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-   -   SuperCharger for RX-7's based on the Tesla Bladeless Disk Turbine (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/supercharger-rx-7s-based-tesla-bladeless-disk-turbine-125445/)

kristopher_d 11-07-02 09:02 PM


Originally posted by ScrapFC
I have to admit to not having the greatest understanding of electronics, but couldn't you just use an electronic boost sensor to drive an amp circuit with a potentiometer to calibrate the boost pressure you wanted? It seems like it should be a pretty simple way of replicating the constant torque curve of a Roots-type blower. Just set for a specific boost pressure with a knob in the dash and feed more or less power to the electric motor to maintain the pressure, right? Seems like it should be almost as easy (and a lot safer) than having the thing come on full-tilt whenever you hit WOT.
Thank you for using some technical jargon to explain what I've been saying for days. Who give's a rats back-side how fast the engine is turning, I want 8psi of boost, and I want it all the time (may go higher (probably) or lower (yeah, right) later on).

Wheels 11-07-02 09:38 PM

Frank,

How about a just a replacement cartridge and compressor/turbine housings for the turbo guys? Seems like that should be pretty easy. You could probably design it over the weekend. I didn't look at the spreadsheet, so I don't know if the exhaust flow is there, but considering that this thing is supposed to be much more efficient than vaned compressors, seems like it shouldn't be a problem. Plus you don't have to worry about fueling (up to a point), where to fit the unit, or how to get the electrical system to support the unit. AND you could just have different numbers of vanes for different boost levels and many people would probably be very happy to replace their blown cartridges with a more efficient and hopefully less expensive design. I know I would.

I have my doubts about this actually working out (mostly because of the electrical generation scheme), but I'm going to put one of these motors (a little tiny one) together this weekend and try it out. Regardless, it's great to see someone trying to put something together for the RX community (especially something new for the older cars).

One last thing - you mentioned a number of times about the extra effort involved in doing this for an RX-7 vs. a 350. Which begs the question, why didn't you do it for a 350 first? At least for proof of concept?

-W

Crusader_9x 11-08-02 12:38 AM

what i said earlier about 10 - 20 posts ago, i was trying to say the same thing that wheels jsut said. i know i would be all over that if u could come out with that.

FrankGermano 11-08-02 07:56 AM

You guys are still missing the basic functioning and workings of a Tesla Turbine/Pump vs a standard or conventional unit (turbocharger in this instance). On a conventional turbocharger, there is the drive stage, and the compression stage - or boost side. Look at the guts of your turbo and you'll see what I mean. Now, take another look at my website (go back up the thread for all the links http://www.frank.germano.com ) and see the guts of a Tesla Pump - single phase. The compression comes from (basically) the internal spacing between the disks and how much you restrict the outlet volute. SINGLE STAGE. It is also naturally dependent on how much "push" or HP is driving the unit once you restrict that outlet volute, however, there is a balancing act there - overpressurize, and the fluid (in our case - air) will heat up drastically at this point. No damage to the unit, but, very unwanted in a supercharger/turbocharger application. So...to answer the last posts, could we just replace the "guts" of the RX-7 turbo? No. Totally different internal design paramaters. Now...the GOOD news is that the case is fabricated, as are all the air conduits and electronics, and the tie-in to the laptop. The unit is sitting in the space previously occupied by the battery. They - (I have two batteries) are remotely mounted in the rear hatch area. The case was (crudely) made out of aluminum, the disks are 304 SS. Size - 10" diameter; 5 primary disks. The DC pancake is conserv. rated at 12 HP and maximum (estimated) boost will be 18psi. I've got it set to kick in gradually at 2,000RPM at 2psi and add 2psi boost for every 500 RPM additional thereafter (2000RPM@2psi...2500RPM@4psi...3000RPM@6psi...3500 RPM@8psi...4000RPM@10psi, etc.). Since the boost curve is totally linear, the boost gradual in an extremely predictable level, it should be very, very smooth and the HP gains should just keep "pulling" without any serious "jerks" or unexpected shocks. My ONLY concern is with my engine, itself. I SHOULD have taken it appart and done a totaly rebuild, but, I don't want to go there - yet. I will in all likelyhood loose the seals at near full boost pressures...but...I wanted a new engine from MazdaTrix anyway. ;) Keep you all posted. Look for some results early next week, as we are working on it all this weekend.

