if u are gonna put a supercharger on chances are ur gonna have enough trrouble with emissions as it is. also if you are so concerned with performance to get this then youd have already pulled the air pump
just my 2c

 

hes making us a supercharger from hell and your complaining about him being 'off-topic' lol.. give the man the info he needs. hes the boss.. needs the infooo.

 

that would be nice if you could fabricate some bracket to hold it, if not.. ac or airpump.. hmmmm. like was mentioned before, for the NA guys the 5th and 6th ports wont be opening if you remove the air pump.. but they can always wire them open and then have that nice boost. then again i guess if you live in california the emissions testing is gonna rape you. but what about a/c.. i know in the summer time i always use mine.. especially if your rx7 is your daily driver. i live in missouri and it gets very humid/hot here. if you can fabricate that bracket i think that would be the best choice. IMHO, but hey whatever works i guess, ill buy it either way.

 

I have heard really bad things about the extra stress on the e shaft with belt driven supercharger units.......one of the primary reasons that I gave up the sc idea in the first place till you came along with the electronically driven tesla. You might want to do a search on superchargers and rx-7 in google and run over some of the enthusiast sites that review this problem. If it would cost more and could still be driven by an electric motor I would still be in.....if cost of new cpu driven rpm controller is really why you opted for a belt driven unit..... O well I am still really lookin forward to the unit for my N/A. FRANK IS MY HERO!

 

If you go belt driven, I'm going twin-screw. I don't want peaky boost. I like my nice linear N/A torque map. Again, forget tuing to engine RPM. Include a boost sensor with output jack, and control the S/C based on actual boost compared to dial boost. If this is going to be too expensive, you're over engineering it. If the motor is the real problem, then you're not getting the efficiencies you claim. I'm not trying to be an ***, just pointing out the apparent dichotomy (and of course, dichotomies don't really exist) so you can fix the problem.

 

I don’t think an electric motor exists that can sustain the guestimated 50,000 rpm the supercharger would have to run at and be a reasonable size and weight and have a low enough draw. Things just get hot at 50,000 rpm, or even 25,000rpm for that matter. I didn’t think the motor idea would work to begin with, but I thought I’d go along with it and hope there was some breakthroughs in electric motor tech that would make this possible, and there has been if you look it car starters now and from a few years back. I want a straight answer why an electric motor won’t work. That was kind of the beauty of the system in my mind.

 

When I did electric R/C cars 15 yrs ago the drag motors were doing 100,000 rpm; I don't imagine they have slowed down any since then. I guess it all dipends on how much torque you need it to produce as these were .05 sized motors (~2"x 4")...

 

i have a side question. if this has success with the rx7 will it be made for other sports cars e.g.. supra, 300zx and others?

 

i know they have electric motors that can do hella fast rpm. But can they do it constatnly? its going to have to be running all the time. Need something with a lot of torque, high speed and a rating for constant use.

 

and were gonna need a massive alternato to supply the eectric motor with the typeof power it needs to run at that kind of rpm, and as we know, our alternators suck.

 

^Bump

BTW, Mods. With over 4000 views, it's obvious this thread has a lot of intrest. Is there any possible way we could make it a sticky or something? Maybe retire the intake porting thread to the archive as to not take up any more room? Just a request and a suggestion.

 

oh ****, these things are gonna work like rc car motors (the electric ones)? i had a 10 turn ball bearing motor in my hpi s2000. damn that sum'bitch was fast. if this really is the case, and this supercharger works like this, are these things gonna be brushless or have some super-brushes that you dont have to tend to...

 

The problem with using an electric motor has several factors. My first concern is naturally getting the necessary current from the alternator. The second is, nothing is "free". To get an increase in HP for the Wankel, we are ramming allot more "air" charge down the intake at increased psi...that "energy" i.e. from the electric motor, has to have come from somewhere. To look at is this way, your AC compressor is probably eating up maybe 5-8 HP when it's on...the energy to run that compressor came from the engine, in this case, transfered through a pulley and belt. Anyway, the same would be true with the supercharger. I need to get "energy" to drive this unit from somewhere. I'm also concerned over the tight and limited space under the hood, and that was why we started thinking..."let's just ditch the airpump or something else and put the supercharger THERE..." thoughts. Simpler. That's all that was to that thought - not - that we didn't WANT to use an electric motor (DC pancake, which will easily drive the unit) Oh...the RPM range is not going to be much over 10,000 RPM. Where the heck did you guys get the 100,000 RPM figure? 10,000 RPM, maybe 12,000 RPM, and probably now an 8 to 10" diskpack with only 4 or 5 primary disks. So...for visualization purposes - think of your standard "Frisbee"...that will be roughly a good indication of the size of this entire unit. As a final little tidbit, we are also thinking seriously about addressing the waterpump issues here, as well. We already HAVE one of those little puppies (http://www.frank.germano.com/gi2.htm ) for ref.
Keep the posts coming. We got allot accomplished over the weekend, and I'll update you all later during this coming week. Thanks again for all the positive feedback. With over 4,000 views to this thread, I guess there is enough interest to make me believe we could sell these little babies when we get it right.

