air pressure vs air volume, theory vs reality - (10lbs here is not 10lbs there)
12-16-02, 07:49 PM
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Originally posted by 13brv3
The ECU only sees temp, and pressure, which are the same as before. Doesn't that mean it's supplying the same fuel as before? If that's true, why wouldn't we be running lean if more air is passing through? Was the stock AFR ridiculously rich, like 8 or 9?
The ECU only sees temp, and pressure, which are the same as before. Doesn't that mean it's supplying the same fuel as before? If that's true, why wouldn't we be running lean if more air is passing through? Was the stock AFR ridiculously rich, like 8 or 9?
Originally posted by 13brv3
Are we really making more power if we keep the boost at 10 psi?
Are we really making more power if we keep the boost at 10 psi?
I hope I don't come off as harsh but so many people on this forum keep saying you can't do this and that with the stock ecu without even spending a little time and effort to verify what they are talking about.
Thanks to Wade for making me see the light many moons ago and verify it for myself with my own car. Nice work, Wade.
12-16-02, 08:36 PM
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Please don't take my "disbelief" as criticism. I've seen enough data to believe that running 10 psi is safe with the stock ECU, and any number of mods. I'm just trying to understand this completely.
The WB test that Wade did, shows that the AFR is plenty rich with the mods, a stock ECU, and 10 psi, but did he check the AFR before the mods? I bet they were still about the same.
(NOTE- what follows is my attempt to understand this, NOT necessarily a statement of fact.)
In thinking about this some more, my current working theory is that we are moving some, but not significantly more air through the engine, and we are not making significantly more "total" power. What we must be doing is applying more of the total power to the rear wheels.
When one face of the rotor is firing, and producing energy, another is trying to push spent exhaust gas out the exhaust. Imagine taking a deep breath, and having to force it out through a straw in one second. Now imagine doing this with a 1" piece of PVC pipe. If this were a restrictive, vs open exhaust, the energy you save would now be available to help accelerate the car. In other words, we aren't really making more power, but we feel more, because we're putting it to good use.
How close is this theory?
Thanks for indulging me.
Rusty
The WB test that Wade did, shows that the AFR is plenty rich with the mods, a stock ECU, and 10 psi, but did he check the AFR before the mods? I bet they were still about the same.
(NOTE- what follows is my attempt to understand this, NOT necessarily a statement of fact.)
In thinking about this some more, my current working theory is that we are moving some, but not significantly more air through the engine, and we are not making significantly more "total" power. What we must be doing is applying more of the total power to the rear wheels.
When one face of the rotor is firing, and producing energy, another is trying to push spent exhaust gas out the exhaust. Imagine taking a deep breath, and having to force it out through a straw in one second. Now imagine doing this with a 1" piece of PVC pipe. If this were a restrictive, vs open exhaust, the energy you save would now be available to help accelerate the car. In other words, we aren't really making more power, but we feel more, because we're putting it to good use.
How close is this theory?
Thanks for indulging me.
Rusty
12-16-02, 10:16 PM
#28
Rotary Enthusiast
that's part of it
Originally posted by 13brv3
... In thinking about this some more, my current working theory is that we are moving some, but not significantly more air through the engine, and we are not making significantly more "total" power. What we must be doing is applying more of the total power to the rear wheels.
When one face of the rotor is firing, and producing energy, another is trying to push spent exhaust gas out the exhaust. Imagine taking a deep breath, and having to force it out through a straw in one second. Now imagine doing this with a 1" piece of PVC pipe. If this were a restrictive, vs open exhaust, the energy you save would now be available to help accelerate the car. In other words, we aren't really making more power, but we feel more, because we're putting it to good use.
How close is this theory?
Thanks for indulging me.
Rusty
... In thinking about this some more, my current working theory is that we are moving some, but not significantly more air through the engine, and we are not making significantly more "total" power. What we must be doing is applying more of the total power to the rear wheels.
