ifryrice

Get over what? While everything you said was true, it seemed like you were responding to something said earlier but I'm not sure what or if it was about me talking about the paxton's powerband.

rotarygod

iTrader: (1)

No I wasn't aiming that at you. I was just merely throwing in the disclaimer for those who may want to nitpick at the details that I didn't get into. It seems like there is always someone somewhere who wants to find any little excuse to argue no matter how mundane.

ifryrice

Very true, most often it's from people who don't really understand either side of the argument too! The paxton units are definitely the way to go if someone is going to decide to bolt on supercharge, they can't be beat. The camden is just terrible in all regards. Even being a 'roots' blower for the 'instant low end' it still can't compete even with the centrifugal Paxton's lower boost in the low-end. Having said that, most modern turbos properly sized can spool sooner/provide way more peak than the older Paxton, but if you're looking or the unique factor or don't want to fab a lot Paxton is the way.

mike_merryguy

iTrader: (8)

its funny how you say don't want alot of power, I never dynoed the paxton but it is supposed to get more HP than the Turbo II about 30hp more, and that is with no other mods, if you were to port it, upgrade the fuel and exahaust I am sure that sucker could put out close to 250 even 300 if properly done.

If I were to do it again I would take a NA engine and rebuild it with TII internals for compressio sake, then keep the 6port system (maybe) it would be a decent street port, amazing injectors and new fuel pump with a better FPR, I would get a standalone, maybe a Haltech, get rid of the AFM and go with a 3 bar MAP nice open exahaust and call it a day at that most likely, that engine I would assume would be close to 300HP with a decent amount of money, of course no one can get over the initial cost of the supercharger itself, if you can get over that you are okay, the only problem with it is you can't get the proper sized pulley to get as much boost as a turbo, but you are still making more HP.... thats just me though I don't care about double digit boost numbers as long as I have the power to back me up...

ifryrice

Pianoprodigy once upon a time through just about everything under the sun at the paxton. Just from the sizing/efficiency (it is kind of dated), he was getting ~235whp which is pretty decent. But that was just about everything that could be done with it. At the efficiency rate of the Paxton at higher levels, the engine's AE would actually be slightly better so it is probably more beneficial keeping the higher CR rotors in there. Stock for Stock against each other, I would have to say the TII would still have quite a bit of an edge. Absolutely bone stock (i mean everything other than the blower) and you'd probably only be around 160.

In summary, if you're even thinking of supercharging do NOT under any circumstance go camden. Not even the unique factor makes up for that thing, you're better off staying N/A. If you're heart is set on a blower, find a paxton kit. If you want more than ~250whp without spending 3x more than the car's probably worth, go turbo. If you're made of gold, buy a twin-screw and have at it! (I think the highest dyno'd supercharged car with a graph/numbers available was the whipple 'vert making ~340)

swilson@assetworks.com

iTrader: (13)

I own the '90 vert with a Paxton SC that Pianoprodigy put together. It has the smaller SC pulley and an external pump and cooler for the ATF that runs in the compressor drive. The car has most of the additional mods mentioned in this thread. FD fuel pump, oversized injectors, SAFC II, cold air K&N air filter, Greddy BOV. I have driven it about 35,000 miles since I got it. The only problem I have had related to the SC was an idler pulley that lost a bearing. Got a replacement from Paradise Wheels that has been working for over a year.

For what is worth I plan on replacing the SC with a Garret T04e turbo and a Haltec E6K. I have been collecting the necessary parts for some time now. When I pull the trigger on this the kit will come up for sale so anyone who really wants one of these kits send me a PM and I will let you know it is FS.

rotordad

Well I like the car & at one time was going to get the Paxton/Nelson kit. The yellow is not my choice in colors, but it does your car nice. Now as far as turbo vs. superharger, to me it depends on what the is used for. I have supercharged & turbocharged cars, each one I like in different circumstances. So much for a little Camden love. I have had the camden set for some time now & love the way the car performs. The highest S/C rotary was way over 340 BTW there was a 13B with a custom GM 6-71 set up with a water to air cooler like mine running meth injection. I'm not sure of the numbers, but it was in the 500+ range I think from Aus. It was a 1st gen

Evil Aviator

What he said was not exactly true. He made that disclaimer because he knows that it is not true, but he also knows that 99% of the people on this forum would not understand if he took the time to try and explain everythng correctly. Therefore, he mixed apples and oranges in order to make a point that most people could hopefully understand.

