Living Throttleless

[mooseheadm5]

I don't think you understand the way combustion works. For one, oxygen is not flammable. Period. It is an oxidizer. Next, extremely lean AFRs (leaner than about 22:1) can really only be achieved with charge stratification. You also don't seem to understand the mechanics of detonation and preignition. You are not going to be able to adequately control detonation. Detonation is very bad, as you have found. The pressure wave travels at the speed of sound in the compressed mixture and will scrub the boundary layer from the piston and cylinder walls. This can very quickly allow the piston surface to reach combustion temperature, which can exceed the melting point of aluminum. It can also crack the pistons, destroy the ring lands, and generally ruin your day. Adding heat sinks to the bottoms of the pistons will do more harm than good. You will likely end up pulling the motor again when they fly off. Any weight added to the backs of the pistons will definitely upset the balance of the engine and severly limit the maximum attainable RPMs. You may not like complex solutions, but what you are describing is incredibly complex and ineffective. In addition, removing the cat is harmful to the environment. To sum it all up:
What you are doing will damage the motor (again, if you persist.)
Removing the cat will increase emissions and is illegal in most, if not all, states. Even though you don't care, NOx emissions are harmful.
The amount of time you spend glued to the instrumentation to prevent detonation and overheating will likely cause a crash and amounts to reckless endangerment if you take this thing on a public highway.
And the best part, you will likely waste more resources trying to get this to work than you will save if you get it to work effectively enough to limp around without crashing. Every time you melt a piston you will waste all sorts of natural resources that are used to make and deliver the pistons, gaskets, engine oil (which you must change each time you experience a catastorphic engine failure) etc.
Essentially, if it were this "simple" to make it work, the OEMs would have done it already to cope with the stringent CAFE standards.
I strongly suggest you study some engineering texts before continuing.

[theunchosen]

The drive line is now disconnected. I've got the engine strapped to my boom lift and. . .I'll finish taking it out. . .um yeah. I regret having gotten it that far now because its kind of stuck.

I've got a 4AGE silvertop on my engine mount and I don't really wanna put my engine on the ground but thats where its going tomorrow morning.

New pumps arrived. Sorry Mike, I had to skip the piezos this time.

Scavenged a resevoir off a Ford TL tractor ^_^ for the 16 PSI coolant inline.

Pistons. . .supposed to arrive next week -_-.

The good news is I bench tested the injectors. All functioned. Fed them some dirty water and tuned it down. no problems.

The onboard shows the egts started pulsing about 85 seconds before meltdown. So the good news is the engine can survive a little over a minute without the mainstay coolant system. Thats much more promising than I had thought. I was rather confident it would go toast almost instantly without it.

The unpromising. . .worrying thing is I have no indication of what killed the injector. Just that it quit working. Since I have plenty of injectors(had to order a case of 30 or 1 at a time) I'm going to put 2 per cylinder and run them both all the time at half. Only problem is half is right at the bottom of their operation and they don't function properly. So I'll have to step it up a little and keep Michelle away from the sub 500 rpm range. . . -_-.

I think Stevey suggested it but I'm going to tie the injectors to the MAP. Theoretically they will be a step ahead of the engine so even if something goes wrong. . .

As of now I need to be moved to ecomodding central. Well sort of. In essence most ecomods limit engine life. . .this one just limited it alot ^_^. On the other side of the coin Michelle had stock pistons, valves and everything else(mostly) and I haven't checked to see if anything was damaged before the melt down. It will be hard to say since alot of the evidence was more or less. . .melted but who knows.

Christ, at this rate I might have to take you up on your d series pistons in a month ^_^.

I also don't remember who mentioned it but I'll be kicking back to a throttle plate for now. I tried to bite off too much too soon and the Go big or go home bit me in the ass ^_^. That said it should go smoothly from there as I'll be able to get her to speed and then tweak her AFR on level terrain(I've got a couple of roads that have extremely light traffic, are extremely flat and are 4-5 miles long with only moderate turns).

I'll let you know progress as it happens.

