High output coils

[bratman2]

Would be curious to see what you produce now myself. Actually I though 53 was pretty good going through an auto. Wish your engine was in my Brat! The .045 I think I got straight out the owners manual.

[tweety]

yeh, not much wrong with this engine now. But to respond to taking it back to the dyno guy. I rode 660 kilometres today, alone no passenger, no load. I wasnt happy with the fuel economy. 

 

First refill 21mpg (Aussie gallons 4.5 litres to one gallon)

Second refill 23 mpg

 

Using 98RON again Australian measures. 98 is what it was tuned for.

 

When I first got the ea81 4 years ago I had a 32/36 weber on it and sold that carb. I then got 29-34mpg. I've decided to buy another one. I can sell the 38/38 easily here.

 

Plug gap. .045 would be ideal for a stock engine (8.7:1 CR) but with CR of 9.5:1 you are suppose to shorten the gap due to turbulence inside the compression chamber. So maybe .042 is more ideal.?

 

I was advised by many that the 38 was "too big" for the ea81. It is. But I like to try things outside the square. Some times I win sometimes not. I'll get one from a junk yard and try it. Think it has the same footprint as the 38

Edited June 10, 2015 by tweety

[jono]

would trying outside the square go as far as fitting an O2 sensor and gauge so you get a constant idea of how economy could be going ?

[tweety]

tell me more Jono.

 

I have a plug in the exhaust for an O2 sensor (for when SPFI was in there).  Are there gauges for this and is it like the old vacuum gauges (but they were more like an accelerator gauge IMO)

[coxy]

Here is a good guide and from an Aussie site to boot so locally applicable to what we can easily source, I agree with Jono they are better than a vacuum guage for looking after economy especially on the open road and with the added bonus they will let you know when something is not happy by the readings.

 

http://www.autospeed.com.au/cms/article.html?&A=3032

 

Considering the whole Ignition saga in this thread here is another one of their Articles this on on Ignition Coil dwell time with electronics,With Points Dwell meant how long the points were shut thus allowing the Coil to recharge between firing events with obvious point being at higher RPM there is less time to recharge the coil before discharging it and with V8's even less time for the same thing to occur hence why so many Modern engines run crank trigger COP (Coil On Plug) systems to aid exactly that situation. The article relates mainly to Bosch Ignitors buy seeing as Nippondenso and Hitachi are actually Bosch designs made under licence it is applicable.

Well worth reading to allow you a better understanding of how Ignitions work

 

http://www.autospeed.com.au/cms/A_113140/article.html?popularArticle

Edited June 11, 2015 by coxy

[comatosellama]

 

MMMM...amazing what you learn. Most members know of my rebuilt ea81 in my trike. SPFI manifold, 38/38 weber, 16/56 cam 9.5:1 CR etc. Then why did it only reach 53hp at the dyno with the right jets? I had platinum plugs

that were black. Economy was not so good at 23 mpg (Oz).

 

Recently due to this thread I started wondering about my ignition module....if it wasnt performing normally. Two years ago I had a master blaster 2 coil when my ea81 was supercharged. But after the rebuild I purchased a new stock one. I never

thought the module would be damaged.

I installed a new module this week. Safely can say about 20% more power. Then swapped the platimum

plugs for stock new ones and opened the gap from my usual 34 thou to 45 thou". Safely say another 20% more kick. Refuelled and went for a long run today. Much much better uphills, much less throttle needed in general riding. Better throttle response. Economy - have to wait and see but is looking good on the gauge. Am using 95PULP (Australian measures). Spark plugs are perfect- light tan colour- not black.

 

So dont use a high output coil, it could damage your module. Replace your module and use the old one as a spare in the glovebox. Use 8mm plug leads. Open up your plug gap if the rest of the ignition is A1- to .045". And tune it with 95PULP. ps

my timing is 11 degrees BTDC. This was the timing set by the dyno operator that got the max hp at that point and wasnt changed during my latest experimenting with plugs.

