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blazinlow 12-06-2012 08:52 AM

edelbrock tunnelram
 
I picked up a SBC tunnelram with dual edelbrock 600 carbs. The carbs are too much for this engine.. Is there a way to lower the cfm on these carbs. I know it can't be done with Holleys , but don't know anything about edelbrock

ap72 12-06-2012 09:35 AM

I have an Edelbrock 1406 (600cfm) carb on a 2.3L 4 cylinder and it runs fine.... So you can throw your "too much carb" theory in the trash can. Its car from too much carb especially when the secondaries rely solely on air demand.

F-BIRD'88 12-06-2012 09:54 AM

The carbs are not too much and you don;t need to lower the cfm.
Where ever you got that idea its false. The carbs are fine.
They will need jetting adjustment. Start with stock default jetting but plan on dialing them in.
The tunnel ram needs some specific set up to be responsive on the street.
But the size of the 600 eddy carbs is not a problem.
Get that out of your head.

vinniekq2 12-06-2012 11:56 AM

what engine are you working with? what other parts are in the engine? How did you determine the carbs are too big?

bondo 12-06-2012 12:07 PM

Quote:

Originally Posted by blazinlow (Post 1619752)
I picked up a SBC tunnelram with dual edelbrock 600 carbs. The carbs are too much for this engine.. Is there a way to lower the cfm on these carbs. I know it can't be done with Holleys , but don't know anything about edelbrock

Ayuh,.... I'd sooner think it's to much Manifold for yer motor,....

Just what, Exactly, is the motor yer tryin' to run this manifold on,..??

F-BIRD'88 12-06-2012 12:58 PM

The velocity valve type secondaries ensure that the carbs never over carburate.
On a tunnel ram you do not want a progressive front rear carb linkage.
You want both carbs to open at the same time. But you do want the correct throttle cable-linkage arm ratio to ensure smooth throttle application.

The ignition advance curve setup is a little different. You can plan on needing to modify the mechanical and vacuum advance systems of your distributor. On a auto trans application a high stall converter is best. Generous rear gearing helps too.
The carbs accelerator pump shot circuit volume and timing will need to be adjusted.

It's all in the setup. I prefer the 750 Edelbrocks but the 600's are not too big.

A manifold vacuum gauge and a air fuel ratio gauge/meter (even a simple basic narrow band type, with heated 02 sensor)
is a big help in getting the carbs dialed in on a tunnel ram.
A selection of AFB main jets, primary metering rods and step up springs (edelbrock timing kit) and a selection of accelerator discharge nozzles or some small drill bits is nice to have.

As posted, you need to let us all in on the details of your engine combo and car.

A different carb will not eliminate the need to dial in that carb for the tunnel ram.
You do not need different carbs or less carb rated cfm.
if you want your tunnel ram to do what it is supposed to do (make more power and torque)
it needs to breath deep to make good power. That means plenty big carbs.
Small cfm carbs choke the power of a tunnel ram and do not work better.
Using the typical converntional carb cfm sizing rules will get you the wrong carbs for your tunnel ram
and limited performance.

hcompton 12-06-2012 01:58 PM

Quote:

Originally Posted by ap72 (Post 1619761)
I have an Edelbrock 1406 (600cfm) carb on a 2.3L 4 cylinder and it runs fine.... So you can throw your "too much carb" theory in the trash can. Its car from too much carb especially when the secondaries rely solely on air demand.

Edelbrock carbs are usally Carter four barrel carbs and not vacum secondary type carbs. all four plates open staggered with cable on my 1406 no electric choke carb. Most edelbrock carbs are the same i think they are rebranding some other types for vacum secondary thunder series carbs.

But tuning is problably the issue. What is it doing. Common problem with those carbs is the accelerator pump must be set to its max setting and them sometimes upgraded for them to wok well in quick off idle throttle movments. Are they both electric choke or manual choke or a mix of both. You may have just gotten them mixed up. manual choke carbs come tunned for performance and electric choke models are tunned for gas milage. you should have two manual choke carbs on the tunnel ram. Yes it will require some good warm up time and a good choke cable setup.

I am betting someone with 500 cfm edelbrocks will trade you straight up and not blink. that being said I would just get them dailed in. Edelbrock is pretty good for phone support if your handy with carbs. if not may need some tuning time with local guru. If they need to be replaced let edelbrock determine this can you may be able to work a good deal for some remanufactured 500 cfm models.

techinspector1 12-06-2012 04:16 PM

You want to go fast?....sell that POS and bolt a blower on.


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