BadAssRX-7

ok been looking in to turbos and chargers, the charger is a much cheaper item to get. anybody have a atkins 5" and 7" charger? ive been looking at them and have quit a few questions
David

phr34k3z

I think that the rotary works alot better together with the turbocharger compared to the super, quote me if im wrong.

Jeff20B

iTrader: (13)

I have to agree with f43k35 or whatever your name is

The turbo being driven by the forceful exhaust pulses of a rotary are better than a shaft driven supercharger. However, Mike B says the Atkins supercharger is the best bang for the buck. I agree with Mike too.

As for what mod I'll be doing... I think I'll go with a Camden from Atkins. I need more bang for my buck. My cooling system is overkill for my gutless engine, so it might be ok for an SC.

MarkPerez

The bad side of turbos is the under hood heat,burns up engine
faster,i read in the want adds you know "rotary,rebuilt,rebuilt
turbos"etc,,not to mention turbo lag,where as a supercharger
fits under hood,no heat problerms,instant power,will bolt right on
top of carb, i like,and will buy a charger when i get to that point.
Er carb will bolt on top,i wonder if hood will rubb on 1st gens w/
nikki.or would a holley have to be used ??

peejay

Superchargers are hard to intercool, and Roots-type blowers are typically VERY inefficient so they badly need intercooling. Extremely hot intake air = detonation = honey, can you come pick me up?

BadAssRX-7

the atkins s.c. kits need hollys

Elevation7

Well if you think of a rotary they suffer from low-end more than anything.

You SC the block, you've got low-end you need, and you street-port, you've got the high-end you need.

Atkins wants to sell their product, but I have talked to a few people who Supercharged their 13B's and they said they liked it a whole lot better.

An upgraded radiator, and the proper fuel set-up should be able to handle it ok, I'd think.

I'd probably call Atkins, or talk to Corky Bell about it, and get his opinions.

Sometimes, according to Corky, intercoolers aren't always needed. I saw a wrtie up once where they used a turbo running about 9psi on a Mustang and it wasn't intercooled.

Elevation7

One other thing:


I bet there's some good stuff in there about it.


Here's the link:
http://www.amazon.com/exec/obidos/AS...049016-6716022


And for this one:
http://www.amazon.com/exec/obidos/AS...049016-6716022

Jeff20B

iTrader: (13)

I might be working on a supercharged RX-7 today. We need to retard the timing a little, and set the Leading/Trailing split to 10*

rotonomo

The problem with a wild cam (or wild porting) and forced induction is that at lower RPM's, there is a tendancy for the turbo or superchargre to blow the intake charge right out of the exhaust ports due to the wild overlap. This in turn makes your motor an inefficient slug down low.

Gordon

I am currently using one of atkins rotaries 5 inch supercharger(of course I wish I had gotten a 7 inch) it is the best bang for the buck I have ever done. Personaly I had to hammer in my inner fender wheel because I had a rx2 but the unit bolts right in to a rx7. You need a tap for the oil line but you use it with the engine in the car but other than that only basic hand tools are needed. I was using a holley but went to a barry grant road demon carb and even more power. Yes the engine heat is more but my griffin radiator handled it okay and any forced indection will give you more heat. I went to the supercharger because of the price, low torque of a rotary, the constant up keep on a turbo and I simply do not know anything about all the little things you need to run a turbo. I have a water injection in my carb with is really only a windshield wiper motor with a sqiuter like a fuel injector cost me 160 from spearco. email me mrmasda@aol.com if I can be any help

kylekyle

Supercharger is very expensive, do you have some used????
I have 12A 4 port motor, streetported

Aico

When do you need to rebuild a SC? And what would the rebuild cost?

Sterling

Hey, Gordon! You got one!?

Jeff...Spill already, would ya?

Jeff has met David Atkins, and has a friend that had to have his SC rebuilt. I don't remember why, but I don't think it was a design flaw. Jeff knows more than he's letting on!

I talked to David over the phone...I think he said the 7 inch was a 112 cid unit.

I'm mating an Eaton M-62 unit from a Pontiac Bonneville to my 12A, and it's only 62 cid. (Will have to spin faster) I just did'nt have the money...Well a deal on a milling machine came along instead, and I said, "Suuuuure...I can make that! (meaning the plenum)."
There the machine still sits, as I have yet to add a 220 line for it in the shop!

According to Mike Bassi @ Mazspeed, he did up an engine with a Camden SC, and it robbed the engine of 70 HP @ peak RPM.
This is a typical occurance, though, so don't let anyone use that fact against your choice od forced induction! The Eaton is a much newer design using helical rotors, rear entry, and alot of research and development for flow dynamics, and it still robs 45 HP @ peak. Magnuson under lisence takes the Eatons and ports them for optimum flow, ect, and they don't get much lower.
Parasitic power loss with an SC is a fact of life.
But you'll never miss it.

For really wonderful math and group discussions on SCs here, do a search for "Eaton", and "Superchargers".
Lots of great info there and people really explained all about the science and physics of boosting an engine. That stuff is necessary knoweledge whether turboing or supercharging....KNOW THY ENGINE NEEDS.
Seems alot more 'productive' discussion is generated by a "what-if-I..." post; even if it is about SCing.

But ask about supercharging in general and there just always seems to be an immediate knee-jerk reaction by the turbo-proponents.
After you do alot of backreading, book reading, and sifting thru the bullshit, you see that about 66.6% of the "educated opinions" are based purely on something that simply stuck out in the 'gifted' persons mind as he read someone elses post a long time ago.
Asking for info here about supercharging can be like asking about dropping in a 350 under the hood.

