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has anyone gotten one of the smaller pulleys installed and taken to a dyno and collected boost figures so we can figure out which can be installed safely and which need intercooler/injectors?
Well, can't help you on your request on dyno numbers but I have gotten 3.0 pulley from that place and I can easily say they did great job and the fitment was perfect.
They flat out advise me against doing 3.0 pulley but I told them about how I am running fine with 3.4 pulley.
I opted for steel version this time with their recommendation and they are right about it. It is better in grip and better in heat dissipation compare to aluminum. However the weight is quite heavier than aluminum pulley but my butt didn't feel the disadvantage of additional pulley weight. (Don't take my word for it, since butt dyno can be quite wrong)
The sizing came out to be about 3.1 so there was little difference in size compare to my older 3.4inch aluminum one.
I am bravely trying 2.6inch pulley and I will be getting them in about a week. I have been still able to rev to 9K rpm with 3.1 inch pulley but with 2.6inch I will definitely limit my rev. to 7.5-8Krpm.
However my report of this won't be anytime soon, since I have to take care of some critical issues with RC injectors and tuning with VAFC.
Meanwhile if you haven't seen my dyno plot with 3.4inch pulley before here it is. There is good noticeable increase in midrange with the smaller pulley.
at the rate you are going, why bother with a pulley, just get a belt that will fit the SC centershaft and run it like that...
using my spreadsheet, you would be getting around 12.4 lbs of boost at 9k with a 2.6 inch pulley. that is equvalent of running at 15,800 rpm with stock SC pulley, i.e. SC rpm of 66171.
of course this all assumes that the boost is linear and has no adjustment for loss at the higher pressure/airflow which i am sure is present. when one of you guys gets dyno figures with boost i can plug that in and make corrections.
i am thinking i will go ahead and get the 4.375 pulley and try that one myself. nowhere near as extreme as what you and some of the others are doing, but i do not see myself as a pioneer, am more than willing to learn from other's success/failure.
"Are you still trying to get more boost ~3-4000rpm? If you'd like to find how it could be done though, check out the GruppeM supercharger for the NSX and pay close attention to the implementation."
It sounds like you need to get a pulley that will generate about 14psi at 9K and then use a boost relief valve to limit boost to 8-9psi. That should provide plenty of grunt in the 3-4k range. Right?
[QUOTE]Originally posted by Damillster
[B]"Are you still trying to get more boost ~3-4000rpm? If you'd like to find how it could be done though, check out the GruppeM supercharger for the NSX and pay close attention to the implementation."
It sounds like you need to get a pulley that will generate about 14psi at 9K and then use a boost relief valve to limit boost to 8-9psi.
