Stacked pulley is not for me...
Did my testing and the dual pulley is interesting but not my cup...
Because of the terrific ratio of about 3:1 the boost gets up real fast. With my intake and stuff I hit 20 PSIG with the 178 Pulley. THis is at the local ambient of 45 to 25 F. I have not taken note of the higher ambient readings, but I feel that it would not change much. No heat issues due to my Super cooler and the LOW ASP temperatures, one less variable today.
I ran with the data logger and you can see the results. What you cant see is more intriguing by far. My boost peaked once at 25 but the belt with my improved wrap on the code 3 could not hold the load and slipped audibly. The low rev power was unique but uncontrollable, went sideways in 2nd from a 4000 rpm "ROLL". Boost drove my fuel pressure to 85 psig several times and the motor went Richie rich, again was hitting 25 PSIG boost.
THe takeoff and run up with partial throttle was crisp and powerful, but full in on the throttle was causing great tire slippage, tranny trying to upshift due to revs in 1 and 2 soo fast. Not an enjoyable ride. Boost did make it go but I do not feel that this is the best use of my limited research time.
I feel that the COde 3 is a great hot little number, lots of pluck and limited distress to the accessories and pulleys, no over speeding issues. Glad I got one for the last 1000miles.
The 178 pulley is great as it gives me lots of power and a generally good balance of boost and response. More power than the Code 3 and what I would call the second tier of power; from boost multipliers.
I had a 181 Pulley for a while and it was good, more audible than the 178 and at one point viewed by a fellow autocrosser as " your car is an animal". Tier three and a great way to get a bit more.
Having said all that I feel that if I can obtain a 185 Pulley system, then I will get it for peak power. That is just on the upper edge of the belt speed limits of pulleys and a good place for me.
The stacked pulley is great for below 4000 rpm power if you are in third gear or higher and dont down shift, or else - - -you may be handed more than you asked for. Power is enormous but wiggy and uneven what with tires spinning, TC kicking in, tranny shifting, and the BIG F/A concerns. AUUUGH no thanks, had to see it, done it, knew enough to put it back.
Be careful of what you ask , you may get it.
Note the boost I got at LESS than 4000 rpm. Be Happy
Woody
Last edited by waldig; Jan 16, 2009 at 12:59 PM.