I'm trying to figure out what running a smaller vs. a larger crank pulley will do on my jrsc, but for the life of me, I can't figure out the math. Not only that, but I'm having a hard time trying to find out what the oem pulley sizes are, so even if I could figure it out, I'd still have no numbers.

I know what my pulley combination is doing for me, but since it's such a bitch to change pulleys, I want to plan ahead so I know what to expect.

Does anyone have this info?

 

come on.

Someone has to have some sort of idea as to what pulleys offer what levels of boost.

At the very least, does anyone have any info on stock crank pulley sizes, and how they would pertain to boost?

 

i don't know.. but i've talked to jim i think his name is.. at motorvations motorsport.
give him a call (205) 661-3600

 

Thanks for the number, but I know someone here has this info.

Come on people, help a guy out.

 

lets start listing our setups.
i hear that first generation b16's crank pulleys are slightly smaller than 91 LS pulleys.


my pulley setup:
stock 4.2(i think thats stock) blower pulley
MVM stepper pulley
b16a1 crank pulley
9 psi on b16

whats your setup

 

what you want is a bigger crank pulley, when my rex was s/c I ran a B20 pulley about 3 or 4 more psi over stock B16.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by madeiniraq &raquo;</TD></TR><TR><TD CLASS="quote">lets start listing our setups.
i hear that first generation b16's crank pulleys are slightly smaller than 91 LS pulleys.</TD></TR></TABLE>

good call on listing setups.
FYI, I measured my stock GSR pulley to around 4.8", and the b16 one that I was using is 5". If I remember correct, it should be a 1st gen, but I'm not positive on that.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
my pulley setup:
stock 4.2(i think thats stock) blower pulley
MVM stepper pulley
b16a1 crank pulley
9 psi on b16

whats your setup</TD></TR></TABLE>

stock jrsc 4" nose pulley
stock jrsc alternator pulley
5" crank pulley
9psi on a high CR b16.

I guess what I'm trying to figure out, is how do I lower the boost?
Will I need a smaller crank pulley?

As it stands, I have a few high boost setups, but until I get my 1.9L finished, I'm not able to run them. 10.8:1 cr is nasty when you're running stupidly high CR.....

 

hey man

if i get a reply to my pulley thread i'll be able to help you out more....but for now, keep this rule in mind:
a larger crank pulley and/or smaller blower pulley will increase boost
a smaller crank pulley and/or larger blower pulley will decrease boost

you mentioned that your blower pulley is the stock 4" one. i've heard of a 4.2" pulley that exists in the stock kits as well, and that makes me wonder which kits come with the 4.2". because in your case, this larger pulley would help you lower the boost. my guess would be they came with the civic si kit, since its the only kit that uses the larger M62 blower on a 1.6L. this would be one option for you. the other would be to find out what the smallest crank pulley is.

HTH

 

That's awesome Keebler.
I've also posted a similar thread to yours in the TOO forums. Hopefully we'll get some answers.

 

it depends really, with larger displacement like a 1.9l as opposed to the 1.6l you have now you will usually see a psi or so less from the same pulley combo. i have roughly a 1.9l now and here's what i gathered from my experience

4.2" Blower pulley , jrsc alternator pulley, and crv crank pulley = 9.5psi

4.2" Blower pulley , jrsc alternator pulley, and ls crank pulley = 6.5psi

4.2" Blower pulley , jrsc alternator pulley, and usdm type-r pulley = 4.5 psi

4.2" Blower pulley , mvm stepper alternator pulley, and ls crank pulley = 9.7 psi

4.2" Blower pulley , mvm stepper alternator pulley, and crv crank pulley = 13.6 psi

4.2" Blower pulley , mvm stepper alternator pulley, and 00 si crank pulley = 5.5psi

These are all the combo's i've tried on my setup and the boost reading were from a dynapack boost probe while dynoing.

 

that's exactly what I've been trying to figure out bxsi.
thanks.


It's interesting to see the difference between the CRV and ITR pulleys. You could easily change upwards of 5-6psi using only crank pulleys, which are so much easier to change. This gives me hope for the jrsc.