Eaton vs. Autorotor

backtobirds

Registered User
I have seen some comparisons of the M90 and Autorotor, but they were biased, and a stock M90 was used. Anyone have any experience or thoughts on these two? I know the benefits of a twin screw blower, but not how it stacks up against the MPIII blower. I will definitely be upgrading the supercharger, just doing a little research first. Thanks.
 
well.. if you know the benefits of the twin screw, you just answered your own question.

right now there are some MP3 cars laying down some serious numbers and E/T's.

It's not too pricey and is a significant upgrade over a stock M90 obviously.

The current AR was 1.7L, Dave is working on 2.0L right now. Which obviously isnt a huge difference, but it will do more with "less".


So right now numbers wise, they would appear to the casual viewer to be similar.

the best answer would be efficiency.


You are just going to go further and do it more efficiently with twin screw. thats the best way to put it lol. and what Dave has to offer is about to get better for the same price.


However, if you are not fully dedicated to the SC platform, you might want to go mess around with a magnum ported blower for now only because of $.

Like me, ill be getting an MPII to mess with until I can get a new 2.0 AR.


If you are dedicated to making some serious gains, drop dave a line :) .

I dont think anyone has been disapointed with switching to AR power, whether it be a fully built engine, or completely stock.

this topic has been beat on before, but im sure some more will chime in with their feelings.
 
backtobirds said:
I have seen some comparisons of the M90 and Autorotor, but they were biased, and a stock M90 was used. Anyone have any experience or thoughts on these two? I know the benefits of a twin screw blower, but not how it stacks up against the MPIII blower. I will definitely be upgrading the supercharger, just doing a little research first. Thanks.

Here is a post that compares the MPIII and the 1.7 AR on a heavily modded SC. Bottom line...the AR makes a lot more power.

http://www.sccoa.com/forums/showthread.php?t=74666&highlight=MPIII+dyno

David
 
Upgrading to a larger blower will make more power potential. Both the 1.7 and 2.0 A/R are larger blowers. If you are looking for more efficient top end boost the A/R by design will give that to you. Low end the Eaton has it..But in low end boost I am talking under 10psi and in reality around 6-7.

You will never get an unbiased review because they really are two different animals and operate efficiently under different conditions.

The only thing I can say for certain is that an Eaton will last longer based on experience and peopel I know of that have them on other vehicles.

You want more ultimate power and high boost the larger A/R is the way to go
 
Damon,

My opinion is unbiased. IMO, Making big power with an AR is as easy as falling off a log, doing it with an M90 is hard work.

David
 
David Neibert said:
Damon,

My opinion is unbiased. IMO, Making big power with an AR is as easy as falling off a log, doing it with an M90 is hard work.

David

My opinion is unbiased, making 1000 rear wheel hp on a 347 with a T76 and AFR 205 heads is as easy as falling off a log, building a AR/Eaton project to do the same is extreamly difficult. Go turbo on the 3.8, it will make more power then an AR SC hands down.
 
CarlisleLandOwn said:
My opinion is unbiased, making 1000 rear wheel hp on a 347 with a T76 and AFR 205 heads is as easy as falling off a log, building a AR/Eaton project to do the same is extreamly difficult. Go turbo on the 3.8, it will make more power then an AR SC hands down.

Motec,

Get with the program....He asked specifically about an MPIII vs. AR, not how easy you think it is to make 1000 rear wheel hp on my car or how to make the most power from a 3.8.