FrankGermano 11-08-02 08:10 AM

Correction - 1.2HP DC pancake motor driving the supercharger.

patman 11-08-02 08:47 AM

something ive been wondering- with this refrigeration unit thingy you are talking about will we still need to add an intercooler? anyway i am glad to see you are making progress. keep up the good work bro!

Gstar 11-08-02 01:08 PM

I don't know anything about boost, but I would think that you would want to program the boost curve to reach 6 psi at around 5,000 rpms instead of 3,000 rpms. Then maybe flatten the boost at 6 psi from 5,000 to redline. See if a na motor can handle this before you try 10 psi at 4,000 rpms as you currently have it set.

OC_ 11-08-02 01:46 PM

Gstar: you dont want to have the boost 'curve' actually a curved line. i gave a link a while ago in this thred that says why this is. a linear line is the best.

frank, is the SC controller a stand alone program?

did u have a compression test done on your engine? that will tell you if you need a rebuild or not. 120psi per 'chamber' is 'like new' i think.

Liquid Anarchy 11-08-02 01:49 PM

I'm with the newbie. Running 18PSI on an N/A will more than likely pop it on the 1st run.

BUT, I'd say take it to 8PSI, with it flattening off at ~ 5500RPM (all the intake peices are open, and not , moving around anymore, so no sudden jolt of Max Boost)

OC_ 11-08-02 02:18 PM

http://pbgarrott.tripod.com/pgsupercharger/index.html

this guy says he can do 10 psi with his street ported NA engine. But im sure the 10 psi is maximum boost at redline.

10psi at 4000 rpm is going to be too much.

make sure you can give it enough fuel to match your boost too. the NA injecters have a really low flow rating and your going to out run them really fast.

what ever you do, make sure you run some high octane, and if you hear pinging, let off immediately. You might have to retard your timing too.

OC_ 11-08-02 02:31 PM

one more thing.... Please take pictures!!!!!

FrankGermano 11-08-02 02:33 PM

we'll cut the boost in half then...see what happens from there. The unit is finished. New injectors are in (high flow fuel injectors - not sure the rating right now). The engine's compression checks out as expected - pretty good for the miles on it, however, it was originally a MazdaTrix rebuilt engine, and no clue what those specs were. We'll flatten out around 10psi as suggested, because, with a simple input from the laptop, I can cram full boost in if we want. See what happens when we get up to around 6,000 RPM. This is gonna be a "cross your fingers" run, for shure. Let you all know the news when we get everything ready. BTW: my partner (MArtin Dorantes from Texas) wants to know how many seriously interested people there are who would actually PURCHASE this unit/kit if it actually works. Price will not be too scary (under 2 grand for starters). If I get him involved, we start working from our machine shop down in Austin...right now, I'm working on my own, from an R&D automotive speed shop up here in PA. It would be MUCH better and quicker to work out of Texas, however, I can only launch that project if we have a solid idea of how many pre-orders we will have. Email me directly at frank@germano.com if you have a definate interest in this package. Thanks.

Phu5ion 11-08-02 02:49 PM

Frank, i know this is still in it's early stages right now but what are you forseeing as to the kits "bolt on" possiblities? Right now you are controlling this thing from a laptop and have your main battery relocated to the thunk. i don't see relocating the battery to be a problem but what about the laptop? i don't want or have a laptop that i would put in my car permanently to control this pump.

For the final version, can you see it being pre-programmed or something to avoid something like this? i don't want to be putting down ~$2000 only to have to shell out several hundred dollars more on a laptop just to make it work. Don't get me wrong, i'm still stoked about having boost, but it's starting to sound like there are going to be more components involved than previously expected.

