2011 Roush with 90 mm pulley

[stanger1]

Group,
Just got the calipers around the Roushcharge pulley tonight and it is a 90mm. This was an early kit in late 2010 for the, then new, 2011 5.0's
Question, Is there much difference by going to an 85 mm pulley from the 90? Power wise.
Does it change the tuning. It is VMP tuned now.
Thanks

 

[by9468840]

90mm to 82mm should give you 2psi increase in boost and around 35-40 rwhp. About the same or little more increase in torque.my car with Vmp and 82mm (all stock with airbox) made 578rwhp. I didn't need tune update.

 

[stanger1]

Cool,
Thanks for the info. I was thinking about jumping to the 82 mm pulley, but I would be very nervous to do that. That's just me

 

[REDNIGHTMARE]

90 to an 85 you would be able to tell a difference I think. I would go to the 82 though. On my Roush with just the 82mm pulley, roush cai and vmp dyno tune I made 614 to the rear. And no you do not need a new tune. Again I am VMP'd tuned and have been told I can swap back forth between pulleys without changing the tune by VMP

 

[bmyles]

Isn't the 90mm kit rated @ 540 from roush and the updated kit with the 85mm is 575.

 

[REDNIGHTMARE]

565 is the number roush claims. It's all in the tune though as well

 

[MNCobra]

wow I always thought that you change pulleys you had to have a new tune...good luck and enjoy your Roush...

 

[REDNIGHTMARE]

wow I always thought that you change pulleys you had to have a new tune...good luck and enjoy your Roush...

I always thought that as well. But when I got my Roush and had VMP tune it they said I can swap pulleys without changing the tune. It took a second for it to sink in

 

[by9468840]

For 11-12 models no tune update necessary with pulley change unless you down pulley too much where you would need more fuel. I heard that 13-14 model factory strategies require tuning with pulley change. Apparently if you don't adjust the tune, the ecu will override wot and cut off throttle as soon as it sees more air coming in with smaller pulley. Can anyone confirm this?

 

[REDNIGHTMARE]

For 11-12 models no tune update necessary with pulley change unless you down pulley too much where you would need more fuel. I heard that 13-14 model factory strategies require tuning with pulley change. Apparently if you don't adjust the tune, the ecu will override wot and cut off throttle as soon as it sees more air coming in with smaller pulley. Can anyone confirm this?

Not true. I have a 2013 roush stage 3. And I have gone back and forth between my 82 and 75. Justin from VMP has confirmed a couple times that I don't need one for I have asked a second time to make sure I heard him right the first time lol