Will swapping the d16y8 head on my d16y7 yeild any increases in gas mileage? With the y5 head? If I remember correctly, I read somewhere that the y8 head is the most effiecient but, while vtec is ingaged, the p2p ecu is very liberal with gas useage?

 

keeping it completely stock will yield the best MPG for you. bolt ons wont change it much, but do help sometimes, if you can keep out of the gas after the mod. the y5 is vtec-e and if you converted your car to vtec-e it would definately increase mileage, but wouldnt be worth it IMO.

 

Swap in the 92-95 CX tranny if gas mileage is what your looking for.

 

is the 92-95 cx tranny geared more efficently than my 98 cx tranny? Also is incorrect then that in the non vtec range the y8 is still less effiecnt than the y7?

 

I wouldnt say it geared more efficiently, it is geared taller. 80 mph reads like 2500 rpm if i remember. Thats for the 70 hp engine from that car too.