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-   Rotary Car Performance (https://www.rx7club.com/rotary-car-performance-77/)
-   -   how does it work (https://www.rx7club.com/rotary-car-performance-77/how-does-work-830989/)

awddrift4 04-06-09 02:24 AM

how does it work
 
how the hell do you supercharge a rotary?
aren't they driven by crankshafts? which the rotary motor doesn't have
just wondering, looks crazy seeing a blown rotary =D

nillahcaz 04-06-09 03:16 AM

almost all superchargers are belt driven, The 7's have an eccentric shaft that is the rotary "crank"
But most SC kits use a serpentine or gilmer belt and may include pulleys.
Google img search reveals all

mono4lamar 04-06-09 11:28 AM

Racing beat did it...

rotarygod 04-06-09 11:35 AM

I know someone who is currently installing a Vortech on a 2nd gen. He's got pretty realistic expectations which would probably get slammed pretty hard on this forum.

doridori-rx7 04-06-09 11:50 AM

SC = E shaft walk = fail

good luck with that.

Evil Aviator 04-06-09 03:33 PM


Originally Posted by awddrift4 (Post 9103718)
how the hell do you supercharge a rotary?

http://www.camdensuperchargers.com/index.php?pag=305


Originally Posted by rotarygod (Post 9104495)
I know someone who is currently installing a Vortech on a 2nd gen. He's got pretty realistic expectations which would probably get slammed pretty hard on this forum.

This forum is boost-happy, and would generally not like a centrifugal supercharger setup because it does not make full boost until engine redline, and would therefore have less "low end torque" than a comparable turbocharger in most cases. Personally, I can understand why somebody would be willing to give up some low end boost in order to gain a more connected feel that makes street and autocross driving more fun. Besides, the centrifugal supercharger makes the coolest noises.


Originally Posted by doridori-rx7 (Post 9104550)
SC = E shaft walk = fail

What makes you say that? I have never seen or even heard of that type of failure in the 21 years that I have been around these cars.

awddrift4 04-06-09 09:28 PM

thanks for the info guys, i was just really curious on this after seeing a few blown drag 7s

rotarygod 04-07-09 08:45 AM

I've actually always been pretty anti centrifugal supercharger on a rotary (however I am in favor of twin screws) but his project has actually gotten me a bit curious. I've just had to think about some things. He's only shooting for 250 hp which isn't much compared to what many others have but definitely more fun than the stock n/a. The thing I like most about his conversion is that it's going to be a relatively simple installation. I don't think 250 should be too hard for him to get. I guess it's just wait and see. I may think it's cool or I may ride in it and hate it. One way to find out.

j9fd3s 04-07-09 05:25 PM


Originally Posted by rotarygod (Post 9107096)
I've actually always been pretty anti centrifugal supercharger on a rotary (however I am in favor of twin screws) but his project has actually gotten me a bit curious. I've just had to think about some things. He's only shooting for 250 hp which isn't much compared to what many others have but definitely more fun than the stock n/a. The thing I like most about his conversion is that it's going to be a relatively simple installation. I don't think 250 should be too hard for him to get. I guess it's just wait and see. I may think it's cool or I may ride in it and hate it. One way to find out.

back in the day one of the guys had a centerfugal SC kit (forget who made the kit!) on his s5, it went like a mild t2.

i see no reason 250isnt possible, back in the 90's we didnt have a good ecu solution!

rotarygod 04-08-09 10:25 AM

The old Nelson/Paxton kit which was very poorly designed did about 210-215 at the wheels. Not spectacular by any means but much better than stock. They did it with nothing more than a rising rate fpr, retarding the cas by a few degrees and no intercooler. Far from optimal to say the least. Those old Paxton units were ball drive systems which were friction systems. They were very inefficient mechanically and turning one by hand was a chore. Big losses from friction. Those old compressors were also volumetrically inefficient by modern standards. I think those systems only ran 7 or 8 psi or so. Something like that.

The Vortec this guy is using may be a bit small. It's a V5G and if he runs 7 or 8 psi he should be somewhere around the 70% island on the compressor map. It's not mid to upper 70's like many other systems but definitely nicer than the old Paxton map and other supercharger alternatives. I spun that unit by hand. It turns very easy. Much easier than the Paxton. I don't see why he couldn't easily top the old Paxton power mark.

I need to ask him what he's going to use for an ecu solution. He had mentioned an fpr , pump, and larger injectors but I don't think he's going to rely solely on that. At least I hope not! I do know he wants to run methanol injection but I need to ask him if there's going to be an intercooler or not. I can see each system being viable if done properly. He's pretty realistic. I also don't know what ecu solution he's going to run. I wonder if he can use an Rtek for a TII and a boost sensor and tune it for the supercharger? He knows more than I do about it though as it's his project. I don't see him much but when I do I'll ask a bit more about it. I'll try to get some pictures if I can. I don't know what stage he's at right now.

It does sound interesting though and with the old Paxton kits hitting 210-215 rwhp, and with the improvements over that old system with this one, I don't see why 250 is out of the question.

j9fd3s 04-08-09 07:12 PM

yep thats the one! since the new SC is so much better, i see no reason why more hp isnt possible.

since its so easy to do, the rtek ecu would be a great idea, even if you keep the NA box.

the old school way works great for fuel, but the rtek can do timing too


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