When one face of the rotor is firing, and producing energy, another is trying to push spent exhaust gas out the exhaust. Imagine taking a deep breath, and having to force it out through a straw in one second. Now imagine doing this with a 1" piece of PVC pipe. If this were a restrictive, vs open exhaust, the energy you save would now be available to help accelerate the car. In other words, we aren't really making more power, but we feel more, because we're putting it to good use.
How close is this theory?
Thanks for indulging me.
Rusty
The big fish is chamber filling. If intake port opens to 10 psi in manifold, but there is still lots of exh gasses in the chamber, then less room for new charge, and less air flow results at same boost.
open up very restricted stock exh for direct backpressure reduction, and better chamber filling. also, reducing pressure drop across the intake and the intercooler means less work needs to be done by the turbo, reducing backpressure from the turbine. each of these 3 mods mean more air flows into chamber at 10 psi boost, which at same a/f would mean more hp produced by engine. but thanks to pig rich stock ecu, even more hp is realized as mix leans out and gets more ideal.
but: very large IC core, mp, or porting, with other upgrades, can result in excessive lean-out, esp with boost spikes.
12-16-02, 10:21 PM
#29
First, I would like to say that this is one of the best threads I have seen on this forum. I like what I have read, and can't resist putting in my 2 cents.
So, boost is measured at the intake manifold right. So, if we take 10psi boost at the manifold, and open up where it exits(exhaust), then 10psi at the manifold can move the engine more easily, creating more HP. I'm not sure that it has to be more complicated than that.
Another issue is how quickly your car will reach maximum boost. By letting it breathe easier, it will boost faster, giving you full power sooner.
Regarding the stock ECU: The 3 mod rule tells me that the stock ECU will adapt to boost levels higher than 10. With 2 mods (DP, intake), boost levels can easily reach 12psi. Most agree that 2 mods are safe. I personally feel that two mods require a boost controller or ECU upgrade for safe engine operation.
I say 4 stars!!
Adam
So, boost is measured at the intake manifold right. So, if we take 10psi boost at the manifold, and open up where it exits(exhaust), then 10psi at the manifold can move the engine more easily, creating more HP. I'm not sure that it has to be more complicated than that.
Another issue is how quickly your car will reach maximum boost. By letting it breathe easier, it will boost faster, giving you full power sooner.
Regarding the stock ECU: The 3 mod rule tells me that the stock ECU will adapt to boost levels higher than 10. With 2 mods (DP, intake), boost levels can easily reach 12psi. Most agree that 2 mods are safe. I personally feel that two mods require a boost controller or ECU upgrade for safe engine operation.
I say 4 stars!!
Adam
Last edited by adam c; 12-16-02 at 10:24 PM.
12-16-02, 10:30 PM
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The following is simply my attempt to explain what might be happening and is based solely on theory and speculation. I offer this only to further all of our knowledge.
Assuming constant boost pressure and intake charge temperatures:
Reducing exhaust backpressure necessarily means that the turbo sees a greater pressure differential on the turbine side. This then must allow the compressor sides to build energy faster and at a somewhat lower engine RPM. A simultaneous reduction in intake restriction will also increase the compressor efficiencies, meaning more volume and/or pressure at a given turbo RPM. The net result is a faster buildup of intake boost pressure occurring at lower engine RPM’s and therefore producing more area under the boost curve and greater power output. Again assuming constant peek boost pressure.
The reduction in backpressure may also mean that each rotor face has less trouble releasing its spent fuel/air in to the exhaust port resulting in some slight decrease in pumping loss, but this also means less of the old charge remains in the combustion chamber which is therefore able to ingest a higher percentage of fresh cool charge. This then suggests that more energy will be produced here, too.
If the above is close to correct, then the engine is confronted with several simultaneous changes; (1) more boost at a lower RPM which it probably can accommodate (up to a point) via the ECU’s OEM maps, (2) increased mass in each compression cycle of which the ECU knows nothing about and which therefore must draw against the original over-rich A/F ratio, and (3) its increased power output is necessarily accompanied by increased thermal loading of the engine and in particular the cooling and oil systems.