[NiHaoMike]

Originally Posted by mooseheadm5

I don't think you understand the way combustion works. For one, oxygen is not flammable. Period. It is an oxidizer. Next, extremely lean AFRs (leaner than about 22:1) can really only be achieved with charge stratification. You also don't seem to understand the mechanics of detonation and preignition. You are not going to be able to adequately control detonation. Detonation is very bad, as you have found. The pressure wave travels at the speed of sound in the compressed mixture and will scrub the boundary layer from the piston and cylinder walls. This can very quickly allow the piston surface to reach combustion temperature, which can exceed the melting point of aluminum. It can also crack the pistons, destroy the ring lands, and generally ruin your day. Adding heat sinks to the bottoms of the pistons will do more harm than good. You will likely end up pulling the motor again when they fly off. Any weight added to the backs of the pistons will definitely upset the balance of the engine and severly limit the maximum attainable RPMs. You may not like complex solutions, but what you are describing is incredibly complex and ineffective. In addition, removing the cat is harmful to the environment. To sum it all up:
What you are doing will damage the motor (again, if you persist.)
Removing the cat will increase emissions and is illegal in most, if not all, states. Even though you don't care, NOx emissions are harmful.
The amount of time you spend glued to the instrumentation to prevent detonation and overheating will likely cause a crash and amounts to reckless endangerment if you take this thing on a public highway.
And the best part, you will likely waste more resources trying to get this to work than you will save if you get it to work effectively enough to limp around without crashing. Every time you melt a piston you will waste all sorts of natural resources that are used to make and deliver the pistons, gaskets, engine oil (which you must change each time you experience a catastorphic engine failure) etc.
Essentially, if it were this "simple" to make it work, the OEMs would have done it already to cope with the stringent CAFE standards.
I strongly suggest you study some engineering texts before continuing.

Just because the auto companies aren't doing it doesn't mean it won't work. We know that aerodynamic modifications definitely work, but so far, no mass produced car is as aerodynamic as the Aerocivic.

And the work that is being done is research! Just like how he's essentially reworking an engine to be more efficient, I'm currently reworking a PC power supply to make it more efficient and to make it support low voltage alternative energy. (The main difference, of course, is that so far, I have not blown any MOSFETs. I did blow out a controller chip by accidentally exceeding its voltage limit, though.)

[basslover911]

Wanna know a little secret?

I have a lawn mower engine that I have been working on with this same principal. The secret is... just add more exhaust gas in the intake to go slower (essentially has the effect of virtually getting the engine displacement smaller), and less to burn more fuel and go faster.

[Christ]

Originally Posted by theunchosen

The drive line is now disconnected. I've got the engine strapped to my boom lift and. . .I'll finish taking it out. . .um yeah. I regret having gotten it that far now because its kind of stuck.

I've got a 4AGE silvertop on my engine mount and I don't really wanna put my engine on the ground but thats where its going tomorrow morning.

New pumps arrived. Sorry Mike, I had to skip the piezos this time.

Scavenged a resevoir off a Ford TL tractor ^_^ for the 16 PSI coolant inline.

Pistons. . .supposed to arrive next week -_-.

The good news is I bench tested the injectors. All functioned. Fed them some dirty water and tuned it down. no problems.

The onboard shows the egts started pulsing about 85 seconds before meltdown. So the good news is the engine can survive a little over a minute without the mainstay coolant system. Thats much more promising than I had thought. I was rather confident it would go toast almost instantly without it.

The unpromising. . .worrying thing is I have no indication of what killed the injector. Just that it quit working. Since I have plenty of injectors(had to order a case of 30 or 1 at a time) I'm going to put 2 per cylinder and run them both all the time at half. Only problem is half is right at the bottom of their operation and they don't function properly. So I'll have to step it up a little and keep Michelle away from the sub 500 rpm range. . . -_-.

I think Stevey suggested it but I'm going to tie the injectors to the MAP. Theoretically they will be a step ahead of the engine so even if something goes wrong. . .

As of now I need to be moved to ecomodding central. Well sort of. In essence most ecomods limit engine life. . .this one just limited it alot ^_^. On the other side of the coin Michelle had stock pistons, valves and everything else(mostly) and I haven't checked to see if anything was damaged before the melt down. It will be hard to say since alot of the evidence was more or less. . .melted but who knows.

Christ, at this rate I might have to take you up on your d series pistons in a month ^_^.

