Which is faster carb or Fuel injection?

[Ed Wright]

Originally Posted by SuperStock 1890

LT1 throttle body 783cfm at 28"
If I remember right it was 660 cfm at 20"

That is more than I was told. Dave Layer knows. Maybe he will see this and let us know.

[Rich Biebel]

Originally Posted by SuperStock 1890

LT1 throttle body 783cfm at 28"
If I remember right it was 660 cfm at 20"

Very good info right there that I had never heard before and it explains why an LT-1 can run
pretty fast as a SS'er or a Stocker...

[Ed Wright]

But, if carbs are flowed at 12", that makes the LT1 throttle body smaller. Quadrants are 750 & 800 at 12", right? That throttle body won't be that at 12".

[rawhide]

Originally Posted by Ed Wright

But, if carbs are flowed at 12", that makes the LT1 throttle body smaller. Quadrants are 750 & 800 at 12", right? That throttle body won't be that at 12".

Holley four barrel carbs are flowed at 1 1/2" of mercury which is a little more than 20" of water. I don't know what others are tested at. The two barrel carbs from Holley are tested at 3" of mercury from what I have read.
Roland

[Ed Wright]

Originally Posted by rawhide

Holley four barrel carbs are flowed at 1 1/2" of mercury which is a little more than 20" of water. I don't know what others are tested at. The two barrel carbs from Holley are tested at 3" of mercury from what I have read.
Roland

That would make it 660 cfm, which about what I was told. Dave Layer told me my LT2 SS engine would be done about 8200 due to the throttle body restriction. It falls off a cliff about 8300 on the dyno. The 305" TPI cars have the same size, if I remember correctly (been a couple of years now.) Dave said the 305"s run right up to 8800/9000. Hope I remember the numbers correctly.

[Adger Smith]

Joe ask the question: All things being equal in a stocker, lift, valve, piston, head, etc.. what would be faster a carb or fuel injection?

The question has not been answered, yet, and probably will never be because of those first 4 words in his question. I'll add 3 more words that will always keep them unequal... Wet & Dry flow.

[Billy Nees]

Originally Posted by Adger Smith

Wet & Dry flow.

Finally, the magic words!

[Joe DeMarzo]

Billy, I thought the magic words were "I love you or is it please and thank you"?

So the CFM of a FI and carb are currently not even if someone was to swap it out at the track? Also I presume the manifolds would not be an even swap????

When looking for an advantage in my original question how would you measure which would be faster or make more power theoretically? By CFM and or air volume?

By the by I have no idea what you FI guys are talking about with all that mojo but it sure is an education. Thank you!

[Jeff Teuton]

I got a pretty good example. We ran Top Stock with a 360 w/ported Edlebrocks, an 850 good carb and it performed well. When the DP's came along, we added FI bungs on the manifold, changed from an QAF 850 to a 1000 CFM throttle body and we were now fuel injected. Same motor, same cam, same everything. It made about 10 or 15 less peak hp, which surprised us. Spoke to Wilson Manifolds. They said quite normal because the fuel starts atomizing in the carb, and the injector is down in the runner. Also said the total management with the FI system makes it better overall, but more technical. Then when NASCAR got FI, the injectors are in the top of the runner, which I think would be legal in NHRA SS. We will get around to trying that someday. My 2 cents

[Adger Smith]

Joe,
I know this doesn't answer you question in a direct manner, but......
Take a look at The Engine Masters Challenge rules for last few years.
When Wesley and I were doing the rules we made some slight differences between FI and Carbs to try to keep them as equal as we could. The differences are not all in the sizing, it is in the total induction package. Study that and you might be able to get a handle on what/where the difference really is.
Billy,
Another magic word to add to the discussion: Atomization
That word adresses the wet flow and the quality of the A/F mixture in the chamber before the combustion process. (touched on earlier)

Jeff, wow! I see we were typing at about the same time, but your got there first. (RT) Great minds must ...well