Superchargers.
Superchargers.
Folks. I am looking to get some opinions. I have been looking into supercharging as an option instead of going big turbo. I know alot of you will spout off about supercharging being inferior, etc. However, I have been examining the new superchargers available today and there are superchargers that can put out more max PSI and max CFM than even the large turbos can. I have been wondering why not supercharge an FD. Correct me if I am wrong but if it can out perform a large turbo in volume air supplied at a given psi and has virtually no lag then isn't it a perfect option for a rotary? Just thinking out loud at this point. Take a look at some of these superchargers:
http://www.procharger.co/models.shtml
http://www.procharger.co/models.shtml
They do supercharge the early models but i have NEVER seen a supercharged FD explored. I realize the NA rotary has little torque and HP at idle so a supercharger, especially a large one, would drag down the engine a bit at low rpms. However, if a "perfect size" could be determined to minimize drag and maximize airflow then the result would have to be better than turbocharging.
have never seen a sc rx7 so i think it would be a good idea
1. Superchargers make their power down low, which is why they are good for v8s. Check out the difference between SC S2000s and turbo'd S2000's. They are totally different beasts. And a rotary can outrev any VTEC and makes most all of it's power up top.
2. Rotary engines have massive amounts of airflow, which makes them wicked good at spooling turbos. No reason to go with something belt driven.
3. SC run on a belt, which causes a parasidic hp loss. You don't have this with turbos.
4. For a bonus one, the custom setup would be no where near financially viable. You would have to make so much custom stuff, have a Power FC and then good luck finding someone who has previously tuned a supercharged FD bc it will not be the same as a turbo'd one.
The only plus to this would be it is something different. But it's not like rotary powered FDs are everywhere, so in my opinion, you already have something different.
This is exactly why it is a bad idea. Usually if no one has did it, it is for a reason. 3 main reasons why this would suck:
1. Superchargers make their power down low, which is why they are good for v8s. Check out the difference between SC S2000s and turbo'd S2000's. They are totally different beasts. And a rotary can outrev any VTEC and makes most all of it's power up top.
2. Rotary engines have massive amounts of airflow, which makes them wicked good at spooling turbos. No reason to go with something belt driven.
3. SC run on a belt, which causes a parasidic hp loss. You don't have this with turbos.
4. For a bonus one, the custom setup would be no where near financially viable. You would have to make so much custom stuff, have a Power FC and then good luck finding someone who has previously tuned a supercharged FD bc it will not be the same as a turbo'd one.
The only plus to this would be it is something different. But it's not like rotary powered FDs are everywhere, so in my opinion, you already have something different.
1. Superchargers make their power down low, which is why they are good for v8s. Check out the difference between SC S2000s and turbo'd S2000's. They are totally different beasts. And a rotary can outrev any VTEC and makes most all of it's power up top.
2. Rotary engines have massive amounts of airflow, which makes them wicked good at spooling turbos. No reason to go with something belt driven.
3. SC run on a belt, which causes a parasidic hp loss. You don't have this with turbos.
4. For a bonus one, the custom setup would be no where near financially viable. You would have to make so much custom stuff, have a Power FC and then good luck finding someone who has previously tuned a supercharged FD bc it will not be the same as a turbo'd one.
The only plus to this would be it is something different. But it's not like rotary powered FDs are everywhere, so in my opinion, you already have something different.
2. Yes rotaries flow a lot of air but there is a reason why even the stock turbos don't come online until 3500 or so rpm.
3. While turbos don't directly drag on the engine they do restrict airflow and generate a lot of heat in the engine, which decrease performance.
4. It wouldn't cost much more than a custom turbo setup. The supporting accessories are already there. ECU, fuel, intercoolers, etc. The only need is a header and a mounting bracket for the sc. As far as tuning, it would be no different than tuning a turbo car except that as boost comes on earlier, more fuel will be needed earlier.
Joined: Aug 2004
Posts: 4,496
Likes: 1,484
From: West Coast
Not all superchargers make their power in the lower revs. The Z-Engineering set up on my old Miata was centrifugal, so it acted more like a turbocharger with no lag.
