ok my chipped p28 was throwing a code 13...which usually means i have to buy a new ecu. this was on my a6/z6 mini me. i was in limp mode but even in limp mode i had a super torquey low end power at least to 3500 rpms where i was limited.
i bought a p75 with vtec added and zif socketed. i threw in the chip i had in the p28 in to the converted p75. the car over all feels weaker. it isnt as torquey anymore. the overalll power band feels weaker. and of course the age old SOHC vtec not feeling it engaging.....
so would this p75 work exactly the same as a p28. p75=vtec added, zif socketed, xs engineering chip.

 

Well, if VTEC isn't engaging and the ecu feels week overall with your supposedley onverted P75 ecu, then yeah, obviously the P75 isn't working out too well for ya. Is the P75 ecu giving you any check lights with your XS chip applied to it?

Reason why your car feels torquier with the P28 is because the ecu is in safe mode and running rich.

 

i have no CELs...
man i thought limp mode was supposed to give me **** for power and torque. I knew it was going to run rich but didnt expect it to be so much more torqueier...i am going to hook up a vtec light this weekend to see if it engages.
but if the ecu is converted right it should work fine right? should mess up anything? or run the car differently?

 

ok vtec is engaging...but like i said overall the ecu makes my car feel so much weaker...

 

well, if you have a p75 converted to p72 and using the same map specs as you had before the car should run the same..
placebo...

 

its a p75 made to run as a p28 . the car was way torqueier when i had a actual p28 in it.

 

I have a few spare Barometric sensors. Would you like me to fix your P28?