ScrapFC 11-08-02 04:43 PM

kristopher_d: I'm in complete agreement with you. IT just seems you have to use the more technical terms to get your point across with engineers. :)
As long as you're using a boost pressure sensor for feedback, it seems you should be able to program for any boost curve you want either in hardware or using a laptop for control.
I'm definitely interested. Unfortunately I don't see having $2K available for forced induction anytime this year. I'll be happy to pimp out my ride as a test mule. Otherwise, hopefully this product will find it's way to market and I'll be able to buy one (Or a few. I have a 6-cyl motorcycle that's just BEGGING for boost!) next year.
Thanks for bringing this out, Frank!

Draven_Pirate 11-08-02 05:29 PM

this sounds like a really good idea. i wish someone would give him the tech info he needs so he can get on with it.

kristopher_d 11-08-02 07:52 PM

I may just break down and apply for a credit card (debt, yuck).

Crusader_9x 11-08-02 08:12 PM

hey in one of ur earlier posts u said
"..I really think this project has some merrit, and I am going to persue it fully. So...what I am going to work on is -
1.) Supercharger
2.) Turbocharger
3.) Intercooler (bladeless disk system to replace the current intercooler either supplied by Mazda or aftermarket)..."
so with what u jsut said is makin a turbo with this design not possible or just not for he stock turbo housing? plz clarify

incendui 11-08-02 08:27 PM

I'm somewhat lost as to why this needs to be driven by a dc motor.I understand the compressor is different than a standard vane compressor, but its still driven by a spinning shaft.
if its most efficient for the shaft on a regular compressor to be spun by the exhuast side of a turbo, why is it beneficial for this to be run off of an electric motor instead (other than making it easier to fabricate)?

kristopher_d 11-08-02 08:35 PM

It's not more efficient to be run off an electric motor. It's easier to install in an NA.

It's not possible to put a tesla turbine disc pack in the stock turbo housing, but it is possible to build a tesla turbin driven tesla pump to replace the stock turbo.

Come on guys, read Frank's site. The rest of us have.

incendui 11-08-02 09:13 PM

heh, the front page of frank's site reads a little too much like an infomercial, I stopped reading there.

And i guess I misunderstood the scope of this project. with the main benifit of a tesla turbine being efficiency, dealing with all the power losses from converting between electrical and mechanical power just seems confusing. as a technology demonstration though, i guess it wouldnt matter. definitly hope it works out, always good to see new products for our cars.

Anarx 11-08-02 11:00 PM

with this post i've noticed something my japanese teacher talked about alot.. 'you american students are so spoiled in japan we have to think for ourselves and try to find the awnser ourselves before asking a question becuse it is so competitve over there.' IE ALL of the answers to about 75% of the questions now whould be awnsered if people whould just READ IE: the full post and franks website...

ok theres my rant

greasmnky 11-08-02 11:46 PM

Hey i do not have a car yet worthy of putting money into, but i am either going rx7(2nd gen) or supra(MKIII) if i were to get the supra would i be able to buy the unit and adapt it to my car? the price of 1,200 to 1,500 i can afford. once you start getting close to 2,000 it is much harder. So i geuss my main question here is, will the unit be stand alone?

Also once you get the program running a sugestion ( i am no programmer) could you set numers to each rpm increment and then hook it up to the throttle position sensor and give that a number, then when multiplied the computer gives the turbine that amount of boost? mabey im way off but i am juss trying to help

VashtheStampede 11-09-02 02:50 AM

video the test run. hehehe =)
shshshshsHSSHSHSHSHSHSHshahahahahaha... tink tink tink - poof.

seriously though. video of the testing would be sweet

annuerysm 11-09-02 08:25 PM

Frank would you mind curious rotorheads dropping by? I looked on the the map and I'm not very far from Lake Wallenpaupack

OC_ 11-10-02 01:15 AM

pre-orders are somthing that has always scared me. Being in the computer industry has taught me never to pre-order anything, and luckly, i didnt have to learn the hard way. I will buy one of these units if everything works out. But as for pre-orders, only if i came and saw what your doing in person... A pre-order is kind of like an investment in a stock to me. id like to do some research and see if my investment is going to have a good chance of return.

Do you need pre-orders to start production?

Could we get specifications on how the control works for the SC? I would like to write my own control program.


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