V8 3.6 litre Ignition - Electromotive

[Hillclimber]

For my race car project I am just about decided to buy from Electromotive:2 x XDi Units ( Manual Knob Timing Adjust ) with Harness's plus 8 x Single Pole Coils +2 x Hall Effect Sensors and the 60-2 timing wheel with two sensors to be set at 45 degree crank angle apart. Each XDi unit then runs 4 cylinders.

Anyone done this?

Anyone got an ignition timing curve for the V8, startup to 6500rpm, so I can get it safely running prior to rolling road tuneup?

Flywhell replaced with CVT transmission primary pulley.

[PanRonnie]

i thought you were going to install a megasquirt?

[Hillclimber]

I am getting nervous about the MS as I am 73 years old and do not understand how to get it up and running plus fault finding. So gone to a system I feel more comfortable with. Same reason I finally went 8 Mikuni carbs instead of EFI. I can read plugs/pistons and change jets - I cant be sure of getting the MS running correctly. One mapping mistake and will be looking for new piston(s) or ???

[PanRonnie]

It,s not that hard and going with 2 ignition systems and carburaturs! !!is not complicated

[racer]

Timing no more than 18 and should have full advance by 5K and ramp up starting at about 4 degrees at 1K. Idle timing may differ from marine use due to drive and no flywheel.

[powerabout]

Are you saying straight line from 4@1k to 18 @5k?
Sounds very conservative?

[Hillclimber]

I finally found the Mikuni carbs:http://www.mikuni.com/pdf/sbn_manual.pdf : which are made for watercraft i.e. they have no float chamber so if I turn over there is no petrol to catch fire. With the CVT transmission, I will tune it to run in the 5500 to 6500 RPM range. The only time I need 0 to 75% throttle is to get from the pits to the startline. On the line its tuned to start driving at 3500RPM. so with external manual main jet adjustment I can easily alter jetting to suit the race venue & weather + some tracks are 2 or 3000 ft above sea level. I then found the manually adjustable ignition system which I feel reasonably confident with once I can find a "Normal" OMC timing curve. Then I am fitting the water radiators in series so I can hopefully get down to the 135F water temp. required leaving the engine. Then I am fitting a small (medical use) 12v pump (50 ml/minute) to supply oil to the 5 main bearings as, with horizontal crank, I have lost the normal lube system. Then noise - I need to get to 105db so I am running 8 x 2" diameter pipes from the 2 - 4" x 3" outlets with 8 silencers and tail pipes. I calculate that this should give me no more back pressure than the normal 6" under water outlet. All this should come together in March 2018 when I plan the 1st startup. Then we will see what happens. Will I need to inject CO2 in front of the rads for extra cooling, will I need more silencing?, how close am I with jet selection, will the ignition keep the plugs clean? It all keeps the grey matter in the head turning over. If it all works OK then I plan to fit twin turbo,s to get around 500hp+ at 6500RPM if my calcs are correct. Time will tell.

[rude tim]

Are you saying straight line from 4@1k to 18 @5k?
Sounds very conservative?

As Al said 18 max at 5k. You might mess mith more timing off idle but with a trans you probably will never be down that low in the rpm range. It may seem not very agressive but you will find that in the upper rpm range this engine does not like more timing. you might play with ramping to 18 faster like in the 3000 to 3500 range and hold it there tell the end. Remember 2 strokes love timing down low but hate it up top. One more thing to remember is when you are braking into a corner and you are off the throttle the engine will be lean due to the throttle position.

[Hillclimber]

Hi Rude tim
Thanks for advice on timing and good point about braking for corners.
Investigation indicates that roller bearings need "3 drops per minute", a drop being 0.025grams!!. Thats about 5 mls per minute for 5 bearings. I will mix 50/50 oil-petrol for bearing pump delivering 50 ml/min and hope this excess will get distributed to cover the braking issue.

[powerabout]

Later Evinrude v8's used a vacuum switch to operate the start primer solenoid for extra fuel under deceleration.
You could do that to be safe.

[rude tim]

I would like to have one of those vacuum switches.

