Why did the 1.8 engines have L-jet? |
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Why did the 1.8 engines have L-jet? |
VaccaRabite |
May 31 2024, 08:05 AM
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#1
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En Garde! Group: Admin Posts: 13,571 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
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 |
technicalninja |
Jun 4 2024, 10:28 PM
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#2
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Senior Member Group: Members Posts: 1,948 Joined: 31-January 23 From: Granbury Texas Member No.: 27,135 Region Association: Southwest Region |
All things considered how is direct injection beneficial to our aircooled cars given how it cakes up the valves? I doubt our injectors could tolerate that piston chamber exposure either. Not a fan of DI. It's NOT economically possible to add true DI to a VW or Porsche engine that didn't come with it originally. (or ANY other manufacture) The very best DI is now incorporating a secondary port injection system. Mercedes is doing it with their 400hp 4 cylinder and Ford is doing it with the Coyote. Mercedes and Ford are currently opposite as to when they fire the port system. The "caking" up the valves problem is more excessive blow by reaching the intake over a direct problem with the injection. Having fuel washing over the intakes HELPS clean the valves better than anything else hence the addition of port. I think many will add some type of port injection to help with this problem. A good catch-can can work wonders as well. I believe the most recent Eco-boost Fords come with a catch can like set up. Now, IMO DI is a SHITLOAD better for one simple reason... The fuel component of the air charge takes up approximately 9% of the total intake volume. If you remove the fuel from the intake track you get approximately 9% MORE air and an equivalent increase in power. ALL ICE engines are oxygen starved. The number of oxygen molecules is the deciding factor regarding power, not fuel as many might think. This is why when they change to DI it's ALWAYS a power bump. They can do exotic crap with DI as well. Some system pulse the injection to make multiple squirts per combustion event. They have better control of the combustion event and run "lean-burn" strategies better. I see the additional control that DI gives will allow 1 full point of compression to be added to the static compression ratio. I'm a fan of DI. It's forward progress for ICE. I WOULD NOT try to install DI on something that didn't have it originally... I'm going to cheat a port set up so I get SOME of the benefits of DI. The biggest thing I'm going to change is the injectors spraying fuel into a closed intake. Just dumping fuel on the valve is NOT the way to make power. |
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