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Message: <blockquote data-quote="sneaky98gt" data-source="post: 939550" data-attributes="member: 11327">While most folks can't do it, it is certainly possible.  I have seen video of a PI head swap, bolt on, geared, 5-speed 98 GT go 13.1 on street tires.  17x9s all the way around, and full weight.  Also have a good friend that has run 12.5 in a PI motor car with bolt ons and a set of Hitech cams, on the stock clutch and not leaving very hard on it. I recently swapped a PI motor in my car, and I have definitely had a drop in gas mileage over the old NPI motor.  With the NPI motor, I got 25-27 regularly; after the cams, I only got 2 good tanks of gas through it, but got 24 and 25 on those; now with the PI motor, I've had a best of 23, but it's usually been around 21-22 mpg.   If someone has a dyno sheet of their car, then you can just do the gear multiplications and see where they cross for each gear to see EXACTLY where the optimal shift point is.  I actually have a program in Excel that will do all of this for you if you input the dyno numbers and gear numbers.For example, here's what the torque on the wheels looks like for completely stock '02 GT (5 speed) looks like shifting at 5800 rpm.  <a href="http://imageshack.us/photo/my-images/27/stock46shiftpoints.jpg/" target="_blank"><img src="http://img27.imageshack.us/img27/1260/stock46shiftpoints.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></a>Notice that the torque just starts to fall off before the 1-2 and 2-3 shifts, which means that 5800 should be just right.  It rises back up a significant amount on the 3-4 shift, which means that 5800 is actually a tick too much, 5700 would probably be about right.And in that case, I can't imagine an NPI headed car EVER being needed to shift above 5700-5900.  With mostly stock parts, I'd say 5700 is a good number to start with at the track, and adjust from there.</blockquote>