Callout collins

[SicStang03]

no that is exactly what im saying.

the MAP cells wont change because they are predictive calculations of the pressure inside of your manifold. Infact you would probably have to hit 50 PSI before you got off the chart.

The map sensor takes your RPM and the PRESSURE and calculates the fuel to add to it. The only time you are tuning it, is when your sensor is saying it is at a certain pressure when it really isnt. (eg porting and polishing). Even then your o2 sensor compensates during regular driving with LTFT and STFTs. After WOT it doesnt know what to think short of what the MAP says and THAT is what needs to be tuned.

All in all, if all you do is change a pulley, you do NOT NEED a tune. The airmass calculations are done unless you mucked with how much flow your getting....eg new intake etc.

Adding boost will change the MAF counts. When I ported my blower and had the same pulley, I DIDN't need a tune. I re-tuned it when I upgraded the injectors. When you go from 8PSI to 13-14PSI, you need a tune. I understand the tune is only for WOT purposes. The o2's controll averything at regular driving

[rrutter81]

Adding boost will change the MAF counts. When I ported my blower and had the same pulley, I DIDN't need a tune. I re-tuned it when I upgraded the injectors. When you go from 8PSI to 13-14PSI, you need a tune. I understand the tune is only for WOT purposes. The o2's controll averything at regular driving

no it doesnt, stop spreading the fail. Ill hook my software up to your stang and show you.

All it does is put you in a different cell you normally wouldnt be in under a smaller pulley. EG: 71 kPa at 1200 RPM under WOT you will just be pushed over to the 78+ kPa cell at WOT but it would still be there without the tune because it was already configured for you.

The only time you need to tune those cells is just to tweak them in to your settings.

As far as the MAF goes, it will go unchanged. NO CHANGE AT ALL. IT SENSES THE AIR coming through. It doesnt change with a pulley. When you changed the pulley all your doing is getting to a higher cell faster.

Also: on a side note... of course you wouldnt need a tune for a ported+polished SC. It doesnt do anything that radical. It wont change your AFR because THE MAP didnt change.

Tell you what. I have a 2.8 pulley in my trunk right now. Ill give you logs of how different my MAF/MAP is beforeand after i drop the pulley to that size.

Guaranteed it will not change, just like when i pullied it from a 3.4 to a 3.0. the new cells i hit will need to be tweaked a little, but not what was already configured+tuned. Hell even my VE table isnt off +/- 1%. Thats unheard of for tuning. (generally 3% difference during different days alone)