Since this all suggest that more total mass of air is moving through the engine, the assumption of constant intake temperature may be invalid. More mass through the intercooler probably means that its thermal efficiency is further reduced (although this might be offset some by higher efficiency at the turbo compressor) and therefore it’s likely that the effective intake temperature will go up. Even 10 degrees could become significant because the engine is already operating at a higher block temperature, with effectively higher compression ratio and no changes in fuel or timing over the stock settings.
Many have reported successfully running the stock ECU with several mods. Their successes suggest to me that either the original A/F ratios are very rich 8-9:1, and/or there is significant variation in the effective A/F ratio due to the combination of so many components, and of course, not every engine is blessed with components functioning as spec’d. Together this would help explain why not all rotary engines are equally happy with three or more mods.
Add in the other realities of boost spikes and creep and it seems to me that the only SMART way to know if your engine can survive modifications is to test it’s A/F ratio using a suitable wide band sensor with the engine under load and with due allowances for variations in components and ambient temperature. And since a long list of component failures is always possible, how do we insure that we still have sufficient headroom in A/F ratio to insure operational safety? Maybe a J&S or similar is the best insurance.
Assuming constant boost pressure and intake charge temperatures:
Reducing exhaust backpressure necessarily means that the turbo sees a greater pressure differential on the turbine side. This then must allow the compressor sides to build energy faster and at a somewhat lower engine RPM. A simultaneous reduction in intake restriction will also increase the compressor efficiencies, meaning more volume and/or pressure at a given turbo RPM. The net result is a faster buildup of intake boost pressure occurring at lower engine RPM’s and therefore producing more area under the boost curve and greater power output. Again assuming constant peek boost pressure.
The reduction in backpressure may also mean that each rotor face has less trouble releasing its spent fuel/air in to the exhaust port resulting in some slight decrease in pumping loss, but this also means less of the old charge remains in the combustion chamber which is therefore able to ingest a higher percentage of fresh cool charge. This then suggests that more energy will be produced here, too.
If the above is close to correct, then the engine is confronted with several simultaneous changes; (1) more boost at a lower RPM which it probably can accommodate (up to a point) via the ECU’s OEM maps, (2) increased mass in each compression cycle of which the ECU knows nothing about and which therefore must draw against the original over-rich A/F ratio, and (3) its increased power output is necessarily accompanied by increased thermal loading of the engine and in particular the cooling and oil systems.
Since this all suggest that more total mass of air is moving through the engine, the assumption of constant intake temperature may be invalid. More mass through the intercooler probably means that its thermal efficiency is further reduced (although this might be offset some by higher efficiency at the turbo compressor) and therefore it’s likely that the effective intake temperature will go up. Even 10 degrees could become significant because the engine is already operating at a higher block temperature, with effectively higher compression ratio and no changes in fuel or timing over the stock settings.
Many have reported successfully running the stock ECU with several mods. Their successes suggest to me that either the original A/F ratios are very rich 8-9:1, and/or there is significant variation in the effective A/F ratio due to the combination of so many components, and of course, not every engine is blessed with components functioning as spec’d. Together this would help explain why not all rotary engines are equally happy with three or more mods.
Add in the other realities of boost spikes and creep and it seems to me that the only SMART way to know if your engine can survive modifications is to test it’s A/F ratio using a suitable wide band sensor with the engine under load and with due allowances for variations in components and ambient temperature. And since a long list of component failures is always possible, how do we insure that we still have sufficient headroom in A/F ratio to insure operational safety? Maybe a J&S or similar is the best insurance.
12-16-02, 10:43 PM
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Re: that's part of it
Originally posted by KevinK2
The big fish is chamber filling. If intake port opens to 10 psi in manifold, but there is still lots of exh gasses in the chamber, then less room for new charge, and less air flow results at same boost.
