Interesting info

russ · 01-01-2007, 10:43 PM

Was gasin to a guy the other day, got onto the subject of engines and gyros etc etc

He asked a lot of questions re "our" engines, and then it began to get interesting.........

Ok............ina nutshell

Soob 2.5's are 10.1 thereabouts compression, as are most late model engines poking out that sort of HP

All get their HP at high revs

All are computor controlled

All have little marjin for error...........now it gets interesting

Most have all sorts of sensors........the real goodin is the "knock" sensor
This in part is there to "save" the engine....
it will sence "knock"..........[ detonation in particular ] and the computor will begin to shut down the engine to a "limp" mode
These sensors are that good, they could pickup "knock" from our redrives as .....detonation, and .......you guess the rest

All these engines should be running on 98 octane.........nothing else.........but the lower grade is ok...............IF IT'S FRESH

Why fresh you ask........coz apparantly unleaded quickly drops it's octane leval, so if you bung in "old" unleaded you is almost guaranteed to get.....detonation, then the computor starts doin it's "shutdown" to "save" the engine

So by using the "high" octane, you got more leeway of loosing some octane, and not getting to the "too low" rating

Could go on and on here, a sugestion from him was .........drop the compression to 8.....this will improve the "torque".......but you sacrifice HP

This will control the low octane fuel problems.

Just thought i'de pass this on............any comments

rotor · 02-01-2007, 12:57 AM

Russ,

you don't have to run the factory computer. As you've already pointed out it isn't really suitable for what you want in an aircraft - the last thing you want is for cruise control to take over

or the computer to try for fuel efficiency during take off when you want all the herbs you can get!

Why not go for an after market computer. I have opted for the "Wolf 3D" on the EA81 which would also run your ej22.

rotor

russ · 02-01-2007, 10:41 AM

Yea geoff..........i hear you

BUT...............if your engine is 10 to 1 compression, your "after market" pewtar is not going to "save" your engine when it begins to detonate, because of low octane fuels. Your engine is simply guna destroy its self.

"Auto" makers are getting engines to do wundrous things......maybe......too techo.

We are running auto engines at quite different demands to that of the family car.

High compressions, higher operating temps, leaner mixes,horse powers/torques etc etc etc are all about car performances, emmission control etc etc, and we are bungin these car engines into our gyros and then asking the engine to behave/operate ina totally different enviroment.

Using these engines by us, can/could be, unchartered waters.........so beware, we must be.

BTW........we is back in "gods country"

Aussie_Paul · 02-01-2007, 02:58 PM

Quote:

Originally Posted by russell

Yea geoff..........i hear you

BUT...............if your engine is 10 to 1 compression, your "after market" pewtar is not going to "save" your engine when it begins to detonate, because of low octane fuels. Your engine is simply guna destroy its self.

"Auto" makers are getting engines to do wundrous things......maybe......too techo.

We are running auto engines at quite different demands to that of the family car.

High compressions, higher operating temps, leaner mixes,horse powers/torques etc etc etc are all about car performances, emmission control etc etc, and we are bungin these car engines into our gyros and then asking the engine to behave/operate ina totally different enviroment.

Using these engines by us, can/could be, unchartered waters.........so beware, we must be.

BTW........we is back in "gods country"

That is why we use aftermarket ECUs Russ. We program them richer and more retarded. That might explain me!!

The NZ link after market ECU has the ability to add a knock sensor.

I knew you were back in "gods country" Russ. You are back to your normal self and getting all hyped up at the drop of a hat.

lol.

All the best for 2007. What is the prognosis for the first flight of your new bird? Any pics?

Aussie Paul.

russ · 02-01-2007, 04:11 PM

Me build is taking that long, i'm beginning to look for a tree to hang meself. Christ, i'll be on the pension before it gets finished............Grrrrrrrr

Flyin down to Brizy in 3 weeks to see the build, and to set up an electric fence around Rods property, to keep out the "Barkers" etc that are holding up me build with their demands of Rod.

Could be more worser i spoze.........may have to buy a "flamed chook"

Then again life ain't that pathetic that i would have to do that........[ the "chook" bit ]

Aussie_Paul · 02-01-2007, 05:21 PM

Well, well, it looks like I am going to beat you into the air Russ.

Yeah, an electric fence to keep those Barkers out and Rod in!!!

by the time it's finished you will be too old to climb up into it.

Aussie Paul.

Murray Barker · 02-01-2007, 07:39 PM

Russ, I only go there to drink free coffee and poke fun at your gyro. His lathe comes in handy too. You better buy the "Hunchback" off me before I get up too many hours in it,another one and a half hours today.

Bell430 · 02-01-2007, 10:09 PM

Hi guys,

Sorry to butt into your little male bonding session....

I have opted to use the factory ECU for my EJ for a couple of reasons. The main one is the fact that the ECU 'map' within the factory computer has a couple of fail safe functions. One example is if you lose say the crank angle sensor, the computer will use the cam position sensor to keep the engine running. some aftermarket computers will not do that and the noise stops.....all of a sudden... Don't get me wrong, the 'limp' mode is a concern but most sensors (that are outside the 'U' check ECU map) can be bypassed with a little electrical magic.

In reference to the knock sensor being excited by other than the engine, you will be able to use the factory computers 'read memory' to see if there has been an event in the past that may have registered as a 'check engine fault'..... although, if you chat to various peoples, it seems that it is unlikely to be a problem because the computer knows the correct wave pattern that is associated with a 1 per - 4 per detonation. It is unlikely that an external factor can replicate the wave pattern for the duration that triggers a fault.

She'll be right mate

Paul

russ · 03-01-2007, 07:16 PM

yea.....gota agree with you paul.

Use all soob gear [ they spent zillions on research ] use right fuels etc etc.........no probs.

Gota little goss from the yank guys sayin some of em had oxygen sensor probs using non genuine pewtars???????????

Paul B...........you said you was using non genuine pewtars, and retarding the timing etc..........does that cost you in less HP ???????????

russ · 07-01-2007, 08:27 AM

NEWS FLASH..............

EJ soob engines........will not take kindly to greater than 45 degrees angle of bank.

Sump oil falls away from pickup........and at 4000 revs you guess the rest.

Got a call last night, sad owner

crankshaft buggered, as is 1 rod, scored bore etc etc..........mess inside.

Good case for a dry sump system.