tomcat

All the carbs "know" is more air is going through them. The amount of fuel delivered at this higher air flow depends on carb setup and could easily be a lower A/F.

Lots of possibilities for no RPM increase but one reason may be that the extra 2 psi is mostly due to heat and air density has not increased much.

blue thunder

Yes, I was afraid that may be the case tomcat. But I was hoping because the the relatively low rotor speed I am turning (even at the higher boost) that would not happen. I am at ~10k rpm and the stock 525sc I believe ran 12k rpm, both with no innercoolers. I'll have to try the larger pulleys again (9.3k rpm) to see if the rpm still remains unchanged. There are just so many variable when trying to water test this stuff, getting meaniful comparisons run to run can be a challenge.

Thanks for all the input.

BT

Griff

The stock 525SC runs the 177 blower at a 2:1 ratio. At 5200 engine rpms, the blower is at 10400rpms. Max recommended rpm for the Wieand blower is 12500 rpms(if I remember right). I was spinning mine at 2.5:1 (7.5#) for right around 13000rpms. Just change the lube often.

blue thunder

I bought some 525sc take off 177s and they came with 3.070" upper pulleys and 7" lowers. I assumed because the upper pulleys were splined that these must have been the originals. I can only find keyed pulleys in the aftermarket. Anyway, thanks for the correction. I did have 2:1 in my notes from winter research but guessed that must have been wrong.