L-jet vs. D-jet

[Scott Bell]

2.0 with single (boat anchor) carb and toying with complete 74 1.8 L-jet and complete 2.0 D-jet. I have been told that the L-jet is more flexible and more efficient than the original D-jet. The 2.0 plenum and runners are larger than the 1.8, not to mention the different manifold bolt pattern. what factory-look intake boot will fit the 90* difference between the 2.0 upright throttle body to the horizontal afm position on the L-jet? I have an 87 911 carrera afm, would retro of it be beneficial?

[This message has been edited by Scott Bell (edited 10-18-1999).]

[JP Noonan]

The only Type-IV 2.0L L-Jet was the '76 912E, only a few thousand of these cars were made so parts are very expensive. The later bus 2.0L (different cam, CR, and completely different cylinder heads with smaller valves) also has L-jet, but it is calibrated for a low horsepower high torque bus.

The best set-up may be to use the complete L-Jet system, includeing the intake and trottle body. If possible, have the TB bored out to the 2.0L size, and run a slightly higher fuel pressure to account for the larger displacement.

Another option is to trade the FI with someone who needs it to pass emissions with a 1.8L.

BTW, if you're really stuck on using the 2.0L TB and need an adaptor. I've used radiator hose from big desiel trucks, for a ram air system on my GT-40 intake. Go to NAPA and look at their unerversal applications, or truck section of their belts and hoses book.

[This message has been edited by JP Noonan (edited 10-18-1999).]

[jmcleod]

why change to L-jet? either keep D-jet or get a L-jet manifold (?, the black mixing manifold the throttle valve is connected to and the cold start valve is attached to) and use the stock L-jet hose.

[Steve M]

I have to agree with jmcleod, why change from the D-Jet to the L-Jet?. Are there performance benifits to be gained?

[Dave at Pelican Parts]

Read again, folks. He says he's going from CARBS to L-jet, not D-jet to L-jet.

I would suggest either using the complete 1.8 manifolds and so forth (a bit restrictive), or fabbing up something from the radiator hose. You'll have to figure out a port for plugging in the AAR and Decel Valve hoses, since they each have a hose that joins in between the air flow meter and the throttle valve.

Good luck, whichever way you decide to go!

--DD

[Steve M]

Sorry about that Scott.