jr69187

Well sterling thanks for the news i was just hopping some one esle made akit cause my friends say the camdem sucks too. They are so insane that they have taken the paxton off the gremlin and are trying to figure out how to make it wokr on a 12a. We happen to have a spare 12a froma junkyard thaqt isa good motor that will end up in a vw if they have thier way. But they are using it as a test setup aND THEY THINK THAT THEY MAY BE ABLE TO GET IT TO WORK. This is the scariest thing letting piston heads play with my spare motor. But what can say if they blow it they will then learn how to rebuild one. But they said they can bold the baxton up wiht an adapter plate and then we should eb able to put a four barrel holey on top and it should be able to run the fun thing is watch them try and make this adapter out of old adapters we have. then we will have to send off the pulleys and spacers we need to another friend who works at a place called sunspac and they will remachine new adapters and pulleys out of our junk adapter and pulley out of nice pretty new metal. Have you every heard of sam co transmission shop. Well we have another friend that works there and they are gonna do some work on my spare tranny and just charge me parts so i should have a tranny that can hold up if everything else comes to gether in about 4-5 mopnths i might be able to sell the parts to supercharge a first gen with a paxton wich should be worth soemthing to some one. But i am gonna ehad out to the junk yard and grab some more parts and two other possible charger as always nothing is set in stone until it runs. then we will have it. And i have been watching your discussion but i do not have the machining equipment. So iwas trying to find the easy way but as my friends \informed me it is better fun to do iut the hard way and there is always more pride into working on it your self. Same poeple who run 454 push rods in a 351 windsor. Think that si wrong well there is less than 10 thousandth difference and well it has worked for quite some time for them. well thanks and keep lettting em know what is going on.

mar3

iTrader: (8)

I guess since you popped your engine, you'll be on the fast track getting your spare 12A into your runner. The attachment is here to give you a professional point of view about the turbo vs. supercharger thing. I know you want to supercharge to be different but that's the same reasoning the civics use for the monster wings. Superchargers are big parasitic beasts on the low end. If you've got 300 ft-lbs of torque to deal with it like a V8, it's no big deal. The 12A makes 100 ft-lbs at PEAK which is well above 4000 RPM. Everyone but everyone will get you off the line and that's where 90% of the races are won. You will not catch a good car on the top end when it pulls 3 car lengths on you in the first 60 feet. The turbo let's you keep your low end to get out of the hole and then stuffs your ports and chambers at the high end to seal the race...and no, I'm not turbo'd nor do I expect to in the future. I'm gonna play with the juice!

REVHED

That's not quite true. Roots blowers provide full boost at extremely low revs which gives a smaller engine an elastic cubey type feel which will actually help performance off the line. It's the top end where they tend to run out of puff. Still, personally I'd rather a turbo.

mar3

iTrader: (8)

I couldn't fit the attachment and I thought I'd cleared that reply but--poof, wala--there you is. I'm going to manually type it into a .doc attachment tonight. Full boost is achieved where you plan it using pulley changes. Low to high boost is fairly linear, it's not all there and plateaus like the solid torque curve of a Pontiac. Change pulleys to get all the boost by 3000 RPM and you'll get spanked when it runs out of breath at 5000 RPM. Everytime...

faster7

Are you still talking positive displacement whipple/roots/Lysholm
blowers here? Or centrifugal?

Many positive disp blowers don't exactly run out of breath, but gear them high enough and you can have other problems that are VERY fun. Wish I still had a picture of what a whipple does when ran 60% past it's spec'd max rpm.

Pele

iTrader: (28)

What's the difference between those types of superchargers?

mar3

iTrader: (8)

The differences between those blowers is small. Whipple is a man who designed his blower with helical lobes to reduce the beating that typical blowers do to the incoming charge air with their straight or even twisted lobes. The air is drawn in from one end and compressed to the other end. It spits out the compressed air out the bottom near the back of the SC base. It's a more modern design that is also more efficient and expensive. Actual Whipple blower manufacturing tolerances are so good that Teflon lining is not necessary to get good boost pressures. One less thing to worry about wearing down. Roots is also the name of a man. His is the grand-daddy of all blowers. Been around forever. The lobes can be straight or twisted but the air is drawn from the top and spit out the bottom. I don't know the specifics of a Lysholm, though I do recognize his name. See the attachment (it's there this time, I promise!!) for the real deal. I ran some comments in red because they underscore the point I'm trying to get across to JR69187, although with his recent engine loss, I'm sure he's more concerned on whether or not he should try to get a 13B into his rex. As an asides, twin turbo beefed-up-STOCK-block Duttweiler Buick GN's run low 7 second 1/4 miles and can run reasonably well on the street. No supercharged engine can do that. Peace out!

.. It dawns on me that I may have the Whipple description confused with the Lysholm design. I still haven't unpacked my reference stuff so that was all from memory. It's too lengthy to retype, so I'll let someone spank me if that is the case. The facts are correct, I just can't remember for sure if the helical lobes design was Whipple's or Lysholm's...the design got NHRA Top Fueler's into the 4's, though.

mar3

iTrader: (8)

Does that help, supercharged gerotor pele?