[powerabout]

I would like to have one of those vacuum switches.
was it a kit as well?
250hp has it as 436689

[racer]

Yes conservative on timing ramp but since we do not know how the clutch will load the engine better to be conservative at first than hurt the engine.

[rude tim]

was it a kit as well?
250hp has it as 436689

That part is no longer available. I guess I could put a vacuum guage in the case and see what it pulls and find a vacuum switch.

[powerabout]

That part is no longer available. I guess I could put a vacuum guage in the case and see what it pulls and find a vacuum switch.
lots of vacuum switches out there, used everywhere in industry

[rude tim]

Al,
any idea how much Vacuum an omc pulls when the butterflies are closed at RPM?

[fastcat1]

So it’s idle to 1K rpm at about 4 degrees BTDC with a max of 18 degrees BTDC somewhere after 3500 rpm. So in a stock motor there is no load base, temp or altitude adjustment? If there is no timing adjustment could they benefit from it? The reason I am asking is I have a stock 4.0 that I would like to install a lightweight flywheel and this would be a good time to update the ignition.

[rude tim]

I would say that you would want 18 degrees much sooner than 3500 rpm. The thing with 18 degrees is keeping the engine from melting down at rpm. A programmable ignition would be a good investment. You could ramp up the timing into the low to mid 20s degrees in the lower rpm ranges and retard it to 16- 18 degrees as it reaches the top rpm. If you ever start porting the engine and want to get more rpm the programable ignition would be even better. Lots of dyno time or on track testing will be key.

[fastcat1]

Thanks rude tim. I like the Electromotive ignition module solution, but would like it even better if they made a module that can handle 8 cyls. Seems that having a two system solution is adding complexity and cost. I am not interested in converting the engine to FI so a complete engine management system would be overkill. Dose anybody make something similar to the XDi, but that it can handle an 8cyl 2 stroke engine? Has anybody done this?

[powerabout]

I think these guys will do you a v8 in one box.
http://www.emeraldm3d.com/
(http://www.emeraldm3d.com/)

[fastcat1]

Thanks powerabout. Its my understanding that the V8 is two 4cyl put together. If so, can the ignition system be wired to run as a wasted spark? Being that it’s a 2-stroke will there be enough time for the coil and driver to recover? Keeping the max RPM below 7000.

[BarryStrawn]

Thanks powerabout. Its my understanding that the V8 is two 4cyl put together. If so, can the ignition system be wired to run as a wasted spark? Being that it’s a 2-stroke will there be enough time for the coil and driver to recover? Keeping the max RPM below 7000.

No on wasted spark. That requires two cylinders to be at at top dead center at same time. On a two stroke that means firing them at same time.

[powerabout]

Thanks powerabout. Its my understanding that the V8 is two 4cyl put together. If so, can the ignition system be wired to run as a wasted spark? Being that it’s a 2-stroke will there be enough time for the coil and driver to recover? Keeping the max RPM below 7000.

Its still an even fire engine and yes the short dwell time and halved crank angle is why very few systems can hack it.

[fastcat1]

Thanks BarryStrawn. OK, I understand.

[fastcat1]

What would be the consequence of running a wasted spark set-up with two cylinders that are 180 degrees of crank separation? Would this effect the intake charge? I know that the Yamaha Banshee (2 cylinder – 2 stroke) has a wasted spark set–up. Does, the V8 have a crankshaft set-up where the cylinder are at 180 degrees separation?

[BarryStrawn]

I suppose it might work but just seems a bad idea to fire the plug at 72 degrees ATDC into the intake charge. With no compression it might never light up.

On the Evinrude/Johnson two stroke V8, I think it would work with four coil outputs like a four stroke V8 "wasted spark" but the spark wouldn't be wasted. Assuming a high energy ignition that can provide enough to fire both. Or maybe I've been working out in the sun all morning:-)

[fastcat1]

No on wasted spark. That requires two cylinders to be at at top dead center at same time. On a two stroke that means firing them at same time.

On a two stroke the cylinders have to be 180 degrees of crank separation not both cylinders on TDC.

[powerabout]

if you run wasted spark ( assuming it will work) you are creating an ignition event twice as often, so dwell time cut in half again