Pullies & Idlers

[Master]

My cobra is stock, but I been looking at billetflow to get some shiny pullies.

1) should I get just an upper pulley or include a lower?

2) should get get idlers also and does billetflow offer a complete kit?

3) what pulley combo should I start off with?

4) would I need a tune after adding pullies?

thanks in advance

 

[BBCOBRA]

My cobra is stock, but I been looking at billetflow to get some shiny pullies.

1) should I get just an upper pulley or include a lower?

You should plan this out in advance. Do you want to port the blower later? or leave it alone? I went with a 2.76 non slip and am very happy with it. do a upper and lower combo only after a port. 2.76 upper/ 2 lb lower or 2.93upper / 4 lb lower are popular. 16psi on the eaton is the recommended max. according to Stiegmeier

2) should get get idlers also and does billetflow offer a complete kit?

go to billetflow.com for details. He does offer kits and you get the best price by buying the kit. At a minimum you'll need an upper, auxillary pulley (if going with a 2.76) and the idler down next to the crank pulley (this one is known to come apart, especially after going with the upper and auxillary). There are only two more to buy for better looks, so just buy the 4 pulley set.

3) what pulley combo should I start off with? Upper (2.76) & 4 idler kit.

4) would I need a tune after adding pullies? Definately need a tune. I'll reccomend milehidyno.com for a mailorder tune. A dyno tune is best (but go with someone very familiar with cobras).

Happy modding, and read up on the forums. Search tool is your friend. You'll end up with more questions than you started with but learn alot along the way.

thanks in advance

later

 

[CobraBob]

Good info above from BBCOBRA, but a ported Eaton is not required when going with a larger lower crank pulley. People have been using lowers since the early days of the Terminator. Upper only combos tend to be more popular because it is more difficult to change the lower than the upper. The main reason you're seeing more lowers with ported blowers is because with the (more efficient) ported blower you can run 1-2 more lbs. of boost than with an unported blower. You would consider an upper/lower combo before porting the blower if you're looking to minimize the possibility of belt slip. The larger the upper pulley the less apt you'll get slip. Adding auxiliary idlers helps eliminate belt slip, too. Non-slip uppers (I used a Reichard Racing UltraGrip 2.90) are good, too. With a non-ported Eaton you want to keep your max boost to 14-15 lbs. With a ported Eaton you can go to 16 lbs., although some push it to 17-18. I have a chart on my website to help you see which upper/lower combos can be used to achieve the desired level of boost. Remember, though, that if you choose to go with a larger crank pulley now (with a non-ported Eaton) install the size you will want when and if you port the blower, and then select an upper to get you the max boost you're looking for for the unported blower. Then when you port the blower you just have to change the upper. Here's the link for the boost chart.
http://www.stangshiftergaskets.com/2003_2004faqs.htm#_Toc35092360