I also don't remember who mentioned it but I'll be kicking back to a throttle plate for now. I tried to bite off too much too soon and the Go big or go home bit me in the ass ^_^. That said it should go smoothly from there as I'll be able to get her to speed and then tweak her AFR on level terrain(I've got a couple of roads that have extremely light traffic, are extremely flat and are 4-5 miles long with only moderate turns).

I'll let you know progress as it happens.

Long windedness... jeeze.

Those pistons are here whenever you want them. Not sure what they'll do to your compression, though.

The code is PG6B... you can check the compression for your engine with P29's and just subtract a bit.

You should probably find some steel slugs? I mean, if you keep suffering meltdown, and you never plan on revving the engine too high, maybe some forged steel pistons would do you good, at least buy you more time to shut down in the event of a malfunction. I bet Arias could make them to spec for you. (They're 75mm)

Maybe running the injectors at their low range isn't a good idea... maybe you could run one at full, and have a signal that turns on the other one if the first one fails?

Or even a signal that cuts fuel to that cylinder if the water injection system fails?

I dunno, they're here for you for the cost of shipping (They might fit in a $10 box or something, but they still have rods on them.)

[Christ]

Originally Posted by basslover911

Wanna know a little secret?

I have a lawn mower engine that I have been working on with this same principal. The secret is... just add more exhaust gas in the intake to go slower (essentially has the effect of virtually getting the engine displacement smaller), and less to burn more fuel and go faster.

Are you adding exhaust gas behind the fuel inlet? SO that you're not adding fuel for the exhaust flow... I presume you're just using a carb with no throttle plate, right, to keep the venturi effect?

I was thinking about doing this, but making a diesel engine out of a small gas engine... no throttle, and using a fuel pump, upping the compression to some sick amount, and putting a fuel injector in place of the spark plug, with a heater plug in the intake stream.

I haven't gotten around to it yet, partly b/c of lack of funds, parts, ambition, what have you.

Looking forward to your reply, and updates to this thread on the OP's project as well.

[basslover911]

Originally Posted by Christ

Are you adding exhaust gas behind the fuel inlet? SO that you're not adding fuel for the exhaust flow... I presume you're just using a carb with no throttle plate, right, to keep the venturi effect?

Correct.

Sit back, and think about it for a moment. The exhaust gas can barely ignite any more, or expand for that matter. Its like a solid in the cylinder- and THATS what you need to measure. Hook the throttle to a valve that opens and closes and redirects exhaust to the intake.

[Christ]

Originally Posted by basslover911

Correct.

Sit back, and think about it for a moment. The exhaust gas can barely ignite any more, or expand for that matter. Its like a solid in the cylinder- and THATS what you need to measure. Hook the throttle to a valve that opens and closes and redirects exhaust to the intake.

I just might give this a shot... if you don't mind. I promise I won't sell it to anyone.

[Mecrez]

Kudos to the OP for trying someting different. I realize my suggestions are unrequested and unqualified, but there are things that can be done to make this work better.

I get the impression that christ is being sarcastic, Basslover I would recommend that you look into ECR (Exhasut Gas Recirculation) there are limits before you get to unstable combustion

Typically when an engine is run lean, more ignition advance will help, higher power ignition such as a CDI system will help too.

There is a limit when a cylinder will not have enough fuel to "fire", but a good strong spark may help that.

keep at it and report back with what does and doesn't work.

[Christ]

Originally Posted by Mecrez

Kudos to the OP for trying someting different. I realize my suggestions are unrequested and unqualified, but there are things that can be done to make this work better.

I get the impression that christ is being sarcastic, Basslover I would recommend that you look into ECR (Exhasut Gas Recirculation) there are limits before you get to unstable combustion

Typically when an engine is run lean, more ignition advance will help, higher power ignition such as a CDI system will help too.

There is a limit when a cylinder will not have enough fuel to "fire", but a good strong spark may help that.

keep at it and report back with what does and doesn't work.

I'm not sure where you got that impression from, but I'm not being sarcastic at all... I'm the guy that's trying to convert small lawnmower engines to run on diesel type fuels. I just don't document it here. (I have a Lil' Fat Boy notebook in my back pocket all day.)

Oh - Christ is Capitalized. It's Christ.

Welcome to EM!