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Discussion Starter · #1 ·
I have a fairly well built 3.0 with triple 45 DCOE's on a ported Cannon intake. I was wondering about the chokes and I saw some info below. Can I remove them altogether and gain some responce/power or is it not beneficial. I live in Savannah, GA and actually have never used the chokes even when I lived in the mountains, my car always starts easily. I am unfamiliar with tuning the webers but I have also never tried. Thanks for any info.

Matt
 

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Not ZR8ED, but have some info...

What are your current specs? See our posts below for what we have and compare to yours. Should be in the same ballpark.

In regards to removing the starting choke, that is impossible. It's cast into the carburetor, and is not removable. But, it's just an additional fuel circuit, and provides no restriction whatsoever, so there's really no need to be concerned about removing it.

The chokes we refer to are actually Main Venturis. They are also called chokes, because they restrict the amount of air the carburetor can injest. They come in a range of sizes for each carb. Stock 45mm Webers come with 36mm Main venturis. You can order them as small as 30mm and as large as 40mm. Depending on your application, determines the choke size you should run. Smaller chokes provide more torque, but reduce top hp and rpm. But, larger chokes reduce low end, but provide for very high revs and high hp. Depends on what you want.

I highly suggest you buy a book on Weber carburetors, it is invaluable, even if you don't mess with them that much. It's a good $15 investment.

Here's a diagram, in case you don't know how a DCOE style carb is put together.

http://www.webercarburetors.com/45dcoe.htm
 

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Discussion Starter · #3 ·
RE: Not ZR8ED, but have some info...

Thanks, I was unclear about the assembly of the chokes but you cleared it up. As for the specs on my carbs I am unsure, but I have a great mechanic that specializes in building true race cars. He even built a car that won that PanAmerica race or something like that. It is an endurance race over like 1500 miles from S. Cali into Mexico. It was a few years back, he also love Z's. He tuned my carbs to my engine and it flys.

Take Care
Matt
 

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<b>ZR8ED here.</b>

As far as the "choke" is concerned Dave has it right. It will not affect performance it is only for initial starting. I have started my Z in -10 celcius and it starts just fine with only 2-3 pumps of the pedal. The other Chokes (venturies) provide a pressure drop that causes the fuel to flow from the jets so it is very important. If you trust your mechanic and your motor runs just fine then thats fantastic! But more info is even better. Ask him for all your jet sizes if you don't know how to get them your self. Post back the sizes. It is always good to get some base line jetting figures for differently modified Z's. It can give people ideas into the possible jet combo's for their own application.
I like to use different combo's for different uses. (you can change all your jets in a matter of minutes) I use different combos when I run the car in late fall when it is cooler. I through in another set of jets for more fuel when the average temp is lower than our summer to keep the car from running lean to maximize performance all season.
Some more info on your engine would be great. whats your cam? power band? what cars can you beat? etc etc..
ZR8ED
 

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Discussion Starter · #5 ·
RE: ZR8ED here.

Sorry I haven't responded sooner, been busy at work lately. I am familiar with changing jets and emulsion tubes and all that, however I am unclear on how to determine what sizes I need based on the spec of the motor. I have all the info written down and I will have to find it. I enjoy sharing the info like you said. I will find the data and post it later. For now my engine is a 2.9L running an E88 head that has been shaved, ported, polished valves resized(to what I don't know, I bought it from a guy that ran in GT2 and he did all the work). The cam is a .495 lift 290 duration. It is stroked with a custom billet crank and rods. Everything is balanced and polished. It currently runs 11.5:1 compression. It is kinda rough on the street but I like it. My carbs are 40 dcoe(my mechanic said I should find some 45's, I agree) but he got all the specs and jetted the carbs. The power band is from 4000-8500rpm. Thanks, I'll get the other spec soon.

Later
Matt
 
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