[Joshinator99]

Originally Posted by Future1LE

Hello guys,

Needing some opinion on what you guys have seen before. My car was tune on 85mm upper pulley and stock lower pulley. Car makes 16-17 pound of boost at the time of tuning. I did a few pull recently in 40* temp and Injector pulse width and fueling did not change much although car makes 18# of boost at the top. I just put on the 80mm upper and and will go out for a data log later. My question is, if boost increase a few pound only, maybe up from 16-17# to 18-19#, do I need to retune or will fuel be ok? Also as weather gets colder, I will probably anticipate that boost would hit 20#, would I then need a retune? I will reach out to my tuner but want to see what you tuners have seen from pulley swap. Thanks

General rule of thumb would be to review the tune when going up in boost since you’ll be operating on a part of the MAF scale you weren’t previously reaching. You’ll probably be fine as long as you watch your low side pressure/high side pressure /injector PW as usual plus keep an eye out for knock…