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Posted by: jjs3rd914 Nov 25 2007, 09:15 PM

Just recently aquired a 73 2L motor with all D-jet stuff (some tin) and a 75 1.8L motor with all the L-jet components (no tin) plus two side shift trannys in a 914 garage sale cleanout. Conditions unknown. We presently have a stock 1972 914 1.7L with stock D-jet (motor just rebuilt) that runs great.

Plan is to rebuild the 2L in the next year or so and replace the 1.7. Question? Assuming the 2L motor has no real internal issues, would there be any advantage in the installation of the L-jet system on the motor. I am not saying we will do this as we want to stick with the D-jet injection. But we all know the D-jet stuff is getting hard to come by, and the L-jet parts seem more available new and there seem to be less parts to go bad. As time goes on, would that be a conversion to consider based on cost, longevity, and availability? I used to have a 74 L-jet and when it ran right, it was great (when it had no vacuum leaks).

Conversley, if the 2L motor is not rebuildable (within a reasonable budget) the 1.8 is a better platform to boost out to around 2L than the 1.7. So the same question applies. Would the L-jet work on the increased displacement 1.8? What mods if any would have to be done in either case to the L-jet to work on a 2L displacement motor. Would it work? How adaptable is it? Were not the 912E's a 2L with L-jet?

Finally, on the flip side, would the 1.7L D-jet work on a stock 1.8L motor with no component replacement?

Thanks for the replies!

jjs3rd914

Posted by: davep Nov 25 2007, 09:29 PM

Complete 1.7L D-jet may work on a stock 1.8L motor but it is not optimal.
Complete 1.8L L-jet may work on a stock 2.0L motor but it is less than optimal; you could consider parts from a 912E system.
Complete 2.0L D-jet will work on a 2056 motor with tweaking.

Posted by: Bleyseng Nov 25 2007, 10:50 PM

1. Not really, I feel Djet has better throttle response
2. yes
3. you should adjust the AFR via the black cog and wiper
4. It would work great
5. Very
6. Yes, but parts are hard to find!

Posted by: Jake Raby Nov 26 2007, 05:34 AM

The 912E L jet was a hybrid of the D and L jet systems and used many componnents from the 2.0L Jet Bus engine...

I prefer L jet over D jet and have been able to get more power from L jet engines without quite as much risk as with D jet.

The **smart** thing to do is retrofit an aftermarket ECU to the stock D or L jet hardware for a programmable system that will support up to 145HP with the stock plenum, runners and injectors... This is initially more expensive, but in the long run it's worth twice it's weight in gold.

I have been driving my 912E with the RAT/SDS retrofit kit and stock plenum, runners, injectors, pressure regulator and pump for 4 years now with incredibly positive results, no tuning and zero maintenance..

Getting away from stock components is key, especially with more and more of them becoming NLA.

Posted by: Bleyseng Nov 26 2007, 12:00 PM

Djet-hard to tune and adjust the AFR
Ljet-easier to tune and adjust the AFR

you can mix Ljet parts from 914's and Buses to get a system.
Djet is not a mix and match system.

Posted by: Brando Nov 26 2007, 07:19 PM

As for stock systems, L-Jet would be the way to go.

You can get all the parts off of a 1.8 car (only model 914 with L-Jet), and pick up a set of 912E injectors at a local VW store, Porsche stealership and/or online parts sellers.

L-Jet starts working better when you do things like:
-Eliminate the EGR system.
-Eliminate the PCV system (and vent to atmosphere)
-Eliminate the fuel-vapor recovery system
-Upgrade to Mallory Unilite and Hyfire system.

The last one is just a general upgrade that makes all 914s run a lot better...

I've been trying to find a MAF conversion setup for L-Jet (similar to Motronic) but no luck; except for one manufacturer who said for about $850 they can make me one and also the extra box that interprets the signal and converts it. Not within my affordability range.

Posted by: Krieger914 Nov 26 2007, 07:40 PM

I got some injectors from an E that have bot been used in a long time if anyone is interested.

Posted by: jjs3rd914 Nov 26 2007, 07:56 PM

Thanks for all the response. I am surprised at the support for the L-Jet. It appears we have some options to consider moving forward. I had forgotten the VW transporters also used the L-jet system so there would seem to be a source for some used parts if they are compatible.

Thanks
jjs3rd914

Posted by: Jake Raby Nov 26 2007, 07:57 PM

I have tons of L jet components- ECUs, harnesses, you name it..

Posted by: blitZ Nov 27 2007, 06:20 AM

It would make sense to me to move to an after market version, SDS or MS. That way you will have a setup which can scale to fit a larger engine if you go that route.

Posted by: Jake Raby Nov 27 2007, 08:30 AM

Exactly.. I have proven that the stock plenum and runners are good to 145 HP effectively, but the ECU is the kill joy...