Pele

iTrader: (28)

Kinda sorta... I'd probably need to take one apart... It's how I learn.

Sterling

There are alot of opinions out there regarding forced induction, but I have yet to read one, written by an expert or not, that fully, comprehensively covers all of the necessary foundation before the opinion is given. And the opinion always seems to be so very definitive. But the truth is that turbocharging and supercharging each provide such different characteristics in an engine, that it's a simple matter of application, personal taste, and how you drive that should dictate your choice on which forced induction set-up to use.

The faults I find with the artical is that time was not taken to explain that there are basically two different kinds of supercharger; "positive displacement" units, such as the roots and the vane; and a totally different animal - the "centrafugal" supercharger, which is essentially a belt driven turbo charger. It can see over 25,000 RPM, and is not positive displacement, but rather by it's design, like a turbo, multiplicatively increases boost with engine RPM.

The positive displacement superchargers like the roots all have their "spin-offs" on design (no pun intended). Before anybody started the manufacture of the twisted, or helical lobed roots blowers, Roots himself had been working on the concept, but was cut short due to WWII.
Eaton does now have in it's hold all of Detroits car makers, as well as Mercedes, Jaguar, Aston Martin, and who knows what else for 2002.They utilize the three lobed helical rotor design, along with a rear entry and a specially ported output designed to release some of the boost into the plenum before all of the rest is released from each passing rotor cavity.

My point is simply that, while all turbos in themselves are basically the same, and can very easily be catagorized as such; not all superchargers are the same.
Comparing the action of an engine force-fed by a turbo with that of one fed by a non-positive displacement centrafugal supercharger would well illustrate the parasitic losses experienced by the engine from the supercharger. It's a fact of life, but both of these units need to 'spool-up' to make any sort of power, so that parasitic power loss experienced by the SCed engine would be quite noticeable. But the parasitic loss from a positive displacement blower is not noticed as easily as suggested by the artical. You simply have nothing to compare it to at all, and the artical attempts to demonstrate this loss by comparing the SC to a turbo; which has to spool-up in order to be effective. Hell- we all know that. But it's a bit like comparing apples and orages.

Unless you have a dual turbo set-up, saying you'll have boost enough to even make a difference right off the line from idle is just plain bullshit!
Both of those vehicals will dog it without a good clutch dump. With the clutch dump, the turbo will leave the centrafugal supercharged car in its wake. -because of the parasitic power losses.

But now let's talk about the positive displacement blowers...They will also be a damn nasty parasite to your engine, but they will make useable boost (Enough to matter, BTW) at idle. So- take the turboed car and the roots SCed car at the line, and start them from idle. The turboed car will be busy catching its breath while the SCed car blows by it. BUT- dump the clutch like a real race...The turboed car will have the boost ready, but will not make the full boost it loves at its "G" spot untill it gets up there in the RPMs. The SCed car is ready to go no matter what, beat the other off the line, but probably be passed as the turboed car has reached its happy-spot in the engine RPMs.

All is not equal...Let us keep on going- no 1/4 mile **** - just keep going flat out for a while. Which forced induction system is going to get hotter? And thus lose it's oxygen-packed, charming appeal?
The turbo.

Let us visit the street for a night...The turboed car has to spool up...awww- too late!- The SCed car already made it to the light.

Now let's look at the old fashioned roots blower - a crude, only by todays standards, two lobed pair of rotors. These things changed little through their re-interest during their use in 70s top fuelers. Then guys like Bowers started giving them a bit of attention.
Todays roots blower really "is'nt your daddys blower", just like the Magnuson site reads. They are of exceptional design, and they've come a long way since the Allison-Detroit diesel helpers that Roots designed.
Often they were so inefficient when the engine was warm, that they acctually caused a loss of power!
Not so today.

This is not to put down turbos, or to shed a light on superchargers by saying, "Aww c'mon guys...look at them - they're different now!"

I would like to express my distaste for anyone who tries to persuade a readers view without all the facts, and not just some of the facts mixed in with his opinions.
When I opened the attachment, I knew two-fold right away it was gonna be written by some self-proclaimed genius who does'nt like superchargers, and thinks that everyone ought to get a ******* turbo for his car. First it was the introduction to the artical itself; followed immediately by the first few lines of the artical itself.

I've asked alot of questions about superchargers on these sites, and I'm always suprised at how little help I get. Perhaps it's because nobody here knows much about them. I really dunno. But what truely both amazes me, and infuriates me is just how many responces I've gotten by "pro-turbo" guys that are not in the least bit interested in answering the question of which I've asked; but rather seem to be bent as hell on some sort of ******* crusade to assimilate every goddamn rotary engine owner into getting a god-damn TURBO!

If someone asks about something specific, and you, the reader, feel compelled to demonstrate his options of which he may seem unaware, than fine -that's copletely understandable.
But when the person continues on his quest for information pertaining specifically to his original question, then help him do what he wants, even if it is just because he wants to be different.

mar3

iTrader: (8)

I'm not pro-turbo but there's a reason turbos are banned in the professional categories in the NHRA and even in most of the racing classes where forced induction is allowed. It's an unfair advantage where your SC "orange" is being crushed on a regular basis by the turbo "apple"......

