Curious about performance differences between running a 5-7 inch Surpercharger on a 13bt over running a Turbo setup

stuff like power response etc etc, My friends tell me cuperchargers are constant boost and the ability to not have to wait for a turbo to spool up would be awesome.

btw If i do go turbo it will most likely end up running around 20-22 pounds and i use the car for drifts

 

My buddy has the Camden 6" charger (atkins kit) and makes ~200 whp with a haltech.

Supers are not done as often, and generally make less power for more money. But hey, why just be another turbocharged FC.

 

The biggest issues with supercharging is that most superchargers are not efficient enough of a design or even (in some cases) able to run from 1000 rpm to 7000 or 8000 rpm.

Most superchargers are designed for lower engine speed applications in V6 and V8 configurations, which tend not to lend themselves to high engine speed applications.

Atkin's Camden set up is okay, and I have seen a couple other setups come and go over the years, but in almost all of them, the pully sizing is the biggest issue... getting that fine mix of power at lower RPM and being able to withstand 6000+ RPM.

 

Overpriced
Overhyped
Waste of time - a properly sized turbo will walk all over most of the SC FC's out there...IMNSHO


-Ted

 

The most you can drift with is 19 lbs After that the tytness fades


But seriously - 20-22 huh? What turbo and where'd that number come from? Have you done any research on cuperchargers or turbos for that matter? Cost, ECU options etc etc etc

I've had interesting discussings with some VERY smart professionals about the advantages of a chuper over a turbo becuase of how well N/A's respond to exhaust mods & porting but no-one is willing to open up thier check-book

 

Don't superchargers take up power to make power?

 

usually about the same as running with the air conditioner on

 

You will find that there aren't any good supercharger setups available for the RX-7. Anything you do will have to be totally custom.

In theory, a supercharger should perform on par with a turbosupercharger but in practice this isn't the case due to the poor blowers that are used. Good ones are expensive, much exceeding the cost of a turbo setup for the same performance level.

A properly sized turbo will not lag and will provide constant and controllable boost over the entire RPM range of the engine.

This means nothing. 22 PSI on the stock turbo is worlds different from 22 PSI on a GT40.
As do turbos....

 

^Yes, 22PSI on a stock turbo is definitely an overheating and dying world

 

Cost doesn't really concern me. And as for stock turbo, who said anything about stock turbo? Made this post on whether I should go the turbo lane (ie invest in a performance turbo) or scrap the engine and go the SC lane.

Also I am aware that SC's are made for low to mid revving engines, however having stumbled upon the camden charger, I automatically assumed that a charger made for RX7's would be able to keep up with the high revs that are associated with rotaries.

on another note, I have heard you can get a charger blue printed to have all the parts running in-sync almost flawlessly, I'm sure a process like this would over come a chargers rev limitation.

 

in someplace is for sale the SC plug&play.........

to easy!

 

I think it's a great idea. Don't listen to anybody on this forum because they are all "haters" and like to discourage really great free-thinking ideas like Direct Exhaust Injection and Leaf Blower turbos. Also, physics is over-rated and often proven wrong, such as that gravity scam and other myths. This is your big chance to prove to the world that a blueprinted Camden blower can push 20-22psi into a rotary engine to make the shift mad quick yo best drift car in the world. Since money is no object to you, why not spend LOTS of it on this project? You can do it!

 

What's a "Surper" Charger?


-Ted

 

they will keep up at 8k rpms. That being said the camden blowers are at BEST about 60% efficient. In order to do that you cant rotate the blower more than about 14,000 rpms. Which with a rotary with an 8k redline you are talking about a 2:1 pulley setup (which would actually give you a blower speed of 16k at redline). With an M90 thats going to be roughly 2L of air per engine revolution (M90 is 1L per revolution). Thats roughly a 1.5 pressure ratio, or about 7.3psi of boost at 100% VE.


