B35/L-Jet/Motronic conversion

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careysd

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Hi All,

I am getting ready to do a B35/Motronic conversion on my carbed Bavaria. I plan on using the L-jet manifold and the 1.3 harness and fuel rail, but will clean up any unused ports, etc.

Since some of you have done the swap, I was wondering if you could share some advice?

1. There is an early L-jet manifold from a 530 in perfect condition in the yard. How different are these from the later L-jet manifolds other than the fuel rail?

2. If I go with the early, will I need to switch throttle bodies due to the mounting of the TPS?

3. Are there any alternatives to La Jolla’s (what I consider somewhat pricey) injector adaptor clips?

4. Does anyone have a tii booster that they are wanting to part with?

I have searched the archives and think I have a good grip on this swap due to them, just a few small questions.

Thanks,

Scott C
 
With respect to #2 on your list check out this adapter and TPS which I used on a 1981 528i throttle body. Includes bracket, hardware and switch and was a perfect fit.

http://www.02again.com/product_info.php/products_id/158

Here it is installed - I might still have the template for the bracket mount to check the holes for alignment and fit or you can ask Tom at 02again.com for a copy..

IMG00054-20100115-1026.jpg


Doug
 
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have you considered the 206 injector? high impedence, barbed and same flow rate.

Why are you wanting to go with the tii booster? Even the long c tubes from a 320i fit fine.
 
Thanks for the replies.

The tii booster thing was an add on from when I originally wrote the thread. I do not want a tii booster.

I looked up the 206 injectors and they seem to be for VW Vanagons 83-91(?). I can find no other cars that cross reference with this (that I might find in the yards). Does anyone know if there are other solutions to this? There must be an injector that will work well!

Second, as far as the return lines go:

1. Is it acceptable to have a nipple brazed to the gas tank?

2. When I put the feed line in, what is the preferred method for ensuring the security of the high-pressure fuel line? (flare and clamps or other?)
 
You can still buy pre-bent OEM fuel lines from BMW or any of the online dealers and just put in in parallel to the original line- I'm assuming the BAV is similar in route. You should also consider buy the modified in-tank pick and pre-pump from La Jolla which gives you the extra port for the return line into the tank. Brazing a nipple sounds dangerous and vaguely disturbing.

You might also consider a surge tank like the OEM model (still available) that provide about a litre of buffer from the sloshing of fuel in the tank under high cornering forces and low fuel volume. I went another route and had a 4 port surge tank welded to give me a gravity surge tank and put the FI pump in the trunk instead of under it.

Meet the squid.

IMGP4658.jpg


I also suggest doing the conversion with the engine out of the car - the 4 hours to remove it will save days of frustration. Wish I had done it.

Doug
 
last 3 conversions I have done I went with the all in 1 pump from the 318i.

No need for the bracket to be welded under the car, no need for 2 pumps.

Keep an eye out at the boneyards- they charge 20-40 bucks for one.

try the 204 from a volvo 240
 
Went to the yard, and although I didn't pull any apart, they appear to be non-barbed on the Volvo 240s. I also cannot find a listing for a Bosch with a 204 suffix.
 
Hey why would you run with L-jet. If you get a d-jet to a large B35 so you get many more horses, and it looks super old school , As a D-Jet has no limit to how much gasoline it sucks:-D tak a look her www.wallothnesch.com ask Christoffer they usually have everything
 
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I didn't think that there was that much difference in the manifolds from d-jet to l-jet other than d-jet was a little cleaner in appearance? Please school me in the differences and why one is better than the other. I am genuinely curious. I was planning on going l-jet, as it seems easier to find.

Thanks,

Scott
 
I have my injectors made for me - 15.9 ohms at 200 cc's with a barb. same flow and impedence as a m30 b35. Comes with the correct hose diameter and length already crimped. I am using a spray orifice rather than the stream.
Let me know if you need a set- they are 75 bucks each rebuilt.
 

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I searched, but only found one reference to someone cutting the booster bracket down. I am not near my car, but it seems possible and quite easy (comparitively) to cut down the stock booster bracket a few inches, reweld it, and shorten the push rod, placing the whole mess closer to the firewall. I imagine the only reason, BMW put the booster where it did, was to clear the dual carbs.

I have an extra bracket in my garage and would think that this might be a fairly easy solution. Of course, you will have to adjust the brake lines, but meh...

I am not near my car right now, to take a look. Is this not an accepted practice?
 
The interface to the runners is the same. The L-jet has several more vacuum lines coming off of it. I have the L-jet on mine only because I couldn't find a D-jet at the junk yard. I pulled the extra vacuum tubes out and plugged the holes. One of the holes is rather large (.7" dia) inthe center and I had to fabricated a plug for it. If you can find a D-jet us it otherwise...

Scott
 
Thanks everyone for your input. SFDon, I ordered the injectors that you spoke of. They arrived today and I have my injectors and are sitting in the garage.

Now, I just have to fab a coolant by-pass pipe and bolt manifolds on!
 
The L-jet has a 3/4" diameter hole right in the center under the two center runners that you will have to plug. I turned a plug on the lathe at work and bonded it in with JB weld. When installed you wont see it unless you look real hard. If you can get a D-jet log go for it, otherwise just need to fill the unused holes. You only need two vacuum lines, one for the booster and one for the fuel regulator. I kept a third for a manifold pressure gage.
 
I wish I knew about those injectors earlier... The "cups" from La Jolla are $35.00 each and then the cost of the rebuilt injectors. The inside of the cups from La Jolla don't have a good surface finish or a good lead in chamfer and tear up the o-rings when installing; I have had two fuel leaks with them so far and had to polish the insides with 600 grit cloth. Those injectors are the way to go!
 
Looks like there's quite a few choices (and $130/ea spread on pricing) for those Vanagon injectors. Anybody have a substantive opinion on the relative merits of Python vs. Beck Arnley vs. Bosch vs. GB vs. Standard?
 
Further Progress!

Since I have this thread started, I won't muck up the board with several others. I am planning on doing writing a summation when done to help others. But first...

I am using an automatic E34 harness. I'll be removing the extraneous wiring beore putting in the car (matter of fact, sitting on the living room floor as we speak with wife nearby sewing!). A few questions pertaining to this:

1. It doesn't appear that the injector harness cover will fit inside the manifold. I was planning on wrapping up the harness with some cloth friction tape and securing it as best as possible. Is this the best course? I am considering using the tubular spark plug holder if possible, but have yet to really look at it.

2. Can someone post a pic or tell me where the best spot to go through the firewall is (for the harness)? There is quite a bit of insulation and I would like to keep it as far from the exhaust as possible. I realize there isn't too many places to do this, though. Use a hole saw of 2" diameter or so?

3. I rebuilt my fuel rail (later L-jet) and the rail seems to hit the manifold. I used what I was told was the proper 2.5" hose length. Since I got the manifold in pieces, am I missing a bracket (besides fuel regulator) that holds this down? (looking at ETk after this)

I appreciate any advice. Also a big thank you to sfdon, as he has been a big help!

Have a good night,

Scott C.
 
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