Why did the 1.8 engines have L-jet? Options

[VaccaRabite]

Has there ever been a reason Porsche/VW speced L-jet injection for the 1.8 engines instead of D-jet like the 1.7 and 2.0 engines used?

Usually when manufactures do this there are financial reasons for the change. Either they have the same engine on other vehicles they produce, or its just cheaper to use whatever part is being used.

But Porsche didn't use the T4 motor on other cars at the time. And if it was cheaper, they would have done away with Djet on the 1.7 and 2.0. I don't think VW was using l-let at the time for the bus... but maybe?

There has to be a reason that Porsche wanted Ljet on the 1.8.

Zach

[930cabman]

Bosch made them a deal they could not refuse (IMG:style_emoticons/default/beer.gif)

[brant]

Djet came out 1970 or earlier

Ljet didn’t come out until 74
Volkswagen was going that direction
And it was the new technology
Plus the 1.8 was sourced from vw
Probably what vw was already going towards and what came on the motors when they contracted with vw

[Van B]

It was the guinea pig for the FI system that was to become the standard for many Porsche and VW cars through the 80's as well as many BMWs and Mercs.

74 was the pre cat and EGR version, 75 added those. It was then used on the 76 912E, followed by 924, 928, and 944 as well as serving as the base for K Jetronic

[technicalninja]

Progress...

The 1.8 was born AFTER Bosch created and de-bugged the L-jet.

The D-Jet was rare enough that I have never had to work on one and I believe that system did not go "World Wide".

The L-jet was the recipe that CREATED what we have today.

It went worldwide and although I have little Porsche experience, I have SHITLOADS of L-jet experience as Nissan jumped on the L-Jet bandwagon early.

If you're not constantly changing, you're stagnating, and the competition will leave you behind...

L-jet was the way forward IMO. (IMG:style_emoticons/default/ninja.gif)

[Maltese Falcon]

Also known as the Bosch 'Barn Door efi. N/Denso also adopted this style on to their market share of cars, trucks. Alfa and Fiat efi cars as well.
The Bosch units on 911 Carrera and 944 Turbos are larger than the 914 1.8L .
(IMG:style_emoticons/default/marty914.jpg)

[Root_Werks]

Thought I read someplace the 914-4 2.0's would also have received L-Jet, but D-Jet was still good enough for emissions until the 914's end of production. Sort of proof of this is the 912E having L-Jet and T2's etc.

I put L-Jet on a stock 1975 914 2.0 years back and it worked very well.

[JeffBowlsby]

D-Jet was not the first EFI, but it was the first EFI that made it to mass production. Yes worldwide. VW beginning in 1968 on the T3, then T4. BMW E9 (3.0si). M Benz: 250E, 280, 300, 350, 450. Volvo 1800E, 142, 144, 164E. Citroen SM, DS. Jaguar XJ-S, XJ12. SAAB 99E. Cadlillac. Renault.

My understanding is that L-Jet came to be for lower emissions, fewer parts (but a more complicated harness!) and is a simpler system than D-Jet.

[dr914@autoatlanta.com]

more modern, simpler and more emissions friendly

Has there ever been a reason Porsche/VW speced L-jet injection for the 1.8 engines instead of D-jet like the 1.7 and 2.0 engines used?

Usually when manufactures do this there are financial reasons for the change. Either they have the same engine on other vehicles they produce, or its just cheaper to use whatever part is being used.

But Porsche didn't use the T4 motor on other cars at the time. And if it was cheaper, they would have done away with Djet on the 1.7 and 2.0. I don't think VW was using l-let at the time for the bus... but maybe?

There has to be a reason that Porsche wanted Ljet on the 1.8.

Zach

[JamesM]

The D-Jet was rare enough that I have never had to work on one and I believe that system did not go "World Wide".

D-jet was on a TON of cars in the early 70s. Just not to many that people care about today.

BMW 3.0Si, 3.0CSi, 3.0 CSL
Citroen DS21, DS23, SM
Jaguar XJ12 XJ-S
Lancia 2000 HF Coupe, Berlina
Mercedes-Benz - To many to list
Opel Commodore GS/E, Admiral, Diplomat
Porsche 1.7, 2.0 (Of course)
Ranault 17 1.6 TS, Alpine A110 1.6, Alpine A310 1.6
Saab 99 E, 99 EA, 99 EMS
Volvo 142 2.0E 144 2.0 E 164 3.0 E, 1800 2.0E, 1800 2.0 ES
VW 411 1.7E, 412 1.7E, 1.8E 1600 1.8E

I would suspect @brant is correct and that it was a result of L-jet being a more modern system and VW updating their engine offerings.

