Is it necessary for a retune after a rebuild... nutin changed but 20over pistons... Better rods and better pistons.... Is it really really needed.. thanks...

 

yes!!

 

How much of a diff will you see in a retune... from just 20over pistons from stock bore..

 

^^^1, unless you really had an engine problem before and you were tuned on it...it aint going to make a bit of difference. You would really have to make an improvement in breathing to need another tune...thats assuming you get everything back like it was--including cam timing.

 

I would say tune it. It may be a small difference but I'm sure the compression ratio has changed somewhat from throwing a different set of pistons in.

 

The car was already tuned before the rebuild... all power mods still the same....

 

make sure you run it in hard with the right oils!

 

2200 miles since rebuild...

 

oh, it shouldn't need one.
would your tuner do a check tune?
it really wouldn't hurt, especially after you've put all that money into it.
if the tune is good, it should cost very little to check

 

Get an afr gauge and check to see. Should be okay, but better safe than sorry. Motors ain't cheap!

 

afk isn't the only thing you should be checking.
if you goto the place that got it tuned, you can see if you're down or up on power too.
if you're up on power, it should need more fuel etc.

 

Why did the motor need a rebuild? If your tune was too aggressive and caused premature failure, then yes, retune.

 

Good point....