Weber 44 IDF's - keep - or find original d-jet? Options

[Gatornapper]

Dave -

Thought I posted a Thank You for your feedback earlier, but don't see it - so - Thank you.

Everything you noted was confirmed today in my call with Pierce Manifolds, only in more detail.

I do remember reading the same about 36mm venturi's on another thread here after a search.

I do know carbs but also have experience with EFI systems - I am an electrical engineer with 30 years in computers. But I hear horror stories on the D-Jet systems, constant problems, parts hard to find, etc. I am used to non-stop "fix-or-repair-daily" on my '70's Triumph motorcycles (I ride them all regularly), but don't need that in a car. Actually, all my old Trumpies are very reliable as I've had them long enough to shake down almost all issues....they all usually start on 1 kick, hot or cold.....who needs electric start?

GN

If the cam has been changed out for a carb-friendly one, you'll never get the D-jet to work right.

Sir Andy got his car to work OK with 44s, but he swapped in smaller venturis. I don't remember the size, possibly 36es?

The larger carbs on the smaller engine will give you a week vacuum to pull fuel into the air stream. Mixture quality will suffer at low RPMs, and low-end torque and drivability will probably be worse. It will be able to wind way up at WOT, but the stock cam and heads limit your useable RPM range anyway.

That said, they can be made to work. But 40s are generally preferred on 914 motors.

As Rob C. said--if you know carbs and don't want to learn D-jet, stick with carbs. Use your best judgement on what size will work for you.

If you're selling the car, it's usually best to do as little as possible to it. You almost never get back the full cost of work done to a car when you sell it.

--DD

[injunmort]

well, you have all the answers, good luck.

[Gatornapper]

Rob -

One of my fav things is diagnosing and fixing things. And learning new things.

My problem right now is time - too many projects going at once, one that keeps pulling my head underwater.

How much is the new harness? Why are the harnesses so problematic? Typically it's not the wiring, but the terminations in connectors. Are the connectors Bosch?

Thanks,

GN

If you don't want to learn D-Jet, do what you know. There will be a learning curve, and yes, the D-Jet components will be in varying states of usability and repair. I'd recommend buying a new wiring harness from Bowlsby if you do go that route, but that's just my thought.

Part of my personal enjoyment with these cars is challenging myself and learning new things, but that's not an interest for everyone. Some people just want it to work and drive it.

Your car, your call.

[Gatornapper]

NO! DO NOT have all the answers. Never have, never will.

I do have a plan.....huge difference......

Tomorrow new information/data may come - new answers - and bring about a new plan.

Your input Mort, has all been greatly appreciated.

GN

well, you have all the answers, good luck.

[BeatNavy]

Here's the link to Jeff's page: http://bowlsby.net/914/WiringHarnesses/

The harnesses are not cheap (depending on your definition of cheap), but they do give you piece of mind and help eliminate lots of troubleshooting variables. Once you get your hands on a harness that's over 40 years old and spent most of its life in a hot engine bay, you'll understand why. The old wiring harnesses get very brittle and "crunchy."

Having said that, if you're not looking long term, it may not be worth the investment. Overall, I agree with DD at this point. I'm fully confident you could figure out the D-Jet system, and we can provide lots of help, but based on the way you described your plans and situation I'd probably recommend sticking with getting the right carbs working properly.

[Gatornapper]

Cabinetmaker -

Long discussion with good friend resulted in a change in strategy on a major investment that just may allow me to keep the 914.

I sure hope so.

A very good friend of mine for 44 years.... http://www.harrisonhigginsinc.com/

About 20 years ago he was asked to head up Colonial Williamsburg's Reproductions unit, his work is in the top executive offices of major NY banks (and my bedroom), has taught in a major university. His son now runs his business. But Harrison (elder) is still in the shop almost every day.

GN

PS: from where I sit, you are young. But old enough to know what I meant for sure....

So, you bought a 914 to flip and make money? I wish you luck sir.

[Gatornapper]

Rob -

Again - thanks.

I've built complex wiring harnesses myself. Wouldn't attempt this one as I have no source for the connectors nor the tools to do the wire crimping/terminating.

Think I'll evaluate and test the harness that I get from Ken and then decide.

Great source for me to study here:

http://bowlsby.net/914/Classic/zTN_Man06.pdf

I'm thinking now if I can keep the car to study the system thoroughly until I know it pretty well, then maybe this winter test all the components, replace questionable ones, and look at installing before spring.

GN

PS: One son says, "Beat Navy!" Another says, "Beat Army!" One son says, "Beat UVA!" A daughter says, "Beat VA Tech!" But we all love one another anyway.....

Here's the link to Jeff's page: http://bowlsby.net/914/WiringHarnesses/

The harnesses are not cheap (depending on your definition of cheap), but they do give you piece of mind and help eliminate lots of troubleshooting variables. Once you get your hands on a harness that's over 40 years old and spent most of its life in a hot engine bay, you'll understand why. The old wiring harnesses get very brittle and "crunchy."

