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Installing Dual Carbs & Performance Gains


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Just wondering who's installed Dual Carbs onto their standard EA81 (non-dual carb EA81) and what was needed?

 

I've heard that the EGR will need to be blocked off. Do the standard choke and throttle cable bolt up? And the manifold too? What about all the vacuum lines?

 

Also, once the carbs are on, are there any things I need to tune?

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I am getting my dual carb intake sent to me right now.I do know that it is a good idea to try to Sync the carbs together so they both open the same amount as the other.Also trying to get the jetting the same.Also setting the idle.Vac lines should be about the same depending upon what carby pair you choose.Not much else is different I think.I will have to see when I get it.

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I'm actually talking about the factory Dual Hitachis that came on some of the Jap spec motors.

 

that's actually what he's getting.

 

bolts right up to a EA81.

 

the stock throttle cable will work, as it rotates a bar that in turn activates the throttles on both carbs.

 

the manifold has a EGR port/valve, just like the single carb manifold. the PCV valve is centered on the back of it though....

 

the dual carb set-up is manual choke.

 

there are a few vac lines to hook up, but I haven't found a decent diagram for it.

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i think you need a vac guage that u put in the top of the carbs to make sure the same ammount of air is going thru each carb. this is adjusted using the idle screws on the carbs. then you mess with the mixture. well this is what i gathered after watching a show on the discovery channel

 

it was a while ago so i might have mixed up which screw to adjust the vacc with

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Guys the best tool of all for twin carbies is a medical stethiscope.

 

(the cold bastard of a thing that doctors use to put onyour chest to hear your heart)

 

With this it is simple to balance the air flow through both carbies.

Without it the engine rev noise makes it impossible.

Make sure you check them at idle, mid throttle and WOT.

 

 

Have fun with the twins, I did.

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Guys the best tool of all for twin carbies is a medical stethiscope.

 

Hey Matty, can you go a bit more in depth with the stethiscope please? I'm not understanding how you can measure air flow by listening to them?

 

How hard were yours to install? Many vac lines etc to muck around with? If you've got pics as well, that'd be awesome! :)

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Sure Xay, when you listen to the carbs you need to balance the 'sucking sound'

 

the fuel levels are set at the float bowls, the idles you can also adjusts by ear, but the actual air flow is either done by a meter place on the carb tops or..

with the stethiscope.

You can get them so close to perfect with just a little bit of patience.

 

My carbs ( the twins, I miss 'em ) were set up by the previous owner.

I have some shots, PM me you email address and I will send them on.

 

Cheers,

Matt

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