The big fish is chamber filling. If intake port opens to 10 psi in manifold, but there is still lots of exh gasses in the chamber, then less room for new charge, and less air flow results at same boost.
Thanks,
12-16-02, 10:43 PM
#32
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boost stays at 10 psi....motor can only hold certain volume at this pressure.....increase the motors volumetric capacity and power will rise at the same boost pressure.....but the turbo will work harder to achieve that pressure.....essentially...displacement is the key factor when it comes to making more power at a given pressure...opening the intake and exhaust allows for power gains due to the fact that the motor and turbo do not have to work as hard to create power at the same level....not to mention that more power is made at lower rpms....
12-16-02, 11:34 PM
#33
Originally posted by 13brv3
Say we open up the intake and exhaust, then limit the boost to 10 psi, and keep the intake temp the same for the sake of simplicity. At this point, we are saying that we have more airflow through the engine than when it was stock. So far so good.
The ECU only sees temp, and pressure, which are the same as before. Doesn't that mean it's supplying the same fuel as before? If that's true, why wouldn't we be running lean if more air is passing through? Was the stock AFR ridiculously rich, like 8 or 9?
Are we really making more power if we keep the boost at 10 psi? The only way I can imagine this is if we're removing some of the restriction on the engine, thus making it more efficient. Are we really just reclaiming power that was being wasted on pumping losses before?
Cheers,
Rusty (NOT a thermodynamic guy)
Say we open up the intake and exhaust, then limit the boost to 10 psi, and keep the intake temp the same for the sake of simplicity. At this point, we are saying that we have more airflow through the engine than when it was stock. So far so good.
The ECU only sees temp, and pressure, which are the same as before. Doesn't that mean it's supplying the same fuel as before? If that's true, why wouldn't we be running lean if more air is passing through? Was the stock AFR ridiculously rich, like 8 or 9?
Are we really making more power if we keep the boost at 10 psi? The only way I can imagine this is if we're removing some of the restriction on the engine, thus making it more efficient. Are we really just reclaiming power that was being wasted on pumping losses before?
Cheers,
Rusty (NOT a thermodynamic guy)
We can't test a before and after with the stock ECU because it runs RICHER than the wideband will measure! Even with some mods it still runs richer than the wideband can pick up. Notice Wade has a car with a lot of mods and the stock ECU. That car got into the 11:1 range IIRC. Leaner than stock, but plenty acceptable for a/f ratios.
Jeff
12-16-02, 11:47 PM
#35
>>Beautiful! That was really the missing piece for me. Man, GREAT thread
>>First, I would like to say that this is one of the best threads I have seen on this forum.
ahh, jeeeesh, thanks guys...I wasn't expecting it to get so nice and gritty...thanks to all those who replied with the goods
but I definetly feel less opposed to adding an itake to my dp-catback setup....then go get a widband lambda dybo run :-)
>>First, I would like to say that this is one of the best threads I have seen on this forum.
ahh, jeeeesh, thanks guys...I wasn't expecting it to get so nice and gritty...thanks to all those who replied with the goods
but I definetly feel less opposed to adding an itake to my dp-catback setup....then go get a widband lambda dybo run :-)
12-17-02, 12:11 AM
#36
Home depot boost controller link
http://robrobinette.com/boost_controller.htm
It works great. Easy to install. Costs less than $15.
You should install this at the same time as the intake.
Adam
http://robrobinette.com/boost_controller.htm
It works great. Easy to install. Costs less than $15.
You should install this at the same time as the intake.
Adam
12-17-02, 05:48 AM
#38
Doritos on a toothpick
BARBAN,ive heard of people digging into the rotors for more capacity in the motor...but i was refering to all engines in general, piston or not......
Last edited by BoostCrzy; 12-17-02 at 06:12 AM.
