4agze Nearing completion, Street legal, & a few more vids/pics Options

[Sev408]

good job bro, i remember it was like a year ago when i talked to you the first time when you started. Time sure flies.

Anyway your sliping problem maybe caused if you bought a new flywheel and you did not clean the face off with brakefluid. Flywheels come with a protective cover on them that needs to be whiped away.

[Coomer]

Edit: Here is my guess: I think the extra exhaust gasses at higher RPM's with a turbo are miniscule at idle compared to the exhaust gasses that are created when the engine is under load.  In that regard, the turbo isn't really "pushing" the air very fast because the exhaust gases are not as plentiful while in neutral as they are when faster and hotter combustion is required to move the car.  On the other hand, the supercharger simply uses RPM's to pressurize the system.  It really doesn't make a difference if the engine has more load or not since the compressor is driven by the crank rather than turbine of the turbo.
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I think that's pretty much right on. Hopefully one of the engine geniuses can chime in and provide a definitive answer though.

[WannabeGT4]

Jay, a 4A-GZE supercharger's boost is based strictly on RPM, since the supercharger is hooked to a belt that's hooked to the crank. The faster the crank spins, the faster the supercharger's internals go, producing more boost.
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The part that I don't understand is that a turbo requires engine LOAD to create boost in the positive boost system. You can rev the engine higher and make more exhaust gases but the boost at idle remains very low.

It doesn't really make sense to me why a turbo (which simply reroutes pressurized exhaust gases back into the intake) requires engine load to create positive manifold pressure while a supercharger (which pushes ambient air into the intake through a simple compressor spun by the crank) does not. I would appreciate further explanation.

Edit: Here is my guess: I think the extra exhaust gasses at higher RPM's with a turbo are miniscule at idle compared to the exhaust gasses that are created when the engine is under load. In that regard, the turbo isn't really "pushing" the air very fast because the exhaust gases are not as plentiful while in neutral as they are when faster and hotter combustion is required to move the car. On the other hand, the supercharger simply uses RPM's to pressurize the system. It really doesn't make a difference if the engine has more load or not since the compressor is driven by the crank rather than turbine of the turbo.
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The turbo doesn't reroute exhaust gasses into the intake. It uses the exhaust gasses to spin the exhaust turbine which is connected by a shaft to the compressor turbine. Super and turbo chargers both suck in and pressurize ambient air. Pressure is created when you're super/turbo charger is forcing more air into the intake than the engine requires. In neutral there is limited resistance to the flow of the intake charge therefore boost will not be generated as much. It is much more difficult to build boost with out resistance when using a turbo. But just like you guys said a Supercharger is driven by the crank which won't require the same type of resistance to build boost since the pulleys can be sized differently to allow for boost when the engine is not under load.

EDIT: Hope that makes sense now.

This post has been edited by WannabeGT4: Jul 26, 2005 - 10:59 AM

[celicast3sgte]

turbos dont nessecarily use just the exhaust gasses to spin the turbine, its actually 80% of the heat from those gasses is what is spinning the turbo. so if you think about it the engine is much hotter under load that at idle and there you have it. More boost under load

[celi_gt_racer]

I say .. do away w/ the tech talk on Turbo vs. S/C ... AND LETS SEE SOME MORE VIDEOS!!!

[WannabeGT4]

turbos dont nessecarily use just the exhaust gasses to spin the turbine, its actually 80% of the heat from those gasses is what is spinning the turbo. so if you think about it the engine is much hotter under load that at idle and there you have it. More boost under load
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I've heard this said at least twice now (might have been you that said it the first time) but I've never seen it in print. I don't doubt you, but I'd just like to know your source. Maybe it's just assumed that with exhaust gas comes heat so none of the articles I've read mention it playing such a drastic role. I'm simply curious as to were you read this.

[Predator]

turbos dont nessecarily use just the exhaust gasses to spin the turbine, its actually 80% of the heat from those gasses is what is spinning the turbo. so if you think about it the engine is much hotter under load that at idle and there you have it. More boost under load

how can heat be converted into kinetic energy unless you use some kind of steam engine or something like that

[celicast3sgte]

think of it as the heat is assisting the gasses move quicker, you know the physics of heat right? it always tranfers the movement of energy to whats colder than the heated area which would be the end of the exhaust so the hotter the air the more it has a need to reach the end. It made sense to me when i was explained this if im totally wrong its cool i just thought it made sense, as for my source i cant remember anymore.

