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]

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).