Improving breathing

[wokkywokky]

Everyone keeps going on about how crap the breathing on the inlet side of things is on the ajp8. Does anyone know where improvements are best made?

I guess it would be the head that lets the side down as the inlet manifold seems simple enough, though I have thought about knife edging the butterflies. A process of streamlining by removing one side of the throttle shaft and adding a radius to the edge of the bufferfly. Can valve sizes be increased and where can I get the heads ported? Cheers

[dannylt]

I don't think the butterflies are a big restriction, if anything it will the the sharp bend in the inlet port afterwards. The red rose engine mods include serious work on this area, though apparently there is waterway you can hit. The exhaust port is reshaped as well, and modified valves are used, but no larger - think they're pretty much as large as you can fit in.

The 4.2 inlets can be ported for around 20bhp, but big increases are only going to be gained by remapping, in addition to mods.

With raised compression and remapping for 97 I guess you can get 50 to 70bhp.

If you have a 4.5, you can get the porting and compression mods done by the factory, and be charged around 4k for the privilege. Seems like a moderately guaranteed 50bhp to get up to about 400. Just make sure you don't plan on selling it afterwards!

danny