twin chargeing a FC?
#51
Rotary Revolutionary
iTrader: (16)
What! you didn't know?....
Efficiency = horsepower / dollars
In which case supercharges lose big (which was basically the point of my other post).
To Rotary God:
Thanks for all the info on supercharges, I had no idea it was that deep! That being the case I don't pretend to have the knowledge to argue that there isn't a theoretical supercharger setup that would be great for a rotary motor, I'm sure that someone could design one.
However, we (at lest me and the OP) live in the real world where theories and postulates take a back seat to practical solutions, and as of right now there are now supercharger setups that can fit in that category.
There might a few that are affordable, but what kind of performance do they offer? There might be a few that offer great performance, but how many turbos and and stand-alones could you buy with what they would cost?
In Summary:
Options are great, and I applaud anyone who is working to give rotary owners more choices for upgrading power. But the fact of the matter is, superchargers (for rotaries) either need to offer a much greater performance advantage OR be priced comparably to a similar performing turbo setup to be a practical solution.
Efficiency = horsepower / dollars
In which case supercharges lose big (which was basically the point of my other post).
To Rotary God:
Thanks for all the info on supercharges, I had no idea it was that deep! That being the case I don't pretend to have the knowledge to argue that there isn't a theoretical supercharger setup that would be great for a rotary motor, I'm sure that someone could design one.
However, we (at lest me and the OP) live in the real world where theories and postulates take a back seat to practical solutions, and as of right now there are now supercharger setups that can fit in that category.
There might a few that are affordable, but what kind of performance do they offer? There might be a few that offer great performance, but how many turbos and and stand-alones could you buy with what they would cost?
In Summary:
Options are great, and I applaud anyone who is working to give rotary owners more choices for upgrading power. But the fact of the matter is, superchargers (for rotaries) either need to offer a much greater performance advantage OR be priced comparably to a similar performing turbo setup to be a practical solution.
#53
Clean.
iTrader: (1)
A twincharger is good for getting power both down low and up high, but so is a twin turbo. I'm guessing it hasn't been done for the FC because there just aren't too many twincharger setups out there for anything. And supercharged RX-7's aren't all that common to begin with. Plus a twincharger might (or might not) be more expensive than other ways.
#54
Rotors still spinning
iTrader: (1)
They used a PSI "B" series twin screw supercharger:
http://www.psisuperchargers.com/viewproduct.php?id=29
http://www.psisuperchargers.com/viewproduct.php?id=29
#57
Rotary Freak
iTrader: (1)
I always figured that since rotaries have hotter exhaust temperatures, a turbo would be more efficient than a supercharger (and moreso than in a piston engine) just because there's more energy there to take advantage of through expansion, even if it does constitute an increase in backpressure. In addition, because the exhaust ports are so close together, the turbo manifold can be much shorter, more compact, and more direct to better utilize the exhaust pulses than a similarly sized I4. This could be more than outweighed by other factors in supercharger design vs turbo design, but to me it seemed the dominating factor if cost were not an issue.
#58
Full Member
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Join Date: Sep 2005
Location: LA
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I always figured that since rotaries have hotter exhaust temperatures, a turbo would be more efficient than a supercharger (and moreso than in a piston engine) just because there's more energy there to take advantage of through expansion, even if it does constitute an increase in backpressure. In addition, because the exhaust ports are so close together, the turbo manifold can be much shorter, more compact, and more direct to better utilize the exhaust pulses than a similarly sized I4. This could be more than outweighed by other factors in supercharger design vs turbo design, but to me it seemed the dominating factor if cost were not an issue.
#64
Lives on the Forum
iTrader: (5)
Okay I've gotta chime in here! I "own" and run a 7" camden and have probably done more r&d than any camden owner (with no support from atkins I might add, but they'll get another opportunity). The blower has been used on a stock gslse engine (hmmm, blew that up though). Then it was on a port gslse engine with s5 internals. Now it sits on top of a 1/2 bridge 4 port with intake port matching and FD rotors. I have run a variety of carbs in the pursuit of experimentation (600 holley, 850 holley, 650 demon, 870 holley, 650 edelbrock--my favorite). My next carb I would like to find is an old 70's carter thermoquad. The engine will take the bigger carb and it helps maintain boost at higher rpm. i have used pulley #'s 6,7,8,10. The tiny 'lil #10 gave about 20lbs boost by 2500 rpm but caused an incredible amount of heat and I could not keep the belt from slipping so it couldn't hold boost. I alternate between the 6 & 7 usually. here I get 10 psi without too much heat. I will be relocating my water methanol injection to the lower intake in the spring along with spraying nitrous up top. I have run both the SE dizzy and now currently a locked dizzy, in the spring I am returning to a normal dizzy with modified weights to have the mechanical advance max out later in the rpm band. I "estimate" that I am running about 200+ rwhp, I had naturally hoped for more. I have to note, and I stress "HAVE TO NOTE" that I rode in a fc (Max's car) with this engine in it and a T51 turbo spooling 23 psi. It had some lag, as any turbo does, but holy **** did it push you in the seat, was dyno's at 400+ rwhp. So I have toyed with the idea of blowing through my camden so I could get the best of the camden (torque) and combine that with the efficiency of the turbo. Hypothetically I figured that the boost from the turbo would overcome the parasitic loss of the s/c and bring about a net gain. Issues, need some custom exhaust manifold capable of routing the turbo way up front of the engine and to the right of the s/c (basically in between the rf fenderwell and the the headlight. Then there are plumbing issues. Carb modifications I can handle, dizzy mods as well. I determined this to be price prohibitive unless I could pick up a large t4 or bigger for a song. Son in the meantime it will stay as is. Future will instead call for a standalone, T51 or comparable and a predictable 450 rwhp with no gamble. This will however be a couple years away ($3000+). So for this year, spray 75 into the charger (already have the kit), relocate the water/meth ($50 maybe), watch the wrecker for the next test carb ($100 including rebuild), street tune the carb using a wideband (already installed), then dyno and I will certainly see 300 rwhp. Do I think think twincharging would be cool, hell ya! Do I think it would work well, definitely! Do I think it is the best bang for the buck, OH MY GOD NO! But, if someone had a healthy engine, found a tbird supercharger, ported it and did a custom mount, had a big holeset turbo (wresker special, $100) and possessed good welding/fabrication skills and finally had a decent standalone, it could work great, but we are talking about lucky finds and applicable skills to make it cost friendly.
My advice, standalone and a trubo that is appropriate to the engine build and driving application. You'll get a reliable 300-450hp car.
Didn't do a word count, but I am sure this matched some of the previous, too tired to bother proof reading for spelling.
That's my 2 cents
Rotarygod, you're right about installing an appropriate sized blower
http://videos.streetfire.net/player....7-A8552F6EDCF6
and another http://www.youtube.com/watch?v=Cz8XM-Pjllk
Been done not on a rotary though http://shell.deru.com/~sgn1/AW11/mod/gsa.htm
My advice, standalone and a trubo that is appropriate to the engine build and driving application. You'll get a reliable 300-450hp car.
Didn't do a word count, but I am sure this matched some of the previous, too tired to bother proof reading for spelling.
That's my 2 cents
Rotarygod, you're right about installing an appropriate sized blower
http://videos.streetfire.net/player....7-A8552F6EDCF6
and another http://www.youtube.com/watch?v=Cz8XM-Pjllk
Been done not on a rotary though http://shell.deru.com/~sgn1/AW11/mod/gsa.htm
Last edited by Aaron Cake; 12-07-07 at 10:11 AM. Reason: Merge 4 posts
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