Sterling

Hmmm...Cute.
So uhhh, that means you're not gonna help, right?
Even if you think my explaination of my perspective on the supercharger and the turbocharger (...and done in a real honest effort not to sound "pro-supercharger", I might add) is total crap; do you at least understand the bit about helping a person out with what he wants, and not-so-much what you think he ought to do?

That to me is the most important part of my previous post - admittedly for the selfish reason of wanting to be able to ask a "supercharger" question without being plagued by the "Get-a-Turbo, Man!" guys.

I mean, what do you even give a crap for, anyway?...You're a "nos man".

B00STED-300Z

Wow...these are some long posts, and I'm in no mood to read it all....Here's my take.

I'm not sure where these guys get the concept of turbo's not making enough PSI?? Most streetable S/C'd cars run nomore than ~14psi. You can run a fully streetable Turbo car with upwards of 25psi! I think it's a well known fact that turbos generally make MORE boost than a supercharger...

Now, you could save yourself a lot of customizing work by just dropping in a TII....but I'm not sure if you have the resources to drop in a new engine, or even know of any wrecked TII's sitting around. It's just a suggestion.

Felix Wankel

sigh....

B00STED-300Z

heh, did I disapoint you Felix?? :P

mar3

iTrader: (8)

It's just a matter of trying to save you some grief. Experience is the best teacher but it's not always the best, sterling. Evolution on the streets has relegated the SC to poser status or OEM applications. Turbos, nos and big cubic monster motors now rule. On the strip, they're given "protected" status because, in fact, they cannot honestly compete against a turbo or juiced mill. Why would anyone want to pursue them, then? To be different? You are absolutely right in one respect and I concede on the point completely. Y'all in the SC camp are asking for useful info and not opinions. Please restate what the application will be for the SC62 Eaton project. Race only? Street--stoplight to stoplight or industrial zones? Post it and I'll dig up my reference stuff and try to get some info tossed in here y'all can use like appx boost and HP ideas, if possible.

Sterling

Cool.
...Thanks.

Felix Wankel

No, I actually agree with you. Its just that you're about the 32985629386932th person to tell Sterling to ''just use a turbo''. I'm surprised his head hasn't exploded yet.

B00STED-300Z

Hah. I guess so...Turbos do seem much more comon on smaller engines. I think it's simply a matter of superchargers creating extra drag on your belt/pullies, and really you lose a bit of power to make it back up. Of course the low end torque is nice though! :p

mar3

iTrader: (8)

And actually, it was jr69187 that started this whole mess by telling the turbo guys that his buddies believed SC was the way to go for ultimate HP. How could they resist that gauntlet? Hell, it even drew me in and I'm a port and juice kinda guy... . Sterling is apparently already beginning on his SC project while jr69187 has to deal with the recent loss of his 12A which changed his experimental options, I'm sure.
....I like the audacity of BOOSTED-300Z barging in (admitting to not caring enough to read the whole thread) and throwin' his$.02 in, anyway. Qhattaguy!............

Sterling

YEP!...I give up!
I'll just have to sift thru the "Get a turbo, man!" crap when I ask about supercharging.
Felix is right...no sense in blowing a ...(GASP!) headgasket! hee hee.

...awww Gueeze.

Sorry - could'nt help myself.
Well, will all of you, Boosted included , all indulge my recent thread entitled "Math Whizes...".

Need all the help I can get, and it seems poor jr69187 has bailed on us here due to his recent misfortune.

rotorhead

i think everyone's all wrong. what you SHOULD do is skip the turbo, skip the supercharger, and mount a really big gas powered leaf blower in the hood of the car. instant boost and no lag!

faster7

Sterling, great post. We can get pretty long winded more on the differences among the positive displacement and other superchargers (was going to mention the glader in this discussion, but again, we're talking real world RX-7 stuff here. How likely would someone run one of those? ;-) just like we could discuss for days centrifugal compressor maps and turbo selection.

Mar3, I could very well add to some of Sterling's criticism of your document and of what that magazine guy said. But Sterling covered it pretty well.

I KNOW JR69187 and have for about 9 years. We'll get him going towards where he wants to go based on the real world.

Anyone that still has supercharger questions, shoot away. Sterling, sounds like there may be some rotary application real world supercharger ideas/questions you have to share!

Personally in most applications I feel the turbo is a better solution. But several supercharged setups have really impressed me, including one 13b 1st gen that was positive displacement. I was a wee bit overdriven, and at 1200-1400rpm in 1st gear with the clutch fully engaged could blow the tires off. :-)

Now, whoever got to thinking about leafblowers stole some ideas right from my head. Right now on sale are 345cfm gas units, time for some R&D. I think it'll take 2... Then again, I think they'd be sweet to plumb into an existing turbo system between the engine and turbine housing. Instant spool!

R

rotorhead

that'd be hilarious! some people reach for the NOS.... you can yank a pull string! then again... electric start...hmmm

spoolin

check it out.....picked it up yesterday for my friend. he's been building it for a while