Typically, a centrifugal supercharger will make it's maximum (quoted) boost at the engine's redline rpm and nearly nothing at 1500-2000 engine rpm. Boost builds exponentially with engine rpm, meaning that boost comes on very quickly in the upper half of the powerband. While this normally isn't a problem for lighter cars with manual trannsmissions, it poses a significant problem to heavier vehicles, towing vehicles, or vehicles with automatic transmissions. If you have a truck, towing vehicle, or an automatic transmission, you may want to consider a screw-type supercharger, which makes full boost as low as 1500 engine rpm
from here:
http://www.superchargersonline.com/content.asp?id=21
Typically, a centrifugal supercharger will make it's maximum (quoted) boost at the engine's redline rpm and nearly nothing at 1500-2000 engine rpm. Boost builds exponentially with engine rpm, meaning that boost comes on very quickly in the upper half of the powerband. While this normally isn't a problem for lighter cars with manual trannsmissions, it poses a significant problem to heavier vehicles, towing vehicles, or vehicles with automatic transmissions. If you have a truck, towing vehicle, or an automatic transmission, you may want to consider a screw-type supercharger, which makes full boost as low as 1500 engine rpm
from here:
http://www.superchargersonline.com/content.asp?id=21
Trending Topics
1. Rotaries have no power down low, so SC would seem to make sense for a rotary.
2. Yes rotaries flow a lot of air but there is a reason why even the stock turbos don't come online until 3500 or so rpm.
3. While turbos don't directly drag on the engine they do restrict airflow and generate a lot of heat in the engine, which decrease performance.
4. It wouldn't cost much more than a custom turbo setup. The supporting accessories are already there. ECU, fuel, intercoolers, etc. The only need is a header and a mounting bracket for the sc. As far as tuning, it would be no different than tuning a turbo car except that as boost comes on earlier, more fuel will be needed earlier.
2. Yes rotaries flow a lot of air but there is a reason why even the stock turbos don't come online until 3500 or so rpm.
3. While turbos don't directly drag on the engine they do restrict airflow and generate a lot of heat in the engine, which decrease performance.
4. It wouldn't cost much more than a custom turbo setup. The supporting accessories are already there. ECU, fuel, intercoolers, etc. The only need is a header and a mounting bracket for the sc. As far as tuning, it would be no different than tuning a turbo car except that as boost comes on earlier, more fuel will be needed earlier.
1. Yes the SC will help make more power down low, where the rotary has none, this is correct. But it will not be as efficient up top, which you just admitted, is where the power band should be. Although yes, a centrifugal would greatly help with this.
2. What? The secondary comes on then, primary should be boosting well before that.
3. Turbos are not parasidic no matter how you look at it. Also, if you go single, it will greatly help the heat situation caused by the twins. Add a heat blanket and wrap you manifold and you are good to go.
4. Header and a bracket huh? That is a very simple way of putting it. Also, their characteristics are different, therefore tuning is different. No, you do not have to re-write the book, but it is not nearly as simple as just adding some more fuel down low.
As far as it costing the same. Custom stuff always costs more. Even if you fabricate, you will spend more money.
Just trying to play devils advocate, and learn a little bit myself. I am not trying to discourage you.
Senior Member
Joined: May 2007
Posts: 285
Likes: 2
From: Wilmington, DE
I'm going to skip commenting on some of the off base stuff here.
A supercharger would be a great way to increase power on the FD. Dave Barninger has done some on FC's and FB's and I am currently doing a 20b that will be supercharged to replace my 20b NA. I am not trying to make the same kind of power that some do with the turbo whether I could or not. I really want the linearity.
There is also the more interesting sound that a 13b with a supercharger would make combing the whine with the buzz instead of just muting the buzz...
A plus for me is that if I am only running 4-8 psi I will only use water injection and no intercooler.
I think its a great idea and hope you do it and do a build thread.
Gordon
A supercharger would be a great way to increase power on the FD. Dave Barninger has done some on FC's and FB's and I am currently doing a 20b that will be supercharged to replace my 20b NA. I am not trying to make the same kind of power that some do with the turbo whether I could or not. I really want the linearity.
There is also the more interesting sound that a 13b with a supercharger would make combing the whine with the buzz instead of just muting the buzz...
A plus for me is that if I am only running 4-8 psi I will only use water injection and no intercooler.
I think its a great idea and hope you do it and do a build thread.
Gordon
pettit and hymee both offer screw-type superchargers for the rx-8. I know it's a different engine but the dynos show an awesome pancake flat torque curve almost identical to stock n/a just higher everywhere.
DO it....just don't let this happen
http://www.youtube.com/watch?v=IYIdJ...eature=related
http://www.youtube.com/watch?v=rw0LFhJFxSs
supercharged rotary does sound sweet tho
this one is crazy
http://www.youtube.com/watch?v=HCbvW...ature=related#
http://www.youtube.com/watch?v=IYIdJ...eature=related
http://www.youtube.com/watch?v=rw0LFhJFxSs
supercharged rotary does sound sweet tho
this one is crazy
http://www.youtube.com/watch?v=HCbvW...ature=related#
Slapping a super charger on a 13b is like cross breading.
