Counter to popular belief I do not stay up late inventing hairbrained questions for you all, although that is tempting sometime given the wealth of knowledge here. As of around 10:30 AM today this will be a real life scenario.
Let’s imagine I have a 2.0l case running 1.8 heads with a single Weber that runs but I want to convert back to FI.
Let’s further image that I have both a 1.8 FI set up and a 2.0 FI set up sitting in the shelf.
Which FI set up would I be best advised to use on this engine, and for bonus points and adding to the community knowledge here, why?
BTW - planning on doing a tech day on this with/for the SoCal mafia once I get a plan together. Given what seems to be a trend back to FI (or at least renewed interest) I think it could be a useful tech day for the community.
Thanks!
For me, I would go with pieces from a bus engine. Use the 2.0 intakes, and larger throttle body. Your choice for fuel injection from there.
2.0 intake tubes and throttle body will not fit in 1.8 heads without modification. I would get 2.0 heads and 96mm pistons and build a true 2056. Why fart around cobbling crap together when the proper parts are readily available?
I'll let the ljet experts answer that
I've built a 2.0 head 2056 engine with Ljet, I saw no difference in power compared to 2.0 Djet.
Only power loss will be because of the 1.8 vs 2.0 heads.
Like i said before, not without modification.
If that is all you have, use the 1.8 fuel injection system, as it is much smoother running than the old 2.0 set up and the intake runners will directly bolt on. The 912e used a similar system, 2.0 engine 1.8 afc type fuel injection system aud it worked well
Bus intake runners are 4 bolt vs 914 3 bolt, so they will bolt directly onto the 1.8 heads.
OK - so intake runners are different. Got it.
It sure looks like the injectors will fit, but worth double checking that.
For 1.8 heads you will need to have a hole machined in the head for the 2.0 intake runners.
Not a big deal.
Thanks Rob.
So bus runners, or drill the head for 2.0 runners. I'd imagine that bus runners are cheap, so that seems like (per Mark's suggestion) like an easier way to go. Good to know that a simple mod will work with the 2.0l stuff however.
OK, so your running a 2.0 L case which tells me you likely have 96mm bore, and standard stroke 2.0 L crank, so probably 2056 cc displacement. The 1.8 L heads are the current performance limiting feature, along with the single carb. Between the 1.8 Ljet and the 2.0 DJet, I would choose the Ljet which is a newer design that can accommodate the increased displacement as proven by use in the 912E. Use the Ljet system as is and it will bolt right up to the heads easily. To insure that it runs well with the brain, make sure all components are working properly, has no vacuum leaks, and is hooked up to a !.8 distributor with the same vacuum connections (advance/retard). If forget if it has one or both.
That said, you may be able to bump up performance by switching to 2.0 heads, use 2.0 runners and adapt to the existing 1.8 plenum. Also consider having your throttle body rebuilt and bored to a larger size by on of the vendors on this site. If you increase the max airflow to the cylinders, you should move up to the injectors used on the 912E and plan on checking A/F ratio to avoid a lean condition at WOT.
The 1.7\1.8 runners are longer and don't line up with the 2.0 plenum. They don't have the same bolt pattern. The throttle body is smaller. You can ask the same question 3 times and word the q different, but it doesn't change the answer.
Bus runners are 1.8 runners. Still won't fit 2.0 heads WITHOUT modifications.
The 2.0 and 1.8 injections are different in all parts (injectors, sensors, throttle body, runners, etc.)
You can use any of them as a whole set on your 2.0 engine. They will work fine. I would prefer the 1.8 setup (L-jet) since parts are more available. For example the 2.0 injectors are NLA and used ones are very expensive while the 1.8 injectors are still available new and cheap.
The 1,8 and 2,0 runners have a different bolt pattern but they can be made to fit by drilling new holes in the right place. This is very easy task so I would not consider it an issue.
The 2.0 heads are a bit different than the 1.8 in term of valve size, plugs location and combustion chamber size. Having said that, they can be interchanged at some performance cost.
Mounting 1.8 heads on 2.0 engine will increase the compression ratio but the less optimal plug location and smaller valves will counter compensate that.
BTW, I forgot to mention that if you want to use the bus throttle body, that's a L-jet part so you have to go L-jet al the way (1.8).
Also, don't go crazy looking for the 912E injectors as they are exactly the same one as any other L-jet injectors, including the 914 ones. The urban legend about them being bigger is fake.
Thanks for the discussion and all the super helpful information. Let me double check what is actually in the car and then report back. After that I imagine it is time to start testing components before doing a swap.
I know my 1.8 injectors are likely skunked....
I would go with the L-jet setup, for the reasons above. It can cope with the larger displacement, and probably will not need nearly as much tweaking to work as the D-jet will. D-jet makes more assumptions about the engine's air needs than L-jet does, as L-jet directly measures the air coming in.
Since you would be using 1.8 heads, use the 1.8 intake parts. They are made to go together, so it's a total no-brainer.
The 2.0 plenum (the intake manifold box thing) is wider than the 1.8's is, so the intake runner pipes for the 2.0 are shorter. There is the different bolt pattern, as mentioned several times. Both of those can be dealt with one way or another, but they are things you have to be aware of. It would be interesting to fit the L-jet's air flow meter onto a 2.0 throttle body; different ducting would be needed and the 912E parts (which use L-jet on a 2.0 914 motor) are hard to come by.
