BlackR1FD3S

Hi again guys.

Now, before you sequential/non sequential/single turbo guys start lambasting me about what I'm doing, let me explain first.
Then feel free to lambast.

Everybody, since the inception of the 3rd Gen FD, has stuck with the twin turbo or large single turbo idea, because, hey, it works and if it aint broke, dont fix it. But I've just had a rear turbo grenade itself on one of my FDs, because of a fatigued turbine shaft. It wasnt pretty, & it dumped a heap of oil out of the turbo seal. Rather than fix it, or bolt the set of Knightsports turbos on instead, I've been eyeing up a blower from a Supra which is sitting in the cupboard under the bench here. I know the blower can feed a 3 liter engine, and it would produce less under-hood heat than the turbos. Also, by using the correct diameter drive pulleys, I could gear the blower to produce positive intake pressure at as low a speed as I like (IE, little or no lag, like the turbo arrangement) and get smooth boost delivery from low down (maybe 1800rpm) up to max rpm. Thats the good points of the setup.

Now for the bad point.
It takes power to drive the blower. Pure & simple, its going to be a parasitic loss, in the same way the air con or power steer units are. Only more so, because it takes more force to turn over the blower than some of the other accessories. It can use the main oil feed lines the same as the turbos used to, and it doesnt need water cooling like the turbos, so coolant temps & exhaust temps should stay down below whats normal for a turbocharged rotary. Big problem is the power loss of driving the damn thing.

I know I'm going to get the whole "turbochargers give free power because they run off wasted exhaust, you dork" trip, so I'm prepared for it. I've googled the whole idea, & I cant find one example of a supercharged Series 6, so I'm guessing its not a common deviation. Looking at the blower sitting in there, I can see room for it, all the plumbing & brackets & it doesnt look too hard to set up. I'm confident the Power FC setup would be able to cope with it & overall there would be minimal system changes, as really, when you look at it from the ECU's point of view, it doesnt know or care what apparatus is providing boost. the main concern is that it gets boost. Which it will, albeit from a much lower point in the RPM range, and much more linearly than from sequential turbochargers, and without any lag like one large single would give. I guess it would be somewhat like having a single turbo setup with an anti-lag injector to prespool for low rpm/startline boost. Except more reliable.
Supercharger in question is a cam-over type, from a Toyota. I've got the specs for it here somewhere..

Thoughts? Ideas? Points about why this hasnt been considered by others??
Already begun making brackets & flanges & things..

Busted7

feel free to do it but there is a lot that i can tell you. I ran a 220 cubic inch supercharger and was turning it at 18,000 rpms and only achived 25 lbs boost. A supercharger for a 3 liter piston engine is small in comparison to what you need to make 10/12 lbs on a rotary. Plus you have to intercool it becouse it generates a lot of heat. I was running methanol so heat was no problem. Not always but most of the time if its not being done theres a reason. Not flaming just telling you i think you would be better of to go single and forget the supercharger. But if you do it and get good results that would be great.

Herblenny

iTrader: (13)

I think some of the problem with supercharger on 3rd gen would be.. space, money, and potential.

Space, I dont know where you are going to mount that thing w/AC/PS and UIM etc.. So, most likely you would need to custom fab.. Which would lead to.. cost....

But at the end, I don't know if you are gaining that much.. Stock turbos could easily surpass mid 300 RWHP and with similar cost to a supercharger, you could get an upgraded twins that will surpass 400 RWHP w/ min effort to install.

If you want to be different, go for it, but at the end, I would rather go buy a used twins for 300-600 than mess around/ experiment.

Mahjik

iTrader: (1)

Some discussions on the topic:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/3rd-gen-supercharging-251596/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/supercharger-turbo-fd-73164/

BlackR1FD3S

Well the fabrication 'cost' doesnt worry me, since I can do it myself. It comes out much cheaper for me than buying even replacement stock twins. As far as space goes, I can see room in there for it to fit, once I finish making the custom pulley to reduce nose length of the supercharger & pull out the stock twins. My car also has the airbox removed & smog/air pump system removed (as well at the cat. converter, etc- not emissions legal at all anymore, but the cops dont know to check for that in a backwater place like this. They also let vent-to-atmosphere BOV cars drive past, so go figure! )

