 Djet vs Ljet, what's the difference |
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| trent1542 |
  Sep 1 2010, 09:05 AM
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#1
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Member  Group: Members Posts: 98 Joined: 19-August 10 Member No.: 12,074 Region Association: Pacific Northwest  |
what is the difference between Djet and Ljet F.I.
And what would be better if I want to restore my '70 1.7L/4 to stock. sorry for the terrible question (IMG:style_emoticons/default/newhere.gif) |
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Replies(1 - 19)
| dr914@autoatlanta.com |
Sep 1 2010, 09:22 AM
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#2
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914 Guru Group: Members Posts: 7,864 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
QUOTE(trent1542 @ Sep 1 2010, 08:05 AM)  what is the difference between Djet and Ljet F.I. And what would be better if I want to restore my '70 1.7L/4 to stock. sorry for the terrible question (IMG:style_emoticons/default/newhere.gif) TO STOCK means d jet. (MPC) L jet (AFC) is the superior system and much simpler than the d, but was only available on the 74 75 1.8 and 2.0 912e models. The systems are totally different one using an air flow meter and the other using a manifold pressure sensor, for starters! |
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| trent1542 |
Sep 1 2010, 09:27 AM
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#3
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Member Group: Members Posts: 98 Joined: 19-August 10 Member No.: 12,074 Region Association: Pacific Northwest |
QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:22 AM) TO STOCK means d jet. (MPC) L jet (AFC) is the superior system and much simpler than the d, but was only available on the 74 75 1.8 and 2.0 912e models. The systems are totally different one using an air flow meter and the other using a manifold pressure sensor, for starters! Is Ljet more reliable too? I want a system that will last long on my 1.7. |
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| dr914@autoatlanta.com |
Sep 1 2010, 09:30 AM
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#4
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914 Guru Group: Members Posts: 7,864 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
Yes. Because of its simplicity, L jet IS more reliable. One needs to watch the air flow meter for lean backfire when starting cold, and keep the dual relay clean, but beyond that it is great.
The caveat is that since the system was only made for two years and that 75 adn 74 are slightly different (seven pin vs six pin air box and harness) that finding used parts for the system would be hard. QUOTE(trent1542 @ Sep 1 2010, 08:27 AM) QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:22 AM) TO STOCK means d jet. (MPC) L jet (AFC) is the superior system and much simpler than the d, but was only available on the 74 75 1.8 and 2.0 912e models. The systems are totally different one using an air flow meter and the other using a manifold pressure sensor, for starters! Is Ljet more reliable too? I want a system that will last long on my 1.7. |
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| trent1542 |
Sep 1 2010, 09:50 AM
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#5
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Member Group: Members Posts: 98 Joined: 19-August 10 Member No.: 12,074 Region Association: Pacific Northwest |
QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:30 AM) Yes. Because of its simplicity, L jet IS more reliable. One needs to watch the air flow meter for lean backfire when starting cold, and keep the dual relay clean, but beyond that it is great. The caveat is that since the system was only made for two years and that 75 adn 74 are slightly different (seven pin vs six pin air box and harness) that finding used parts for the system would be hard. Thanks (IMG:style_emoticons/default/biggrin.gif) Now I need to get this project (IMG:style_emoticons/default/driving.gif) |
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| Root_Werks |
Sep 1 2010, 09:58 AM
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#6
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Village Idiot Group: Members Posts: 8,321 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest 
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There is a ton of good information on both D-Jet and L-Jet systems. Read up on my thread, I recently installed L-Jet on a 2.0 and it's working great.
http://www.914world.com/bbs2/index.php?sho...104990&st=0 The good Dr. already mentioned D-Jet is a MPS-Manifold Pressure Sensing system vs. L-Jet wich is a much more modern platform AFM - Air Flow Metered. Many vehichles used what they called "Motronic" (Really L-Jet) like the 944 etc. Others will chime in I'm sure. If you want all original and have a 73-76 2.0 914, stick with D-Jet, it does work great and will keep the value up on your 914. If your starting from scratch and not too concerned about 100% originality, then go with L-Jet. There's still tons of parts out there for the systems. |
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| trent1542 |
Sep 1 2010, 10:10 AM
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#7
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Member Group: Members Posts: 98 Joined: 19-August 10 Member No.: 12,074 Region Association: Pacific Northwest |
what about Ljet vs dual weber carbs?
or just F.I. vs carburation |
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| type47 |
Sep 1 2010, 10:32 AM
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#8
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
I would suggest instead of spending money to get an L-jet system or dual carbs, spend it getting your stock factory FI system running correctly. Rather than break new ground learning a new FI system or learning to deal with carbs, start w/factory system. Enjoy driving what you have then start on the slippery slope of improving the car.