I totally disagree! j/k lol

I doubt that.

Some people must learn the hard way.

rotordad

For some to say that roots blowers are crap they must be narrow minded & have no clue of what they are talking about. I am in no way insulting anyone with this comment, but I'm just stating that roots blowers have made big numbers for years. Just because the R&d isn't there when it comes to kits for the rotary powered vehicle doesn't mean they are crap. In the world of performance vehicles you have to expect one thing to be more costly than the next & to be prepaired to spend some money in the process. Without more intrest & money S/C rotaries will not rise to the bar that a good turbo kit may provide. As far as roots blowers Crap I say not, if you take a moment & look at an old nitro funny car making big numbers using a roots style blower I think you might respect thier capabilities. Like I said before I currently own both turbo & supercharged vehicles & have owned a few different types of supercharged cars so here's is my opinion again. The choice would be up to you as the builder to decide what the cars is to be used for & how much time & money you would like to invest. These different set ups will have thier own advantages in different circumstances.

Evil Aviator

Roots blowers are crap from an engineering standpoint, and those who think otherwise are actually the ones who are narrow-minded and have no clue of what they are talking about. That is not to say that there is no use for a Roots blower, just that it is archaic and many better options exist to produce boost more efficiently. Hopefully the new Eaton TVS supercharger will help the old Roots blower compete a little better, but then again I think the TVS better resembles the Lysholm twin screw design, even though it is technically considered a Roots type due to its external compression characteristic.

I can guarantee you 100% that a nitro funny car would make more power with a more efficient type of supercharger. The only reason you see Roots type superchargers on drag cars is because the supercharger companies sponsor the race series.

rotordad

Never did I say that there wasn't better options out there. I agree that the twin screw type blowers are more efficient & that there is other superior blower designs, but the fact still remains that roots type blowers make power. My brother had a 66 Nova witha 468ci & a 8-71 roots blower it made plenty of power & with a large Whipple I'm sure it would have made more, but it was hardly crap.

Evil Aviator

Well, if it isn't "crap", then it is whatever word you use to describe the worst available option. For example, the Yugo GV is one of the worst cars of all time according to Time Magazine. Some people would call it crap, even though it does get you from Point A to Point B.

mike_merryguy

iTrader: (8)

gaaaa you guys are killing me..... blowers + rotary = not much power, period.. yea other cars and other systems on pistons are great, and the simple fact is NO -> TYPICAL <- FC owner is going to spend the proper planning, time and money on a GOOD blower for the rotary.. some have tried I know, but in order to get a decent result the price tag would be between 10 and 20K I would assume...

pick a blower price ???

custom brackets ???

fuel upgrade ???

tranny / rear end / flywheel / starter ???

exhaust ???

custom 6port activation b/c of exhaust ???

ECU ??? 2k at least + a tune and rewire...

gage setup ????

oh yea lets not forget at least stage 2 clutch ???

anyway I am going to close this thread for now, you guys can go back and forth for 50 pages with this crap...

and I am not downing anyones comments I am no blower expert by any means and you all seem to know what you are talking about

I will post up the video soon, I have it in my camcorder I just have to convert it to PC from JVC format and upload it to you tube, I will add a link in my sig...

OK RX7CLUB why can't I lock my own damn thread anymore... stupid mother #$#(*^& son of a )(#$)*( PITA web site...
just happy I am not a vendor.... and your server is SLOW AS )&$#(* to boot.... man I am glad I don't come here often...

later all happy slow surfing...

rotordad

^^LoL Evil nice comparison. Also sorry Mike didn't intend to take over your thread, just simple discussion. By no means were we arguing & I'm sure we won't go at it for 50 pages. The site has been slow.

Evil Aviator

OK, then allow me to enlighten you...

