going to com pare damon kuhn Diamondback carbs to C & B Edelbrock 800 Carbs

[SUPERSTOCKRACER]

When the Carb Builder didn't build the cars to YOUR combo, I don't see how Diamondback would be getting a fair shake by you doing this comparison.

same jetting for each set of carbs, same metering rods, springs.
can't see any different modifications from diamondback for his carbs other what I see here, what other modifications could be made differently for each application is beyond me. edelbrock/carter carbs are a basic design, other than different jetting, i highly doubt there are any other changes from the standard.

 

[SUPERSTOCKRACER]

got the damon kuhn carbs on the hemi and will b e trying out them out next sunday.
I like the fact that the choke horns are milled off so now they sit lower under the hood and I have more clearance under the hood scoop.
I needed to raise up the fuel psi to 7.5 to get a lean pop out of them as I raised the rpm's up.They feel nice and crisp as I raise the rpm's up. Time slips will tell as the weather is getting cooler here as fall is upon us. We got 1.5 more months of racing. i hope these carbs pick me up. I like the design alot.

 

[fugly]

they are likely set up for 8-8.25 lbs- if they don't hold the the float off the seat at that pressure, they are.

 

[SUPERSTOCKRACER]

they are likely set up for 8-8.25 lbs- if they don't hold the the float off the seat at that pressure, they are.

are you recommending putting the fuel psi to 8.0-8.25 psi?
i'd like to run it that high if possible. they are holding at 7.5 psi right now WITH NO PROBLEM BLOWING THE NEEDLE AND SEAT.

only thing i'm a little confused is there were a long machine screw on the left side of the carb base in one of the holes. not sure why they were on there?
they were in the side of the body of the carb.

 

[fugly]

I am recommending you try it and make sure it holds as if they are set the way I think that should be correct- if set up that way, they will actually hold about 9 cold, but should not be set that high. No idea what screw you are talking about

 

[mguner]

When the Carb Builder didn't build the cars to YOUR combo, I don't see how Diamondback would be getting a fair shake by you doing this comparison.

Ditto! Keep it real... I don't have Diamond Back carbs and never met Damon. It's not a Texas thing it's a logic thing!

 

[Cranky]

And Amarillo Brillo is a long ways from Houston too lol

 

[poppaj]

Going to be hard to tell how much they pick you up. If it runs better with them now I would wonder how much better they would run if they were set up for your application.

 

[HEMI-ITIS]

Will there be video??:bootyshake:

 

[SPICER]

Going to be hard to tell how much they pick you up. If it runs better with them now I would wonder how much better they would run if they were set up for your application.

He's going to A-B-A test them correct? There will be no question of which makes more power...

Fugly, you have a pm

 

[SUPERSTOCKRACER]

Damon, got my best MPH with your carbs but secondaries are real lazy off the hit, 60 foot was horrible 1.40 to a terrible bog almost chipped my front teeth on the steering wheel.
i think it has something to do with the secondary weights.
I'm seeing these weights were modified to open a little later for a smaller CI motor.
Hope you'll chime in.
I swithed to my old carbs and went a 1.33 60 foot with great torque and very good et.
so i think if i can get the secondaries to open up instantaneously at the hit like my 800 edelbrocks, these carbs
will work awesome.

 

[poppaj]

They are setup to add or subtract weight, that is what the threaded holes are for in the weights.

 

[SUPERSTOCKRACER]

They are setup to add or subtract weight, that is what the threaded holes are for in the weights.

I could use some more info.
can you elaborate a little more on this topic.

more or less weight. could really use some help with this issue.

 

[poppaj]

Adding weight opens the airdoors quicker which should take the bog out of your car. I have a feeling those carbs were setup for a mild small cubic inch motor which wants the secondaries "eased" into, The way the doors are setup now it is causing the motor to lean-out because they are opening to slow causing the bog.

 

[SUPERSTOCKRACER]

Adding weight opens the airdoors quicker which should take the bog out of your car. I have a feeling those carbs were setup for a mild small cubic inch motor which wants the secondaries "eased" into, The way the doors are setup now it is causing the motor to lean-out because they are opening to slow causing the bog.

So where do i go from here?
i thought less weight would open them quicker?

 

[HEMI-ITIS]

:eusa_boohoo:

 

[fugly]

I am not sure where to start here as there is no real information to work with. I do have to admit I expected to see nothing positive for response so for that I must give you credit. That said, I have no records on those carbs to know what they were originally set up for and I have no idea what your setup is.You don't say if you are footbraking, staging with the pedal on the floor or what, and I have no clue what rpm ranges you are dealing with.I ask a bazzillion qiestions about the car when I set These up and keep records on particular carbs for two years- after that they get deleted as there are hundreds of sets out there and usually people have a handle on them and don't require assistance. The carbs ship with screw in weights and original settings on a tech sheet. I doubt that sheet exists in your case as the woman who contacted me knew nothing about what they were. To clear the mud, adding weight slows the doors down. There are 2 or 4 threaded holes in the weights for tuning them, but they are also generally lightened or made heavier for the combo they are set up for as the screw in weights are for fine tuning. If you did not get all the weights with the carbs, 1/4-20 set screws are similar in weight to what ships. LeAVING HOLES EMPTY MAKES THEM LIGHTER/PUTTING WEIGHTS IN MAKES THEM HEAVIER.The air doors open as a product of the weight of the doors, the airflow thru them ( dependent on car/launch settings, etc) and the shape of the flaps( yes they can be changed) That said, I seriously doubt that is the problem. I don't know what jetting you have in them, and I can't see much in the pictures, but it appears the mixture screws are nearly all the way in. This suggests too RICH on the primary jets or too far open on the idle speed screws- again I can't tell from the pics, but it looks like ( judging by the apparent angle of the levers) you have the idle speed screws too high. This will uncover the transfer circuit and cause a bog and is generally a result of jets too lean up front or the wrong metering rod springs. In earlier posts you announced that you were going to jet these the same as the other carbs- this is likely a mistake - this is where part of my aggravation comes from-the statement that all you can do is change jets and metering rods could not be further from the truth - I have repeatedly stated that there are many internal mods to these carbs and this is a prime example- most of the time, they are modified so that the car they are originally set up for uses stock jetting (113/7147 and 110 in this case)or one size bigger where a stock carb would have to be jetted differently. The point behinfd this is many fold but if you are any further up than 116 or down than 110 on the primary, something is wrong with the basic settings on the carb. my suggestion at this point is to look at the jetting and basic setup to start.I have a white paper here http://www.diamondbackengines.com/technical-white-papers/carter-afbavs/ that explains proper basic setup. I would start there -

 

[SUPERSTOCKRACER]

DAMON, thankyou very much for your professionalism.
I want to make these carbs work so I can order 2 more sets for my 2 other cars.
I removed the set screws out of the carbs and went with a 6849 metering rod with .116 metering jets squared.orange springs and accelerator pump rod in top hole.
I am footbraking with going up on the converter to about 2800 rpm, nothing crazy.
I wish I could get more than 1 pass per race since I have to go back to my old cars so I can figure out a dialin for eliminations.
So any input is greatly appreciated.
You are a wealth of knowledge and I appreciate it. Thanks again.

 

[poppaj]

Damon will get you going the right way on the carb tune for sure.

 

[daredevil]

Glad to see this thread took this turn.