12-17-02, 06:20 AM
#39
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Part of the question is that we are talking about a operating system, not static. No, 10 PSI doesn't equal 10 psi at all times. Just look at any dyno chart, if the touque curve is flat, then the mass the engine is ingesting is constant. But air has mass and has to be accelerated into the chambers. The intercooler has flow restrictions and so does the exhaust. All these things conspire to make 10 psi just a # representing intake pressure. A better measure would be chamber pressure right before ignition, however pretty impossible to measure. Also the porting and exhaust contribute to dilution of the intake charge with combustion gases. The complete thermodynamic cycle of the rotary is very complex as are all internal combustion engines and must be looked at as a complete system. Small changes in one part of the system can have large consiquences for the rest of the system. Thats why in concert with the rotary's dislike of detonation, I have always felt that this is the one power plant that DEMAMDED mass flow engine management. But alas I guess doing it right was too hard for Mazda. Measuring A/F ratios after each mod is truly the only way to be safe. All the rest is russian roulette. But that's just my opinion and YMMV.
J
J
12-17-02, 07:53 AM
#40
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Originally posted by turbojeff
You must not have looked at Wade's site. Jeff
You must not have looked at Wade's site. Jeff
Actually, I just missed the one skinny line at the top of the chart, which is the only stock reading. It reads 10:1 like most every other 10psi/stock fuel reading, regardless of mods. In other words, we can't really measure the difference between stock, and several mods at 10psi. Still, the important thing was to prove that there's pleny of fuel for mods at 10psi, with the stock ECU, and as I said before, I'm convinced.
Cheers,
12-18-02, 09:03 AM
#41
Alright let me take a crack...
Basis:
Air can be assumed to behave as an ideal gas at pressure below 2atm (1atm=14.7psia) and temps below 500F.
Therefore from the ideal gas law:
PV = nRT
Isothermal (constant temp) or Boyle's Law:
p1V1 = p2V2
Isobaric (constant pressure) or Charle's Law:
T1/V1 = T2/V2
Clearly, the temps change (intercooler), pressure change (lower deltalP)
What is important is to not confuse gravimetric with volumetric flow. So once the air hits the turbos and then a temp drop exists after you do not suddenly get more air by mass because of the temperature drop across the intercooler. After the turbos the air in essence, is in a closed system so dropping temps does not suddenly produce more air by mass it simply occupies less space (lower partial pressures P*)
For example, commonly turbines are sized by displacement or cc/rev or ft^3/rev so a number results from this being volumetric but what really is important is the mass number so the volume must be multiplied by density to get rate.
(ft^3/rev) * (lbmol/ft^3) = lbmol(air)/revolution
Well, we are not done yet...to complicate matters even further, the density of any fluid is a direct funtion of temperature. So as temp increases, the same amount of gas (isochoric = constant volume) occupies more space per unit volume which is measured as partial pressure.
So here is what does not make sense to me:
I do not know the operational basis for the FD ecu fuel maps but...
The manifold pressure pressure cannot be a good operational basis for fuel addition if total volume and temp of the system is not known. Really it is the mass flow rate of air that is important. So yes, you can run the same pressure (boost) and get different amount of air flow by mass if the system volume changes (lower deltaP, bigger inlet pipes, lower frictional losses blah blah) and the inlet air temp changes (more air by mass is displaced per turbine revolution)
But what continues to fail to make any sense are the singles running the 15psi boost with the same intake system claiming all this exceptional horsepower.
If the system volume does not change ie cai, pipes, flow factors and you run the same inlet temp and manifold pressure YOU ARE NOT GETTING MORE AIR OR HORSE POWER by running a bigger turbo...your turbine (assume larger) is simply running more efficiently (or not) depending on the turbine design.
Lastly, for those that may have forgetten, the air/fuel ratios are STOICHIOMETRIC or MASS numbers...specifically molar ratios.
Basis:
Air can be assumed to behave as an ideal gas at pressure below 2atm (1atm=14.7psia) and temps below 500F.