Jeff20B

iTrader: (13)

Huh? Spill what? lol!

Wattz

Can you supercharge a 12a?

And I'm guessing that if you super charge it, you need to mod the exhaust and everything too?

Uh... To make it simple, what all do I need to buy in order to supercharge a stock 12a? And what is best and works best together?

MIKE-P-28

iTrader: (1)

Another one from the dead...

My thoughts on it, superchargers dont give a lot of power in a rotary for the great expense they are... I'll go turbo anyday, the rotrays main thing that makes them so turbo happy is the fact of their exhaust velocity, theres a TON of wasted energy there....

Besides who wants to change pulleys to change boost? Ill pass

Sterling

From Mazspeed; and a thread I started inquiring about the Camden kit...

RE:Opening a Can o' Supercharged Worms...(again) (modified 0 times)

Jeff20B

Heh!
My friend (Tom with the black RX-7 pictured on my web page) got an sc kit put together by Skip while he was working at Mazdas and More. Let me just say that Ken and the others used their own oil line setups and siezed the sc bearings evry time! Well, my friend and I didn't lnpow this, but I had a rotary style gut feeling (I always get those when I'm doing cool rotary stuff) about the oil line on my friend's sc which he chose to hook up like Ken's.

I've been to Atkin's shop a couple times with my friend after his sc locked up on him 3 times! The first time we went there, Dave told us that it was an older unit with the slant cut gears in it which had slipped a tooth (the rotors went slightly out of phase he said). He replaced them with straight cut gears and all was fine, until it locked up again. It literaly smoked the belt (the engine was still spinning but the sc wasn't. No damage to the belt or pulley)! So we took it back and Dave didn't charge him anything to replace the bearings. We got it back and drove on it quite a bit. All was well, but then one day it locked up again! This was the third time! It stranded him at work. I think I finaly got through to my friend about the oil line. We took it back and it was finished the next day (that was quick!). He got a fitting from Dave for the oil pedastel (I don't remember if we got one from Ken, but we ended up using the Ken style T fitting on the oil pressure fitting which is way too small. High enough pressure at 90psi, but low flow/volume), and Tom got it running at his work. It's been running ever since. When we were at the shop, there were a couple other scs on the bench which had failed due to the owners using a different oil line. The moral of the story is to use the oil lines and fittings that come with the kit! I can't stress that enough!

Well, that's the story as I remember it. I really would like to get an sc for my REPU's gutless 13B. Maybe it'll finaly have some power!

Two lobed rotors which look like peanuts.
Straight.
Teflon "apex" seals hehe.
Drive gear pitch? Dave redesigned them for a straight cut. They are stronger. Does that answer your question?
70HP to drive it? You'd never feel the HP loss. Infact, my friend's RX-7 can break the tires loose in gear, with LSD, on dry road, with two 170LBS adults, with just the flex of an ankle! Heh, for comparison, my REPU can bearly break one tire loose, in gear, on wet road, with only one person in the cab (I weigh less than 170lbs) + an empty bed, and only after the secondaries open! GUTLESS! No wonder I've been trying all these experiments on my engine. At least my low end torque is better than a 12A
Mike B has opinions about everything! From disliking the RX-8, to disliking the sc. Everyone is entitled to their own opinion, and I happen to like the RX-8 and the sc. As for engineering of the sc, Dave has made some improvements. I personaly would much rather get an sc than a turbo. That's my opninion, and I'm sticking to it!


Nov 15, 2001 03:18:05 P.M.

(That's what.)

Jeff20B

iTrader: (13)

Ah that's what you meant!

My friend's 5 inch SC is still running great. By the way, the belt did actually get damaged on the serpentine ribbing in that one spot where it locked up (and smoked lightly as I could see it with some halogen lights lighting our work area that night). The belt had a weak spot and ripped through one day one the highway. Well, I had to go and pick him up, take him to Schuck's and he quickly found the correct replacement belt before the dork parts guy could even mumble and ask the make/model etc (not a bad thing to use common automotive belts in my opinion). We got back to the car and tossed the new belt on and away we went. It's been fine ever since. This was some time in Feb. He fired it up Saturday and we went for a spin.

Light throttle = very smooth response and drivability. It seems well suited to towing like in an REPU for instance. Tom's got an aluminum flywheel from RB, so it's not as forgiving as RB's steel one, but you get the idea.

Heavy throttle = extremely fast response and posi action on dry roads that I've only ever experienced on wet roads previously. The sound is really cool too! I worry about things like motor mounts and stuff on that car hehe!

By the way, he's going to get a 7 inch very soon. It's going on his '77 REPU. I wonder how that'll run compared to his FB? The REPU has a GSL-SE engine and the high geared diff at 3.90 or so. The GSL-SE engine has a Nikki carb and modified 12A manifold. We aren't quite sure what the previous owner had in mind with that mod. Oh well, it runs with about the same low end as my truck, but my secondaries feel better when they open (his high end is still better though).

82streetracer

iTrader: (1)

I am going with a centrifugal one so that I dont need to change my exhaust or intake.

well I have to change the carb and fuel system but thats it.

Sublime

i would like to SC my '79 12a (stock) would it be worth it?? i know the air is gonna be pretty warm and i'll lose alot of feul-air mixture. (higher temp.=less volume) , but, will the SC make up for the in-efficentcy?

me=no money=tryin to get the most for my cash

Sterling

Run a search. You have few choices for your car, unfortunately. There is alot of info in the old threads.
Not trying to be crappy to ya, but if everyone started doing the "broken record" thing with all that info everytime someone came along and asked basic questions, we would'nt have room or time for any other discussion.

So read all the old **** and then post more specific questions.