Excellent Article on supercharging

[nonwoven29]

Out of all the books and articles I've read on the subject this is by far one of the best!!!

I always take what I read from mfg with a big grain of salt. This lays it out in an unbiased way.

PRESENT-DAY SUPERCHARGING - EXPEDIENCY OR EFFICIENCY? / AJ6 Engineering

 

[toms89]

Out of all the books and articles I've read on the subject this is by far one of the best!!!

I always take what I read from mfg with a big grain of salt. This lays it out in an unbiased way.

PRESENT-DAY SUPERCHARGING - EXPEDIENCY OR EFFICIENCY? / AJ6 Engineering

I have read all the pro's / con's of all the variety of blowers including turbos throughout my years. Also have run a Centi... After running a roots for some time now I have come to the conclusion that the roots blower gets much more negative feedback than it actually deserves primarily due to the competitors exaggerated claims.

Roots blowers are actually fairly efficient at low boost levels due to the fact they do not compress air internally. But as you increase the speed of the blower to try and make more boost it does hit a brick wall and becomes much less efficient. Correct size blower is also critical as with all makes for optimum efficiency. Roots blowers have improved through the years but the competition tends to quote the efficiency levels of early versions.

IMO...

Roots kept at 6psi boost or below would be fairly efficient and maybe the best choice between the different models as far as driveability. Beyond that your much better of with a twin screw.

Yes, I am overspinning the hell out of mine just to get 12psi boost or so and pushing it well beyond it efficiency range. But cannot afford a twin screw yet..

What surprises me is my IAT temps still are quite manageable. Typically 20-30 degrees above ambiant. A large part of this has to do with the efficiency of my intercooler setup.

File:Roots Supercharger efficiency map.jpg - Wikipedia, the free encyclopedia

 

[nonwoven29]

I hear you Tom! People do trash them pretty hard. That is until we get into the 6-71,8-71 etc. then the trash talk stops.

I've had all types as well from a 300z turbo in college to twin screw KB on my old missed fox body.

I agree 110%. You pick the right compressor for the job and then some.

The very first blowers were the roots type pump. First used in mining then Reciprocating engines. They have there advantages as well as draw backs.

I be leave in using the right tool for the job. If done right its all academic.

What do you think of the article as a whole as far as truth be told?

 

[toms89]

I hear you Tom! People do trash them pretty hard. That is until we get into the 6-71,8-71 etc. then the trash talk stops.

I've had all types as well from a 300z turbo in college to twin screw KB on my old missed fox body.

I agree 110%. You pick the right compressor for the job and then some.

The very first blowers were the roots type pump. First used in mining then Reciprocating engines. They have there advantages as well as draw backs.

I be leave in using the right tool for the job. If done right its all academic.

What do you think of the article as a whole as far as truth be told?

I have seen what I would consider better articles but would have to find them to post link. That article seemed strongly biased as far as anti-roots. But if you go to their website it makes sense to me as they sell a twin screw upgrade.

I had an thought which came up when you realize the roots does not internally compress the air.

You have a roots blower, centi and twin screw. 2 compress air internally 1 does not. Which do you believe would be more efficient when not into or at low boost? Assume they all have bypass valve of sufficient size.

 

[toms89]

Don't get me wrong... I would still much prefer a twin screw as far as making more power but a roots has its advantages. Much cheaper to manufacture, very reliable, excellent throttle response and low end power.

 

[nonwoven29]

I have seen what I would consider better articles but would have to find them to post link. That article seemed strongly biased as far as anti-roots. But if you go to their website it makes sense to me as they sell a twin screw upgrade.

I had an thought which came up when you realize the roots does not internally compress the air.

You have a roots blower, centi and twin screw. 2 compress air internally 1 does not. Which do you believe would be more efficient when not into or at low boost? Assume they all have bypass valve of sufficient size.

I think I know where your going with this. Sense the roots Isn't actually compressing air but moving it. It should in theory have a much higher temp Efficiency to the other 3 types of FI?

And I think they do in this respect.

 

[toms89]

Damn if I can find any of the original articles I have read before...

Did find this one which seems bit outdated... at least I think the screw blower info is a little off with the variety of sizes now available.

Roots vs. Centrifugal vs. Screw Type Supercharging : SuperchargersOnline, Worlds largest Supercharger Resource. Get Serious About Power

 

[nonwoven29]

I would have to say whipple played a role in that write up. I would have to say the TS still keeps climbing all throughout the power curve. The only thing I didn't like abot my bell was the nasty heat Soak.

The only other thing I can think of is how quiet the ts is compared to a roots. I cruised as a child in some 6-71 & 8-71 el camanos ,novas and you knew there was thunder under the hood. It's not even funny how violent they get with just the stabe of the throttle.

I always thought of the centrifugals as the eniem back in the day. They certainly suck off the line. Even with a high stall the cant give you tire blistering performance.

On the other hand these centrifugals pull like crazy mid range and never stop.

What I would really like to see is a particle version of the axial flow. Tons of flow with modrate pressure.Sounds like a winner to me!

There are compines screwing around with it in the rotary engine dept.

Another company to take a look at is vandyne industry's. they mfg. a Superturbo. A cross breed centrifugal turbo set up on the class 8 over the road trucks.

I don't think there is a heathy completion currently. If there all competing for our business then there should be a good amount of new or expanded upon technology coming of it.