Toyspeed.org.nz Message Board

by **sergei** » Wed Oct 05, 2011 9:45 am

Why don't you use aftermarket ECU and tune it the way you want it?
This way you eliminate crusty and unreliable K-Jetronic (I believe you are taking it off some car and modifying to your use?).

EFI is more reliable than mechanical systems, as there are less moving parts. If you are paranoid you could introduce redundancy in the system (secondary injectors, fuel pump and ECU). EFI is light enough to have this without much weight gain.

As far as I remember K-Jetronic has an airflow meter like device that operates a "tap" to regulate fuel, the way I see it it is major reliability factor, where actual metering of the fuel is directly depended on a single mechanical device (which also might affect the fuel mixture depending on the incline of the aircraft).

by **kiwi4agze** » Wed Oct 05, 2011 10:10 am

The O2 sensors dont do lead fuel, MAP/AFM cant cope with the change in air density plus if one thing goes wrong it would shut down and thats not too good

K-Jetronic is realiable, if maintained its just as good as EFi
plus its a constant fuel system which is whats needed, EFi is a pluse setup

The AFM in the Mfi system is not like the AFM in EFi, it operates with manifold vaccum pulling it not on the air going thru it.

I am running a back up AFM in order to counter the failure of the 1st one, its a very small chance it would but still better safe then sorry.

by **Rookie** » Wed Oct 05, 2011 11:08 am

Why do you have to use leaded fuel? there are many better and cheaper fuels out there today, if it is just for convienence then fair enough.

You are incorrect, an ecu can easily be setup to correct for altitude, which a K-Jet can't and why do you need CIS?
A K-Jet is just as susceptible to failure as a EFI system Proabaly more so given the fact that they are all old now, and very difficult to rebuild and tune.

I'm sorry but it seems as if you have come on here to ask for opinions that agree with your own and nothing else..

by **kiwi4agze** » Wed Oct 05, 2011 11:18 am

Rookie wrote:I'm sorry but it seems as if you have come on here to ask for opinions that agree with your own and nothing else..

Thats not it at all, if you feel thats what is happening please make a complaint with the mods, but I am not out to do that.

Again I appologize for making you feel like that, its not wanted!

by **kiwi4agze** » Wed Oct 05, 2011 11:30 am

I think its better if I stop talking about this..... My bad everyone.....

by **sergei** » Wed Oct 05, 2011 11:56 am

kiwi4agze wrote:The O2 sensors dont do lead fuel.

O2 sensor is not necessary for EFI. If you use aftermarket ECU, you can make sure if most of the things go wrong it will still run (ie no limp mode).

kiwi4agze wrote:MAP/AFM cant cope with the change in air density plus if one thing goes wrong it would shut down and thats not too good

Au contraire: you can add a barometric pressure sensor (another map sensor), which many cars already have, to compensate for air pressure. Mass airflow meter is immune to air density change anyway.

kiwi4agze wrote:K-Jetronic is realiable, if maintained its just as good as EFi
plus its a constant fuel system which is whats needed, EFi is a pluse setup

What is wrong with pulse setup?

The matter of the fact is that your setup will not work well with forced induction. You will need an ECU to control the ignition, so why not make another step and increase reliability (mechanical injection is more unreliable, because it "assumes" too many things, as well as relying on a single mechanical metering device which has a lot of moving parts)

Looking at this: http://www.scribd.com/doc/3299223/Bosch ... on-Manual-
The system is too dumb to deal with many factors that might change.
You need to think about how well it will run with supercharger on and without supercharger (clutch/belt failure), at partial atmospheric pressure and at full atmospheric pressure.
Additionally it contains a lot more moving parts than a typical EFI system.

Basically if you want to use mechanical injection, you will need one that has been setup for the engine and purpose you want to use.

In case of experimenting, you are far better to use what is proven to work with that engine.

If you value your life, you are far better in using aircraft engine, as in long term you will save $$$, by spending $10000 on an engine that is suitable than spending $1000 on engine that is not, then spending another $10000, on making it work, while getting an inferior setup because your engine is too heavy, under powered and unreliable.

by **kiwi4agze** » Wed Oct 05, 2011 12:57 pm

I think this whole thing needs a re-think....

Maybe i should just bite the bullet and buy an aero engine...

by **Mr Revhead** » Wed Oct 05, 2011 12:59 pm

Or at least find out exactly what others have done to run car engines. And also maybe check things like CAA regs on fuels etc?

oh btw, just to be a pedantic prick, It's Rotax

by **kiwi4agze** » Wed Oct 05, 2011 1:06 pm

Mr Revhead wrote:oh btw, just to be a pedantic prick, It's Rotax

So you are one of them who support rotax....

Been offered a Rollys Royce engine, finding more detials out on it within an hour or so.. $28,000NZ+GST...

by **Mr Revhead** » Wed Oct 05, 2011 1:07 pm

Nope, I don't have anything to do with aero engines.
I just get a twitch on when people use wrong terms/names :lol:

Better be a Merlin :twisted:

by **kiwi4agze** » Wed Oct 05, 2011 1:16 pm

LOL @ A Merlin... all 28L of v12 fitting in my plane.....

by **kiwi4agze** » Wed Oct 05, 2011 2:36 pm

Microturbo TJA24, 430lbs thrust, 32kg total weight... $9914+GST, 1.5hrs with log book... DONE!!!!!!!!!!!!!

Picture to follow in a few minutes, paying the bugger now!

by **mr_monkey** » Wed Oct 05, 2011 2:44 pm

Well done man!! That will be so much better

by **kiwi4agze** » Wed Oct 05, 2011 2:47 pm

Photos!!!
[img][img]http://img809.imageshack.us/img809/7544/unledpeo.th.png[/img]
[/img]

[img][img]http://img809.imageshack.us/img809/7544/unledpeo.th.png[/img]

[/img]

by **sergei** » Wed Oct 05, 2011 2:49 pm

That is awesome!

by **kiwi4agze** » Wed Oct 05, 2011 2:58 pm

2nd picture is the turboprop gearbox..
It should make around 600kw or around that.

by **BZG Wagon** » Wed Oct 05, 2011 4:08 pm

MEAN!!!!

Still vote for you to put up a vid of the 4AGZE running no manifold.

by **kiwi4agze** » Wed Oct 05, 2011 4:25 pm

Small note:

Tell wife before spending $17,000!!!!

Want to know the kicker, I need a new airframe.. the current one wont work with the turbo-jet....

Any ideas????

by **Mr Revhead** » Wed Oct 05, 2011 4:27 pm

3/4 scale F16.....

by **kiwi4agze** » Wed Oct 05, 2011 4:31 pm

Whats up with you and the F-16????

If i wanted a gay plane i would have brought a Cessna!!

I am thinking a P-51, Spitty or something like that.. or maybe modifiy the storch to fit he new engine

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Running a 4agze with no exhaust manifold, or stump type.

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