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| johannes |
Sep 1 2010, 10:46 AM
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#9
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Club Porsche 914 France President Group: Members Posts: 3,084 Joined: 13-January 06 From: France Member No.: 5,409 Region Association: France |
QUOTE(type47 @ Sep 1 2010, 08:32 AM) I would suggest instead of spending money to get an L-jet system or dual carbs, spend it getting your stock factory FI system running correctly. Rather than break new ground learning a new FI system or learning to deal with carbs, start w/factory system. Enjoy driving what you have then start on the slippery slope of improving the car. (IMG:style_emoticons/default/agree.gif) |
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| dr914@autoatlanta.com |
Sep 1 2010, 10:50 AM
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#10
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914 Guru Group: Members Posts: 7,864 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
Forget the carbs!!! Remember you started off saying original! Reinstall the d jet and have a car that leaps off the line (for a 914) gets great gas mileage on regular fuel, is relatively quiet, pollutes less, and starts every time on the THIRD!!!! try without pumping the accelerator pedal!!! QUOTE(trent1542 @ Sep 1 2010, 09:10 AM) what about Ljet vs dual weber carbs? or just F.I. vs carburation |
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| MartyYeoman |
Sep 1 2010, 01:33 PM
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#11
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Senior Member Group: Members Posts: 1,519 Joined: 19-June 03 From: San Ramon, CA Member No.: 839 Region Association: Northern California
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L-Jet was also installed on VW bugs and Vans (not sure of the years though).
Lots of parts out there. |
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| trent1542 |
Sep 1 2010, 04:16 PM
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#12
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Member Group: Members Posts: 98 Joined: 19-August 10 Member No.: 12,074 Region Association: Pacific Northwest |
thanks guys I'm gonna stick to djet for now. (IMG:style_emoticons/default/smile.gif)
but later when or if I upgrade; would dual weber carbs 34 ict, or would F.I. Ljet be better? I don't know how much it would cost for Ljet but I have a friend that has a new in the box dual weber carbs, 34 ict; that he would sell to me for $300 or less he said. |
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| RFoulds |
Sep 1 2010, 05:10 PM
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#13
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Green Teen 66 Group: Members Posts: 837 Joined: 10-August 09 From: La Quinta, CA Member No.: 10,656 Region Association: Southwest Region
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my take on carbs vs. FI in a 914. Carbs for serious track use, FI for everything else. Daly driver, autocross, weekend fun, DE track car, etc. All experience more reliability, better performance, and better fuel mileage with FI. My first 914 had a fresh 2056 with new twin carbs. so much fuel flowing in there, eashed teh cylinders pretty much and wore out the rings in just 5,000 miles.
that plus constantly balancing them was enough to convince me, stick with stock FI whenever possible, and make it run right. |
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| trent1542 |
Sep 1 2010, 05:52 PM
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#14
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Member Group: Members Posts: 98 Joined: 19-August 10 Member No.: 12,074 Region Association: Pacific Northwest |
QUOTE(RFoulds @ Sep 1 2010, 04:10 PM) my take on carbs vs. FI in a 914. Carbs for serious track use, FI for everything else. Daly driver, autocross, weekend fun, DE track car, etc. All experience more reliability, better performance, and better fuel mileage with FI. My first 914 had a fresh 2056 with new twin carbs. so much fuel flowing in there, eashed teh cylinders pretty much and wore out the rings in just 5,000 miles. that plus constantly balancing them was enough to convince me, stick with stock FI whenever possible, and make it run right. Thanks (IMG:style_emoticons/default/biggrin.gif) |
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| VaccaRabite |
Sep 1 2010, 06:32 PM
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#15
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En Garde! Group: Admin Posts: 13,444 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Carbs have thier place in the 914 world, but that place is starting to dwindle with the advent of the programmable EFI systems. Carbs can be a living hell in tuning (which I am going through now) but allow you to use much more aggressive cams and develop more power.