But since money "isnt an issue" you can go with a TVS blower from Eaton that is over 70% efficient at peak efficiency, and size an appropriate blower for your application. A call to Eaton would go a long way in helping you decide which blower you need. then figure you are going to need a custom intake manifold, custom belt tensioner, custom pullies, standalone, and either meth injection (probably not best on a drifter due to the excessive slip angles and meth pooling int he resevoir) or a custom W/A intercooler. Assuming you can do the work on your own you are probably looking at somewhere in the neighborhood of $6-7k US. If you cant, most people really cant even if they think they can, you are looking at over $10k.


BC

 

The Camden S/C system is a ROOTS type system...
What of the hybrid, or centripetal (some say centrifugal) superchargers?
http://www.procharger.com/superchargers.shtml overview
http://www.procharger.com/models.shtml model specifications

Essentially a gear/belt driven "turbo compressor"... a turbo w/o the exhaust side...

 

- Yes, Camden uses a Roots type supercharger, which is actually a blower rather than a compressor.
- "Hybrid" usually means a supercharger that is built with components of another supercharger model, or a supercharger that is run by electricity.
- "Centripetal" means directed inward and usually applies to a turbine which is more commonly called "radial inflow", while "centrifugal" means directed outward and usually applies to a compressor. The two terms are the exact opposite of each other.
- It is not that a centrifugal supercharger is a type of turbocharger, but rather a turbocharger is a type of centrifugal supercharger. A turbo is a type of supercharger but a supercharger is not a type of turbo, similar to how a car is a type of vehicle but a vehicle is not a type of car. Make sense?

 

I got that...completely...
No...really, I did...

I'm gonna blame "Bill Nye the Science Guy" for miscombobulating my understanding of that...centripetal/centrifugal dyslexia! heh heh heh

but, yeah; wouldn't these fill the bill for efficiency, capacity, and r.p.m. capability

(Actually, hybid mean "Prius", and the Avalanche automatically steers for them - scary, but true!)

CENTRIFUGAL S/C's
how they work
http://auto.howstuffworks.com/supercharger4.htm

 

What do you mean when you say money isn't really a problem?? How much we talking here? 10k 20k 30 more?? to get anywhere near the power level of a turbo rx7 with 20-22 lbs of boost is gonna be alot. The cheapest way and something i'd like to see would probably be a vortec or procharger centrifugal type supercharger. Unfortunatly those have lag too. if you want a roots type blower they you'd have to custom fab alot of parts and somehow squeeze a large Weiand blower on there

 

I am currently running a paxton/nelson (centrifugal)setup, and it will NEVER make more than 10lbs of boost. I have never seen more than 7.5#- and would not dare to go any higher. Above that, and you are just pumping hot air. And yes, it is not cheap, nor easy.

 

IF money isn't an option, go for a 3 rotor.

 

Yeah, science guys don't always understand engineering all that well, and vice versa. My college degrees were a combination of the two, which is an advantage in some cases, but I am totally confused about subjects outside of my narrow focus of study, lol. Talking about Nye, have you seen the Nye Thermodynamics website?
http://www.gas-turbines.com/

Yes, but a centrifugal supercharger only makes max boost near the engine redline. A good ball bearing turbocharger will produce better performance across the engine rpm band. The main advantage of a centrifugal supercharger is that the boost is directly related to the engine rpm, which gives the car a better feel and responsiveness as opposed to the disconnected mushiness of a turbocharger.

Note on page 1 "In fact, the term "turbocharger" is a shortened version of "turbo-supercharger," its official name." Also, please ignore "no special shutdown procedure is required with superchargers. Because they are not lubricated by engine oil, they can be shut down normally" as it is not only misleading with respect to turbos, but it is also not applicable to all mechanically-driven superchargers.

If designed to do so, a centrifugal supercharger could produce the same boost level as a corresponding turbocharger. However, a traditional Roots type supercharger is designed to run well up to about 8psi, and can usually only run up to about 12psi before the losses become completely unacceptable.

 

IF money is no option, then buy us all a 3 rotor, and a cup of tea?

 

Ever used a IC + WI?

 

No, but such a setup would of course help intake temps AND add considerable cost to the system.

I have toyed around with the idea of using water injection, and using the microtech to control it. Just gotta remember to fill the bottle