Questions re: Weber 44 IDF carbs:

1. Is anyone running these on a stock engine, and if so, how do they perform? National Carburetors kit for stock engines is 34 ICT's, lightly modified 40 IDF's, and only 44's on heavily modified engines.

2. What problems do you introduce using 44's? other than dumping too much fuel in the engine......

3. Venturi's are 45mm, someone pointed out that one should use 40mm venturi's - is that with a stock engine?

4. Anyone run 44's and then convert back to EFI? How did that go? Labor cost?

TIA,

GN

It'll be more work than just slapping on a set of carbs, but I think you'll be happier in the long run if you install the original D-Jet setup. Plus, the car will be worth more once it's all done.

If you're going to stick with carbs, the 44s are too big for a stock engine. The 40s might work for a 2.0, but might be too big if you still have the stock cam. The 34s will give you the best drivability around town and fuel mileage, but you might sacrifice a little on the top end on a 2.0.

Bill -

I restore old motorcycles so I know the more original, the more the value....

The 44's are on the car now & I'm rebuilding them. My good friend in whose barn the car has sit for 10 years said the car was running perfectly when it was driven in the barn and he had been riding in it with the PO (another friend of his) that day.

I'm now thinking I want to flip the car ASAP.

Will the car run ok with the 44's? 10mpg?

And where would I start looking for the original D-Jet setup and how do I know I'm getting a full, properly working system? Reliable sources?

Thanks!

GN

The PO told me the Weber's didn't produce any more power, but made the engine a lot more responsive......

GN

Don't you have to pull the engine to change the intake manifold?

Or can it be done from on top? Doesn't seem possible from looking at things.....

GN

A long-term member here has a complete D-Jet system in his garage for $250 - think I'd better grab it.........

GN

Yeh the 44s are technically too big but

D-jet is not supported by me personally cause it is waaayyyy
To complex or spookey weird

Carbs are simple , me i just trust them alot more

But they constantly want to go wide open throttle



D-jet never gos wide open throttle




Where is the go to 914 world , individual throttle body
Fuel injection conversion , that i would buy .
But carbs till then

????? So why won't the D-Jet go full throttle?????

GN

Logo -

Options:

1. So, If I put a cam in the engine and high-performance exhaust on, the 44's would work?

What would that do to the value of the car? Money in, value down it seems.

2. Buy the kit for the 34 carbs, easy install, sell the 44's (they'll be looking like new after my rebuild) for the cost of the 34's. Simple, easy, little to no cost - engine should run great.

3. Buy the D-Jet system from an "original" member here ('04), go through the hassle of learning the system (experienced with old Volvo EFI systems), finding & replacing possible defective parts, sell the 44's for a profit.

Decisions, decisions, decisions. #2 is the most simple for me.

On #3, how to I ensure that the D-Jet system I purchase is good? Lots of parts could be defective, including the difficult-to-find ECU.

GN





[quote name='thelogo' post='2536095' date='Oct 9 2017, 10:27 PM']
Yeh the 44s are technically too big but

D-jet is not supported by me personally cause it is waaayyyy
To complex or spookey weird

Carbs are simple , me i just trust them alot more

But they constantly want to go wide open throttle



D-jet never gos wide open throttle




Where is the go to 914 world , individual throttle body
Fuel injection conversion , that i would buy .
But carbs till then
[/quote]
[/quote]

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.

D jet won't go full throttle?

Yeah, I didn't understand that either

Just


Another



Useless



Post?

BN -

Normally I LOVE mechanical/electrical challenges, and all things being normal, I'd really enjoy doing this.

But right now I am (at 72) totally overloaded with technical challenges flipping a fairly expensive house with a lot of issues and fighting a dozen other alligators (someone ask me where "Gatornapper" came from sometime - name given to me by a major US newspaper.....in 1965), and the last thing I need is another challenge.

I only bought this car because of all the work IT DIDN'T NEED, but have worked on enough old vehicles (I restore old motorcycles) to know there would be plenty of hidden issues to deal with. I just don't need to add more......

