I did not say it would increase boost, I was only saying that it is needed more on a posi blower like his.

R

 

Colby, what is the compression of the motor?

R

 

Here is a dyno sheet on my Inlet Forward MP122HH TrailBlazer SS when John was tunning it at 15 psi on a Mustang Dyno. It is a Forged 370 with WCCH L92 Heads and a Custom Cam. We were getting a fuel pressure drop at the rails and stopped there at the time. I have since revised the fuel lines and am running 17-17.5 psi without the pressure drop at the rails. I need to get it back on a dyno to see where it is now in comparison.

 

I had the GT2-3 Cam Pro checked when I had my first engine (347ci).
Overlap =
35.3* @ .006"
5.4* @ .020"
-22.1 @ .050"

Rick (Synergy) actually tuned that engine and it ran like a champ with the MP112/2.85" pulley and 9.1 cr--same GT2-3 cam and AFR225 72cc. We saw 11 lbs peak boost (see graph) and put down 460/470 on the same dyno as the 383/122HH above. But as the chart shows, the 112 was not keeping up. I'd like to see a boost graph on the current setup to see the status of the new setup.



Rick, it calculates to 11.5 SCR/9.03 DCR. EDIT: Used different SCR/DCR program for calculation...includes intake/exh durations, centerline & lobe separation.




And yours is one of the installs I was using as a yardstick. Although I never intended to see 15 lbs...I was aiming for 10-11 lbs, and anticipating 600/600. We will see, as I won't quit till all avenues have been explored.

 

I am just curious Joe, at 17 psi, is the Maggie in its effecieny range? If not, how far out of is it?

What size pulley and what do the intake temps look like at 17 psi?

 

I have not seen any real change in IAT's since increasing the boost to 17. I usually run around 108-118 around town and 130-140 during a long pull at WOT boost. It cools down real fast unless you go right to an idle and restrict the airflow through the intercooler. As with any forced induction I am not out pounding on it during 100 degree days either.

 

My IAT's are about the same as yours under load. How fast are you spinning the blower? Mine is turning 1800rpm when the motor is turning 750 rpm. Math tells me that at 5K engine rpm, the blower will be spinning 12K rpm. How fast can I (or should I) spin it? I'm running a 2.8" pulley. Do they make them any smaller?

 

I have a 2.6 pulley that I got when I bought my kit, If someone wanted it I'd sell it for $60.

 

You have a PM.

 

This is your Rotor Speed with different size Crank Pulley's. You will need to convert to an 8 Groove Pulley setup at some point due to pulley slip on the smaller Blower Pulley's with a 6 Rib Belt.

(Crank Pulley Size / Blower Pulley Size x Blower Drive Ratio) x Engine RPM

(8" Crank Pulley / 2.8" Blower Pulley x 1 Blower Drive Ratio) x 6500 Engine RPM's = 18,571 RPM's

(7.5" Crank Pulley / 2.8" Blower Pulley x 1 Blower Drive Ratio) x 6500 Engine RPM's = 17,411 RPM's

My setup is a little different because it is a Front Inlet and has a Rear Drive Ratio in the computation. The Inlet Forward has different Drive Ratios to choose from when building them. I am still below 21,000 RPM's Rotor Speed with my setup.