Intercooling it is no problem either, as the boost outlet pipe will just hook up into the stock existing line into the intercooler, same as the turbos used to. It wouldnt generate as much heat as the existing turbos- remembering how hot the cast iron exhaust housing gets on those things, a blower will never get that hot. Boost control can be done in several handy ways- the electronic clutch on the front drive pulley of the toyota supercharger can be switched on & off manually via a small hidden switch by the driver- disconnect the clutch via the switch before anyone (such as the guys installing a new exhaust system for example) decides to go joyride the car.. For boost control while running, an external wastegate only needs to be plumbed onto the boost pipe from the supercharger, set to open at max manifold psi, (add a screamer pipe if I want to be noticed) and also add a BOV before the throttlebody throttle plates, to eliminate boost spikes or reversion when the throttle is shut. There doesnt seem to be any really hard parts to this, only a week or two getting it all mounted, then the finer points of controlling it & getting the boost when I want it through driven pulley size & gearing. When the engine is spinning at say, 1800rpm, the ratio of the drive & driven pulleys for the supercharger will need to be sized correctly to allow the supercharger to turn at such a speed that it begins to produce positive intake pressure. Whether or not it will build that pressure too quickly from that point & wastegate let off before say, 7500rpm, remains to be seen I guess. Because this blower is from a 3L engine, it should produce near stock manifold pressure & boost to the 13B, since the 13B is statically a 1.3L, yet dynamically it is more of a 2.6L while running. Yeah, the blower could be a little small, but think about this- it was rated for a 3L engine, with the stock size of pulley driving it. Once you start the under/overdriving experiments with ratio size, it will likely produce more capacity than it did on the original toyota, although maybe with a reduced lifespan. At AUD $400 worth of blower, they're cheap enough to be replaceable after a few thousand miles/Km. I dont need this to be the ultimate power setup either, just something that can give similar power to the stock turbo setup, boost from lower in the rpm range, & is driveable in city traffic & commuting, yet still has the guts for high speed highway runs sometimes. This is my roadcar after all- there's a race prepped SP in the shed for the racing stuff

And also, I've never heard an FD pull up next to me with a supercharger whining & a screamer pipe. I like being different! So thanks for the suggestions, I'll keep going with this & see what happens..

Much appreciated for the lack of flaming

TEDDER1

iTrader: (1)

Will it sound like an N/A (chainsaw) out the exhaust/back box without the turbo manifold to deaden the sound?

It probably would need resonators right?

BlackR1FD3S

Well considering the manifold will get replaced with a normal N/A type of header manifold, it could be a fairly loud car.. I'm not sure exactly what it'll sound like, but it will be interesting the first time it goes. If it sounds like the nitrous chainsaw from hell when under boost, that may be a good thing, since everyone over here is scared of the car & stays away from it (it has a 3" stainless exhaust system, no cat converter & an Apexi N1 exhaust on it at the moment) which is pretty damned loud. Also, most of the locals dont know what the car actually is (the Efini badging throws them off) so I always get the "jeezus your Corvette is loud!?" sorts of remarks. There are only about 10 FD's registered on the road in Tasmania, & they are a rare thing- most people dont know what they are, & there are no shops in town who can work on them, so this thing is an alien car to most other drivers. All the better if it has a strange exhaust note to go along with it I guess..
But resonators may be needed if its excessive.

hey how do I attach a picture on here?

bryant

sound like montgomery alabama.

KFC3S

Just out of curiosity, which toyota supercharger is it?
I dont remember any supercharged supras unless its been custom fitted from another model.

Is it a SC12 or SC14 charger? The SC12 came on the 1600CC 4A-GE engine.

Juiceh

iTrader: (4)

Because there are supercharger kits for the Series 4 and 5 that have been proven to be massive wastes of money for the power they produce. People learned from that failure and didn't waste the effort on the series 6....


The heat from the turbine housing is not what makes the air hot, its the actual compression of the air itself that generates the majority of the heat.

Some would argue that the engine is more like a 3.9 liter. I think there is a thread in the rotary performance section about it. Weather or not thats true is debatable, but keep that in mind when your sizing a SC for the engine.

Shrieking turbo > Whining blower

slo

iTrader: (1)

Here's a little heat for the fire,

"turbo's don't give free energy and don't use wasted energy"

It takes energy to pump exhaust through the hot side of the turbo's. Even large efficient turbo's commonly see double the intake pressure in the exhaust before the turbine.

Go to any website which provides calculators for injector sizes, that allows you to enter a BSFC, generic figures given for NON turbo piston cars are in the .4-.5 range (most efficient) as in power generated per fuel used, supercharged cars in the the .5-.6 range which is less efficient than NA, and turbocharged cars are in the .6-.7 range which is the least efficient.

