gnarkill87;1238184 said:
You might want to do some research. I'd be impressed to see a tiny turbo alone on a 3rz hold 30 psi even if it fell off on the top end. Anyone else want to add anything?
single over twin
- Thread starter zSP3CTERz
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You might want to do some research. I'd be impressed to see a tiny turbo alone on a 3rz hold 30 psi even if it fell off on the top end. Anyone else want to add anything?
I got an answer.
Why single over twins? Because it gives me something to do then chit chat all day on forums
Why single over twins? Because it gives me something to do then chit chat all day on forums
tturnpaw;1238343 said:
Your right a tiny turbo on a 3rz would put out 30psi and hold it thats why you compound two turbos. Right now with the stock cams it has it goes stong to 6k, btw there using a t/4 and a gt-45, so not really a tiny turbo. a 3rz is a 2.7 so its got noproblems spooling both turbos. your right iam no expert on the subject but they are, and i know how there setup works.
tturnpaw;1238343 said:
tturnpaw;1238171 said:
I really don't know where you do your research... There's a big difference between flow (volume/time) and pressure (force/area). A BIG difference. The pressures produced by turbines on a diesel application are much higher due to the nature of a diesel engine. It's not apples to apples... but the same rules apply for turbocharging.
Regardless, there's an interesting phenomenon with compressors where they compress air. For instance, when you have a single turbo putting ~14psi, it's (on average) packing twice as much air into the same volume as ambient (atmospheric) air. Now, were that compressor inlet air to be already at 14psi, and coming into the turbine set to compress the same ratio, it would double the pressure again. A turbine's limits are essentially at what muiltiple it can step up the pressure, because to do so it must spin faster, creating more heat and stress in the turbine itself.
You cannot compress compressed air? How did you arrive at that scientific conclusion? How is stepping up the pressure from ambient, to 20psi, then to 40psi, then to 80psi, via 3 compressor stages, any different from having one compressor capable of 80psi? Have you ever seen a 5000psi compressor? There's no difference between the compressor on my garage floor, a supercharger in a top fuel dragster, and a turbo in your car... they all do the same thing from a physics point of view, only they are designed for different purposes by different means. Yet, the laws of physics are not independant for each application.
Tubrocharging for horsepower is not about volume or pressure, it is about flow... or volume per time... CFM (Cubic Feet Per Minute). The amount of air flowed per unit time. For example, if your turbo could have 1000000000 cubic feet capability (volume) and my turbo could flow 600CFM, I would tend to think my car will go faster than yours... yours will probably not even start. Infact, I don't think one could really quantify a turbo with only volume. Maybe a compressor tank, yes, but not a turbo.
Pressure in the concept of turbocharging ICE engines, is essentially the pressure created by the difference between the volume of air compressed by the turbo per minute and the volume of air actually used by the engine in that minute. Imagine drinking water from a pressurized hose... if you don't drink fast enough, you'll wear most of it.
I question if you know anything about turbocharging theory. Perhaps you should go do more research.
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In regards to the real topic of this thread, unless one is going to go through the struggle to make a true sequential setup, a single turbo will always be better on an inline engine. Reliability, simplicity, cost, and performance will all be superior.
The JZ motors had twin turbos because turbo technology was much different in the late 80's and early 90's. New turbine and bearing design has made the 'stock' turbos obsolete and archaic technology. Very agricultural, as IJ would say.
Twin turbos on a V shaped engine just makes sense... trying to put a single on it would be a massive headache of pipes and exhaust. An inline engine does not suffer these maladies.
The JZ motors had twin turbos because turbo technology was much different in the late 80's and early 90's. New turbine and bearing design has made the 'stock' turbos obsolete and archaic technology. Very agricultural, as IJ would say.
Twin turbos on a V shaped engine just makes sense... trying to put a single on it would be a massive headache of pipes and exhaust. An inline engine does not suffer these maladies.
Perhaps I should. Besides the fact that most diesels use this setup for more low end tq and faster spooling with the compressor routing they are running as posted up earlier rather than one switched favoring the larger turbo. I would love to see this 30psi at 3000rpm and the 3rz hold it. So my understanding with that turbo setup it's in the 700whp+ range. I want to see some actual proof that you can recompress compressed air at a higher volume and doubling boost. So far what you've said is you can make more psi but I'd like to see this cfm like I was speaking of before double along with the psi like you are stating. Yes I know it's about cfm because cfm is air flow at a duration of time. How is what I'm saying not making sense to you? I can only see it produce faster spool times. When you take the air flow or volume or better yet a duration of volume if it makes you happy then shove it into a compressor of the smaller size it's compressing even more instead of backing up and making the larger turbo surge due to the low restriction on the exhaust side?
