PSI blower boost numbers for hi-helix 14-71 on a 526 good bad?

I have worked a car that has a PSI High Helix 14-71 on a BAE 526 and so far I am not overly impressed but it is not bad. It is an unmodified PSI. Everybody says they get better the higher you go on OD and the outlet temps get lower which is good. No temp sensor on the car yet.

These are actuals I have measured on Racepak graphs. They are were all pretty fresh blowers on a 526s. I put in some other blower data for a good comparison

PSI 14-71
At 20% OD at 9000 rpm in high gear I see 31 lbs. (that is 9 lbs down from a M5)
At 35% OD at 9000 rpm in high gear I see 38 lbs (that is 4 lbs down from a K-11 Superman)

With a K-11 Superman (slightly modified)
At 30% OD at 9000 rpm in high gear I see 40.5 lbs
At 35% OD at 9000 rpm in high gear I see 42 lbs
At 40% OD at 9000 rpm in high gear I see 43.5

An M5 at 20% OD at 9000 rpm in high gear will make 39 lbs

 

The PSI and the M5 cars both had the same camshaft which I believe is the BAE 477 (is that the right numeber for a 20% Promod cam). Don't know about the degreeing. Not sure what the Superman had. They are all 526 motors.

Good question and I should have though to record more info when I started keeping a spread sheet. I will have to add that data. Thanks

 

Remember all my boost readings are at 9000 RPM for comparison. If you take these blowers up higher in RPM then they will make more boost than what I listed. Wow, I would love to see 48 lbs max out of a PSI at 33% OD but haven't seen it yet. Would see more boost if the cubes were smaller or the heads didn't flow as much. I do know that the stripes last a long time in some of the PSI blowers but I would rather have a blower that put out more boost at a lower temperature and had to be restripped more often that a blower that didn't put out as much but have the stripes last longer. I do understand that there is a problem with some of the PSI HH blowers on the positioning of the rotors in the center of the case. Some rotors sit off center so the fit in the case is not as good and they don't make as much boost on those and the stripes don't last as long.

 

Just to keep everything in the same perspective you are not going to see that 48 lbs on a 526 at 33%. If you take that PSI at 33% on a 451 Brad 5 and put it on a 526 Brad 5 at the 35% it will probably make the same boost within a pound of 38 lbs of what I am currently seeing. So now you need to think on how much boost in pounds costs in $$$$$$ and what you are striving for and who your competition is and how fast do you want to go. When the PSI HH first came out and the Promods in ADRL started to run them they were out performed by other new model Roots blowers pretty fast and we didn't see them again.