Autorotors? 1.7L VS 2.0L

ricardoa1

Registered User
How are the bigger 2.0L autorotors stacking up against the 1.7L

Is the 2.0L slight overkill or is it the way to go to beat the 1.7L cars.

Not trying to start anything I just want to see if theory is the same as reality. Are the efficiency maps better matched on the 1.7L for our car or the 2.0L

Mind you I dont have either so I just want to educate myself.
 
With the stangs the larger blowers spin slower to produce same boost at a lower outlet temp...How much a difference between a 1.7 and 2.0,,,,I DUNNO

but thats what the stang guys been experiencing when going BIG 1.7 2.0..Kinda very close
 
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Theories aside I think in practice the difference is minimal. The 2.0 cars were not breaking any records the 1.7's haven't done.
 
The 2.0L blower will support more boost at a higher efficiency than the 1.7L blower. Where the 1.7L blower's "sweet spot" seems to be around 20 psi (+/- 1psi) the 2.0L blower's peak efficiency will be around 23-24 psi without creating the extra heat that a 1.7L blower will produce at those boost levels.

It depends on what boost you would like to run, which follows what power you can make.
 
Well I have been using this calculator extensevely.
http://www.sprintex.com.au/files/Blower_Calculator.xls

And for example a 2.3 OD to make 20psi shows up as being underdriven. But what about our intake manifolds, can we move enough air that 23psi is useful? Or are we creating more unwanted heat by doing so.

What about camshaft selection also. Do we need to get a super big camshaft to move the power band further past 6000rpms in order to get to the sweet spots for the bigger displacement blowers to work?
 
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A twin screw blower is definitely better for higher RPMs. I don't know what cam you are using, but a ~230* duration cam with around .600" lift will support every bit of 6500rpm.

You won't experience excessive ACTs with a blower that is efficient at those boost levels.

If I were you, I would get a 2.0L blower. You have plenty of boost to play with, from 18-25psi (or so). With the blower I have, 30psi is still in it's efficiency range on an SC motor.
 
A twin screw blower is definitely better for higher RPMs. I don't know what cam you are using, but a ~230* duration cam with around .600" lift will support every bit of 6500rpm.

You won't experience excessive ACTs with a blower that is efficient at those boost levels.

If I were you, I would get a 2.0L blower. You have plenty of boost to play with, from 18-25psi (or so). With the blower I have, 30psi is still in it's efficiency range on an SC motor.

At what point will the high volume pumps (255) cease to provide enough fuel? At what point will a fuel line prove to be to small?

You are correct Ricardo in that a 2.3 needs to be underdriven. How much HP is gained by running a 2.3 slower and how much less heat is generated? I have never been a fan of the M90 (no matter how well designed) being over driven 25% or better. The roots style blower is a heat pump and your results at the shootout should back that up. Add a shot of cold nitrous and bam your heat problem went away and big numbers

Ken
 
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