Having said that, if you're not looking long term, it may not be worth the investment. Overall, I agree with DD at this point. I'm fully confident you could figure out the D-Jet system, and we can provide lots of help, but based on the way you described your plans and situation I'd probably recommend sticking with getting the right carbs working properly.

[BeatNavy]

Here's another resource for you: https://members.rennlist.com/pbanders/djetparts.htm

I've read that page probably 100 times or more.

I've got a son who says "Beat UVA" and a daughter that hopes to say the same in a few months. And another daughter who should be saying "I need a job. Hire me."

[Gatornapper]

WOW! What a gold mine! I can pre-test all the components before installing the system!

PRICELESS!

I can also see issues ahead I need to address: return line on tank sealed off, and more.

Car has new Electronic Ignition - need to open distributor to see what's inside - points? Or electronic? wonder if I can use EI with the FI.....?????

Lots of questions.....

GN

PS: We are a VA Tech family, and it was really hard on me when my daughter decided to go to UVA, but she graduated Phi Beta Kappa with distinction, so we are grateful. Have graduates of VA Tech, UVA, Liberty, Univ. of Richmond and ODU - all who put themselves through. Daddy told all 8 kids, "No way Dad will ever make enough to put 8 kids thru college, and wouldn't be fair to pay for some and not others - so here's the deal: you earn your own way through college and Daddy will buy you a nice car!" It worked. I bought 5 cars, they have 8 degrees among them. 3 chose no college but are each very successful in their careers. Family pic on Thread "What the Heck do you look like?"

Here's another resource for you: https://members.rennlist.com/pbanders/djetparts.htm

I've read that page probably 100 times or more.

I've got a son who says "Beat UVA" and a daughter that hopes to say the same in a few months. And another daughter who should be saying "I need a job. Hire me."

[Dave_Darling]

If you like staring at analog circuits, you can download the circuit diagrams for the D-jet ECU from Brad Anders' page there. The diagrams were drawn up by Frank Kerfoot, who I believe was a sparky at Bell Labs at the time. I was able to get ahold of a copy and scan them, and Brad volunteered to try to make sense out of them. (Better anyone else than me!!!)

The D-jet is electronic, but just barely. Everything is analog, and the basic injection pulse width (time the injector is open) is determined by the inductive coupling between two coils of wire, moderated by a metal rod that is physically moved by air pressure.... It's massively funky to someone who is more used to 1s and 0s!

Anyway, sounds like you have a plan, which is more than half the battle.

--DD

[Gatornapper]

Dave -

Ha! Like I'm gonna want to dig into analog circuitry before I even understand how the system works? No way!

But very kind and gracious of you - thank you so much!

Even in the '70's when I was fiddling with Volvo's analog ECU, I didn't bother getting into their analog circuitry - grasping all the I/O devices was enough! And that will be enough for me on the D-Jet system as well.

While I am anal/retentive (boy, haven't heard that one in a long time), I am not so much so that I'd want to dig into analog circuitry.

But your feedback is indeed greatly appreciated!

GN

If you like staring at analog circuits, you can download the circuit diagrams for the D-jet ECU from Brad Anders' page there. The diagrams were drawn up by Frank Kerfoot, who I believe was a sparky at Bell Labs at the time. I was able to get ahold of a copy and scan them, and Brad volunteered to try to make sense out of them. (Better anyone else than me!!!)

The D-jet is electronic, but just barely. Everything is analog, and the basic injection pulse width (time the injector is open) is determined by the inductive coupling between two coils of wire, moderated by a metal rod that is physically moved by air pressure.... It's massively funky to someone who is more used to 1s and 0s!

Anyway, sounds like you have a plan, which is more than half the battle.

--DD

[Gatornapper]

Got a call from my good friend in whose barn the 914 was parked for about 12 years. I brought him up to speed on how things are going with the car, and the whole issue of the carbs.

He re-affirmed to me today what he had told me earlier: he had been riding in the car through that day with the PO (also a good friend of his) and he said he was really impressed with how strong the engine was for a 2 liter. He affirmed again how well it ran.

SO, I am going to initially install the 44 IDF Weber's with the 44mm venturi's.

I gotta find out what he is talking about. And if the Weber expert at Pierce Manifolds in CA was correct about no mid-range torque.

Who knows? If it runs great mid-range, I just may return the 32mm venturi's.

On a related issue, Ken in Cinci (bigkensteele) sent me a pic of the D-Jet system and I was blown away at the tiny throat on the throttle body. Looked like 28mm. How can that thing breathe? And the air intake nozzle is even smaller!
Heck, the throat on the Amal carb on my '71 Triumph Trophy 500 is 26mm!

So anyone tell me the diameter of the throttle body throat on the D-Jet?

