Weber 44IDF's: Care, feeding, jetting, etc.

[Rouser]

I'm about to rebuild the Weber's on my '73 2.0L (car contained these; save the carbs vs. FI flames), and have a few questions.

When I purchased the car, it had a cheap-o-crap, napkin-designed linkage assembly that I had to make due with. Syncing and adjusting the two devils has been, how do you say, eventful. I recently purchased the CORRECT linkage from CB Performance to correct this hassle. I also purchased Haynes TechBook Weber manual (excellent) and Bob Tomlinson's (of CB Performance fame) Weber Tech manual (outstanding), both absolutely must-haves for any carb-modified 911/912/914 owners.

1. Before installing this beauty of a linkage, I'm rebuilding/refreshening the IDFs. Any references/opinions/baselines as to how others have jetted/tuned these carbs for 2.0L use? I think they're in the ballpark, but with the slop-o-matic linkage installed, I've only managed to lessen the rare pop in the intake/exhaust, with decent driveability and not-too-sooty plugs. I know they can be set up to run marvelously, I'm just looking for some recommendations?

2. Bob's Tech manual is outstanding when offering information in setting up the carbs. I have the 009 distributor (with Pertronix, of course) already installed, but is this "carb cam" absolutely necessary to run them, or can I wait till I install the 2.1L upgrade (http://www.markstephenshp.com/twelve.html) to split the case and install a Web-Cam (http://www.webcaminc.com/volkswagen.html#vw4)? It runs vicious right now, but I don't know what the major difference is?

Appreciate any assistance.

[MJHanna]

OK for a stock set-up per “HP Weber Carb book” use, as a baseline with 44’s, Main Venturi 36, Aux Venturi 4.5, and Main Jet 135, Em. Tube F11, Air Corr. Jet 175, and idle jet 50. This is the jumping off point start, use this as a baseline,

You can run the stock cam. But before you decide on what cam you need, figure out your intended use for the car. Webcam has various cams, Mark Stevens will recommend a lower cam than you can run so that they are on the “safe side of a recommendation”: I.e. doesn’t want to tweak it” solution.

I run an ox sensor to verify that my mix is correct. (Its easier that pulling plugs etc.) Webcam has a bunch of cams but if you the pick the wrong application for your use you will not be happy.

[michael]

The above post is right on for the jetting and recommendation for the sensor. Why get out the wrenches when you got a gauge telling you how you are burning?

However, I would use the 050 distributor. The 009 has flat spots, was originally designed for VW for off road. The 050 was the best one I ever used. Both stock cammed and with a wild grind from Webcam. I also used the Crane optical unit.

My $.02. Good luck.

[Rouser]

An oxygen sensor? Pardon me for being a total ma-roon, but where "exactly" is this sensor placed/located, what is its gauge, and how do I read the whole shebang? Where's a retail source for this set-up?

I understand the operational theory of O2 sensors, and I've replaced the little buggers in my other FI vehicles, but as far as utilizing them in such a non-native, non-catalyst application has me scratching scalp. Explain ….

[MJHanna]

I have a 4 into 1 header on my car so the OX sensor is placed at where the collector for the 4 pipes. You can find the ox senor gauge at Summit Racing (I think their on line also) or Racer Wholesale WWW.racerwholesale.com Pelican maybe? I run the K&N Surface mounted unit (it fits inside the side vent on the drivers side.) Everybody calls them “Fuel –Air Ratio Monitors.” The theoretical ideal mixture is 14.7:1 they have either lights or LEDs that move based on what the OX Sensor is telling the gauge.

[michel richard]

Getting a bit off the original thread, but, still, how is your 4 into 1 designed ? is simply something boleted on to the back of the headers or does the exaust flow into 1 closer to the engine ?
I thought ox sensors had to be preety close to the heads to work properly, although that could be different if the sensor has its own heater.
Let me (us) know !

[Rouser]

I've located some of the A/F Ratio Monitors at 2 sites;
http://store.summitracing.com/Product.asp?product=312&make=0&model=0&year=0&engine=&material=&finish
and
http://www.splitsec.com/products/electronics.htm

These devices seem to be exactly what I (and every shade tree mechanic) should have, but at present I have other plans for the $170+ premium to purchase one of these. I guess I'm going to have to check for a rich mixture the old fashioned way; a vacuum cleaner hose on the exhaust pipe and the other end strapped to my nose, while checking the plugs periodically.

NOTE: Kids, don't try this at home.

[MJHanna]

The pipes from each cylinder are equal length and meet at the “collector” where the four exhaust pipes come together. The OX sensor is located at this position, that is a hole is drilled into the collector and the sensor is placed here. You are reading “all cylinders” in this application of the gauge. It works because you would change all jets not just the jets in one carb if you’re richening or leaning the engine. The headers are “Kerry Hunter” you can see a picture of them in Pano, or Excellence magazines.

[JP Noonan]

Check out the Pelican tech articles, they give instructions on how to make a A/F monitor for cheap.

[michael]

FYI-The posts to this site will include new technology. These cars were designed over 35 years ago. So, new ideas are submitted that may not be accepted. An oxygen sensor is a relatvely new idea and can be added to any exhaust system to monitor engine operation. Some of the "star wars" type fuel injection for the bad boy race cars have lap top computers to monitor performance.

The D-Jet and L-Jet FI installed on the 914s was ahead of its time back in 1970. Now, it is a dinosaur. Ever wonder why you can't get a "chip" to upgrade your performance like every other clone coming from Japan, Germany and Detroit. Progress my friend.

Let's face it, the 914 is an antique. An antique that still kicks butt.....but still an antique that needs upgrades.

My 914/6 with a 3.0 supprises a lot of people. Both at the stop light and in the curves......

;>) Happy running.

[Dave at Pelican Parts]

CB Performance sells an air:fuel mixture meter. Theirs is a round one the same size as the standard aftermarket VDO gauges. (You know, the ones that are just too small for the 914 center console?)

It runs $108 and change for a 3-wire setup, plus tax and $9 shipping. Total was just over $125 last week. I'll let you know how it works if I ever get my car together again.

The gauge looks a bit cheaper than the VDO gauges, which is a bit unfortunate. Hopefully it works as advertised.

I have SSI exchangers and a stock-style muffler. So the tailpipe is about the only place common to all four cylinders. I'll be mounting the sensor in the pipe from the #4 cylinder (most likely) somewhere near the head. I've had the seat from intake #4 drop twice so far, so I figure that's as good a place as any to mount the sensor.

--DD