bigg_86

iTrader: (1)

i have a crank pulley i bought from the BM and i was sure to ask if it was the stock size, the seller stated it was but once i compared it to the one in my car it is slightly smaller. i want to install it but i dont want my boost level to go up since i do not have a meth kit installed yet. i do have a HBP that i am going to install once i get the meth kit ready to go. but in the meanwhile i do not want to boost any more than 3.5psi.

will this crank pulley affect my psi level?

Excelerate

iTrader: (1)

What's the part # on it and the brand?

Yes a smaller pulley will reduce your boost level, at least on a supercharged vehicle.

maharajamd

iTrader: (1)

What's smaller? The actual pulley part or the lips?

If it's not UR it's probably that Ralco one.

Opel

A smaller pulley will reduce your psi. I doubt it's bigger than stock.
Don't compare your pulleys from outer diameters.
Measure from the ribs... Where the belt rides on

Excelerate

iTrader: (1)

If it's the Ralco pulley I'm pretty sure it's the underdrive one.

maharajamd

iTrader: (1)

^This is what I was trying to say. Lol

bigg_86

iTrader: (1)

uhmm im pretty sure is the UR pulley. i checked the part number when my friend got his n i noticed that mine was smaller than his. when i looked it up it didnt say anything about being an underdrive pulley. and i specifically asked the seller if it was the stock diameter and he confirmed it was.

Opel

I know

Op....... Here

http://www.pulleyboys.com/images/PulleyDiameter.jpg

bigg_86

iTrader: (1)

Ill get the part number when i get home and double check.

justnspace

iTrader: (1)

Opel ftw!

bigg_86

iTrader: (1)

UR P/N 0206114 REV A D F 06.
THAS everything stamped in the back

maharajamd

iTrader: (1)

That's the UR under drive buddy. Sorry. :/

Opel

I say try it and see at what level it brings your boost (its going to bring it lower, not higher)..... Even though at stock diameter you're going to run 6.5 or so, and while having water/meth as a safety device I still dont recommend it, unless you at least have some tuning means. At minimum, be able to pull some timing even if can't add additional fuel.

Some may have run 6.5 with water/meth and untuned with no problems, but not each motor is exactly the same... I'm not trying to scare you, i'm just trying to say that 1 psi shy of your goal *might* help you go a long way without blowing up the ring lands.

2 engines with the same setup, one might blow and one might not, due to the simple difference of one of them having less compression pressure (more blow by), which would relieve some of the excess pressure in the combustion chamber.

CR can be the same, but pressure may differ

bigg_86

iTrader: (1)

Thanks! I will not be using this pulley, my friend is gonna let me trade mine for his if I do the swap.will I need a shorter belt then?

I'm planing to install my HBP once I get the meth kit n the fic all set up

bigg_86

iTrader: (1)

Btw I have rdx injectors too. Also, I thought the stock boost was 3.5. I don't have a gauge so I can't tell how much I'm boosting with the stock SC pulley

maharajamd

iTrader: (1)

You probably want to monitor if you plan to use the FIC and HBP. Lol

bigg_86

iTrader: (1)

^ lol yeah I know I just have been lazy since I can't find a nice pod or where to mount the gauge...

bigg_86

iTrader: (1)

Do I need a shorter belt for the smaller pulley?

maharajamd

iTrader: (1)

Well I would certainly figure that out before you install the HBP.

Edit: Yes. I believe UR recommends the Gates.

maharajamd

iTrader: (1)

Anyone care to tell me why they recommend that ft lbs but then 60* more? Why not just say 90 ft lb or whatever?

Opel

If you're going with the stock diameter crank pulley, and only changing the SC pulled with the 6.5 psi one, you don't need a belt. The pulley is slightly smaller, but not enough to get the tenssioner out of play. I went back and forth between pulleys too many times, even smaller than the 6.5 psi one, with the same belt for stock SC pulley.

If this doesn't work for you, then you have a wrong belt altogether. But you should have no problems, considering that you have the belt which was recommended for the SC application when you first got the SC (length wise).


In addition...
Since you're going to tune, and have slightly bigger injectors on top of water/meth , you should be fine with running the HBP. As long as you don't get too aggressive with tuning.

bigg_86

iTrader: (1)

I thought the HBP would put me at 9psi n that the stock pulley that comes with the SC WAS ONLY 3.5. Please correct me if I'm wrong. (Considering that I'm running the.stock size crank pulley

Also what mods did u have done to get up to 375whp? My best run was 318whp with PCDs jpipe greddy exhaust high flow 3rd cat n a CAI.

Opel

To get 9 psi the SC will have to be spinning very fast, in fact fast enough to get out of its efficiency, and will make nothing but heat. HBP should get up at about 6.5 psi. \
Stock is around 4.5psi.

Everything you mentioned plus water/meth, 6.5psi, and custom exhaust, but cutout at 3rd cat, but that's history now. Right now i'm only at around 350

Xiomaro

iTrader: (5)

how much psi would it reduce? .5 at the most i would think???

Opel

IIRC at the time I first installed the SC, I was getting 3.5psi as I tested it right after installation. I had forgotten all about the under drive crank pulley I had on the car. After I figured out why I was getting 3.5, then I changed back to stock, and got 4.5-5.

I don't know what difference it will make with the 6.5 pulley, but also environment factors make a difference too, with any pulley

bigg_86

iTrader: (1)

I just installed the rdx injectors n the car was running great. It iddles great n I was able to feel a little increase in power. Then I got in the freeway n when I'm at WOT at around 5krpms it stumbles like crazy n my engine light came on n flashed for a min or so n then went away. I checked the codes n I have pending all cylinders misfiring and random misfire.Do u have any idea of what could be causing this?