David
 
Hey he also asked for an unbiased opinion...Saying it makes more power hands down is not unbiased...Giving him a good overall understanding of the pros and cons of both is..SOmething I barely touched on..But at least I touched onit
 
Another thing to ask is what goal are you looking to achieve? And how much effort do you want to put into your car
 
its been a while since this debate came up. they are both great blowers, I personally think the MPIII can produce just as much HP as the AR. I am running the MPIII and went 11.30 @ 122.6 MPH at 21 lbs boost. with very poor traction. that kind of speed would have been pushing the 10's with good traction. many people were unsatisfied with the MPIII, mainly due to the fact that they did not want to spin it fast enough to produce high boost. the MPIII is designed to be spun much faster than any other M90 eaton. I have been accused of being anti AR. I am not, I am just pro MPIII. Dalke is a good friend, but i don't want people thinking that you have an AR to go fast. I just recently talked to Dave about the efficiency of the 2 blowers. he had some very interesting data. basically saying the MPIII is nearly as efficient as the AR. maybe dave will speak more on this, but i don't want to say too much since Charles and Dave are good friends of mine. and i don't want to make anybody upset. Most that switched from an M90 to an AR saw huge results. but most also went higher in boost. plus they were slipping the belts badly on the M90 which would eat up HP also. cause 18 pounds of boost with no belt slip will create more HP than 18 lbs with belt slip. that is why I feel that the MPIII has been getting some bad press. they just weren't running it properly. I have spent much time trying to figure out this belt slip issue, and I think we have figured it out with a new 20% OD jack shaft pulley. lastly, I have come out with a way to data log blower RPM vs crank RPM, and will be able to see the two side by side. I have told dalke about this and hopefully he will be doing this when he tunes.
 
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DamonSlowpokeBaumann said:
Hey he also asked for an unbiased opinion...Saying it makes more power hands down is not unbiased...Giving him a good overall understanding of the pros and cons of both is..SOmething I barely touched on..But at least I touched onit

Damon,

Unbiased opinion is what I gave, and it was based on first hand experience. I've also witnessed the same type of results on several other cars.

It's always the same....whatever someone is able to do with an M-90 based blower (including MPIII), switching to a 1.7 AR increased the rwhp by an average of about 60. They also run faster and quicker on the track. I also agree with Kevin that alot of the added power has to do with more boost and less belt slip.

David
 
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David Neibert said:
It's always the same....whatever someone is able to do with an M-90 based blower (including MPIII), switching to a 1.7 AR increased the rwhp by an average of about 60. They also run faster and quicker on the track.

David
I don't think anyone has run the MPIII properly yet, including myself, so of course you would see results, Dave D as told me many times the 1.7 won't do anything for me, the MPIII is pretty new, and we have just touched the tip of the iceberg with it. I can't wait to see what some peoples blower RPMs are. i think you will see that they will be suprisingly low, compared to the amount of OD. yes with Dave installing the AR and tuning it and making sure everything is perfect, yes it is easier with the AR, but that soon will change, when the average joe will be able to get the right parts to make an M90 run with the best
 
Well, you can look at it this way.

MPIII might be the peak of any kind of roots blower you will ever see on this engine. as far as an application you can buy and not fab yourself.

The fact that you have to spin it so much, and would def need tensioner upgrades is kind of a downer.

Its kind of a pain to be smoking belts, (hell i get irritated with my early model just running 10% and seeing black on the snout).

The twin screw is a superior positive displacement type, and has proven itself against roots, on plenty of applications. Has now pretty much shown in a handful of cases superiority.

Like Kevin said, people are mislead by it. This is true, but people will turn their head away at the most trivial things. The AR could be a better color and people would choose it over MPIII.

You can make big numbers with both.. but the twin screw still will do the same and more with less.
 
I would agree that the larger 2.2 AR has more power potential, but i think our engines couldn't handle the power potential, where i think the MPIII and the AR are both capable to go to the limits.
 
Kevin,

I hope your right about the average guy being able to get good power out of the MPIII. I gave it what I thought was a well above average effort and still could not get the results Charles thought the blower was capable of. I can also assure you that is was not because of the tune.

BTW, I still think your car would gain a great deal of power with the 1.7 AR and even more with the 2.0.

David
 
well like dalke has said, the 3.8 cant take FULL advantage from the 2.0.. just not big enough, doesnt move enough air.

but, that sounds good to me. Because then it will require less grunt to make 400+ rwhp.

