carbies
04-21-02, 08:03 AM
#2
Nikki-Modder Rex-Rodder
Join Date: Feb 2001
Location: Trying to convince some clown not to put a Holley 600 on his 12a.
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That's a little too basic!
VERRRRY simply...
Holley are four barrel carbs, which are good for street cars because they have a wider power band.
Webbers (two barrel carbs) are good on the racetrack because they have a more powerful powerband but the trade-off is that it is a narrow one.
The power band reffers to the engine RPMs.
For example, a with well tuned 4 barrel, the power band might start at 4000 RPMs and last to 8000 RPMs.
That means that at 4000 you can expect it to give you power when you gas it. Below 4000, it'll bog down before it climbs up to the band if you nail it.
Somewhere between 4000 RPM and 8000 RPM, there is a "peak HP" where the carb is delivering fuel and air so perfectly, that the engine is at its greatest power potential with that carb. Typically, as you go up in the RPMs by increments of 100, you see that the power number goes up a little each time, hits a high spot, and starts to come down, and then finally (in this case 8000 RPMs on the dot, ) the power begins to drop off significantly. (The carb has maxed out its ability to deliver the correct amount of air and fuel to feed the engine.)
A Two barrel might have its powerband start at 5800 RPMs and go to beyond 8500, but tends to put out more power at it's peak. You want one for racing, because you are rarely running at a low RPM anyway. But on the street at the red light, at anything under 5800 RPMs, you nail it, and the engine wants to puke on ya.
It's a trade off, and people have been trying to get the best of both worlds into one carburetor for years.
Those RPM numbers are not at all accurate for any particular brands of carbs. I only used them to illustrate the differences.
VERRRRY simply...
Holley are four barrel carbs, which are good for street cars because they have a wider power band.
Webbers (two barrel carbs) are good on the racetrack because they have a more powerful powerband but the trade-off is that it is a narrow one.
The power band reffers to the engine RPMs.
For example, a with well tuned 4 barrel, the power band might start at 4000 RPMs and last to 8000 RPMs.
That means that at 4000 you can expect it to give you power when you gas it. Below 4000, it'll bog down before it climbs up to the band if you nail it.
Somewhere between 4000 RPM and 8000 RPM, there is a "peak HP" where the carb is delivering fuel and air so perfectly, that the engine is at its greatest power potential with that carb. Typically, as you go up in the RPMs by increments of 100, you see that the power number goes up a little each time, hits a high spot, and starts to come down, and then finally (in this case 8000 RPMs on the dot, ) the power begins to drop off significantly. (The carb has maxed out its ability to deliver the correct amount of air and fuel to feed the engine.)
A Two barrel might have its powerband start at 5800 RPMs and go to beyond 8500, but tends to put out more power at it's peak. You want one for racing, because you are rarely running at a low RPM anyway. But on the street at the red light, at anything under 5800 RPMs, you nail it, and the engine wants to puke on ya.
It's a trade off, and people have been trying to get the best of both worlds into one carburetor for years.
Those RPM numbers are not at all accurate for any particular brands of carbs. I only used them to illustrate the differences.
05-08-02, 11:31 PM
#5
From personal experience, a Dellorto carb is an awesome streetable carb with plenty of power across the entire powerband.
Racing Beat modified them for rotary use as well. On a Stock 6-port 13B with just that carb and headers, they would get about 180-185 hp. Those are HP numbers that usually requires opening the engine up to get at.
I'd say it's the best for a daily driven rotary by far. I think Treceb is selling one right now.
Racing Beat modified them for rotary use as well. On a Stock 6-port 13B with just that carb and headers, they would get about 180-185 hp. Those are HP numbers that usually requires opening the engine up to get at.
I'd say it's the best for a daily driven rotary by far. I think Treceb is selling one right now.
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timmya2
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02-18-08 11:14 AM