I just have a uni air filter on my machine, I cannot change exhausts in my state without risking a ticket. If I install one of these will the power increase be worth it on an otherwise stock machine? Or do i save my money?
I could get into a very long conversation about this stuff and what my tests have shown but to keep it short and sweet, these things only change the mapping which alters the injector pulse-width and increases spark advance. That produces an increase in flow volume. The intake side is probably OK but could stand not to have the restriction in the stock intake tube at the head but the exhaust side..well, my tests have shown that under hard acceleration there can be as much as 4psi on the pipe-side of the muffler. Yes, I freaked out too. I'm used to ounces not pounds. So it is my thinking that they did this for EPA and other approvals and if you can not allow it to flow better, you may find yourself with little increases in performance but also problems with higher head and valve temps which may lead to a more rapid top-end issues. On a side note...and I am in no way suggesting anyone circumvent and local laws or requirements, but one other thing my tests showed was that without the spark arrester, that 4psi back pressure dropped to around 1.25psi....which is strange as that's the biggest/longest screen I've ever seen for a spark arrester. That drop also made mine run so lean it was clear it was outside the range of the EFI system to make up for it. I either needed one of these programmers...or a spark arrester to add some restriction...which is what I did by adding an HMF arrester to my modified system. That took the back pressure back up to 2.80psi with my 2" end mod. Still on the limits but usable with the stock EFI system. Just providing info-not suggesting anything.
