First off thats a great run. Second it's bad *** that its in a 6 speed. Third, im surprised the trans stood up to that!

Finally... I'd love to track that down in my crew. Time till tell... but I'm comin for ya.

 

👆is str8 Rollin out I like that setup too.

 

Im hoping I will be mid 10s with this 2.3 whipple....might have to put a plate kit on top of it

Ive been beating my engine with 25psi from a turbo so I think 15psi from a blower will be a welcome break for it. Should still make 650-700 at the wheel when I get done with it.

 

It'll be interesting to see if the blower makes 15psi on your engine.

 

So my math says with a IW OD crank pulley and a 3" blower pulley with 85% engine VE and 97% blower VE it should make 17.6psi. I might be optimistic with the engine VE though, but its important to remember boost does not mean more power. More air mass means more power.

 

What rpm are you assuming the motor and blower will run at to get the 17.6psi?

 

Is the blower really that efficient? I will be curious to see how it shakes out... I know there are guys on here who dont make that much boost out of the 2.9 whipple with similar CI. Different heads and cam of course.

And I agree that more air mass means more power... but its not as simple as a formula of air mass to HP with a blower. With a blower you have to worry about the parasitic loss. For example a cam with a lot of overlap could allow the blower to run in a more efficient lower boost zone at a given RPM, but you may be better off with no overlap and less blower RPM to create the same power... and likely be moving less air mass while increasing boost.

 

Well, thats what whipple says, but I have my doubts. My model needs some refinements I will admit, but I think it will be ball park.

Keep in mind VE with a blower is usally very good. When most people think efficiency they think adiabatic efficiency, which is a measure of how idealy the air is compressed. VE is a measure of how much air is injested vs how much could theoreticly be injested per cycle (this applies to engines as well). Blowers are usually worse than turbos because blowers are not compressors (roots anyway), they are pumps.

Less boost is a good thing, with a blower, you want very low boost but move a ton of air. Not the same as a turbo. A blower at 4psi and at 30psi move the same VOLUME of air, since airflow only depends on rotor speed. Driver power goes way up with pressure, so the lower boost you can run while still moving the most air is ideal.

To your point, its all a balance. A cam makes more power because it increase VE at a higher rpm (or everywhere if its a good cam). But with a blower (and NA engine), the higher the rpm the more power is required to spin it. So you get a lot of competing factors, namely blower drive power, blower VE, engine VE, and engine parastic loss (drag).

 

8.3" crank pulley with a 3" blower pulley. Blower is 140cu and engine is a 402cu. 85% engine VE and 97% blower VE.

 

Apples to oranges, but my KB 2.8'' with IW crank, 3.25'' blower on 5.7 made 17 on my old setup.