D-jet "calculates" airflow by a Speed-Density calculation, that is it senses manifold pressure, air temperature, and RPM and applies those values to an ECU tuned to a specific engine configuration. Granted d-jet did this with very complicated analog circuits it is the same concept as Speed-Density base systems today. Basically a look up table that returns the predetermined amount of fuel based on the inputs. Some shortcomings of this sort of system ANY changes to the engine that impact airflow at a given RPM and load result in your mixture being off as the engine is flowing differently than the ECU was set to fuel. So displacement change, cam change, possibly exhaust changes and even engine wear over time will throw your mixture off.


L-jet actually measures the airflow via an early airflow meter so when conditions of the engine result in airflow changes at a given operating state you still have an accurate mixture as its measuring the airflow and not calculating it from a lookup table based on other factors.

I imagine Bosch and VW moved to it as a cleaner, more efficient way of fueling and the 914 got it as a result of the VW product offering changing.

But Porsche didn't use the T4 motor on other cars at the time. And if it was cheaper, they would have done away with Djet on the 1.7 and 2.0.

Porsche did actually wind up eventually doing away with D-Jet on other variants of the Type 4. The 1976 912 E got L-jet on the 2.0 Type 4 (914 motor) Had the 914 survived longer I suspect all motors would have received L-Jet. Suspect it didnt in 76 as the 76 cars were basically Porsche clearing out the remaining parts from 75.

[wonkipop]

more modern, simpler and more emissions friendly

Has there ever been a reason Porsche/VW speced L-jet injection for the 1.8 engines instead of D-jet like the 1.7 and 2.0 engines used?

Usually when manufactures do this there are financial reasons for the change. Either they have the same engine on other vehicles they produce, or its just cheaper to use whatever part is being used.

But Porsche didn't use the T4 motor on other cars at the time. And if it was cheaper, they would have done away with Djet on the 1.7 and 2.0. I don't think VW was using l-let at the time for the bus... but maybe?

There has to be a reason that Porsche wanted Ljet on the 1.8.

Zach

correct answer. way simpler. way cheaper. emissions emissions emissions.

D jet by Bosch (Germany) is Electrojet by Bendix (Chicago).
They bought the patents or the license when Bendix and Chrysler gave up.
L jet is the native german system. completely their own idea.

and.......it wasn't anything to do with Porsche. or Porsche's choice.
100% VW.
VW backed Bosch on D Jet even beore Mercedes Benz decided to dip their toe in the water, despite being asked first. VW never hesitated. And they got L jet first.
Primarily it was all about VW engines. The 914 had one of those.

Porsche don't use L jet on their aircooled engines until the 964 comes along 15 years later. i think its on the 924. but thats a VW engine again. and i suppose its on the 928 or a version there of.
by then everybody was using L jet on everything pretty much.
or later versions of L jet.
yes - its on the 912E. but thats a VW engine. plain and simple. supplied to Porsche.

The VW 412 is numero uno for L jet. 3 months before the 914.
same 1.8 engine more or less. but the honour goes to the 412.
the California market VW bus is the 3rd car, about 3 months after the 914.

Production of the 1.8 in 74 is delayed by 3 months because the L jet components were new and in limited supply. a staged introduction.

thats not to say Porsche were sitting on the hands during all this.
no. they were developing this.
(finally found a decent image of one).





this would have been in the replacement for the 914.
intended for production in 1972/73.
its the engine (or one of the versions) for the aborted VW EA266 -Porsche Project 1966.
came in 3 cylinder and 4 cylinder laid flat version for what would have replaced the beetle. with power range from 50hp up to 110 hp. the 4 cylinder 914 would have got the 110 hp version along with a souped up version of the VW saloon. basically a Golf GTI before the GTI.

not sure what version of fuel injection this would have got. its hard to tell.
but it dates from 1967-1972 development period.

all under engineering direction of f. piech.
the idea was a modular engine family.
f piech was one hell of a evil genius.
but this project blew up in his face big time.

porsche were developing flat V versions of this for their own cars.
a flat 6 derived from the VW flat inline 3. and a flat V8 derived from the inline 4.

but it all got detonated.
so they battled on with the tail end of the aircooled cars while VW under a lot of pressure very quickly developed up the Golf and other water cooleds and cut Porsche adrift, terminating their development contract which had been in place since the end of WW2.

basically the 73 onwards 914s were never really intended to exist in f piechs masterplan for "world domination".