First of all, your Paxton supercharger is a compressor not a blower. A blower, such as a Roots supercharger, moves air which is then later compressed by a restriction in the intake tract. Your Paxton supercharger compresses the air inside of it, as it is basically a turbocharger driven by a belt and transmission rather than exhaust gas.

Secondly, the reason your Paxton supercharger is not capable of a lot of boost is simply because the compressor is sized for lower boost levels. It has nothing to do with the physics of the design, which is actually pretty good. A Roots supercharger, on the other hand, is a much less efficient design than that of the centrifugal compressor design of your Paxton.

Finally, a Roots type supercharger is the bottom of the barrel from an efficiency standpoint on ANY type of engine, piston or otherwise. A centrifugal supercharger like your Paxton is considered one of the more efficient designs. There are advantages and disadvantages of every type of supercharger, but I am just addressing efficiency here.

Your math is pretty much correct, but it also applies to a good turbocharger setup, which will typically run in the $10-20K range. A supercharger typically costs more to produce due to the more complex drive system vs. a turbocharger, and some of the supercharger head units are more expensive to produce than a turbocharger, but that should only add $1-2K or so, which is only about 10-20% difference when you consider the price range for the entire setup.

I think the reason why you don't see quality supercharger kits for the RX-7 is because the typical RX-7 owner does not have the money to buy an entire kit outright, but can maybe afford to gradually piece together a good turbocharger system over time. You may have noticed that there are few turbocharger kits available for the RX-7 right now like there were 15 years ago when RX-7 owners were made up of wealthier people.

1. This is not your thread, it is a public thread in a public forum. If you want your own thread you will need to start up your own forum.
2. I have been on this forum since the late 90's, and you have never been able to lock your own thread unless your account is set up as a Moderator or Administrator.
3. Most of the vendors came here because for many years this was one of the top 10 automotive websites in the world. I'm not sure about current stats, but I would imagine that it is still one of the busiest automotive websites.
4. Yes, the forum is getting slow again, lol.

Evil Aviator

I should have mentioned that the Yugo GV still beats the heck out of walking or riding a bike.

rotordad

Evil the Paxton is a centrifugal type blower as stated in over 6 different supercharging/ turbocharging books that I have on my shelf right now. Blower is a term used for any supercharger, it may be a Centrifugal, Lysholm Screw, Roots or Sliding Vane. Both turbo and centrifugal blowers have compressors, just turbos have the turbine/ hot side which I know you already know. A big problem with roots blowers is the heat made, that's why I have a sandwhich plate style water to air aftercooler on my set-up. Evil is totally right piecing together a nice turbo kit is cost effective when on a budget.

Evil Aviator

Wow, I know more about engineering than at least 6 different book authors. I am quite humbled.

Seriously though, if one of the books is "Supercharged!" by Corky Bell, then he makes a point that an actual blower does not have an internal compression ratio, but states that he uses the blower, supercharger, and compressor terms interchangeably as slang in the book. If I remember correctly, Hugh MacInnes, one of the more prominent modern turbocharger engineers, has been known to call the Roots blower a "compressor" (as has Mercedes), even though that isn't exactly correct. Some of the other authors may actually lack the engineering background to know the difference.

rotordad

A common, but perhaps more correct, term for a Roots supercharger is "blower. One defining characteristic of a Roots is that charge air compression occurs outside the supercharger, in the space between it and the intake valves. In effect, it blows air into the intake manifold where it becomes compressed due to the system's pushing more air in than can flow out.
An Internal Compresssion Supercharger actually compresses the air inside the supercharger. It functions like an air compressor. The Powerdyne Supercharger is an internal compression supercharger. External compression blowers, like the well known GMC, and the B&M, Weiand, and other roots type blowers, are just air pumps. They pump air into the manifold and cylinders and the actual air compression takes place there.
Larger inlet. The air inlet on the Powerdyne Supercharger is 3-1/2 inches in diameter compared to only 3 inches on most other centrifugal blowers. The outlet duct is 3 inches in diameter while others are only 2-3/4, which permits up to a 77mm mass flow sensor with no modifications, and can be used with even larger units. These are very important differences because more air flow (which is possible with larger inlet and outlet ducts) means more power. And more power is what you get with the Powerdyne Supercharger system. This is from thier site as a plus to thier sys.