Just kidding. Thats would be cool. Look up the username "Alak" He Supercharged his FB. Looks pretty awesome with the blower sitting on top. Good guy too.
-Mark
Just kidding. Thats would be cool. Look up the username "Alak" He Supercharged his FB. Looks pretty awesome with the blower sitting on top. Good guy too.
-Mark
I'm going to skip commenting on some of the off base stuff here.
A supercharger would be a great way to increase power on the FD. Dave Barninger has done some on FC's and FB's and I am currently doing a 20b that will be supercharged to replace my 20b NA. I am not trying to make the same kind of power that some do with the turbo whether I could or not. I really want the linearity.
There is also the more interesting sound that a 13b with a supercharger would make combing the whine with the buzz instead of just muting the buzz...
A plus for me is that if I am only running 4-8 psi I will only use water injection and no intercooler.
I think its a great idea and hope you do it and do a build thread.
Gordon
A supercharger would be a great way to increase power on the FD. Dave Barninger has done some on FC's and FB's and I am currently doing a 20b that will be supercharged to replace my 20b NA. I am not trying to make the same kind of power that some do with the turbo whether I could or not. I really want the linearity.
There is also the more interesting sound that a 13b with a supercharger would make combing the whine with the buzz instead of just muting the buzz...
A plus for me is that if I am only running 4-8 psi I will only use water injection and no intercooler.
I think its a great idea and hope you do it and do a build thread.
Gordon
Good luck, I am going to have to watch this from the side lines. I talked to Logan about this same idea when we first meet. He said it is all very doable but at a price...
I am a little envious...
I think this is a very interesting idea, chemicool. Lacking low end power, adding a supercharger to the rotary will definitely change the nature of that engine. I am looking forward to your results....
I am assuming this application is intended for the street? With new low end power from the sc, I think this would be great for the street.
I am assuming this application is intended for the street? With new low end power from the sc, I think this would be great for the street.
Just as a note, http://wwwCamdenSuperchargers.com makes 9 and 12 inch versions (8-10psi) for the 20b and the cost of the kit is about $3400...
The pictures of the larger units are on a 20b.
Gordon
The pictures of the larger units are on a 20b.
Gordon
Rotary Enthusiast
Joined: Apr 2008
Posts: 1,092
Likes: 5
From: NZ
[QUOTE=chemicool;8914017]1. Rotaries have no power down low, so SC would seem to make sense for a rotary.
2. Yes rotaries flow a lot of air but there is a reason why even the stock turbos don't come online until 3500 or so rpm. QUOTE]
dont boost till 3500 on stock turbos lol? you must have a bit of a problem!
I boot from just under 2k rpm all the way to redline. Only engine mods i have is 3" exhaust and Apexi intakes.
2. Yes rotaries flow a lot of air but there is a reason why even the stock turbos don't come online until 3500 or so rpm. QUOTE]
dont boost till 3500 on stock turbos lol? you must have a bit of a problem!
I boot from just under 2k rpm all the way to redline. Only engine mods i have is 3" exhaust and Apexi intakes.
Rotary Enthusiast
Joined: Apr 2008
Posts: 1,092
Likes: 5
From: NZ
[QUOTE=96fd3s;8933406]
dont boost till 3500 on stock turbos lol? you must have a bit of a problem!
I boost from just under 2k rpm all the way to redline. Only engine mods i have is 3" exhaust and Apexi intakes. (iv got 3mm seals n stuff too but they wont make me build boost any quicker)
I boost from just under 2k rpm all the way to redline. Only engine mods i have is 3" exhaust and Apexi intakes. (iv got 3mm seals n stuff too but they wont make me build boost any quicker)
[QUOTE=96fd3s;8933414]
yes the primary turbo does start boosting a bit earlier but you don't get any decent boost until after 3K. No decent boost means no power down low. If you look at ANY dyno graph on this site you will see a common trend. No power/ no torque until around 3K. The slope looks like Mt Everest. Anyway, just thinking a larger supercharger would solve several problems. Low end power, heat, reduced weight.
yes the primary turbo does start boosting a bit earlier but you don't get any decent boost until after 3K. No decent boost means no power down low. If you look at ANY dyno graph on this site you will see a common trend. No power/ no torque until around 3K. The slope looks like Mt Everest. Anyway, just thinking a larger supercharger would solve several problems. Low end power, heat, reduced weight.