[Rjb23]

Jet engines use heat to spin a turbine which pushes air so I guess a turbo would work the same way.

And why would steam push a turbine any faster than hot exhaust, its still hot air.

This post has been edited by Rjb23: Jul 26, 2005 - 10:38 PM

[celi_gt_racer]

no my good sir, steam is not air... it is water heated up until it is in vapor form... lol

[Predator]

no my good sir, steam is not air... it is water heated up until it is in vapor form... lol

lol, i know, what I meant was that a steam engine can "pick up" excess heat from a engine etc and convert that heat energy into movement. I can't think of many other things that are able to do that.

think of it as the heat is assisting the gasses move quicker, you know the physics of heat right? it always tranfers the movement of energy to whats colder than the heated area which would be the end of the exhaust so the hotter the air the more it has a need to reach the end. It made sense to me when i was explained this if im totally wrong its cool i just thought it made sense, as for my source i cant remember anymore

Yes, the heat is always transferred from a warmer object to a colder one and not the other way around (unless you add energy to do so), though this doesn't affect the air, just the heat it contains.

Jet engines use heat to spin a turbine which pushes air so I guess a turbo would work the same way.

a turbo and a jet engine isn't working in the exact same way.

As the jet engines fuel is ignited it the air is heated and it expands, the air is then pushed backwards onto the turbine fan, the turbine fan is connected to the compressor in the front which suck more air into the engine and it starts all over again.

but in the turbo the exhausts is already heated as it reaches the turbo and therefore it won't expand more, and this is why it can't work the same way as a jet engine.

[FAQdaWorld]

Me and a buddy down at the shop figured out the axle problem. (we think), so it is very streetable now. Body work starts in a week or two, and then fmic and new clutch / crank pulley. And then there will be some new video's posted

[soulshadow]

Wow that is tottaly Awesome! A 4agze in a 6g, have you got to the part where you can Dyno it yet? I want to see how much power that engine is willing to pull!

[[Freemantle]]

I'd love to see this car launch. I take it from the markings that this thing is LSD equipped?

Heated gas takes up more volume. A quantity of gas at a higher temperature will always attempt to occupy more space than the same quantity of gas at a lower temperature. When there is no new space to occupy, then the heated gas will exert more pressure than the cooler gas.

This is PV=nRT.

In both situations, V, n, and R are constant. Therefore, if T increases, P must increase to balance the equation.

Same applies for your statements of "pressure under load". And engine at 5000 rpms and low load is moving a lower quantity of air than an engine at 5000 rpms in third gear. The inertal force of the clutch, transmission, halfshafts, wheels, and curb load increase the force of the engine's vacuum.

PV=nRT

Volume is the cubic area of the manifold - constant.
R is a theoretical constant - constant.
We could assume temperature to be constant, but the inertal forces listed above will make the piston more resistant to motion change - we will assume it to be higher
n is the number of air molecules - this has increased due to the increase of the engine's inertial force.

Pressure must increase due to the increase in Temperature and Number of Air Molecules.

[/nerd voice]

[tomazws]

O_o

I'd love to see this car launch. I take it from the markings that this thing is LSD equipped?

Heated gas takes up more volume. A quantity of gas at a higher temperature will always attempt to occupy more space than the same quantity of gas at a lower temperature. When there is no new space to occupy, then the heated gas will exert more pressure than the cooler gas.

This is PV=nRT.

In both situations, V, n, and R are constant. Therefore, if T increases, P must increase to balance the equation.

Same applies for your statements of "pressure under load". And engine at 5000 rpms and low load is moving a lower quantity of air than an engine at 5000 rpms in third gear. The inertal force of the clutch, transmission, halfshafts, wheels, and curb load increase the force of the engine's vacuum.
PV=nRT

Volume is the cubic area of the manifold - constant.
R is a theoretical constant - constant.
We could assume temperature to be constant, but the inertal forces listed above will make the piston more resistant to motion change - we will assume it to be higher
n is the number of air molecules - this has increased due to the increase of the engine's inertial force.

Pressure must increase due to the increase in Temperature and Number of Air Molecules.

[/nerd voice]
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