Frank

 

i have a thought. wich one will give you a straighter shot to the intake.. removing the ac compressor or the air pump? i cant remember where the ac compressor is, but i know the air pump is on the same side as the intake.. either way i think the air pump should go. id rather not sweat to death in the summer, it gets hot here!

 

ac compressor is on the right side under the power steering... and i agree, leave the ac, it gets too hot.

 

Why can't you bleed cat/6-port air from the Tesla SC?

 

there are already all kinds of ways to operate the 6 ports w\out an airpump and what the heck do ya need a cat for?
i kinda like the electric motor idea better too, but i already removed the airpump (damn thing) so if it goes there so be it.

 

We did allot of internet searching for anything out there as far as superchargers for the RX-7. It seems there were quite a number of problems with them, particularly the ill-fated "Nelson" unit which used the Paxton supercharger. It gave us allot of good ideas and ref. numbers to work from, though. If we can find a spot to mount the unit and electric motor, we'll go that route. Right now, Jeff and I (one of my partners in crime) are even considering ditching the space now occupied by the air intake box and placing the whole thing right there. So little "useable" space under the hood...

 

You should make it for people w/ bareblocks. Plunty of space there

 

Underneath the air cleaner is a muffler of sorts for the airpump bypass. Obviously on a performance tuned car, this is unneccessary. Also, the space in the FC engine bay isn't all that restricted. The Twin Screw setup I've been researching (on hold pending your ELECTRIC version of the Tesla SC) would have included all of the stock components, including the air pump. As far as emissions are concerned, in WA the regulations are in parts per million, so Super charging an N/A wont make it harder to pass emisions, but running richer will. As long as the A/F ratios are maintaned in the emissions range, you'll be okay. The moment you go belt driven, you've done nothing but build a more efficient centifugal super charger. By going electric, you get the best of both worlds. Constant boost levels like the positive displacement units, and efficient boost like the centrifugals. Don't sacrifice the quality of your product in the name of expediency. I haven't caught wind of the dogs barking at your heals with their own versions, so we can wait for you to build it right.

On an earlier note, I'm going to say it again: don't waste your time trying to calculate for a specific engine's VE at a given RPM. Your units purpose is not to figure out how much air the engine is using based purely on arbitrary constants which are obviously going to be different on every car due to various levels of modding and wear. Your unit is supposed to make boost. I still say to use a pressure sensor and some simple if/else logic to set the motor speed. Don't try to engineer for a specific engine, engineer for a specific result (boost = X).

 

well, if you go with the traditional pully and belt drive method, i guess thats cool. Tried and true. But wouldnt the HP loss be about the same driven with an electric motor (at least in a perfect world). isnt it just 2 different ways to the same end? i see you would need to get an upgraded alternator, but i feel thats a pretty small price to pay. They say you actually free up HP with electric water pumps....

 

I think I am beginning to see that it would be useless to just "build a better mousetrap" in the case of belt drive. Okay...we will concentrate on the DC electric drive. I like the idea of ditching the stock airbox and locating the unit there, as does my partner, Jeff. Let's see what kind of fabrication tricks we can come up with. At least the run to the inlet is there, and we'll just fabricate a stronger funnel/velocity tube to route it. Still gonna need some suggestions on the electronics and controls. I can do my best to "shoot in the dark" however, it may end up really generic if I am not designing this soley for my 88 N/A. I'll keep you posted.

 

if you are still looking for space for components then maybe just removing the old snorkel will provide quite a bit of space to rest components on the fan shroud. well that only works for those of us still using the stock shroud. or another place is to place it near, or in place of the overflow resivour.

i'm talking about any other components here like a small motor or any kind of electronics, not the actual unit. that will need to be, like you said, in the space near the stock air box.

 

what are the estimated physical dimensions for the unit?