Weber DCNF vs IDF, DCNF for type IV application Options

[Alapone]

Hello all,

I am relatively new to the world of the 914. I have been wanting to convert my (mostly stock) 1975 914 2.0l from FI to carbs since I bought it about a year and a half ago. I recently purchased, via an obscure but cheap ebay add, a pair of what turned out to be Weber DCNF 40mm carburetors and manifolds. I was under the impression they were IDFs (rookie move I know)...

I have done a little research on these carbs for type IV application and have read widely varied opinions on the matter ranging from "throw them away immediately" to "could be a nice setup". I have a set of manifolds that look as if they will match with the engine and if they do I will likely give these DCNFs a shot. I am told these DCNFs were primarily used on alfa, ferrari, fiat and vw type I and III engines for a variety of reasons and are not the ideal carb for the type IV. Having these DCNFs in hand though makes me think twice about starting from scratch looking for some IDF 40s or 44s. My main question is, can I run these DCNFs with my 2.0l without problem in proper tune? If these are an ok carb for the type IV engine does anyone know where I can get a set of manifolds?

Please excuse the rambling and/or inconsistent information gathered by a 914 newb. Any help with this matter would be much appreciated.


-Andrew

[Mark Henry]

I'm probably the closest thing to a DCNF Guru here and I say no, they are a bad choice for a 914.

The DCNF works well in a type one beetle/bus application for a cruiser type car. In fact for a performance daily driver, that you need to get decent fuel economy, perfect AFR and engine longevity out of it is one of the best carbs.
But once you add high side G-loads to the DCNF the carb starts to have fuel/float issues. A hard left in a 914 will result in the carb's completely shutting off.
Please keep in mind the a DCNF is a Lambo/Ferrari carb that is mounted 90* of the VW mounting, thus they are not affected (the same way) by these G-loads.
Also they are great in the type 1 as the barrel are a perfect match for the close together intake ports of a type one head, but this is not so great for the type 4, even in a bus.

So I'd say they work great in a type one, sketchy in a type 4 engine bus, but they really suck in a 914.
BTW the 1967 bus in my signature has real Gene Berg DCNF "42 specials" on it, That engine I built form a GB kit in 1991.

[Alapone]

I'm probably the closest thing to a DCNF Guru here and I say no, they are a bad choice for a 914.

The DCNF works well in a type one beetle/bus application for a cruiser type car. In fact for a performance daily driver, that you need to get decent fuel economy, perfect AFR and engine longevity out of it is one of the best carbs.
But once you add high side G-loads to the DCNF the carb starts to have fuel/float issues. A hard left in a 914 will result in the carb's completely shutting off.
Please keep in mind the a DCNF is a Lambo/Ferrari carb that is mounted 90* of the VW mounting, thus they are not affected (the same way) by these G-loads.
Also they are great in the type 1 as the barrel are a perfect match for the close together intake ports of a type one head, but this is not so great for the type 4, even in a bus.

So I'd say they work great in a type one, sketchy in a type 4 engine bus, but they really suck in a 914.
BTW the 1967 bus in my signature has real Gene Berg DCNF "42 specials" on it, That engine I built form a GB kit in 1991.

Thanks for all the help here. So assuming that the IDFs are the way to go, am I still going to need to swap out for a hotter cam for the carbs to run well? I currently have no autox or track day ambitions or want for substantial performance improvement. Is the cam 100% necessary to go with the carbs?

[ThePaintedMan]

Thanks for all the help here. So assuming that the IDFs are the way to go, am I still going to need to swap out for a hotter cam for the carbs to run well? I currently have no autox or track day ambitions or want for substantial performance improvement. Is the cam 100% necessary to go with the carbs?

I like carbs, but only on cars where someone has already made the conversion or for strictly track-built cars. I think you'll find the consensus here is that you'll be much happier sticking with the fuel injection. Though primitive by today's standards, it works wonderfully when you have all your bases covered. Is it running currently? A working fuel injection is highly desirable with these cars, especially a 2.0.

[Alapone]

Thanks for all the help here. So assuming that the IDFs are the way to go, am I still going to need to swap out for a hotter cam for the carbs to run well? I currently have no autox or track day ambitions or want for substantial performance improvement. Is the cam 100% necessary to go with the carbs?

I like carbs, but only on cars where someone has already made the conversion or for strictly track-built cars. I think you'll find the consensus here is that you'll be much happier sticking with the fuel injection. Though primitive by today's standards, it works wonderfully when you have all your bases covered. Is it running currently? A working fuel injection is highly desirable with these cars, especially a 2.0.

Yes the car is currently running FI not sure which setup it is but I am told it is original and my car is a 1975. Aint broke don't fix it type of thing?

[ThePaintedMan]

Yes the car is currently running FI not sure which setup it is but I am told it is original and my car is a 1975. Aint broke don't fix it type of thing?

Precisely. The money and headaches you'll go through trying to get carbs to work right simply isn't worth it. Instead, spend a few bucks of that money to put in new fuel lines and seals for your 40 year old injection system. You'll be much happier in the long run, IMHO. Many of us who run carbs only do so out of necessity or because we received our cars with the conversion already done. Others like Zach, a moderator here, have endeavored to get their cars back to injection well, because it just makes more sense, not to mention power and better mileage.