Axial Flow Supercharger
#651
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It shouldn't be bad from his standpoint. He has to analyze rotary engine airflow and then build a suitable unit for it's needs. This is no different than any other engine. Fabbing it up so it fits in the car shouldn't be much of an issue either. Only tuning the ecu is the big hurdle but he isn't designing an ecu so that isn't his concern. He isn't the only one designing, building, installing, and tuning this you know. He is working in conjunction with others to make sure it comes full circle.
#652
Well Hymee I should have known when I said you could take pictures that you were copying the engineering files. I may as well go into retirment now, you've done it all even advanced polimers.
Sure beats the ones they are selling on E bay. Get those stators done and you will kill the market.
Sad to say that there are people out there that will go for it like they do the heater motors.
RX8 dx No I am very happy with the Mazda idea and it fits my personal ideals for high tech product. Besides I wouldn't trade you guys for any other group. No BS I mean that.
Any how the dash 2 blower is off the test stand and all went as predicted. Now we will work on adapting to the engine.
Sure beats the ones they are selling on E bay. Get those stators done and you will kill the market.
Sad to say that there are people out there that will go for it like they do the heater motors.
RX8 dx No I am very happy with the Mazda idea and it fits my personal ideals for high tech product. Besides I wouldn't trade you guys for any other group. No BS I mean that.
Any how the dash 2 blower is off the test stand and all went as predicted. Now we will work on adapting to the engine.
#655
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RG ..... why does your avatar have a piston ring compression tool?..... I can understand a torque wrench. Or is that one of the new fangaled oil filter removers? ![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
I can't wait to see how well this SC does... this is by far the most interesting project on this site. Hymee's is second.... not interested in the turbo's i have enough lag on the bottom end as it is.
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
I can't wait to see how well this SC does... this is by far the most interesting project on this site. Hymee's is second.... not interested in the turbo's i have enough lag on the bottom end as it is.
#656
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Originally Posted by rotarygod
Without fuel and ignition we can't make any power. It is vitally important that we control, these properly.
The craze with the older RX-7's right now is to buy a used Eaton M90 supercharger off of a late '80s-early '90s Ford Thunderbird and adapt it to the car. Those guys are just using a pigguback ecu such as an S-AFC to add fuel. They aren't adding a whole lot of power. Also keep in mind that the older RX-7's use a air flow meter which knows how much air is being sucked through it. It compensates automatically up until the flapper door in the sensor is fully open. From here it is up to the S-AFC to add more fuel. The ecu's in those cars is far less invasive than that in the RX-8. They can make things work alot easier. There is still no getting around good tuning. Many of thier systems are bandaids and they are missing the true potential of their engines. A standalone is always the best option. Just like any other car, if those guys try to push it to hard, they will blow stuff up.
The craze with the older RX-7's right now is to buy a used Eaton M90 supercharger off of a late '80s-early '90s Ford Thunderbird and adapt it to the car. Those guys are just using a pigguback ecu such as an S-AFC to add fuel. They aren't adding a whole lot of power. Also keep in mind that the older RX-7's use a air flow meter which knows how much air is being sucked through it. It compensates automatically up until the flapper door in the sensor is fully open. From here it is up to the S-AFC to add more fuel. The ecu's in those cars is far less invasive than that in the RX-8. They can make things work alot easier. There is still no getting around good tuning. Many of thier systems are bandaids and they are missing the true potential of their engines. A standalone is always the best option. Just like any other car, if those guys try to push it to hard, they will blow stuff up.
thank you ......iv ben saying that for months. every one freaks out when you even bring up "stand alone"
#657
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Originally Posted by RogueRX8
RG ..... why does your avatar have a piston ring compression tool?.....
#661
Hymee, after looking at your design I realized that you could have done better if you took advantage of the electric motors. By using the magnetic feild created by rhe motors you could utilize the force to give positive and then negative charge to the ions. This could then be used to get a more true axial flow without any spiral. Thus getting the extra vslosity pressure and more efficency.
I don't know exactly how to give the results since they are complex and volumous.
Just to give you the ones you most likely want, it made 12 psi and over 600 cfm.
Which is what was predicted.
I don't know exactly how to give the results since they are complex and volumous.
Just to give you the ones you most likely want, it made 12 psi and over 600 cfm.
Which is what was predicted.
#666
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Thats not a good one....
We won the world biker build off remember![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
A testament to american engineering![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
ok.. back to topic...
We won the world biker build off remember
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
A testament to american engineering
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
ok.. back to topic...
Last edited by davefzr; 10-07-2004 at 10:58 PM.
#667
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Originally Posted by davefzr
We won the world biker build off remember ![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
At least an Aussie was the first rotar to break 200MPH
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
Cheers,
Hymee.
