DCNF 44 suited to volumex race car.

Competition engines and ancillaries - general discussion
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keithvx
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DCNF 44 suited to volumex race car.

Post by keithvx » Tue Jun 19, 2007 9:05 am

Hello
I am racing and slowly developing my vx beta coupe race car. I have just purchased a dcnf 44 carb (well priced, sec/hand) which I hope to install with a short path, self made manifold.
I am currently running standard cams with hi flow exhaust and intake manifolds. Future improvments will include light flywheel, small supercharger pully and limited slip diff.
I am not happy installing a sidedraft due to clearance problems. I am generally running 4000 to 7000 rpm, wide open 90% of the time.
What chokes,tubes and jets etc should I use ?. Could this carb be too big?.

Any advice would be greatly received .regards Keith

Guy Croft
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Post by Guy Croft » Tue Jun 19, 2007 9:18 am

Keith, hi

that carb is fine, but you'll need to hunt down some 32mm chokes first of all. When you've got them, remind me and I'll go thru the rest of the jetting.

GC

keithvx
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Post by keithvx » Wed Jun 20, 2007 3:59 am

Thank you. Will start looking around.

ShanalNZ
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Re: DCNF 44 suited to volumex race car.

Post by ShanalNZ » Wed Jul 24, 2013 9:35 am

Hi Keith, I know it is some time ago since this post but how did you get on with the 44 DCNF on the VX?

I only want to complete a small number of modifications from standard, e.g. a larger carb and smaller pulley, and any information that you have learned along your journey, and are happy to share, would be appreciated.

I have an opportunity to purchase a Weber 44 DCNF with 36mm chokes (I note that GC suggested they need to be 32mm)...thoughts?

Thanks
Shane

Guy Croft
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Re: DCNF 44 suited to volumex race car.

Post by Guy Croft » Wed Jul 24, 2013 5:14 pm

You must run small chokes with the VX suck-thru unit. Change to comp inlet cam you'd have to go smaller still. A VX unit with GC 3A inlet cam on a 45 DCOE would have to run 28mm chokes.

It is the opposite to tuning an atmo unit, it does not adversely affect the power output in any way.

You also need a big-bore straight-thru 33-36" long 4-1 header. Supercharged engines just don't run well with any back pressure. Which is by way of saying if you ignore this you will never achieve the full potential of the unit per-se.

G
Guy Croft, owner

ShanalNZ
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Re: DCNF 44 suited to volumex race car.

Post by ShanalNZ » Thu Jul 25, 2013 12:39 am

Many thanks Guy.

Grundo Farb
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Re: DCNF 44 suited to volumex race car.

Post by Grundo Farb » Tue Aug 13, 2013 7:56 am

Hello,

I bought Keith's car off him and got the DCNF to work. He made up the manifold to mount it on the VX unit but never ran the car with it. In the end I replaced the 44 DCNF with a 40 DCNF as someone had cut the auxiliary venturis down and also the 44 was too big, I tried 32mm chokes (as that is what the 44 came with) but the car ran far too lean and smaller venturis for a DCNF are very hard to get. I changed to a 40 DCNF with 28 mm chokes. Fantastic.

I would NOT recommend a 44 DCNF nor a smaller pulley. I have extensively modified the bottom end of my engine and not changed the head on it. I have a modified exhaust as per Guy's spec and to be honest the car is limited by wheel spin and torque under acceleration from corners (I run it in tarmac rallies) and the car has serious torque. To give you some context in terms of its competitiveness I beat a 2006 Mini Cooper John cooper works (modern and supercharged) in a rally in April.

Go with a 40 DCNF but also help it breathe. It makes a big difference.

thank you,
Adam
# 405 of 500

Guy Croft
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Re: DCNF 44 suited to volumex race car.

Post by Guy Croft » Tue Aug 13, 2013 11:50 am

MODEL POST!

1st-hand, concise, informed, accurate, proven.

Thanks adam!

GC
Guy Croft, owner

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