[wonkipop]

there is more to this too.
there was a rival proposal within Porsche engineering tor the VW beetle replacement.
piech won out.
i believe h. bott was behind the other one.
and guess what. the rival was a front engine inline with a rear transaxle.
for a beetle replacement.

what does that sound like. 924/928 anyone?

in common with both porsche engineering ideas was an absolute refusal to do front engine front wheel drive.

piech overcame his porsche rivals with his single minded edict that all cars, yes all cars had to be mid engined.

VW settled the argument savagely in 1972.
basically said you are all wrong.
and..........we are going front wheel drive front engined.
and by the way. bye bye.

VW does not get a lot of credit for what it was doing in the late 60s and 70s.
but it was really pushing it behind the scenes.

we all got L jet in cars thanks to VW. no thanks to Porsche.
VW did all the testing and proved its reliability in hand with Bosch.
and VW got first dibs as a result.

GM europe also put their money where their mouths were.
the Opel Kadet was #4 to get the system.

the rest of the USA battled on with strangled carbs and generally what is known as the maliase set ups until they got on the bandwagon.

Australia sat back like it usually does, waited until the american public had finished being used as guinea pigs and then just straight out applied the same regs to car design beginning in the 80s. by then it was japanese licensed versions of L jet on everything that came here.

[wonkipop]

Progress...

The 1.8 was born AFTER Bosch created and de-bugged the L-jet.

The D-Jet was rare enough that I have never had to work on one and I believe that system did not go "World Wide".

The L-jet was the recipe that CREATED what we have today.

It went worldwide and although I have little Porsche experience, I have SHITLOADS of L-jet experience as Nissan jumped on the L-Jet bandwagon early.

If you're not constantly changing, you're stagnating, and the competition will leave you behind...

L-jet was the way forward IMO. (IMG:style_emoticons/default/ninja.gif)

no D jet was world wide techninja.

we had it down here. it was on the VW type 3 fastback top of the line model.
marketed as the "hot rod" engine. from around about 69 on.
pretty rare but basically first car with EFI in aus.
hardly any survive.

also a lot of the Lancias and Alfa saloons had D jet as an alternative to twin carb set ups.
again the D jet was more powerful. but expensive. on top of the line models.

a few other things floated around down here with D jet on them. I am pretty sure the big citroen DS also had it.

wasn't just the USA and was not about emissions at that stage in other parts of the world. it was more about high tech and power outputs.

L jet less so. all the VW models that had L jet in the USA were sold as twin carb versions of same engines down here.

i dont think we got the merc D jets down here that came out soon after the VW fastbacks. everything i have ever seen is dual carb set ups or mechanical injection during that era.

[wonkipop]

there is another reason for L jet and it being necessary in 1974.
i'd forgotten it but was a discovery in digging up all the "minutia" as steve calls it - for our L jet research.

VW could not get the 1.7 with D jet to work with automatic transmissions and pass CARB emissions regs (california) for 1974 calendar year. the D jet with auto could still pass USEPA regs for 74 but EPA was one year behind CARB.

that meant their big sedan/station wagon was a goner for 74 and they still wanted to sell it for one more year. the water cooleds were not ready.
and 99.9% of 4112/412s sold in the states were autos. thats what the customers wanted.

so.........L jet was absolutely the only way they could go with the type 4 engine.

only auto 412s as 4 door sedans and 2 door variants were sold in california in 1974.
no stickshift and no fastback version.

the 2 door fastback was sold in the rest of the USA with a D jet 1.7 in 1974 and only with a stick shift. very small numbers were sold. the rest were auto 1.8s as 4 doors and variants. there was some difference with california models i believe. no EGR in 49 states is think what happened.

so.......thats the big reason. the 1.8 low compression unleeaded fuel engine HAD to have L jet to get through california emissions with a slush box.

and.....that was it, VW just made the executive decision that all the 1.8s aircooled in the USA got L jet and committed to it.

rest of the world lost D jet on aircooled type 4 engines and they all reverted to twin carbs. no L jet in rest of the world. only in the USA.
i have a feeling that the 2.0L 914 engine in europe might have been it for type 4s with D jet from 74 on. not 100% but it appears D jet just stops around that time for the rest of VW range in ROW.

in europe the opel manta was released with L jet and became first car in europe market to be sold with it.

time line is
AUG 73 VW 412 (usa model).
NOV 73 Porsche 914 (usa model)
JAN 74 VW bus with 1.8 engine and auto box for california only.
MARCH 74 OPEL manta (german domestic market).