Nonetheless I'd like to see this 3rz with pics and Dyno charts hell even a vid if you can get one.
Nonetheless I'd like to see this 3rz with pics and Dyno charts hell even a vid if you can get one.
In case that didn't make sense how can you force a large amount of cfm or air into a smaller area and expect it to compress even more so than it was nearly compressed to from the start at that same volume?
tturnpaw;1238649 said:
You've got the right idea, pressue would go up as volume goes down. There's a fancy diagram somewhere that shows Boyle's gas laws and how they all relate.
Unless Flight Doc comes back to post turbine sizes and a horsepower number, I suppose we can continue to wonder.
I certainly see what you're asking in that how does a small turbine feeding a larger turbine make enough flow to feed an engine and maintain 30psi@3000rpm (which is probably near redline)? Well, we would need the compressor efficiency charts to know this for certain.
For 700whp out of a 3RZ-FE, would be somewhere in the land of 300hp/L. For a 3L gas engine like a 7M or 2JZ to do those sort of numbers, it would not spool a turbine of sufficient size until late in the rpm band. This engine would want to make boost off of idle.
On further thinking, I do think these turbines would be intended to spin much faster than on a gasoline based engine. We would spin a 2JZ to +5000rpm to make 300hp/L because we cannot pack that much air and fuel into one combustion cycle and still be able to ignite it at the right time to prevent predetonation. We use things like methanol and crazy coatings to try to keep cylinder tempratures down to control knock, ect. And still make good power.
Throw all that out the window for a diesel. You want it to predetonate because that's how it runs. There's no spark timing to control... an engine knock is a good thing. The engine casting and pistons, thus, are much more stout to handle these pressures (I presume). Thus to make 300hp/L we would have to jam pack a rediculous amount of air and diesel into a cylinder to make big power at low RPM (power produced per bang would be MUCh higher in this case than an equivalent gas engine). I think in this case pressure is more paramount than flow because you need a very highly compressed charge to get that much fuel into the cylinders with that much air in order to obtain that much power at such low RPM. A small turbine size is necessary so that there's off idle power, perhaps?
I suppose then I'm pointing out that the purpose of such a small turbine isn't to flow a HUGE volume of air, but to flow just the right ammount of air to get enough pressure and a high enough density to produce that much power.
It may seem anti-thesis, but I think it aligns perfectly to what we're agreeing on. Thusly, the engine isn't breathing in much overall volume, but it is breathing alot of air (thus, highly compressed air). We're trying to make 300hp/L out of a 2.7L diesel spinning at less than 3000rpm... it's going to need a serious amount of air in each cylinder for each power stroke, and for that you're going to need to compress the crap out of that air.
Throw all that out the window for a diesel. You want it to predetonate because that's how it runs. There's no spark timing to control... an engine knock is a good thing. The engine casting and pistons, thus, are much more stout to handle these pressures (I presume). Thus to make 300hp/L we would have to jam pack a rediculous amount of air and diesel into a cylinder to make big power at low RPM (power produced per bang would be MUCh higher in this case than an equivalent gas engine). I think in this case pressure is more paramount than flow because you need a very highly compressed charge to get that much fuel into the cylinders with that much air in order to obtain that much power at such low RPM. A small turbine size is necessary so that there's off idle power, perhaps?
I suppose then I'm pointing out that the purpose of such a small turbine isn't to flow a HUGE volume of air, but to flow just the right ammount of air to get enough pressure and a high enough density to produce that much power.
It may seem anti-thesis, but I think it aligns perfectly to what we're agreeing on. Thusly, the engine isn't breathing in much overall volume, but it is breathing alot of air (thus, highly compressed air). We're trying to make 300hp/L out of a 2.7L diesel spinning at less than 3000rpm... it's going to need a serious amount of air in each cylinder for each power stroke, and for that you're going to need to compress the crap out of that air.
Exactly. So much heat would have thought to be involved in a gasoline engine meth or nitrous would need to be induced to help from deto, not even accounting the pressure on the compressor housing and wheel.