Yes I do own Corky bells Maximum boost, Earl davis S/C, T/C & nitrous handbook, Hugh macaines turbocahrger & Mark warners street turbocharging among others. the above statements would support your comment, but look at the last statement by Powerdyne.& yes the blower is a slang used to describe superchargers. If I can find it a good friend had a Vortech Blower kit as stated by them in the paperwork provided by them when he purchased it. Paxton & Vortech two of the leading centrifugal supercharger companies have been known themselves to use the term blower for thier products. You being an engineer dosen't change the fact that it is a commonly used term for such. The OP said blower because that's one term as well as huffer used, just as turbos may be called snails or hairdryers maybe not correct it's just simple that way. So I will not argue engineering or supercharger dynamics, but commend you on being informative.

mike_merryguy

iTrader: (8)

yea i know, like he said its slang, even the guy that owns the rights to Paxton calls it a blower, he is in San Marcos, Ca at Paradise Wheels, you can call and talk to him and correct him on the product that he owns the rights too and 'enlighten' him as well...


not correct, it can push higher PSI easy, just not on an RX7.. as stated numerous times already the pulley size had to be increased from the stock kit because if you redline the engine you are already past the redline of the blower causing the internal oil pump to fail and not lube the front bearings and then they fail and your unit goes pooey, with the smaller pulley installed that I sold the car with (in a box not on car) it was capable of 12psi, the Previous owner did in fact push 12 psi into his car and blow an apex seal, and the blower which is why i had to rebuild it, I don't know what the mustang guys get out of them, oh just search one guy has a 9 to 10 psi kit and i just saw a kit that cundracing sold in 07 that got 11 to 16 lbs...

so the paxton isn't the problem its just that it wasn't specifically designed for a rotary engine...


yea and most guys just go and buy a turbo car, not try to upgrade a N/A which is a MAJOR price cut as well

yea i agree and like i said if you already have a turbo car you can upgrade cheaper than from n/a...

1. i have my own forum and i lock threads all the time.. and yea I made the thread so its mine... i know its on a public forum, but if you post something YOU are still the one that posted it...

well i must have been one of those cause for the last couple months I could lock my threads under thread tools, maybe its just in the f/s section.. i dunno....

thats cool but I was only saying that b/c If I had to pay to use this site I would loose my damn mind...

i think they need some maintainance, or maybe jesus.. not sure but they need something...

Flash

iTrader: (2)

I read through all the bickering and no video ...

mike_merryguy

iTrader: (8)

crap i keep forgeting to upload it... i will do it i swear...

rotordad

Yeah I would like to see the vid. It's been a while since I have heard a Paxton rotary.

Evil Aviator

Thanks for taking it the way it was intended.

Paxton does produce industrial blowers. Regardless, I can check with my friends in the industry if you think this guy wants to hire an engineer to help him out on technical issues.

True, and in outer space my car can travel several thousand miles per hour if it gets a good shove. Meanwhile, back on Earth, this is the 2Gen RX-7 forum and all we care about here is the 13B engine unless otherwise stated. I was not intending to imply that Paxton made a mistake, but rather state the facts as they apply to the engines in our cars. A lot of people on this forum are under the misconception that they can add a different pulley to any supercharger to get any boost level they desire, and it bothers me when they spend thousands of dollars and a lot of time and effort chasing a false hope.

Many paying vendors left for exactly that reason.

Jesus would most likely work the best, lol.

As an automotive enthusiast, I would also like to take the time to also rag on you for not uploading the video.

mike_merryguy

iTrader: (8)

OK OK OK I finally got my damn camcorder to sync with the computer... so after MONTHS of waiting.. got the video on youtube... not the best I wanted to get a drive by but didn't have anyone to help me out...

lets see if this works.. here is the URL..
youtube DOT com/watch?v=7ZNHHUQTS7c

embedded???

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/7ZNHHUQTS7c&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/7ZNHHUQTS7c&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>