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-   -   Modern EFI in the old Benz (https://www.benzworld.org/forums/vintage-mercedes-benz/2644825-modern-efi-old-benz.html)

TZ_280SEL 06-10-2016 01:08 PM

Yes. This is on the euro 4.5. I have a detailed spreadsheet with every part I purchased. I can also take some photos and sketch how I did my crank sensor mount, idle valve, and coil mounts.

alabbasi 06-10-2016 01:33 PM

I have to wonder how well this car runs compared to a US 280SEL 4.5. HP wise, it should be getting close to 6.3 territory.

TZ_280SEL 06-10-2016 08:15 PM

According to what I've learned, this engine was 225hp from the factory thanks to higher compression and different cams. People claim to add power to these engines with better fuel/ignition control. That with my cold air intake may put it at 235-240hp and a bit over 275ft-lb so that's enough for this chassis. She definitely saw an improvement going from the us spec to the euro. Now that I've driven it with mega squirt for a week, it DEFINITELY has a large improvement over d-jet.

TZ_280SEL 06-14-2016 06:25 AM

Quick question for all you gear heads. I removed the old distributor and installed the LS2 coils for ignition. I replaced the long resistor plug wires with short (about 16") wires by MSD which I added the special 45 degree LS boots to. Because I went from resistor to non resistor wires, I felt obligated to change plugs too.

So, because I put on LS2 coils and new wires, I decided to go ahead and install plugs for a chevy LS2 engine. They are same depth from the seat to the electrode tip. They are smaller socket size. But they are gapped at .050

I am now running the .050 gap. I figured match the plug to the ignition system, not the motor. Agree or no?

During testing, I had a plug laying on the valve cover. Boy do those coils/plugs throw a spark.

On another note, slowly tuning the car a little every day. I pretty much have it idling at AFR15.0 and very responsive. She seems to have a very throaty growl under heavy throttle now....almost like secondaries on a carb opening up.

Mike D 06-14-2016 06:44 AM

Plugs are plugs. If they fit, have the proper heat range and electrode extension then you're good to go.

Nothing wrong with opening up the gap to take advantage of the hotter spark available using the coils.

I'd be cautious running 15.0 AFR. Because you are running a hotter spark on an older engine you might run into some heat dispersion problems using the old technology pistons you have.

The older engines liked to run "fat" to achieve a smooth idle. I think you might want to bump the 700-1200 RPM areas into the 14.1- 14.6 AFR range.

Pay attention to your advance curve. A hotter spark will slightly delay the actual ignition point and also prolong the actual event. Probably such a slight difference it may not make any difference but it is something to be aware of.

TZ_280SEL 06-14-2016 09:02 AM

Right now, at about 850 rpm idle and 15.0 AFR, idle oscillates about 25 rpm every 2 sec or so...almost imperceptible. I've yet to really tune idle, it just like to run that way. Doesn't change much with AC on or off. So far, I'm loving that aspect.

It is currently real lean on lift throttle and a bit too fat on heavy acceleration (think 17.0 and 12.0) but we are getting better every day. Baby steps. Log on trip to/from work...new tune at night....repeat.

Mike D 06-14-2016 10:58 AM

Throttle lift will always show lean. Nature of the beast. Hard for the O2 gauge to keep up with the rapid change.

The slight "blip" you are getting at idle is the result of a too lean condition. Fatten it up a bit. Maybe try 14.8 AFR. Once you get the idle set, LOCK that cell! Having a stable idle is a keystone in the tuning process.

I usually tune by Stoich, then go back and adjust my AFR.

I warn you. Tuning gets to be addicting!

I've been adjusting my M110 for three or four years now and there's always that "little bit more" I think it could have.:laugh

TZ_280SEL 06-22-2016 10:30 AM

Time for a quick update now that I can get back into my Benzworld account.

Filled up the tank for the first time since the conversion. Only averaged 13.0 mpg. I know, that sounds not so good, but consider; No trip was over 6 miles, there was a LOT of sitting and idling in the driveway as I waited for the car to warm up so I could do some tuning, The car still does not have a 100% tune, the majority of trips involved a lot of full throttle accelerations (both for tuning/data logging AND because it is a whole lot of fun now). All in all, it is about where it was prior to converting, but it has no place to go but up.

Car now idles at a rock solid 795 rpm (ok, it hunts +/- 5 rpm) when warm. I have the engine VE map pretty solid now so my AFR is pretty solid.

I'm taking time off of tuning VE to tweak the timing a little. I have no advance map so I'm trying to sneak up on a good curve. Keep in mind this is a 8.8:1 euro, not a 8:1 USA engine so results may vary.

I currently have cranking advance at 7 BTDC. Idle is at 10-12 BTDC. Full throttle above 3000 rpm is 26-30 BTDC and cruise at 3000 rpm+ is about 40 BTDC. Right now, I think I may have timing coming in a bit too fast as there is a very slight ping at the 1500-2000 rpm and heavy accel so I'm backing that area off a little.

Suggestions?

alabbasi 06-23-2016 04:19 PM

No suggestions, just looking forward to the next tank of fuel once backed off the timing.

Baybear 06-23-2016 04:26 PM

Perhaps the octane gas you are using makes a difference?
Will


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