K20 project off to a good start

kmead said:
I suspect the biggest area he is avoiding cutting is the structural tub around the front of the engine or at least minimize it. The firewall is primarily along for the ride so cutting into that I don’t think bothers many aside from losing the spare. Personally I would go after the downdraft manifold approach to minimize manifold issue.

Having a K24 in several of my cars I agree about the need for access and space on the front of the motor given the difficulty of accessing the alternator. Not having to fiddle with the AC compressor to change the alternator will make it much easier.
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The cuts to that crossmember component (I think what you are referring to) might look scary, but the way I did it involved replacing the original steel with something slightly heavier and basically the same shape turned inside-out. At the same time, the subframe, once bolted on, lends its strength to the cut area.

Anybody afraid of a strength and material loss in that area could easily sink a piece of 2" square tubing into the opening and set it on the floor of that crossmember. Just drill large holes for clearance above the two projection nuts that are welded in for mounting the subframe and Bob's your uncle. Weld it all together and you should have something stronger than what you found.
 
leox19 said:
All good stuff - however the long intake runners and plastic plenum underneath are only there for one thing - low speed torque and enhanced efficiency - all good in a heavy car striving for fuel efficiency. Looking at short quad throttle bodies = more power at top end.
Regarding access all that will remain on the block front side is the starter motor , a new one here will last me out!
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Plastic plenum? Which intake manifold are you referring to?

The K20A2 and Z1's PRB intake is not going to be easy to improve upon. The K20 is an exceptionally well-engineered engine with few stops left in. The intake manifold can be ported for more power, and new ones can be built that might offer better top end power at the sacrifice of low end power, but keep in mind that the A2 and Z1 happily rev to 8500 as built. Honda developed these engines as performance engines, not under-stressed family haulers that could be uncorked for loads more power.

I suspect that without a whole lot of modeling and testing, a willy-nilly approach to a SRI is going to cost power somewhere and gain it nowhere. Keep in mind that what sometimes feels like a high RPM surge in power is actually just climbing out of a loss of mid range power created by a SRI, a shorty header, etc.
 
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