dmax or missy.

[engineeradam]

i was just hoping dmax or missy could answer a quick question. What is the power gain from a h-pipe? you guys have been right on everything you seem to say, so would it be to my advantage to add a h-pipe in my 6.2 that has true 2.5" dual exhaust right now? and stock mufflers. Thanks,

[Robyn]

Power gains ??? Can't really answer that one.

With a true 2-1/2 exhaust system, the little 6.2 is going to give about everything it can.

One big reason for the "H" or cross pipe back down the system and ahead of the Mufflers is to Kill the RAPPPPPPPPPPPPPPP sound that these will make.

The 6.2 will make terrible rap sounds when run with a heavy foot.

I have heard that power gains are possible.

It will not hurt anything at all to add the cross connect pipe.

Dmax will probably jump in here and add something.

The theory as far as power gains is to add a "Pulse" back into the opposite pipe.
The Fireing order is such that the power pulse(exhaust pulse) comes from one side then the other of the engine.

The back pulse may help the scavenging effect.

I am not sure on the valve overlap specs of the cams used so can't say for sure.

The same cam specs are used with the NA engines as with the turbo engines.

The cams are pretty benign grind. With such small clearances between the piston and the valves as the pistons near TDC the cam specs have to be fairly laid back or there would be a serious wreck in there.

Hope this helps some.

Missy

[DmaxMaverick]

Robyn's right. The H-pipe is very effective to kill the combustion pulse (rap) at the tail pipe. It also optimizes exhaust gas scavenging. Good with manifolds, better, and almost necessary, with headers. It cuts the back pressure early in the pipe, as the gasses cool downstream and dam up. The only drawback is they really should be tuned to the ideal RPM and load, like an expansion chamber and tuned pipe on a 2 cycle engine. Properly located, it can dramatically reduce the exhaust note. Noise is evidence of expended energy. Less noise (all else being equal), is less wasted energy. Less wasted energy results in more usable power, and/or increased economy.

[engineeradam]

Awesome thanks guys. i knew you'd know.

Much appreciated :D