The L-jet and D-jet injectors are operated differently (D-jet supplies power to open them; L-jet supplies a ground to open the injectors) and I think may use different power levels and have different impedance. I recall the late Cap'n Krusty telling us that the Bosch reps cautioned to never switch L-jet and D-jet injectors, as that could cause some electrical issues and possibly even fry something.
So: Use the L-jet, complete. It fits what you have, and it should cope with the larger displacement just fine. No mix-and-match of parts required, no machining required, just bolt it all together. (And spend however long it takes to fix all of your vacuum leaks!)
--DD
Thanks Dave, and all. Great discussion and very helpful schooling along the way.
Didn't this discussion happen within the last few weeks?
I'll repeat what I know.
Ray Greenwood & Jake had a discussion on STF regarding single plenum 2270 motors. The condensed version is 2.0 runners, bus plenum works better than 2.0 plenum. Now it could be that the id of 1.8 & 2.0 runners are the same. I only have 2.0 runners so, I can't say. Essentially you get better flow with ljet plenums because the intake air hit the floor in the 2.0 plenum and loses velocity.
So it seems the best intake setup would utilize a ljet plenum. I purchases a 2.1 plenum and cc'ed it. The difference in volume compared to a 1.8 plenum was small or non existent.
With your bits in hand, I would go ljet. If you're getting the heads refreshed, go with 2.0 valve sizes.
If you find the id of 2.0 runners is larger, dubshop sells intake flanges flanges & you could make your own.
The post I replied to does have a link for the STF discussion or you could search the aircooled technologies archive there.
Use the L-system as is will get you a good running motor. Replacing the throttle body with a VW bus throttle body will wake up the motor. You can actually feel it in the seat of your pants. But remember to leave the snorkel off the air intake, it is smaller than the throttle body with the bus throttle body on it, and causes a restriction.
Whomever said there are no differences in the L-Jet injectors is mistaken. The 912E injector flows more than a 1.8L injector. Factory 912E injectors are hard to find, but there is good news. The Datsun/Nissan 280ZX uses a Nippondenso licensed built version of the Bosch L-Jet system. The injectors for the 280ZX are identical to the 912E injectors. And they are available from FLAPS.
The 1.8L heads are a bit of a restriction, but they make up for it in two ways. They have a slightly smaller combustion chamber, so you get a slight bump in compression, and they don't drop valve seats like the 2.0 heads.
FYI... I have run all possible combinations of L-Jet systems over 33 years, and this is the current combination running on Betty's 400K mile 914.
Thanks gentlemen
I dug out my old paper manuals from the 1980s when I worked for VW in Fort Worth.
914 1.8 PET part number 022906031C
Bosch EV1 Fuel Injector
pintle nozzle
Flow rates @ 41.5 psi / 3 bar
17 lb per hour
178.5 cc per min
2.4 Ohm resistance
Bosch # 0280150112
Volkswagen # 022906031C
912E PET part number 92360610900
Bosch EV1 Fuel Injector
pintle nozzle
Flow rates @ 43.5 psi / 3 bar
19 lb per hour
199.4 cc per min
2.4 Ohm resistance
Bosch # 0280150105
Fiat # 6052340
Porsche # 92360610900
Peugeot # 7700582691
Jaguar # EAC3620
Volkswagen # 022906031D
The 914 1.8L injector is VW number 022906031C and the 912E injector is VW number 022906031D. What you are seeing is the current listings offered by the dealerships and parts suppliers. It is the standard superseding process that goes on with all car manufactures. The eliminate what they consider "duplicate" inventory to cut replacement parts costs. If you use an original 914 1.8 injector, you don't get the same fuel flow as a 912E injector. If you buy new, you will get the 912E injector even if you want a 914 1.8 injector. The 914 1.8 injector was discontinued.
So basically, you and I are both right. The currently available injectors for a 1.8L 914 are the same as a 912E. But it didn't start out that way.
Great info, thanks.
EDIT: I took the lead from Clay and went to Rock Auto and did a cross reference based on a 1980 Datsun (under Nissan) 280ZX;
ALFA ROMEO GT VELOCE 1972-1974
ALFA ROMEO GTV-6 1981-1986
ALFA ROMEO MILANO 1987-1989
ALFA ROMEO SPIDER 1981-1988
ALFA ROMEO SPRINT 1977-1979
FIAT 124 1981-1983
FIAT BRAVA 1981
FIAT STRADA 1981
FIAT X-1/9 1981-1983
JAGUAR XJS 1980-1983
NISSAN 200SX 1980-1988
NISSAN 280Z 1975-1978
NISSAN 280ZX 1979-1983
NISSAN 810 1977-1981
NISSAN MAXIMA 1982-1984
NISSAN STANZA 1984-1986
OPEL 1900 1975
OPEL MANTA 1975
PORSCHE 912 1976
RENAULT FUEGO 1982-1984
RENAULT R17 1976-1977
RENAULT R18I 1981-1983
TRIUMPH TR8 1980-1981
$60 new, $35-45 re-manufactured.
Thanks Mark (and gentlemen).
It will be a couple weeks before I start testing components, bigger fish to fry right now, but this has been very helpful. Thanks!
Only working off feel right now but this car feels strong, not sure if that is the engine or being stripped (less weight) or both.
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