Precisely. Heat and predetonation is out of the equation.
I was thinking about it, and it seems that putts/min becomes the defining point. We know that to make 700hp with a diesel or a gas engine would require somewhere around the same volume/time of air. I did some further reading and found that although the 'ideal' stoichiometric mixture is about the same as gasoline, diesel will still combust in a wide range of variences (anywhere from 3:1 to 42:1, but I cannot varify those numbers atm).
So it would seem not apples to apples. Comparing a 2JZ with 700hp to our 3RZ with 700hp, it would seem we make much less power per cylinder rotation with the 2JZ because we need to be spinning at 5000rpm to even think about making that kind of power (we have to keep the piston intact, temps down, and ideal A/F ratio). So thus, flow becomes paramount and pressure is a necessity to keep the air packing into the cylinders when the valves open, and the throttle plate controls the flow of air between the turbos and the cylinders. All the while we're throwing massive volumes of only moderately compressed air at the cylinders as they whir away at breakneck speeds.
However, on our 3RZ, there is not a throttle plate at all. The throttling of the engine is controlled by the injectors (which are in the cylinders I think), and thus, when more diesel goes into the cylinders, most exhaust comes out and spins the turbines faster, getting more air packing into the cylinders. I'm tempted to say this is why the turbines seem so small, because boost must be available at idle. Literally, the turbines must be producing pressure at idle for the engine to run ideally. Keep in mind that since there's no real 'ideal' running A/F ratio in a diesel (there's more of an 'ideal range'), there's much less to worry about at all states of running (idle, WOT, high load, engine braking, ect) in terms of fuel mixture ratio.
I'm tempted to say that the 3RZ is a ball peen hammer at 300hp/L compared to the 2JZ as a razor sharp surgical blade at 300hp/L. Until now I didn't really realize just how vastly different a deisel was from a gas engine, lol. The rules of turbo charging are still the same but they are utilized to accomplish different goals.
I was thinking about it, and it seems that putts/min becomes the defining point. We know that to make 700hp with a diesel or a gas engine would require somewhere around the same volume/time of air. I did some further reading and found that although the 'ideal' stoichiometric mixture is about the same as gasoline, diesel will still combust in a wide range of variences (anywhere from 3:1 to 42:1, but I cannot varify those numbers atm).
So it would seem not apples to apples. Comparing a 2JZ with 700hp to our 3RZ with 700hp, it would seem we make much less power per cylinder rotation with the 2JZ because we need to be spinning at 5000rpm to even think about making that kind of power (we have to keep the piston intact, temps down, and ideal A/F ratio). So thus, flow becomes paramount and pressure is a necessity to keep the air packing into the cylinders when the valves open, and the throttle plate controls the flow of air between the turbos and the cylinders. All the while we're throwing massive volumes of only moderately compressed air at the cylinders as they whir away at breakneck speeds.
However, on our 3RZ, there is not a throttle plate at all. The throttling of the engine is controlled by the injectors (which are in the cylinders I think), and thus, when more diesel goes into the cylinders, most exhaust comes out and spins the turbines faster, getting more air packing into the cylinders. I'm tempted to say this is why the turbines seem so small, because boost must be available at idle. Literally, the turbines must be producing pressure at idle for the engine to run ideally. Keep in mind that since there's no real 'ideal' running A/F ratio in a diesel (there's more of an 'ideal range'), there's much less to worry about at all states of running (idle, WOT, high load, engine braking, ect) in terms of fuel mixture ratio.
I'm tempted to say that the 3RZ is a ball peen hammer at 300hp/L compared to the 2JZ as a razor sharp surgical blade at 300hp/L. Until now I didn't really realize just how vastly different a deisel was from a gas engine, lol. The rules of turbo charging are still the same but they are utilized to accomplish different goals.
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Keros- you know that a 3rz is not a diesel right? and iam have problems with the camera uploading the vid, now this 3rz is nowere near being done tuned, its only been running few weeks and they dont yet have a clutch to hold the power. but in the next few days ill post a vid of it running and some pics of the setup. and if there's anydoubt that a 3rz cant make that sort of power you should check out paradiseracing.com he's running 60psi and making over 1200hp.
Keros;1239738 said:
No problem lol, iam been sick laying in bed the last to days so ill try to get somepics up over the weekend.