I think at this moment, you could take an MPIII and run with an AR car ( well i shouldnt say that considering the fastest is an M90 car ).. its just it takes everything to get there. Like I said its about what you want to spend.
obviously the MPIII is cheaper but requires more work and tweaking.

but hey hats off to anyone running sub 12s in these land yachts. but hey Who am I ? I own a Gen 1 blower :p I dont want to start flame wars.

I will just say, MPIII is awesome bang for buck, and you can get good results out of it for an M90 based product.


However, from what I know about forced induction. ( and not from watching kevin and dave in argument ) twin screw is a more efficient design.

If I had to choose, I would choose AR. But obviously money and dedication comes into mind. You get what you pay for.

but considering Kevin is running the fastest time.. he has every right to back the MPIII.

and considering the results of Neiberts car, he has every right to back the AR. with good reason.

If a full weight ( kevins car is not full weight btw) AR car beats an 11.3.. then no one is ever allowed to compare AR and MPIII again.

then its settled. lets go david. :)

but no disrespect.. i bow to anyone with a faster SC than mine..
 
David Neibert said:
Kevin,

I hope your right about the average guy being able to get good power out of the MPIII. I gave it what I thought was a well above average effort and still could not get the results Charles thought the blower was capable of. I can also assure you that is was not because of the tune.

BTW, I still think your car would gain a great deal of power with the 1.7 AR and even more with the 2.0.

David
dave, I really think that 2 5 rib belt thing was a huge mistake,you essentially had 1 5 rib belt, when i put the MPIII on i was VERY disappointed, i saw Nothing! But I believed in Charles, and i knew it should work. so i tried different things, I told him at the shootout that we needed a bigger crank pulley, he made me one, i tried it, went 1.5 tenths quicker still at 20% OD went to 25 % saw minimal gain, until i put on home made tensioner helper springs, went 2 tenths quicker, told Charles about it and now we have a spring mod. I went from 11.80 last year to 11.30 with nothing but 10% more OD and better belt grip. and at 30% i saw minimal gain, but with bad belt slip. now with the 20% jackshaft and with 8 ribs on both sides i think belt slip will b e greatly reduced, i just can't wait to record the blower speed. that is going to teach me alot! But i have the capability to go to 40% OD now. and i will try it after the shootout! you tried everything you had at the time to combat slip, but the right products just weren't avaliable at the time. the 10 rib set up i think was bad due to the increased cetrifugal force on the belt as it tried to turn around the blower. i literally have gone through around 100 belts trying this and that. I think that is why i ran so good on an s model because of my persistant fight against belt slip.
 
Thunder427 said:
.




If a full weight ( kevins car is not full weight btw) AR car beats an 11.3.. then no one is ever allowed to compare AR and MPIII again.



[/a QUOTE]
The MPH is where the difference is. dave ran 119.? and i did 122.6. my times were slow due to the traction issues. it should have been closer to 10.9 to 11.0 . yes my car was light last year around 3500, this year it is 3200. and that wasn't a freak run, i did many 11.31 at 121- 122MPH. but the best back up dave has is a 11.7?. I am by no means trying to make your run less accountable Dave, you did awesome, and i will try to help you go faster too! I just wanted to show why i think the MPIII is better:p
 
Wow. Sorry guys, didn't mean to open this can of worms again. I haven't been here for years (TCCOA had me with my LX) but just recently got a SuperCoupe and now I'm interested again. As far as my goals, I basically just don't want to get my doors blown off by some wicked import. I do think that the technology/concept/physics/whatever of the twin screw is better than the Roots type, but that new MPIII does look very promising. I'll probably go with that until I hit a power wall or end up with money and nothing better to do with it than get an Autorotor. BTW, is there a website for that? Plenty of info from Magnum Powers, but I haven't been able to find much on the Autorotor. As for the turbo, I have an LX for that. Ported the crap out of the plenum and intake but they have been sitting behind my toolbox for months now that I have my SC. LOL.
 
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