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

[wonkipop]

@technicalninja

mr. b (Jeff Bowlsby) knows everything there is to know about D jet.
i've never owned a D jet i only know the history in a typically skim the surface way.
though digging out precise times and dates from obscure documents is something i have enjoyed regarding L jet. i've got an emotional stake in L jet and even 30 odd years ago when i got the car i knew it was significant for being the first car with the system.
(or so i thought until 3 or 4 years ago when i discovered it was actually the VW 412 - but if we say its the 1.8 air cooled engine in both cars then its true it was the first).

yes - basically D jet is an american home grown invention you might say.
D jet owes a tremendous amount to the schematic layout and elements of the Electrojet system.

I believe somewhere in the USA a person owns the only surviving intact specimen of this system. it was fitted to a certain low production chrysler model.

as to mercedes benz and their mechanical fuel injection systems.
as for instance applied to the gullwings, or stirling moss's famous racer.
straight from WW2. virtually the same system that went in the BF 109 fighter plane.
why....germany relied on artificial synthetic fuels made from coal processing.
very low octane. the engines needed mechanical fuel injection and superchargers to match the performance of british spitfires etc. the engines were also inverted in 109s so they could run the destructive 20mm cannon straight through the centre of the crankshaft. i think fuel injection was almost necessary to run the engine upside down so to speak. if you were in a 109 and you wanted to escape a spitfire you put it into a negative g at the top of the curve dive. the spitfire would stall trying to chase the 109.
until there was some kind of mrs shillings orifice or something like that to fix the problem of the carbies on the english engines.

but i digress. none of that stuff is electronic fuel injection. purely mechanical.

porsche were the same about injection. everything had to be for racing. at least during f. piechs time there during the 60s. so it was mechanical mechanical mechanical, even in the road cars.

i guess the point about L jet and its been made a million times is it was simple simple simple and cheap cheap cheap(er) than anything that had come before it.
still more expensive than a carby or two but.........if you are making a mass market car in huge numbers with a tiny engine that is going to be massively crippled by emissions laws you know its the only way you can go.
VW had its backs to the wall when it came to the USA market after the Nixon Clean Air Act of 1970. when bosch engineers rocked up with a fastback clandestinely fitted with a prototype system in the mid sixties, VW did not even hesitate. straight into it. lets go sort of thing. its a well known and often told story. about the merc sedan and the VW type 3 that were driven straight to the VW and Merc engineering departments with the keys tossed to them for a drive. birth of D jet.