Stevo wrote:I was able to get a respectable 175 hp at the wheels on a stock 120,000 mile longblock with forced induction, there is potential in the engine, just have to develope it. Too many dismiss it as a poor design, it is not, just needs to be enhanced with better a better intake and exhaust. First place to find extra power is to construct a better exhaust manifold, if you have ever taken a good look at the stock manifold (internally) then you will understand what I mean.
Just because the engine left the factory with 88 hp doesn't mean that's all it can possibly make, it just means that's all the power Mazda wanted it to make, for whatever reasons (mileage, sound/vibration/harshness control, engine smoothness, etc).
Stevo
One of my old Swifts ran 193whp at 11.5psi out of 1.3 dohc 4 cylinder with good power curve. The head design was decent, minus valves and ports were not meant for over double the power. Some extensive port and valve work was required to make the exhaust valves live longer than a year or two with the increase of hot mass air past the valves.
As for sohc, I haven't seen the sohc apart, although I imagine ports and valves are smaller than the BP. The BP has very nice looking ports, good valve size, and I can probably gaurantee that running 175whp on a completely stock sohc will present more long term driveability problems than 175whp on a stock BP.
I'm not saying you can't pick an engine and make it fast, but the BP has easier and more potential. As has been pointed out, it's also very simple to swap and probably cheaper than a rebuild on a sohc. Everybody has a different dream though...
Thanks to all who responded. I'll order the CAI and play around with the exhaust a little when I get some extra change.