 

This all means that the 53hp at the rear wheels (through a VW type 3 auto trans axle) was not near its potential. I'm not going to take it back and get an updated reading. $60,000 spent on this machine over 6 years is enough. But I'm guessing

that with the increase in power and torque I might have 70-75hp ATW now. More than enough for some thrills on a 660 kgm trike. Cheers

 

Is that a V12 in the backround?

Edited June 11, 2015 by comatosellama

[tweety]

good observation cosmasellama,

 

I assuem it is. The pic was taken at the engine builders factory.

[tweety]

Coxy,

 

Just read your links. one of them stated

 

"

Correct coil current

The only way to guarantee reliable service is to set the coil primary
current to the same level that is used in the standard vehicles the
components are used on. Vehicle and component manufacturers do many
severe tests to check reliability. If you use aftermarket or cheap
replacement coils, then you’re on your own!

There are gains to be had by raising the coil current slightly but
long-term component endurance will be a gamble. Manufacturers have to be
conservative for a reliability margin and to allow for manufacturing
tolerances; they really know their limits."

 

That was from :  http://www.autospeed.com.au/cms/A_113140/article.html?popularArticle  

 

Thanks for those links .Another reason for sticking to the original Subaru coil with the distributor module, both new in my case.

 

BTW, I found after some testing (riding) that the new NGK standard plug gapped at 0.42 were the ideal gap for my engine.

[tweety]

More follow up-

 

Sent an email to MSD asking if the Master blaster 2 coil is suitable for my ea81 engine. This was the response

 

"the master blaster coil is suitable for your engine"  end reply.  Would have been nice to get reasons or technical supportive comments for such.

 

I'm not convinced.  I'd love someone with technical expertise to confirm/deny the benefits/potential damage aftermarket coils do. We know the stock coils has a primary reading of 1.1 ohms. The master blaster 2 coil has 0.7 ohms which I think is too much drop from stock to be reliable for other components like the dizzy module. If someone could recommend a coil that perhaps has 0.9 ohms with evidence that its install would not hurt the module I'll be listening. Cheers.

[bratman2]

Like I posted previous I have been using the Accell Superstock coil for at least 15 years on my Brat. Looking back at them again I believe it is a 8140 model, USA made. Back in the late 90's several people were running them on EA81 motors. I have no idea what the resistance readings are on the coil. I also installed 8mm Accell wires at the same time. Though that is not the same coil you have.

[tweety]

High Bratman,

 

I've seen the specs for your Accel coils being - ACCEL Yellow can. 42000 volts effective up to 6500 RPM 1.4 ohms on the primary.  The primary ohms being the topic of conversation and importance.  The stock coil is about 1.1 ohms and anything less is a concern in terms of possible damage.

 

That being the case your coil is more than the stock coil and likely a good choice IMO. Whereas my Master Blaster 2 coil has a primary of 0.7 ohms. See the issue here? Hence my pursuit of some real good technical answers as to what is the boundaries of the primary spec for a compatible coil for the standard ea81. Say if someone proved that 0.9-1.5 ohms and 42,000 volts would have zero adverse effect on the rest of the ignition system I'd be happy.

 

http://shop.accel-ignition.com/super-stock-coil-points.html

 

I also read on another USMB thread that GD stated that air/fuel has more to do with engine output than spark if the ignition is stock and working well. I think many coils are not ideal. Yours is one that is a good replacement.

 

I wonder if supplied volts can be safely measured at the spark plug ensuring 100% function?

Edited June 18, 2015 by tweety

[DaveT]

Measuring high voltage can be done. You need specially built high voltage resistors. Or expensive HV probes. Several hundred megohms total. High voltage resistors are very long so the voltage doesn't just arc around them.

[naru]

These work OK

http://buy1.snapon.com/products/diagnostics/dis.asp

 

Voltage will only go high enough to jump the gap regardless of which coil you use though.

[bratman2]

Gotcha! With the factory mounting in an EA81 engines laying in its side instead of straight up many later "made in Mexico" Accel coils would crap their oil out. So may not be a good choice for a new replacement. Wonder if anyone makes a better made comparable model that can be mounted on it's side?