So how much is a new wiring harness?

I know it's inevitable that "components will be in varying states of usability and repair." - and some parts are getting very hard to find.

I think I have a plan - will post it next.

Thanks man!

GN

Ok, here's the plan:

1. Purchase D-Jet unit (complete) from bigkensteele;

2. Finish rebuilding existing Weber 44's, see how car runs. If I can tune carbs where car runs well (or find a tuner who can), get car in top mechanical and beauty shape and sell it & the D-Jet system with it; a strong position.

NOTE: Local Porsche dealer service manager remembered every detail about this car and the carbs being put on. Said it was running perfectly when service was finished installing the carbs & there were no issues then.

3. If Weber 44's cannot be tuned so car runs well, I will pull them and install the D-Jet system. Invariably there will be issues, problems to solve. Big Ken said car was not running well when he pulled the system from his '76 2.0. If I can get car running well with D-Jet installed, I'll sell it that way and come out ahead - I'll sell the Weber 44's for a good price as I'll have them like new & they only have 2,000 miles on them. An even stronger position.

4. If a good Porsche mechanic cannot get the D-Jet system running well, I'll purchase and install the Weber 34 ICT kit, get car running well (should be very easy), and sell car WITH the D-Jet kit so new owner can install it if he/she wants to. I'll sell the almost-new, rebuilt Weber 44's for a good price. Not a bad fall-back position.

Hey, TEAM!......

Sound like a plan?

GN

PS: Wife (wonderful, beautiful) normally lets me do what I want vehicle-wise. But she has strongly communicated she wants only one Porsche in the family.

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

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

Actually I bought it to keep it. And to enjoy driving it.

Very recent changes in our financial situation dictate that we need the cash.

Ever had that happen? If not, you are young.......

GN

Hmmm, my profile says I was born in 1948, so I guess I'm not very young

ALL NEW INFO!

My expert friend in GA advised me to call Pierce Manifolds in CA as they are one of the top Weber carb experts in the nation. Had a great long talk with Steve who blew me away with his knowledge of Weber setups with the 2.0 engine.

Findings:

1. The existing setup with the 44's with 44mm venturi's would work fine on the stock 2.0 engine, producing this performance: no low-end torque, great performance between 4500 and 6500 rpm. I.e., racing. As the PO used to race 911's, he probably DID know what he was doing and wanted to get the best performance out of the stock 2.0 engine, while sacrificing all low-end/street-drivability performance. Low-end and mid-range torque would both be weak.

2. The 44 IDF carbs would perform perfectly fine for regular street driving, up to 5000 rpm, using 32mm venturi's, providing good mid-range torque.

3. I had him run his calculations (was he using a calculator? Sounded like it! Certainly wasn't a computer as he was doing square roots, etc.!) for 34mm, 36mm, and 40mm venturi's. For each one he would give me the torque levels at various rpm.

4. All venturi's larger than 32mm suffered a loss of mid-range torque, with the gain of high rpm torque. After listening to all the numbers he ran by me, it was clear that even the 34mm venturi's would require almost constant driving above 4500 rpm - which is not - to me - normal driving. Not on a 41 year old Volkswagen engine with 60k miles on it.

So I ordered a set of 32mm carbs and cannot wait to see how they run. If all is as I expect it will go, I'll leave the 44's on the car and let the next owner decide on the D-Jet system.

If I feel the higher rpm performance is lacking, I can easily try 34mm venturi's - for just $60.......

GN

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

well, you have all the answers, good luck.

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

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

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.

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....

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 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."

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?"

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

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

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

Closer to 50mm

More better. Hard to tell from the pic.

Thanks.....

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

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.....

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?

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

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.

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

have at it bro. but a statement like you want more power than d-jet is capable of is moronic. you can get more power, less longeivty out of a 2.0l type 4, but d-jet is not the limiting factor. displacement, compression ratios, flow, etc, are. d-jet works for up to 2500cc without cam or ecu mods. so, flow your head, deck your cylinders, do cams, and run 44's. oh, wait, then its not a stock 2.0l type 4, then,is it. no, now you are in raby territory. great engines with the r&d to back up, but at $20k you get what you pay for. whoever told you 44's are a better delivery fuel system is an idiot, ever though they dont work on allot of 914's.