#668
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I just brought that up to be funny and the fact that it was on not to long ago.. just trying to be funny of course, didnt mean any disrespect at all....
ok.. back to the regularly scheduled programming....
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Last edited by davefzr; 10-07-2004 at 11:25 PM.
#670
Interesting concept but still curious: If the axial flow supercharger is superior to the centrifugal supercharger why isn't a company like ABB not using axial compressors on their turbochargers? After all they are using axial flow turbines on the exhaust side of their turbochargers, so they should know how to engineer them?
http://www.abb.com/global/abbzh/abbzh251.nsf!OpenDatabase&db=/global/seapr/seapr035.nsf&v=6311A&e=us&m=9F2&c=580E4A407A088ED1 C1256A16003B208E
Also if it has to be spun up to 42'000 rpm wouldn't this add a lot of rotational mass and reduce the responsivness of the engine? Apparently it's pretty light but are several rotors still lighter than one rotor of a centrifugal (radial flow) supercharger?
http://www.abb.com/global/abbzh/abbzh251.nsf!OpenDatabase&db=/global/seapr/seapr035.nsf&v=6311A&e=us&m=9F2&c=580E4A407A088ED1 C1256A16003B208E
Also if it has to be spun up to 42'000 rpm wouldn't this add a lot of rotational mass and reduce the responsivness of the engine? Apparently it's pretty light but are several rotors still lighter than one rotor of a centrifugal (radial flow) supercharger?
Last edited by globi; 10-11-2004 at 02:32 PM.
#672
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I'm just guessing here, but I would think for an automotive turbocharger, the linear boost increase w/ rpm (in this case, its unrelated to engine rpm) would be a disadvantage when compared with the more exponential boost increase in the centrifugal units. You want to hit your max boost as soon as you can with a turbo, and its related to exhaust flow rather than engine rpm. Just a guess though...
jds
jds
Originally Posted by globi
Interesting concept but still curious: If the axial flow supercharger is superior to the centrifugal supercharger why isn't a company like ABB not using axial compressors on their turbochargers? After all they are using axial flow turbines on the exhaust side of their turbochargers, so they should know how to engineer them?
http://www.abb.com/global/abbzh/abbzh251.nsf!OpenDatabase&db=/global/seapr/seapr035.nsf&v=6311A&e=us&m=9F2&c=580E4A407A088ED1 C1256A16003B208E
Also if it has to be spun up to 42'000 rpm wouldn't this add a lot of rotational mass and reduce the responsivness of the engine? Apparently it's pretty light but are several rotors still lighter than one rotor of a centrifugal (radial flow) supercharger?
http://www.abb.com/global/abbzh/abbzh251.nsf!OpenDatabase&db=/global/seapr/seapr035.nsf&v=6311A&e=us&m=9F2&c=580E4A407A088ED1 C1256A16003B208E
Also if it has to be spun up to 42'000 rpm wouldn't this add a lot of rotational mass and reduce the responsivness of the engine? Apparently it's pretty light but are several rotors still lighter than one rotor of a centrifugal (radial flow) supercharger?
#673
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Not quite true.
Say you have 3 superchargers, 1 positive dispacement, 1 axial flow, 1 centrifugal.
Say they are all designed to make 12 PSI boost at 9000 RPM. Assume they all take the same power to "turn", and put the same heat in. (Not strictly the case, but we are keeping this simple.)
Centrifugal - Boost increases in proportion to the square of the RPM (in rough terms). So if you 1/2 the RPM you 1/4 the boost.
So at 4500 RPM we get 3 PSI.
8000 = 9.5 PSI
6000 = 5.3 PSI
3000 = 1.3 PSI
2000 = 0.6 PSI
Axial Flow - boost is proportional to the RPM. At 1/2 the RPM you get 1/2 the boost.
So at 4500 RPM you get 6 PSI boost.
8000 = 10.7 PSI
6000 = 8 PSI
3000 = 4 PSI
2000 = 2.7 PSI
Positive Displacement - boost is linear. At any RPM you get the same boost
So at 4500 RPM you get 12 PSI boost.
8000 = 12 PSI
6000 = 12 PSI
3000 = 12 PSI
2000 = 12 PSI
Now, in practice, the numbers are not so precise, but that is the general trend. And the other factors I mentioned above come into play - heat added, power taken to turn.
But you can see why I believe the Axial Flow is far superior to Centrifugal. Especially on a rotary, when we want some low down boost for better drivability. Centrifugal is probably slightly smaller, and measureably cheaper to manufacture.
