combo, or do you think I should change to an S&S manifold? I realize a manifold change isn't going to make much difference, but I know it's the right combination of parts, gaining 1 hp here and there that makes an efficient engine.

 

[john sachs]

John, I have my 45 mounted to a SE 44mm manifold. Do you think that is a good combo, or do you think I should change to an S&S manifold? I realize a manifold change isn't going to make much difference, but I know it's the right combination of parts, gaining 1 hp here and there that makes an efficient engine.

The SE combo 42-45 intake manifold is IMO every bit as good as the S&S. Wouldn't pay to change. Just be sure it fits properly on the taller S&S engine.

 

[mleach72]

The SE combo 42-45 intake manifold is IMO every bit as good as the S&S. Wouldn't pay to change. Just be sure it fits properly on the taller S&S engine.

Yep, it seems to fit perfectly as far as I can tell. I was told it was the manifold for the SE 44mm cv carb and made for the taller engines. Thanks!