Therefore from the ideal gas law:
PV = nRT
Isothermal (constant temp) or Boyle's Law:
p1V1 = p2V2
Isobaric (constant pressure) or Charle's Law:
T1/V1 = T2/V2
Clearly, the temps change (intercooler), pressure change (lower deltalP)
What is important is to not confuse gravimetric with volumetric flow. So once the air hits the turbos and then a temp drop exists after you do not suddenly get more air by mass because of the temperature drop across the intercooler. After the turbos the air in essence, is in a closed system so dropping temps does not suddenly produce more air by mass it simply occupies less space (lower partial pressures P*)
For example, commonly turbines are sized by displacement or cc/rev or ft^3/rev so a number results from this being volumetric but what really is important is the mass number so the volume must be multiplied by density to get rate.
(ft^3/rev) * (lbmol/ft^3) = lbmol(air)/revolution
Well, we are not done yet...to complicate matters even further, the density of any fluid is a direct funtion of temperature. So as temp increases, the same amount of gas (isochoric = constant volume) occupies more space per unit volume which is measured as partial pressure.
So here is what does not make sense to me:
I do not know the operational basis for the FD ecu fuel maps but...
The manifold pressure pressure cannot be a good operational basis for fuel addition if total volume and temp of the system is not known. Really it is the mass flow rate of air that is important. So yes, you can run the same pressure (boost) and get different amount of air flow by mass if the system volume changes (lower deltaP, bigger inlet pipes, lower frictional losses blah blah) and the inlet air temp changes (more air by mass is displaced per turbine revolution)
But what continues to fail to make any sense are the singles running the 15psi boost with the same intake system claiming all this exceptional horsepower.
If the system volume does not change ie cai, pipes, flow factors and you run the same inlet temp and manifold pressure YOU ARE NOT GETTING MORE AIR OR HORSE POWER by running a bigger turbo...your turbine (assume larger) is simply running more efficiently (or not) depending on the turbine design.
Lastly, for those that may have forgetten, the air/fuel ratios are STOICHIOMETRIC or MASS numbers...specifically molar ratios.
12-18-02, 09:51 AM
#42
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But what continues to fail to make any sense are the singles running the 15psi boost with the same intake system claiming all this exceptional horsepower
most likely due to the fact that the stock twin turbo manifold sucks in terms of flow, the pressure drop through that thing has to be very high with all the twists, bends, and sharp corners
there is likely less stress on the turbines to produce 15 psi with a well designed single turbo manifold
at 15 psi, a single puts out what, 375-385 hp? compared to 340-350 for a twin? not as big of a diff as you may think
most likely due to the fact that the stock twin turbo manifold sucks in terms of flow, the pressure drop through that thing has to be very high with all the twists, bends, and sharp corners
there is likely less stress on the turbines to produce 15 psi with a well designed single turbo manifold
at 15 psi, a single puts out what, 375-385 hp? compared to 340-350 for a twin? not as big of a diff as you may think
12-18-02, 10:11 AM
#43
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Originally posted by cover8
But what continues to fail to make any sense are the singles running the 15psi boost with the same intake system claiming all this exceptional horsepower.
If the system volume does not change ie cai, pipes, flow factors and you run the same inlet temp and manifold pressure YOU ARE NOT GETTING MORE AIR OR HORSE POWER by running a bigger turbo...your turbine (assume larger) is simply running more efficiently (or not) depending on the turbine design.
Lastly, for those that may have forgetten, the air/fuel ratios are STOICHIOMETRIC or MASS numbers...specifically molar ratios.
But what continues to fail to make any sense are the singles running the 15psi boost with the same intake system claiming all this exceptional horsepower.
If the system volume does not change ie cai, pipes, flow factors and you run the same inlet temp and manifold pressure YOU ARE NOT GETTING MORE AIR OR HORSE POWER by running a bigger turbo...your turbine (assume larger) is simply running more efficiently (or not) depending on the turbine design.
Lastly, for those that may have forgetten, the air/fuel ratios are STOICHIOMETRIC or MASS numbers...specifically molar ratios.
