Page 1 of 1

Weber DCNF 40 Carb

Posted: March 21st, 2011, 2:26 am
by 124racerinIA
Hi,
Does anyone have specs. or pics. of an adapter to match a DCNF to a standard Fiat TC manifold? I've heard that this is an improvement over the 34DMSA carb I'm using now. The engine is a slightly modified 1756. The current intake manifold does not have a provision for heated water from the engine. I've also installed Alquati 24/1 cams, gasket matched the intake, and a header with free flowing exhaust.
Thanks,
Jon

Re: Weber DCNF 40 Carb

Posted: March 21st, 2011, 9:55 am
by Guy Croft
no and for good reason, the DCNF is for transverse units. It's to to with the float chamber orientation.

FWIW (in stating that) I am frequently told, 'well I run IDFs transverse and they work oK,' or 'I use DCNF on a RWD setup and they work OK.'

And when I ask if they ever suffer fuel starvation they say, ' yes but it isn't too bad.'

So be it, what can I tell them??!!

G

Re: Weber DCNF 40 Carb

Posted: March 21st, 2011, 12:59 pm
by 124racerinIA
Thanks for checking in Guy, I've heard of an adapter that turns the carb 90 deg. That is why I came here to get good advice.

Jon

Re: Weber DCNF 40 Carb

Posted: March 21st, 2011, 1:11 pm
by engineerted
Jon,

I will email you Jim Scurria contact info, He ran this setup as well as I. I don't like the adapeter I have it is too thin and dosn't seal well.

Ted

Re: Weber DCNF 40 Carb

Posted: April 29th, 2011, 3:23 am
by vandor
Hi,

>no and for good reason, the DCNF is for transverse units. It's to to with the float chamber orientation.

I think he wants to use it as a single carb on a 124, so it would be oriented the correct way, East-West :-)

The adapter can be a simple piece of aluminum, about 10-15mm thick, with 2 sets of holes drilled, one to bolt it on the
manifold, and one for the carb.
bye,

Csaba
Auto Ricambi, LLC

Re: Weber DCNF 40 Carb

Posted: May 1st, 2011, 6:57 pm
by 124racerinIA
Csaba,
Thanks for checking in. I have e-mailed Jim and mounted the carb. I'm currently trying to work out a stumble off idle. Any thoughts?

Jon

Re: Weber DCNF 40 Carb

Posted: May 10th, 2011, 5:40 am
by vandor
Jon,

I has been a long time since I tuned a DCNF, but I would look at the accelerator pump sizing. That, and the idle jet.
bye,

Csaba

Re: Weber DCNF 40 Carb

Posted: May 21st, 2011, 5:58 pm
by 124racerinIA
Csaba,

I've gotten the idle jet sizing worked out by using Pat Braden’s method. I currently have 45 jets in the carb. I tried 40's in it and that made it way too lean.

I'm going to try a 45 accelerator pump jet next to see if I can prolong the pump shot. I looked into the carb as I accelerated it by hand, and I feel like the fuel was not transitioning from the idle circuit through the pump shot into the main circuit smoothly.
I also feel like the main circuit is not vaporizing the fuel enough, so my next step is to increase the size of the air correction jets. It now has 180 airs in it. I'll go up to 200 next etc.

Let me know what you think and if any of my logic is flawed.

Thanks,

Jon