What is the diameter of the stock blower pulley?

[Xcentric]

...and how is diameter measured? Outside diameter at the flange edge or inner diameter where the belt ribs contact the pulley?

Mine is 76mm / 3.0" outside diameter and is copper colored. Is this a stock pulley?

 

[Wwabbit]

Belt sheaves normally use 'pitch diameter' which is roughly half the distance from the top of the belt groove to the bottom. But that can vary with belt design.

 

[Xcentric]

Okay...I googled "sheave." A sheave is a pulley. I learned something new today! I cannot measure pitch diameter. Do I have a stock sheave?

 

[Wwabbit]

The OEM pulley measures 3.5" across the flange and is dark, almost black color. You likely have a 2.9" pulley and so long as the car is tuned for it, you should have a nice hp boost.

edit; if it idles good and runs like stink, you're good.

 

[Xcentric]

Thank you! Yes, it runs like stock, but feels stronger than I expected. What made me wonder is it came with an Accufab throttle body and there is no reason to do that and nothing else. I think I will get it dynoed just to make sure A/F ratios are good.

 

[Wwabbit]

If you dyno the car you may want to get Torrie involved to optimize the tune. He can remote tune for you.

 

[Xcentric]

Can anyone ID this pulley?

 

[STORMCAT]

View attachment 26124

View attachment 26125

The stock pulleys are 3.25" or 3.23" in diameter . Most of the higher boost ( 15 to 16 pounds of boost) pulleys are in the in the 2.75" - 2.80" range. There are many after market pulleys out there. Heffner, Hennesy, Steeda, Roush and the list goes on.. Is it Steel or Aluminum? Looking at the finish I am guessing it is aluminum. Did the car come with a flash tuner? Did you ask the previous owner?

 

[Xcentric]

The stock pulleys are 3.25" or 3.23" in diameter . Most of the higher boost ( 15 to 16 pounds of boost) pulleys are in the in the 2.75" - 2.80" range. There are many after market pulleys out there. Heffner, Hennesy, Steeda, Roush and the list goes on.. Is it Steel or Aluminum? Looking at the finish I am guessing it is aluminum. Did the car come with a flash tuner? Did you ask the previous owner?

This one appears to be ~2.9", but it's hard to measure with the belt on. IDK what it is made of. No tuner. Previous owner consigned it to a dealer, so I have to go through the dealer and may or may not get any info.

I'm taking it to a performance shop with a dyno Friday, so maybe we can get some answers.

 

[STORMCAT]

So many guys have this or similar set ups. If the car is running good and it's showing 15 to 16 pounds of boost you are making about 700 HP at the crank and 620 HP to 650 HP at the wheels. From there any minor tuning may net a few horsepower but you would not feel any major difference. You should try to locate the aftermarket tuner box. It will be need to make any changes or revert back to stock if need be.

I would skip the dyno if it's just to satisfy your curiosity. There are different dynos and differences in exact reading so the number you end up is going to vary day to day and dyno to dyno.