One more thing - remember, boost is not air flow. The "boost" is the presure inside your intake manifold. That is a function of how much air the supercharger is blowing in, and how much air the motor is taking out. So if you where to plot those curves above, and integrate them to mass air flow, the differences would be even more dramatic.
Anyway - that is enough for theory. I can't wait to get onto the engine dyno and get something working!! :D
Cheers,
Hymee.
Say you have 3 superchargers, 1 positive dispacement, 1 axial flow, 1 centrifugal.
Say they are all designed to make 12 PSI boost at 9000 RPM. Assume they all take the same power to "turn", and put the same heat in. (Not strictly the case, but we are keeping this simple.)
Centrifugal - Boost increases in proportion to the square of the RPM (in rough terms). So if you 1/2 the RPM you 1/4 the boost.
So at 4500 RPM we get 3 PSI.
8000 = 9.5 PSI
6000 = 5.3 PSI
3000 = 1.3 PSI
2000 = 0.6 PSI
Axial Flow - boost is proportional to the RPM. At 1/2 the RPM you get 1/2 the boost.
So at 4500 RPM you get 6 PSI boost.
8000 = 10.7 PSI
6000 = 8 PSI
3000 = 4 PSI
2000 = 2.7 PSI
Positive Displacement - boost is linear. At any RPM you get the same boost
So at 4500 RPM you get 12 PSI boost.
8000 = 12 PSI
6000 = 12 PSI
3000 = 12 PSI
2000 = 12 PSI
Now, in practice, the numbers are not so precise, but that is the general trend. And the other factors I mentioned above come into play - heat added, power taken to turn.
But you can see why I believe the Axial Flow is far superior to Centrifugal. Especially on a rotary, when we want some low down boost for better drivability. Centrifugal is probably slightly smaller, and measureably cheaper to manufacture.
One more thing - remember, boost is not air flow. The "boost" is the presure inside your intake manifold. That is a function of how much air the supercharger is blowing in, and how much air the motor is taking out. So if you where to plot those curves above, and integrate them to mass air flow, the differences would be even more dramatic.
Anyway - that is enough for theory. I can't wait to get onto the engine dyno and get something working!! :D
Cheers,
Hymee.
Last edited by Hymee; 10-12-2004 at 04:47 PM.
#674
Well, I still have my doubts or why are small gas turbines using centrifugal compressors and large gas turbines axial compressors?
Anyway it doesn't really matter since both types of compressors don't deliver pressure at low rpms, there would be no low end torque gain and that's what is kind of missing on that engine.
So you'd probably want to chose the positive displacement compressor anyway unless you're gonna drive these compressors with electric motors or something.
But then again apparently the rotary engine breaths a lot of air without burning it which would mean that you're wasting a lot of energy with any supercharger so you'd probably would prefer a turbocharger (in order to recycle some of that wasted air). Which brings us back to the topic why aren't there any turbo chargers with axial flow compressors?
Besides all that I wouldn't want to hook up any fast (or even slow) spinning compressor on a high reving engine. After all why are people getting lighter flywheels?
Don't get me wrong I believe that this compressor is more efficient than any other type but why not installing it on a low end torque big displacement engine instead? Also the way it's build it could probably accomodate a high frequency electric motor in the center and you'd end up with a really neat electric supercharger. (Which might eventually substitute the mechanical supercharger due to its much higher flexibility).
Anyway it doesn't really matter since both types of compressors don't deliver pressure at low rpms, there would be no low end torque gain and that's what is kind of missing on that engine.
So you'd probably want to chose the positive displacement compressor anyway unless you're gonna drive these compressors with electric motors or something.
But then again apparently the rotary engine breaths a lot of air without burning it which would mean that you're wasting a lot of energy with any supercharger so you'd probably would prefer a turbocharger (in order to recycle some of that wasted air). Which brings us back to the topic why aren't there any turbo chargers with axial flow compressors?
Besides all that I wouldn't want to hook up any fast (or even slow) spinning compressor on a high reving engine. After all why are people getting lighter flywheels?
Don't get me wrong I believe that this compressor is more efficient than any other type but why not installing it on a low end torque big displacement engine instead? Also the way it's build it could probably accomodate a high frequency electric motor in the center and you'd end up with a really neat electric supercharger. (Which might eventually substitute the mechanical supercharger due to its much higher flexibility).
#675
Registered
Originally Posted by globi
why aren't there any turbo chargers with axial flow compressors?
In Richard's case, his company is called axial flow engineering. That's what he does. It may cost more and be more complex but he is also specializing in a different product. Being unique in a marketplace seems like a good idea but it actually takes bravery to try something that no one else has any experience with. In this application it will definitely be a specialized market and it will take a special buyer for it but it will sell.