Do I need a re-tune after specific pulley swap

[88foxbod]

I'm sure your brain is yelling YES!
But my question is, I have a 2.76 upper with the stock lower putting down 15lbs.
I also have a 2.93 upper with a 4lb lower sitting in my garage that I hear also puts down 15lbs.
Since it's putting out the same PSI do I need a re-tune?

 

[88foxbod]

I'm sure someone has done this before and has the answer!

 

[01Jes]

I'm sure someone has done this before and has the answer!

I would get it checked. A revision which is <$400 vs a damaged engine>$3~4K:shrug:

 

[Ford2ner]

My pops said no. Just do some data logging and send to him after the blower port too.

 

[88foxbod]

My pops said no. Just do some data logging and send to him after the blower port too.

Yeah just wanted to see if anyone else did this swap to be certain . I'll definitely do some data logging.

 

[cj428mach]

I say yes you'll be fine.

I had a tune that was on the rich side (low 11's) from Amazon that I was running with 15lbs of boost on my Whipple. I went to 16lbs and no change on the AFR and now I'm at 17lbs with no noticable change in the AFR. I say datalog it but I'm beginning to think people on this site over tune, or claim you need to retune for every little thing when its really not necessary. If the MAF curve is right and injector settings are in I think you should be fine no matter what.

 

[Ford2ner]

Lol I agree. There is a commanded AFR depending on the load throttle % etc so it should stay at that AFR even if you change the boost until you run out of fuel. Like I change my pulley from a 3.75 to a 3.25 and go without changing a thing on the tune.

 

[88foxbod]

Good deal, thanks for the insight. Hopefully have her up and running this upcoming week. That is if my valve covers are fully cured and I get my roller rocker back on that somehow was off just laying on the head :shrug: