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

[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.

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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.