Is it ok to use underdrive pulleys with a supercharger, because I was told otherwise. If so, have any of you w/ SC's noticed any difference with them?

 

I have been told or I have heard that the underdrive pulley is not good with the sc ...

 

Underdrive pulley+SC=no good, you want to go with a lighter drive pulley made by Unorthodox Racing(i believe that is who makes it)

 

You would get less boost unless you got a smaller pulley for the SC. If you get both then you would have very less belt connected to the two most important pulleys. That would probably be a bad idea and would increase the chance of slipping. The lightened (but not underdrive) one from UR is probably your best bet.

It would probably make more of a difference since you have more power than an NA max. However there are more important mods to get when going SC. A good fuel system and some other mods are just more important.

 

or you can just do them all

 

right, you can do them all.

i had planned on getting one of the lightened crank pulleys with my xmas $, but i bent a rim and got volks instead.

ferhan, the guy who had the kit before me, had a 2" pulley paired with a UDP.

he pushed maybe 9psi, but people say that there should be major belt slip due to the smaller contact surfaces.

 

2" and 9PSI? That is all I need to hear. I guess I'll need to add that to the buy list next winter. How much are the lightened ones? I don't have power steering so I'm interested in having UR make a lightened pulley that doesn't have the power steering groves and therefore would be even lighter.

 

No UR pulley use is recommended....

 

When you use the Vortech kit does it come with a 6-rib crank pulley? or is the 4th and 5th gen have a 6rib crank pulley already??? I bought a 4-rib pulley to replace the 6-rib on the SC, cuz the 3rd gen only has 3 - 4rib pulley slots on the crank pulley.

Brian

 

All VQ's have a six rib crank pulley.

 

all 3 belts are 6rib? or just the outer one? what acessories does it normally drive?

 

the outer one, the other part drives the power steering and thats a 4 rib

 

VQ has only two belts(Mine has only one). Outer is six rib and in OEM config drives the A/C and Alt. Inner is four rib and in OEM config. drives the power steering. All other accessories are chain driven.

 

So a lightened drive pulley is ok w/ a SC?

 

Shouldn't be a problem.

 

I've always wondered how much lightened pulleys would do on a SC'ed car. Isn't most of the drag loss due to air resistance the impeller blade encounters? If anyone cares, I plan on having ASP make me a OEM diameter crank pulley except without the Power Steering ribs to further reduce weight.

 

At high rpm yes. You can estimate the hp loss from the blower by multiplying CFM x boost pressure x .0044

where CFM is the flowrate through the blower in cubic feet per minute and boost pressure is in psi.

So, if you are pushing 500 CFM at 10 psi, the blower is using about 22 hp. On top of that there is hysteretic loss through the drive belt, but that is probably pretty low. There is also frictional loss from the SC gearing and bearings.

 

Cool. Thanks for that formula. Is the flow of the blower linear? Or is that what those eliptical graphs are for? The frictional losses you speak of are what I want to reduce by doing away with the secondary idler pulley.

 

Air flow through a centrifugal supercharger is exponential with impeller speed.

 

So last question...is it going to be worth the money?

 

also, is called an Unorthodox Racing Ultra S Standard Belt Crank Underdrive Pulley? Just want to make sure that is the one before I buy it.

 

thats the one.

no one has tried it yet. i was going to get one for with my xmas bonus, but then it had to go to new wheels instead.

if you do get it, do before and after dynos!

 

Correction...I have tried it and notice a huge difference. But never got to dyno the difference. (just by dyno) Big difference is that I het the rev limiter much quicker.

Yes that is the one I got. I git it thru Courtsey Parts. I can't remember the price, but it was around $200 bucks.

IMO a worth while mod.

 

cool, i didnt know that you had tried it!

 

Just bought one

 

Chris, let me know how much of a diff it makes with you being SC'd too.

 

Latin Max--What kind of SC setup are you running w/ your crank pulley.

 

got an exact part #? all the descriptions are very similar and courtesy appears to not stock them anymore.

 

I have the V2, 2.87" pulley, FMIC with 2.75" piping, CAI, Dual stage water/alcohol injection, eManage, J&S, PFI 510 injectors, and a auto custom tranny.

Make sure call and talk to Brian. I will call also and get the part number from him.

 

LatinMax- What are FMIC, J&S, and CAI? Also, where did you get your water/alcohol injection system?

 

FMIC = Front Mount Inter Cooler
J&S = A device which monitors and warns of detonation. Basically a really good knock sensor.
CAI = Cold Air Intake.

 

The water/alcohol injection system, is made by Cool Mist and eveything that was said above by Broaner.

 

Thank you both

 

If you look on Unorthodox's site, they want $230!!! And that's before shipping. Ouch.

Ultra Sc 12-Volt Charger Series Crank Pulley 121001012
http://www.unorthodoxracing.com/nissan_maxima.html

http://unorthodoxracing.com/cgi-bin/...Code=121001012

However, I requested a group buy and this is the price/response I got from Import Car Parts:

http://forums.maxima.org/showpost.ph...&postcount=144

$184 shipped. Not bad. And I don't beleive it needs to be a group buy either. I think I might just go for it.

 

Whats the difference between the Street Crank Pulley and the 12Volt Charger Series Crank Pulley?

 

The Street Crank is an underdriving pulley. The Charger Series is OEM diameter.

 

The Charger Series us what you need on a SC car. That's what I have

 

How long of an install would it be at a shop?

 

I assume your talking about the pulley. I'd guess about an hour.

 

thanks for the info .