You can whip out all the Thermo 101 you want but the simple fact remains that you make more horsepower at the same manifold pressure when you have less restrictive exhaust and intake paths. I made 240 rwhp/226 lb-ft with a downpipe and cat-back vs a stock car at about 215-220 rwhp/185-190 lb-ft at the same 10 psi.
I don't think single turbo guys are CLAIMING anything, I've seen enough dyno plots to know they are making more hp at 15 psi than the twins ever would.
12-18-02, 10:35 AM
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Originally posted by cover8
well I understand the benefit of improved air flow...really dont see the benefit of large singles unless they are running significantly more boost (20psi)
well I understand the benefit of improved air flow...really dont see the benefit of large singles unless they are running significantly more boost (20psi)
Also, I believe nocab72 is hitting over 450 rwhp at 15 psi with his GT35/40, albeit with a "big-***" streetport.
12-18-02, 11:00 AM
#47
Originally posted by rynberg
You can whip out all the Thermo 101 you want but the simple fact remains that you make more horsepower at the same manifold pressure when you have less restrictive exhaust and intake paths.
You can whip out all the Thermo 101 you want but the simple fact remains that you make more horsepower at the same manifold pressure when you have less restrictive exhaust and intake paths.
"..So yes, you can run the same pressure (boost) and get different amount of air flow by mass if the system volume changes (lower deltaP, bigger inlet pipes, lower
frictional losses blah blah) and the inlet air temp changes (more air by mass is displaced per turbine revolution)...
I think less restrictive exhaust applies to the above.
Actually, I like to simplify in order to improve communication to those less technically oriented...of course, we can dicuss equations EQ thermo, Redlich-Kwong virial equations of state, steady-state, non-steady state blah blah...anytime
Nick
Registered Chemical Engineer (OK, MO, IL, IN)
Last edited by cover8; 12-18-02 at 11:05 AM.
12-18-02, 11:13 AM
#48
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Originally posted by cover8
"..So yes, you can run the same pressure (boost) and get different amount of air flow by mass if the system volume changes (lower deltaP, bigger inlet pipes, lower
frictional losses blah blah) and the inlet air temp changes (more air by mass is displaced per turbine revolution)...
I think less restrictive exhaust applies to the above.
Nick
Registered Chemical Engineer (OK, MO, IL, IN)
"..So yes, you can run the same pressure (boost) and get different amount of air flow by mass if the system volume changes (lower deltaP, bigger inlet pipes, lower
frictional losses blah blah) and the inlet air temp changes (more air by mass is displaced per turbine revolution)...
I think less restrictive exhaust applies to the above.
Nick
Registered Chemical Engineer (OK, MO, IL, IN)
My only excuse is that I'm not fully awake yet. BTW, no need to be so harsh, I could make equally scathing comments regarding the private school system.....
12-18-02, 11:41 AM
#49
no problem rynberg....I have had too much candy!!
Would your discontent with private(s) schools stem from your resentment and sexual frustration of not having the priveledge to meet our fine priests...lol..or our very alcoholic, liberal coeds in plaid laden, knee highs?
Would your discontent with private(s) schools stem from your resentment and sexual frustration of not having the priveledge to meet our fine priests...lol..or our very alcoholic, liberal coeds in plaid laden, knee highs?
12-18-02, 12:31 PM
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Originally posted by cover8
no problem rynberg....I have had too much candy!!
Would your discontent with private(s) schools stem from your resentment and sexual frustration of not having the priveledge to meet our fine priests...lol..or our very alcoholic, liberal coeds in plaid laden, knee highs?
no problem rynberg....I have had too much candy!!
Would your discontent with private(s) schools stem from your resentment and sexual frustration of not having the priveledge to meet our fine priests...lol..or our very alcoholic, liberal coeds in plaid laden, knee highs?
hmmm....drunk girls in catholic school girl outfits...
wow, never thought I'd actually use THAT smilie......