I have a 1.7L engine with single carb now. So I bought some dual Weber 40 IDF 70 B3, with 32mm venturis with hex bar, mount, intake headers, etc. from Stevegm last year and am getting ready to install them. I'm a novice mechanic at best, so I have some basic questions:

1. From what I read, I need smaller venturis. The power I have now with a single carb is fine for me, but I'm only getting 19 mpg and I see some guys getting 40 mpg, I would like more fuel economy. Any recommendations?

2. For the fuel line, ss there a special fuel line splitter I need to install, or just a "T" or "Y" connector?

3. I have gaskets for the "carb to intake header", is there a gasket for the "intake header to the engine" or can I just use hi-temp RTV?

4. Since I'm so visual, I would love to see some photos of your set up if you have dual carbs.

Thanks in advance.

1 - yes you will need smaller I believe my 2.0L is running 28s

2 - No special splitter, but the stock fuel inlet on the Webers is an odd fuel line size. I don't remember if the Dellortos are the same, but make sure to get the right size or it wont seal well.

I put a fuel filter between the fuel pressure regulator and the carbs.
If you get the glass fuel filter from your FLAPS they come with multiple sizes of hose barbs that thread in so you can go from 3/8 fuel line to just about any other size without an additional adapter.

3 - Between the intake manifolds and the heads, you want to use the phenolic spacers to keep from conducting heat from the heads to the carbs.

If you're a novice you should really get the Tomlinson Dellorto book from CBPerformance. It will have all the info you need and more, HERE

CB used to be the Dellorto importer so they're also a good place for parts HERE.

Thanks for your input guys.

Stugray, I'll have to check the fuel inlet size and see about the phenolic spacers. I may have those, do they look like rubber gaskets?

DBCooper, I do have a weber carburetor book.... I'm sure I'll have to break it out if I try to adjust/tume them myself.

How about some photos?

Can't help you with photos, it's been a long LONG time since I ran Dellortos. Or carburetors. Just google "914 dellortos" or "VW T4 Dells" or something similar and choose "images." That should be all you need.

I'm not sure how much help that Weber book will be. General tuning is the same, of course, but most everything else is different. Book is thirteen bucks, and I bet you'll find it's worth every bit of that. There are also some good tuning explanations on the web, for example I used to recommend the one on Aircooled.net. Don't remember if it's Dell-specific, but John's been fielding those questions for decades so has learned how to explain things, plus he's really good at it, which helps a lot.

No, they are quite think (line 3/8") and very stiff.
I might have a set for a 1.7/1.8L engine at home.

If I do, I'll send them to you.

DBCooper, would the book on Dellortos help me since I have Weber carbs? I'll definitely look up images on the web, I just thought if some 914members had photos, I could be assured the photos would it was done right or "righter"

Stugray, thanks for the info on the spacers.

Carb tuning:


Weber 40 IDF

http://www.redlineweber.com/html/Tech/Table_of_contents.htm

http://www.redlineweber.com/html/Tech/idf_...nt_controls.htm

I found the set of spacers.
If you confirm that you have 4 bolt heads & PM me your address I'll send them to you.
I have no use for them as they dont fit a 2.0L Head.

They are 8mm thick Victor Reinz BTW.
I also have a set of "shorty" intake manifolds that would fit those heads if you are interested.

PM sent. I'm pretty sure I have 4-bolt heads, see the photo below. I have some intake headers that came with the carbs that should work, I'll PM you if they don't.
Click to view attachment

I have run both webbers and dells. Dells work better , but since you have webers here goes.

1. Venturi can be smaller, but is the least of your worries. This is the "dells flow better than webers secret" from the internet. Dells had bigger vents out of the box than webers. The real secret is the number of transition ports, plus dual fuel banjos and better jet location for tuning. I would try 30/32 after I have the idle and main jets set up.
2. In my boy racer days before the internet, I ran 32 mm vents on a 2.0 car with DRLA 40's out of the box from CB Performance.. With the gas on/brake on mode of driving I still made an avg of 28 mpg.
3. webers are right handed only. You should look at the kit that cb offers to change the throttle linkage. Dells are right and left handed. Better linkage geometry.
4. crossbar linkage is trash. too hard to setup and tune, save for the end or until you're tired or dicking around with it. Cable or CSP linkage is the way to go.
Well that should eat up the rest of your summer. You probably need to tell us what distributor you are running. Don't crank the advance past 28 degrees. You will cook the motor. Better to tune the carbs correctly.
5.Now my disclaimer. I have run carbs on 914's since I first met Daniel Bernoulli. I pulled the motor and have set it up for crankfired, single plenum. Hopefully I can drive it before next winter. I'm too old for the noise now.
Have fun

Carlos

Uhh... no, wouldn't help a bit. Sorry, I'd been reading another thread about Dellortos and somehow... lost my way. Carry on.

I will ship the spacers out this afternoon.
And you should definitely get the Tangerine Racing dual carb linkage instead of the crossbar linkage type.

Thanks for all your help fellas. I report back in once I start the switch

Well said. A venturi is, for the most part, a venturi. It's the other differences that make Dells more palatable for some.



Not to nitpick, but that will likely mean changing the jetting as well. More inlet velocity means more fuel. But I understand where you're coming from.

Stugray,
The spacers arrived yesterday. Thanks for your kindness & help!

You are welcome!

If you use the crossbar linkage, be sure to have the spacers installed before you fit the crossbar. It changes the spacing a little.

If you use the tangerine racing linkage, it does not matter.

I'm about to change to twin dellortos, could anyone suggest which side should the throttle linkage be? Firewall or transmission, I seem to have seen both, I'm using the tangerine racing cable linkage.
Thanks
Robin

A good cross bar works fine and is fairly easy to setup if you are patient.

If you want a set of Dels let me know, I have 36's and 40's laying around.

the crossbar linkage sucks. pain in the ass to set up and a lot of fiddling. never used bellcrank, so I don't know. tangerine racing cable set up is the way to go. not cheap, but easy install, easy sync and it will return the feel of a throttle instead of it feeling like a lightswitch under your foot. fwiw.

Since you have the engine out, I'd set up a run stand on your garage floor, easy to do and way easier to tune carbs and adjust valves. I had trouble setting idle air flow since you now have 4 butterflies so flow per barrel is way lower than your present config.
Carb linkage adjustments easy as well..

Click to view attachment

Click to view attachment

CSP makes an excellent, simple bellcrank type throttle linkage. It's easy to install and adjust.

https://www.csp-shop.com/en/engine/type-4-b...ida-23951b.html

McMark has made a cable bracket, not sure if he keeps them on hand.

Takes me about 15 minutes to get it set up and working properly

If you have your heart set on a crossbar, the one from Triad is superior than the CB style ones. The centering springs on the CB can be problematic as well as the flimsy heim joints. Plus, the Triad comes a dandy cable holder. The CB does NOT.