[wonkipop]

the member here who cracked all this open was @L-Jet914 .
he had the keys to the info vault and threw me a set. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

thats when you realise a porsche 914 really was a marketing exercise as a porsche in north america.

behind the scenes VW-North America are handling the whole thing.
all the documentation for USEPA and CARB certification is handled by VW NA.
the 914s are lumped in with other VW models.
the documentation is not handled by car models but rather by engine types.
then the various models utilising the engine type are listed as subsets.
the documentation applies to engine by engine listings.'

and porsche are off on their own with the 911 models.
and all the documentation for their cars is submitted and processed by Dr. Ing Porsche Stuttgart etc. they have absolutely zero to do with US certification of the 914s.

so anything to do with those VW engines is VW doing it and making the calls.
and the other interesting thing is its ultimately VW handling all the warranty matters to do with the cars. like if your engine blew up. VW handled the new engine etc.
sure you went to a Porsche-Audi dealer but in the USA that was a subsidiary of VW North America.

this is despite or slightly against the idea that porsche take over responsibility for control of the 914 project from 1973/74 onwards. i think its a little more complex than that.
its more like VW pull out of it, and start to become more the builders of the cars and the suppliers of all its components. they still call shots because essentially they tell porsche what they can have for the cars from an available pool of components and secondly what they will certify and warranty in various markets in terms of those components.

[L-Jet914]

the member here who cracked all this open was @L-Jet914 .
he had the keys to the info vault and threw me a set. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

thats when you realise a porsche 914 really was a marketing exercise as a porsche in north america.

behind the scenes VW-North America are handling the whole thing.
all the documentation for USEPA and CARB certification is handled by VW NA.
the 914s are lumped in with other VW models.
the documentation is not handled by car models but rather by engine types.
then the various models utilising the engine type are listed as subsets.
the documentation applies to engine by engine listings.'

and porsche are off on their own with the 911 models.
and all the documentation for their cars is submitted and processed by Dr. Ing Porsche Stuttgart etc. they have absolutely zero to do with US certification of the 914s.

so anything to do with those VW engines is VW doing it and making the calls.
and the other interesting thing is its ultimately VW handling all the warranty matters to do with the cars. like if your engine blew up. VW handled the new engine etc.
sure you went to a Porsche-Audi dealer but in the USA that was a subsidiary of VW North America.

this is despite or slightly against the idea that porsche take over responsibility for control of the 914 project from 1973/74 onwards. i think its a little more complex than that.
its more like VW pull out of it, and start to become more the builders of the cars and the suppliers of all its components. they still call shots because essentially they tell porsche what they can have for the cars from an available pool of components and secondly what they will certify and warranty in various markets in terms of those components.

@wonkipop I have no idea what your talking about (IMG:style_emoticons/default/lol-2.gif)

[wonkipop]

the member here who cracked all this open was @L-Jet914 .
he had the keys to the info vault and threw me a set. (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

thats when you realise a porsche 914 really was a marketing exercise as a porsche in north america.

behind the scenes VW-North America are handling the whole thing.
all the documentation for USEPA and CARB certification is handled by VW NA.
the 914s are lumped in with other VW models.
the documentation is not handled by car models but rather by engine types.
then the various models utilising the engine type are listed as subsets.
the documentation applies to engine by engine listings.'

and porsche are off on their own with the 911 models.
and all the documentation for their cars is submitted and processed by Dr. Ing Porsche Stuttgart etc. they have absolutely zero to do with US certification of the 914s.

so anything to do with those VW engines is VW doing it and making the calls.
and the other interesting thing is its ultimately VW handling all the warranty matters to do with the cars. like if your engine blew up. VW handled the new engine etc.
sure you went to a Porsche-Audi dealer but in the USA that was a subsidiary of VW North America.

this is despite or slightly against the idea that porsche take over responsibility for control of the 914 project from 1973/74 onwards. i think its a little more complex than that.
its more like VW pull out of it, and start to become more the builders of the cars and the suppliers of all its components. they still call shots because essentially they tell porsche what they can have for the cars from an available pool of components and secondly what they will certify and warranty in various markets in terms of those components.