But if you are keeping your engine stock, go with the stock FI for sure. If the programmable EFI systems were cheaper or more easy to use, I'd be happy to ditch my dual carbs for EFI. I still think about trying MS for my 2056 with an aggressive carb cam, but that would be a project on down the line, and I have other car projects right now to get running. Zach |
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| Bleyseng |
Sep 2 2010, 03:39 AM
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#16
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Aircooled Baby! Group: Members Posts: 13,034 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
QUOTE(Marty Yeoman @ Sep 1 2010, 04:33 PM) L-Jet was also installed on VW bugs and Vans (not sure of the years though). Lots of parts out there. 75 to 83 Buses and Vanagons have Ljet so lots a parts to steal and use from |
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| Cevan |
Sep 2 2010, 06:29 AM
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#17
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Senior Member Group: Members Posts: 1,079 Joined: 11-December 06 From: Western Massachusetts Member No.: 7,351 |
D-Jet was phasing out at the same time L-Jet was being introduced. I think the '74 1.8 was one of the first production cars to use L-Jet.
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| 76-914 |
Sep 2 2010, 08:46 AM
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#18
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,502 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California
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QUOTE(trent1542 @ Sep 1 2010, 09:10 AM) what about Ljet vs dual weber carbs? or just F.I. vs carburation This ought to get the pot boiling. (IMG:style_emoticons/default/stirthepot.gif) |
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| realred914 |
Sep 2 2010, 09:54 AM
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#19
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Senior Member Group: Retired Members Posts: 1,086 Joined: 1-April 10 From: california Member No.: 11,541 Region Association: None |
QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:30 AM) Yes. Because of its simplicity, L jet IS more reliable. One needs to watch the air flow meter for lean backfire when starting cold, and keep the dual relay clean, but beyond that it is great. The caveat is that since the system was only made for two years and that 75 adn 74 are slightly different (seven pin vs six pin air box and harness) that finding used parts for the system would be hard. QUOTE(trent1542 @ Sep 1 2010, 08:27 AM) QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:22 AM) TO STOCK means d jet. (MPC) L jet (AFC) is the superior system and much simpler than the d, but was only available on the 74 75 1.8 and 2.0 912e models. The systems are totally different one using an air flow meter and the other using a manifold pressure sensor, for starters! Is Ljet more reliable too? I want a system that will last long on my 1.7. i would not say L:-jet is more relaible nor has more simplisity. the L-jet has a very delicate air flow meter, (back fire can ruin it) L-jet is hyper sensitve to vaccum leaks. although the 914 L-jet is more modern, than D-jet, the D-jet system was more sorted out by the time 914 used them, the L-jet was new then, not as well developed. the D-jet is extremely simple, with less complex moving parts (pressure sendor verses air flow sendor) D-jet is not hyper sensitve to leaks like the L-jet is. I'd stick with D-jet a well proven system on your 1.7 enigne. everything will fit and be right, not some bastardized set up. |
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| Als914 |
Sep 2 2010, 12:40 PM
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#20
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Lighting my way Group: Members Posts: 330 Joined: 1-January 06 From: Hemet,Ca. Member No.: 5,346 Region Association: Southern California |
QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:30 AM) Yes. Because of its simplicity, L jet IS more reliable. One needs to watch the air flow meter for lean backfire when starting cold, and keep the dual relay clean, but beyond that it is great. The caveat is that since the system was only made for two years and that 75 adn 74 are slightly different (seven pin vs six pin air box and harness) that finding used parts for the system would be hard. QUOTE(trent1542 @ Sep 1 2010, 08:27 AM) QUOTE(dr914@autoatlanta.com @ Sep 1 2010, 08:22 AM) TO STOCK means d jet. (MPC) L jet (AFC) is the superior system and much simpler than the d, but was only available on the 74 75 1.8 and 2.0 912e models. The systems are totally different one using an air flow meter and the other using a manifold pressure sensor, for starters! Is Ljet more reliable too? I want a system that will last long on my 1.7. Hey George, I have the six pin ('74) air box and as stated it is very reliable...love it. What does the 7th pin connect to on the 2.0, 912E? |
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