Who is running a +4 (10 psi) lower?

 

I was but took it off. Went to the dyno one night when the temperature was in the low 70s and my tuner claimed I was running about 11.5 psi. I got a tune for it and I'm going to run it again next spring when the temperature gets close to 90 F. I data logged it when I first put it on and my IAT was the same as the +2 lb pulley.

I will say this...it makes a difference!

 

Ger Rod, what belt does the +4 use? I have the pulley and my tunes for it should be here in the not-too-distant future. Any problems or drawbacks encountered while running the +4? Who wrote your tune?

 

You can use your stock Roush belt with the 4lb pulley. It's hard to put on but it'll work.

I had no problems at all with the pulley. I'm just being a little cautious for the upcoming colder temperatures. Its going back on as soon as it warms up next year.