Who would be interested in our RAT/SDS EFI arrangement if it came as a complete kit retrofited for the later style Bosch injectors with our air filter mods, as a complete kit.
If I could make up at least 8 of these it would be worth my time to offer the arrangement that we generally use for in house turn key engines. These would be all powdercoated and ready to bolt on with a fuel map programmed that would "get you close".

Posted by: Bleyseng Nov 27 2007, 08:40 AM

What cam would you have to use with this SDS FI?

Posted by: 396 Nov 27 2007, 08:48 AM

Since I'm new to this stuff.. elebrate / provide digrams on how to perform all the above 'eliminate items' ? .. ..just unplug all the items listed above?

Thank you!

Posted by: type47 Nov 27 2007, 09:51 AM

EGR system are tubes into the heads. either cap off the tubes (new AA catalog offers caps) or remove tube and fill with suitable threaded item. remove egr pump and pulley (pump should be on top of the engine, above the cooling fan.)

i'm not sure about the eliminating the PCV valve and the vapor recovery system. my thoughts on those are to keep and eliminate sources of vacuum leaks.

Posted by: type47 Nov 27 2007, 09:56 AM

me, me, me.....

the next engine i want to build is a GA case, 71mm stroke ('cause i already have them), 96mm piston, modern digital EFI system. have been reading the discussions on megasquirt and SDS systems ...

Posted by: charlesmac Nov 27 2007, 10:35 AM

I have been thinking of using an SDS system with stock runners in a 2.0L that I plan to put in my VW fastback, so count me in on the interested list Jake.

Posted by: blitZ Nov 27 2007, 12:10 PM

What type of performance improvement can be expected with a 2056 with a 9550 cam switching to SDS? Do you have to drop the engine for this install?

Posted by: jhadler Nov 27 2007, 12:41 PM

Would this be for retrofitting to existing plenums? Or would you be supplying the plenum/throttles?

I'd be interested in a setup that could use the existing plenum, but that could use newer style injectors and not have to rely on the 40 year old MPS design.

(I also have some TWM's sitting on a shelf that I'd like to move to in the future)

What might the price tag on this be?

-Josh2

Posted by: Jake Raby Nov 27 2007, 01:16 PM

I recently built an 8:1 2056 with 9550 cam and LE 180 heads and my older version of the SDS EFI retrofit kit (I dropped it due to not enough interest)

The engine made 129HP, which is more than the engine in my 912E that has both more cam, more CR, OEM 2.0 heads and the same SDS kit.. This 129HP combo is included in my engine kits that we are updating now, for release next week. Reports from the owner that has it in his 912 are 35 MPG and more power than he can use daily.

I can bring back the old kit at any time, it used stock pump, pressure regulator, plenum, throttle body but updated the ECU to SDS as well as the harness and TPS. I sold these for about 1600 bucks.

The newer arrangement I am contemplating would include runners set up for late style bosch injectors, injectors, ECU, optimized air filter and etc. The stock pump and FPR could be used up to 130HP.

I would need 8 parties ready to put 2,200.00 in my hands UP FRONT to make these happen.

Posted by: blitZ Nov 28 2007, 06:40 AM

Is this the SDS EM-4D system? I already have stock Djet, so I don't need the runners, TB, etc. What comes with the kit besides the base system? Do I have to install a trigger wheel behind the fan?

Posted by: ottox914 Nov 28 2007, 07:41 AM

Here is a link to my SDS install. I used some ITB's from Jake, so some of the install will be different from an install w/stock intake pieces, but you'll get the general idea.

Yes, dropping the engine is about 99% manditory. Finding a way to mount the crank sensor is the reason. If you went with SDS fuel only, and used a Mallory dizzy, dropping the engine would not be needed, but for a couple hundred more, the advantages of programable, crank fired ignition were enough to convice me to drop the engine and go with the full meal deal.

http://www.914world.com/bbs2/index.php?showtopic=53733&hl=

Hard to know what the engine "made" for HP, as Jakes numbers come from an engine dyno, and mine are from a chassis dyno, and one known to be "low" compaired to a dynojet or mustang. I'm expecting the corrected HP to be 105-110 at the crank for a stock-ish 2.0. It has euro p/c's, a slight head shave, resulting in ? for an actual compression ratio. I'm guessing its just over 9:0-1, but the builder (Brad Mayeur) did not check the actual ratio when building it. At the time, this was his "standard" performance upgrade. Stock lame-o cam, stock heads. Kerry hunter exhaust and supertrapp. Thats about it.


EZ to install? With the exception of the crank sensor, which was not all that bad to do anyway, this was a breeze.

Do it again? In a heartbeat.