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D-Jet to Megasquirt conversion

Started by thysonsacclaim, 05 October 2010, 01:18 PM

npk

Unfortunately, I could not Dyno BEFORE cos the engine kept stalling  :( :( :(

thysonsacclaim

I wish I had the money to DYNO the car. The best I will be able to do is a sniff test and spark plug test to see if the car is running at the perfect 14.7:1 (unless I get the wide band O2 sensor, which has a digital read out showing Air-Fuel Ratio).

I will keep you guys posted. Also, I plan on uploading pics as well as the product numbers and places to buy the parts I am going to use.


450SLC 5.6 supercharged

Hi   cool thing with EFI convertion   and i just whanted to tell that 14.7 is at light load  and medium cruise at full pull (maby you allready new this),  but anyway those engines whant around 13.2 A/F  at WOT   otherwise you will end up in engine trubbel. keep up good with work  i will look farward to follow this project.

npk

I tune 13-13.5 at WOT and acceleration, 13.5 on idling(or higher if engine health is good and engine doesn't wobble too much)....on cruising, 14.7-15.5(and higher until I find the car is slowing down at fixed accelerator pedal on flat road).

I always believe that these numbers change based on engine health....my W123 could idle at 14+

thysonsacclaim

Yeah it will change depending on the health of the engine. I was being optimistic, I suppose  ::)

450SLC 5.6 supercharged

well  its true    and  at the same time  the combustion efficiency  will affect on that   but that  must be an engine that have lost  the compression to much   ore  something else is not good  like camtiming  is wrong ore ignition advance is to low.  And those 450 engines i tuned  so far by the years  now  did idling good  at 14.5-14.7  and light cruise 15.7   and gave most power  right at 13.2    and 31.4 degree ignition advance  from 3150rpm  WOT  N/A  no turbo .  comp ratio 8.8   and light load 39.8-41 degrees      idle 10 degree  and with D-drive in i mapped 13.5 degrees to compensate the RPM diff.  it  worked out perfect

npk

Quote from: thysonsacclaim on 05 October 2010, 08:42 PM
Megasquirt Conversion Costs:

8 x Low impedance (14.4 ohm) Fuel injectors (19lb/hr) - $60

1 x Saab Bosch Throttle Position Sensor (POT) - $65 (new), ~$10 (used)
1 x Heated Wide Band Oxygen Sensor - $60
1 x Megasquirt 3 - $359
1 x MegaSquirt-II - $259
8 x Fuel Injector pigtails - $15
1 x TPS Pigtail - $5

Total: ~$344-$404

When I finish this, I will be selling the working MPS, ECU and injectors.

Aren't you upgrading the Ignition System?

thysonsacclaim

It's possible I will. Although initially, I'm not so sure.

I really don't know anyone reliable to put the gear on the crankshaft for me... or where to look. The rest of the EDIS is fairly cheap and easy to do.

npk

#23
Maybe you can explore getting a 36 tooth plate that you can bolt onto the harmonic damper

Just thinking aloud

Maybe one of these will work

http://www.diyautotune.com/catalog/trigger-wheels-c-48.html?osCsid=242061f3d93942cbc1e9e8e100367aea

npk

Quote from: thysonsacclaim on 06 October 2010, 01:35 PM
I believe I am going to use the stock injectors because I think they will actually be easier and better to use than trying to find another set that meets the lb/hr spec, impedance, and hose connections. I will clean them and re-do the connections. Edited the price list.

By the way, NPK, a good site: http://www.megamanual.com/v22manual/minj.htm#size

Do you know if the D-jet original Injectors are HIGH or LOW impedence?

(need to check if I need to add resistor to the Injector supply).

Thanks


thysonsacclaim

The D-Jet to Megasquirt on that 1974 SLC says to add resistors, so I assume low impedance.

npk

#26
Measured the D-jet injectors on my 280SE, it reads 3.3 Ohm per injector


From http://www.megamanual.com/v22manual/mtune.htm#constants

"If you have low impedance injectors (less than 4 Ohms), set the:

   * PWM Time Threshold to 1.0 msec, and
   * PWM Current Limit to 30% in most cases (all V3 main board with active flyback installed, and all V2.2 main board with flyback daughter board installed).

     Set the initial PWM% to 75% if (and only if) you have low impedance injectors and have NOT installed:
         o the active flyback circuit on a V3 main board (assembly manual step #69), or
         o the 'Flyback Board' daughter card on a V2.2 main board). "



http://www.megamanual.com/v22manual/minj.htm#size

Since I am using less than 4 injector(3 to be specific), I will use PWM current limit

thysonsacclaim

NPK,

Which MS board are you using? 1, II or 3?

npk

MS1 Extra 029Y4

Decided to add 10 Ohm resistor to every injector (converting them to High Impedance)...think this is a more reliable way to run the car.

thysonsacclaim

Here are pictures of the work being done by NPK on their car:


Coil packs mounted on the engine:


More coil packs mounted:


He plugged the distributor mount hole very nicely with a 27mm water jacket:


And finally... the trigger sensor mounted near the alternator bracket:






Again, the pics are courtesy of NPK. Enjoy.