40 or 44 IDF Webers, size matters Options

[Racer]

I ran 40's on a "stock" 1.7 and the same 40's on a 2056. As mentioned, 44's would be better on a higher revving race motor / race cam or larger displacement motor.

[Tdskip]

For 90% of your driving throttle response matters more than max power, id look hard at the 40s.

I’d cooperatively disagree on the Bosch Spiders, reliable and well supported.

[brant]

[/quote]
1985 Alfa spider, maybe it was L jet, but very similar. ECU, sensors, many many connections. When operating correctly the Bosch system is far superior to any carb system, but with 50 years old stuff, it's another story
[/quote]


Nope... was not L jet either... 20 years difference in technology
you took off motronic... same injection that every 914/6 owner wants on their 3.2/6

[Root_Werks]

You want 40's. With that engine the vacuum signal in 44's is going to give you problems. It will probably run very well with 40's and 28mm chokes

(IMG:style_emoticons/default/agree.gif)

Especially if you are running stock compression and cam designed for FI.

A properly tuned D-Jet system works very well on a stock and even slightly modified engine as many have done. Think you'll find over time carbs will make a cool noise, but not really produce any additional power and reduce fuel economy.

[ClayPerrine]

I am on the side of Fuel Injection.

I have run both Carbs and FI on a variety of engines in 914s. I have had a L-Jet four, a D-Jet four, a Carbed four with both Dells and Webers, a Carbed six, a MFI six, and a Motronic six.

The carbed four was the worst of the bunch. I never could get the carbs to stay synced, I always had problems with hard starting and fuel smell issues. I also had issues with hydraulic lock when it rained. Picture me in a driving rainstorm in the parking lot at work trying to get my car started so I could drive home.

Putting the stock D-Jet back on that engine made all the problems go away.

The second worst was the MFI six. It was great when it was running right. Fantastic throttle response, great power and it SOUNDS great. But when it got off, it was a bitch to fix. Hours spent with the protractors, and a wrench to get each stack synced, then syncing the pump to them as a group. (IMG:style_emoticons/default/headbang.gif) Even when it was right, cold starts were an excrsize in frustration. Ether in the air cleaner. Cough sputter die. Another shot of Ether, cough sputter.. start running on 4 cylinders. Keep it running until the other two finally start to fire. Wait 5 minutes for it to warm up before I could drive.


The best is by far the Motronic. Turn the key, it idles... rain, shine,cold or hot. Second best is the L-Jet. But it is the father of the Motronic. It has cold idle issues, but that can be overcome with a little heel/toe until it warms up a little.

The d-jet is better than carbs. Even the carbs on our factory six irritate me.

I would buy a Bowlsby harness and put the D-Jet back on the car. Better gas mileage, better performance, and less gas stink.

Just my $.02.

Clay

[930cabman]

It's looking like D jet might be winning.

First, thanks to all for your insight(s). I am trying to get this project running for my wife, so from that perspective the D jet works. I have three ECU's, last I checked there was a shop in Florida who could diagnose/repair these, but I cannot locate them. Then injectors, probably wise to send them in for cleaning. Wiring harness, other sensors, ...
From a dollars/value point could the D jet be the smart play?

Thanks again

[930cabman]

I committed to D jet, sending the ECU to Module Experts in FLA and speaking with an injector service in Houston. A new carb setup is in the $860. range. Looking like the D jet is the winner

[ClayPerrine]

I committed to D jet, sending the ECU to Module Experts in FLA and speaking with an injector service in Houston. A new card setup is in the $860. range. Looking like the D jet is the winner

Make sure to get a refurbished harness too. That will fix the majority of the D-Jet ills.

Clay

[bbrock]

I committed to D jet, sending the ECU to Module Experts in FLA and speaking with an injector service in Houston. A new card setup is in the $860. range. Looking like the D jet is the winner

I think you made a good choice. I tore my engine down in pre-Internet days because the combination of flaky D-Jet and increasing volume of oil pouring out of the case. Back then, access to info on D-Jet was hard to find where I lived and carbs were cheap so I rebuilt the short block with a carb cam. Fast forward to this year when I finally buttoned up the long block. Now I have these carbs and I'm sure they will be fine, but if I knew then what I know now, I would have put a stock cam in, invested money on a new FI harness instead of carbs, and used the wealth of info now available to put the D-Jet back in.

[930cabman]

I committed to D jet, sending the ECU to Module Experts in FLA and speaking with an injector service in Houston. A new card setup is in the $860. range. Looking like the D jet is the winner

Make sure to get a refurbished harness too. That will fix the majority of the D-Jet ills.

Clay

Whom can cleanup the wiring harness?

The injectors will be going to InjectorRX in Houston. On first reaction twin Webers appeared more simple, but thanks to all responding the Bosch D jet wins.

[Superhawk996]

I committed to D jet, sending the ECU to Module Experts in FLA and speaking with an injector service in Houston. A new carb setup is in the $860. range. Looking like the D jet is the winner

@930cabman

Check reviews on Module Experts. I have no experience with them, never used them but when I visited the page, it doesn't seem to me that they specialize in vintage Porsche stuff. Likewise Google reviews aren't great . . . but obvioulsly on-line reviews can be garbage too.

I believe Jeff Bowlsby who is a regular on this site, has the OEM ECU tester. He can tell if unit is OK but I don't believe he offers repair. Jeff fabricates all 914 harness wiring for engine and ECU harness that you would need. I've purchased his ignition harness as well as his alternator harness. Both are nice kit. FI harness is next up for me.

https://bowlsby.net/914/WiringHarnesses/#SpecializedEquip

You may want to consider Jeff unless you have a confirmation from Module Experts that they have the OEM ECU test equipment to test a vintage 914 ECU.

Don't quote me but I think Automobile Atlanta also can do ECU checkout if you're looking for a second source that is at least familiar with 914 ECU hardware.

[bbrock]

I've gotten the impression from reading various threads on here that these ECUs rarely go bad.

[Superhawk996]

I've gotten the impression from reading various threads on here that these ECUs rarely go bad.

That is true. However, they are 50 years old now. I'm planning to send the two I have to Jeff for checkout. The hope being that of the two I have, one is good and if both are, then I'll have a spare.

I really dislike troubleshooting with parts that you have no idea whether they are good or bad. (IMG:style_emoticons/default/dry.gif)

The main issue for me is that I'm buidling up my D-Jet as a MY73 system to match my car vintage which was a bit of an oddball system so 73' ECU's not as easy to come by.

Of course, eventually it will all go byebye for the /6 conversion.

[930cabman]

Yes, I have gathered the same, these rarely fail, but my thought is to eliminate as many variables as possible. The Bosch system we are cobbling together is from several "baskets". I managed to clean up the case/trans today and couple them up, hook up a starter and try a compression check. 120 - 125 - 120 - 130 cold engine

Today was a good day in the shop, our new "rust free project" may be rolling down the road soon

Thanks to all for the input

[stownsen914]

I didn't read the whole thread, but my experience was that 44 Webers were too big for a 2.0L. My motor had Euro pistons, a sporty cam, ported heads, and headers. I was told 40's would've been better for that motor. Made nice power above 4000 RPM with the 44's though.

[930cabman]

I didn't read the whole thread, but my experience was that 44 Webers were too big for a 2.0L. My motor had Euro pistons, a sporty cam, ported heads, and headers. I was told 40's would've been better for that motor. Made nice power above 4000 RPM with the 44's though.

Agreed, from what I have determined the 40 with 28mm venturis is the right size for a stock motor. I have made the decision to go with stock FI