Haven't read all the posts, but some referred to MPG. Just a note - I'm running 44's on a 2270 and even with hard driving, I'm getting 20mpg on the average. Got 25+ on a 2500 mile road trip. High teens with a heavy foot.

As you are running a 2270, I know it wouldn't apply - but still would be interested in knowing the sizes of your venturi's, main jet and air jet........

thanks,

GN

Venturi - 36
Main jet - 155
Idle jet - 55
Air correction jet - 200
Emulsion - F11

Hope this is helpful. Karl

Thanks - wow, large main. Don't know about air correction and emulsion jet.

What in the world is emulsion? Have to read my Weber Tech manual.....

Almost 2 1/2 years later........an update........

Engine is running GREAT with lots of mid-range torque with the IDF-44's, but took a long time to get there. Here's what it took:

Venturis: 36mm
Main jets: 135
Idle jets: 60
A/C jets: 175
Emulsion: F11
Pump jets: 50
Pump jet valve: 50 w/no bypass

AND an 050 distributor.

All jets are as Porsche dealer had them, when I got the car, except for idle jets which were 50's, and pump jet valve which had bypass. I could not get a good idle with the 50's.

I tried 32mm venturi's - engine had half the power of the original 36's at all RPM - car would not get out of its own way......was a dog. Totally unacceptable. Don't know why since so many say the 44's need the 32mm venturis - I just could not get them to work. Clearly they are better carb tuners than I am.

My car runs far stronger than I ever dreamed a little 2.0 could. My good friend Rickb45 has a new 2.0 with a cam for carbs and Dellorto 40's - and I've driven it......sure seems to me my car is faster at WOT than his, and my mid-range is fine - as he will attest - as he has driven mine several times. Really want to drag-race the cars to find out - but, as that's illegal, we'll have to find another way. Like time 0 - 60 runs with stopwatch.

So no thoughts of putting the D-jet in - I still can't see how it could provide the power I have now, in spite of the limitations of the cam, etc. I'll keep the D-jet I got from Ken Steele so when I'm gone my family can get more $$ for the car if they decide to sell it.

Me? I'm keeping the car, no plans to ever sell it. Had no idea a well-running 914 was so much fun to drive and would have half the power this little 2.0 has. It will be my go-to car....just hate to be putting all the miles on it....just turned 63k - 2400 miles my doing.....in last year.

Will be moving on to improving suspension in the next year.......as well as a repaint to the original Malaga Red.

Thanks to all here for all the input....

GN

44s for racing only

And that explains it. P.O. raced 911's, bought this for his university professor girlfriend, and thought she'd want to drive it like he would I assume and set it up accordingly.

And yes, I often have a heavy foot. But as I'm getting 25 - 30mpg, not that often. The engine is very happy at 2500 RPM and up.....and very smooth below.....

And I could not be more pleased with how the engine is running and am very happy with it. And other 914'ers who know about it agree.

As always George, thanks for the feedback.

And huge thanks for free testing of my VR's, I owe you postage back - and will be placing an order soon.........

GN

[quote name='dr914@autoatlanta.com' date='May 8 2020, 09:02 AM' post='2812986']
44s for racing only

Just chatted with the PO......it was no less than Peter Gregg who told him to put the 44's on the stock 2.0.

And yes, the local dealer told him they were too big w/o putting in a cam for carbs.....but he went with Peter Gregg's advice.

So the PO knew Peter Gregg before his death in 1980, obviously. Trying to get more info on that. And while Gregg raced 911's and 914-6's, he surely knew the 2.0's quite well too.

And yes, this matches with what you said George........

GN

Jake had told me to use 44's if I built up a high performance 2270. He said the 40's I had could be modified but the 44's would be best for a 175+ hp type 4.