Turbo charging is less efficient than supercharging, which is less efferent that NA when it comes to HP per fuel consumed.

This isn't just for piston engines, this same theory works for rotary engines although from all the testing I have read about rotary engine BSFC is less effected by turbo charging than piston engines.

I'm not endorsing you're idea, what you need to do is figure out how much air that supercharger can push at max efficiency, and what its safe speed range is, from there you should be able to figure out if its capable of making the kind of power you want, over the RPM range you need.

Unless it was making 700+ hp on the supra then its just to small for a rotary engine.

chemicool

iTrader: (1)

Hey, A fellow supercharger potential. I too have been thinking about ditching the twins and going with a supercharger rather than waste money on a big turbo. I have been looking into the Procharger superchargers. They have superchargers that are capable of making 2000 hp at very high cfm and max boost over 30 psi. Now of course those are too big and would likely drag down on a little 13b too much. But they have everything in between. I am looking at their C-2 charger which has been compared to a T-04 turbo. It will make very nice boost and I would think boost earlier and provide a flatter torque curve. All of the supporting mods are already in place on a 13b-REW so it would not be too difficult. As long as one can fab a mounting solution for the beast the rest is just tuning. Likely the airpump location would be the location. On my thread someone mentioned that Knightsports/ Monster Garage in Japan made a 500 hp FD supercharged. I am trying to get more info on that one. Good luck man.

RotaryDreamz

iTrader: (29)

one year bump.

chemicool

iTrader: (1)

Oops. Didn't notice it was a year old...but, big dreams die hard! Bump it again

Sarusanj

iTrader: (9)

It's funny this got bumped since Panspeed had a supercharged FD at TAS 09.

arghx

iTrader: (3)

people have done it on second gens, they are making in the mid 200s to the wheels. same thing with Rx-8's. I guess nobody has tried to go all out, but mostly because there's no point.

GoodfellaFD3S

iTrader: (213)

waste money on a big turbo? how do you figure?

500 hp on a single turbo FD has been done a million times, there are numerous bolt on kits to meet the need. my setup makes 500 flywheel hp without breathing hard at all.

Being different and unique is to be commended, I wish you guys the best of luck. But usually there's a good reason it hasn't been done before....... it's not like SC'ing is some voodoo black art, it's done all the time. Just not on rotaries

Alec

Advantages with going single turbo:
-cheaper
-easier
-done one million times before (tons of expertise and experience)
-the best way to gain more power
-you get to choose between a lot of options and possibilites
-a turbo (or two) is extremely efficient on rotaries


Advantages with going supercharged:
-special and unique


Still, I have to admit that I admire the person that are willing to mount a supercharger on their seven simply because its unique

Miata_mx5

The only supercharger that i think would work is a centrifugal type.

RotaryDreamz

iTrader: (29)

really looking forward to see your set-up if you do get a supercharger.

khoveraki

I disagree strongly with the whine of a supercharger. To me that screams cobalt, camaro, old muscle car. A 3 rotors beautiful pitch, IMO, is best N/A or with a screaming turbo accenting it. Not masked by the whine of a blower.

On the other hand I love new options explored for rx7s. I feel like a solid sequential system would be way easier to get a fun, linear powerband...

but let's see some videos of how supercharged 20bs sound

Kento

The problem there is that you have to significantly multiply the turbine shaft speed from the engine mainshaft speed (a centrifugal turbine needs to spin at speeds in excess of 80-90,000 rpm to generate meaningful boost). This causes even more parasitic drag on the engine, and the rotary has precious little torque to spare.

The Whipple is the type of positive displacement supercharger that all the OEMs use, because the screw design doesn't have the efficiency disadvantage of the roots-type petal blower at higher rpm. The problem is that nearly all the other OEM piston engine applications have comparatively tons of room to work with; the FD engine bay is a veritable sardine can. And there still is significant parasitic drag, especially at lower rpms (although Gordon's 20b powerplant obviously won't have too much problem with that ).

Kento

Not that you were directing this at me, Gordon, but unless the idea is really out in left field, I only state the problems and disadvantages with that idea, not that it's "bad" or "that it won't work." There needs to be discussion on issues or disadvantages that can occur with any new idea, otherwise it's misleading information.

chemicool

iTrader: (1)

Well I finally found a few pics of the Monster Garage Supercharged FD. Monster Garage in Singapore and Knightsports are working on this car. It is using a Rotrex supercharger.

chemicool

iTrader: (1)

I am told this car make 500 hp