TIA,

GN

[TheCabinetmaker]

Closer to 50mm

[Gatornapper]

More better. Hard to tell from the pic.

Thanks.....

Closer to 50mm

[mgphoto]

FYI Volvos 142 2.0 E 144 2.0E 164 3.0E 1800 2.0E 1800 2.0E S all D-Jet.

[Gatornapper]

So the Weber 44's with 44mm venturi's are going to allow 3 1/2 times the air into the engine at WOT....and at least 3 1/2 times the fuel.......5 mpg?????

This will be interesting. Waiting on my Weber Technical Manual.....

More better. Hard to tell from the pic.

Thanks.....

Closer to 50mm

[injunmort]

dude, you are all over the map. get the car running with the 44's. thats whats on hand. the fi works better, period. as i said before, the 44's will work decently, with compromises. the d-jet is better. since you are trying to flip for paymax, running with carbs is better than not running with anything. stock d-jet, running car is worth more than non running carbs or running with carbs that just need "a cleaning. get the car running first. then, you can ponder the theoreticals. like, are yellow cars really faster. btw, i have a very fast, running and driving yellow 914. have i mentioned that?

[Gatornapper]

Mort -

Am I all over the map? Not quite - but I get your drift. And I have very good reason.

I have been very successful in life and one reason is I research things to death before I move. And if circumstances demand that I zig when I'm in the middle of a zag - I do that well.

I keep getting new information in my research - and that's why I make changes in my plans.

I am on hold while I wait for parts, Weber Tech Manual, and much more. I won't even be able to start the car for several weeks. I've been rebuilding carbs for over 50 years. When I'm done, they will be as good as new. The time to ponder the theoreticals is now, not when I have all the parts.

I think if you track every change I've made in my plan, each one is a logical and reasonable result of new information. Just this week I've received three or four bit of information that logically suggested a change in direction.

"Get the car running with the 44's" - of course. But if it truly was running strong when parked, why not try the existing 44mm venturi's at first? My good friend who kept the car but didn't own it would not lie to me. The car was running strong when parked.

I HOPE to keep the car and drive it regularly. I didn't buy it to flip it. I bought it as a non-depreciating investment that I could enjoy.

Future cash-flow situations will dictate whether I keep or sell the car. If I sell it, the EFI will go on it for sure. I currently have a huge investment in a project that is taking most of my time and most of my discretionary funds - so it has my attention.

I really won't even have time to spend on the car for a month or more.

In the meantime, pondering the theoreticals is what I'm going to do.

Tell me more please about your fast yellow 914....or send me link to that info.

I love learning from others.......and while I have 50 years wrenching vehicles, machinery, tractors, etc. I am very ignorant about 914's - which are truly unique animals.

Your thoughts are always appreciated.

GN

dude, you are all over the map. get the car running with the 44's. thats whats on hand. the fi works better, period. as i said before, the 44's will work decently, with compromises. the d-jet is better. since you are trying to flip for paymax, running with carbs is better than not running with anything. stock d-jet, running car is worth more than non running carbs or running with carbs that just need "a cleaning. get the car running first. then, you can ponder the theoreticals. like, are yellow cars really faster. btw, i have a very fast, running and driving yellow 914. have i mentioned that?

[Justinp71]

I personally like carbs on these old cars because they are very reliable and simple (although sometimes takes awhile to get it tuned just right), if I was doing an engine swap with a modern FI though I'd probably keep it. I have no experience with D-jet, only with CIS. I was super happy when I ditched my CIS and put on webbers. dont forget to change your fuel pump or use a reliable regulator that can take FI pressures.

[Gatornapper]

Thanks Justin.

Looks like carbs vs. FI on 914's is like Dems and Repubs.....about a 50/50 split on which is best, each side arguing strongly why they believe what they believe.

Cannot count all who have told me to avoid the D-Jet system, that it's non-stop problems and issues and not that good as it was really a Gen I EFI. My service mgr. at the local Porsche dealer strongly advised me to stick with carbs, for both performance and reliability. He doesn't see many 914's, but most of those he does see have problems with the FI.

I will get Ken's D-Jet system tho so that if I have to sell the car, I can restore it to original - but I'm sure it will need a lot of new pieces, like the manifold pressure sensor, harness, etc.

Get a carb set right, and forget it!

And for sure I want more power than the D-Jet can supply on a stock engine.....

Oh, I have both the original fuel pump that was on the D-Jet AND a new Carter 3.5psi fuel pump & filter for the carbs. Carter is in the car now.

GN

I personally like carbs on these old cars because they are very reliable (although sometimes takes awhile to get it tuned just right), if I was doing an engine swap with a modern FI though I'd probably keep it. I have no experience with D-jet, only with CIS. I was super happy when I ditched my CIS and put on webbers. dont forget to change your fuel pump or use a reliable regulator that can take FI pressures.