@wonkipop I have no idea what your talking about (IMG:style_emoticons/default/lol-2.gif)

(IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/beer.gif)


he he he.
those secret files explained it all.
quite clever those 1.8 engines.
all done by just taking a hose off and leaving it disconnected and slapping a different sticker on.

i got to the bottom of the auto box problem for VW.
they couldn't make their double vac distributor retarded idle work with a torque converter at the lights without it blowing the gauges down at the EPA when they stuck the hose up its backside. D Jet didn't have a hope in hell.

they just managed to do it with the 412 engine by deleting double vac and then going full tilt on NOX clean up at cruise with an EGR. dirty as hell at the lights though standing still. in between L jet cleaned it up just enough to scrape through.

wasn't really such a big deal for 914s. but they got the whole deal anyway in slightly less compromised form. at least for 74.

the top pick is either a 74 49 states 1.8 or a 75 california 1.8 (believe it or not).
the 74 cals and the 75 49 states ran hot at cruise (at least if you left them the way tney came from the factory without the advance can hooked up).

[L-Jet914]

I can see why they left the vacuum hose on the advance side of the vacuum advance/retard unit on the distributor and tucked away for CA certified vehicles because as the ignition curve advances it increases NOx. Being in CA their emissions standards are nuts so 1st thing to go after would be NOx and then HC and CO. So I don't know why mine was reconnected by whoever connected it onto the second port on the t.body.

[wonkipop]

I can see why they left the vacuum hose on the advance side of the vacuum advance/retard unit on the distributor and tucked away for CA certified vehicles because as the ignition curve advances it increases NOx. Being in CA their emissions standards are nuts so 1st thing to go after would be NOx and then HC and CO. So I don't know why mine was reconnected by whoever connected it onto the second port on the t.body.

so that it only did the NOX reduction thing at idle at lights/standstill - but behaved like VWs were expected to at cruise. run cool. run economically. and run a bit smoother on and off the throttle at cruise. someone in the know did the obvious thing. i think back then the VW dealers understood what was going on with that hose and "on the QT" probably advised - here do this.

all you would had to do was disconnect it again for annual smog. and afterwards re-connect it.

the problem with the 75 state engine (which was identical to 74 cal) was the throttle body appeared to have a vacuum port delete - at least from factory. so you had no choice. i think the 74 calis had a cap over the port you could remove and connect hose.
but again anyone in the know could have just installed a 75 Cal TB or a 74 49 state TB and problem solved.

the 75 cali had an EGR. so even though ignition retarded for NOX reduction at cruise it had the TB port like the 74s and it was connected to EGR. EGR helped the engine to run cooler and cancelled out effects of retarded ignition a little. also restored some fuel economy.

i think what has happened over the years is the knowledge has been lost as to just what that double vac can dizzy and the two hoses did. of course in aus 30 years ago it was completely esoteric. all the cars here just had the single advance can dizzy.

-------

when i posted above i said that no L jet VW aircooled type 4s ever came to australia.
i'm not sure if its true but i do now remember a story from back in the 90s from a VW bus guy i met from time to time. and he told the story as we was looking over the engine of my 914 at some historic races thing i went to. he claimed a small batch of 1.8 L jet buses came into Aus in the mid 70s sometime. he said they were fully imported from germany unlike the more usual CKD buses (complete knock down) that were being brought in at that time after local production had ceased. if that was true i have never seen any of them. must have been a very small batch of cars. most all i see of the later buses are the 2.0 twin carb ones.

[wonkipop]

@technicalninja

here you go for some "world wide" D jet.
sorry to side track off L jet.

a mate of mine's lancia saloon.
neat little car.
still running its original D jet.
think its a 72 but don't quote me on that.
(has a 5 speed box with identical dog leg shift pattern to a 914).
there were quite a few of these in aus.
i believe they were preferred to the twin carbs. did not go out of tune.
but kind of intimidating to your average fix it again tony mechanics.
you had to find a rational german to look after it because the italians got hysterical.





he had a pile of swedish rust under a tree a few feet away from it.
under the faded paint and oxidation also lurked an intact D jet system.
74 SAAB.
i scored a fuel pump off it as a spare for my 914 before it went to the graveyard in the sky.



most of the SAABs that came here in early to mid 70s ran D jet standard.
and there were lots of these SAABS.
they sold like hot cakes. great cars actually.
very sad that SAAB keeled over.

D Jet was more common than you think. on a lot of euro cars of that era.