More on so-called Tuned Exhaust

[GAHorn]

Looks more like a dead donkey to me. What's that she's holding?

(One of the nice things about open discussion forums is the fact that each individual is in charge of which topics he wishes to read and which he wishes to disregard. If the subject line of a topic has lost interest for you, then there's no obligation to click on that subject and read it. I believe it was one of our earlier commentors in this thread who (in a mood to shut another person's participation down) issued an admonition against shutting others down. We can all choose which threads to participate in. There's none that are required.)

[doug8082a]

I know, George, I know. But I couldn't resist it. I find the subject interesting, but I would think you guys would have tired of the back and forth by now. It was strictly meant as a little levity.

P.S. Bruce is right

[GAHorn]

My last comments weren't especially directed at you, (or anyone particularly) Doug. (Besides, I thought the donkey was funny!)
This is a great group, and I hope it's fun for all.

[doug8082a]

No harm, no foul.

[Jr.CubBuilder]

One thing point that I don't think anybody has mentioned here is that a "tuned" exhaust system is very dependant on the rest of the induction system, the intake side,(Inserted by George: Oh, reaaally...

"You never answered my question if you thing a tuned exhaust works in any installation." A'contrere, my dear Bruce. I did indeed remark/imply how individually tuned exhausts are beneficial when mated to tuned intakes....gahorn

most importantly the camshaft profile, valve lift, duration, and overlap.

Unless these variables can be tailored to suit, the exhaust side of the engine has very little effect on performance. Especially in the case of our aircraft motors which are detuned to trundle along at about 2500 rpm for thousands of hours.

There's plenty more power to be had out of our 300 cubic inch six bangers, but not at 2400 rpm, not without some sort of forced induction, which in turn would probably lead to excessive heat problems. Heck they got another 30 or so ponies out of these motors just by spinning them faster and called it the GO300.

If the valve timing were changed, along with cam lobe profiles that used a significant amount of overlap then a properly "tuned" exhaust system would indeed result in more power. There is a very real science to this, but getting more power out of a motor this way involves spinning it faster, and gives up longevity for performance.

I know that a tuned exhaust CAN help milk more power from a gas motor. However, unless it replaces a system that is just grossly inefficiant it really won't make much difference, if any. The stock exhaust on our C145 and O300 motors is actually a very efficient looking setup for the kind of rpms we spin them at.

[Walker]

What did you do Jr. Cubbuilder, find a lawyer to rewrite my opinion? (no effense intended) Sorry to all about delaying the burial. Time for me to move upwind. Good discussion, enjoyed it.

[N1478D]

Driving by a yard sale noticed that there was an old red Electrolux sitting there. Grabbed it, went down to Austin while George is out of town and hooked the Electrolux up to the exhaust on that old slow red B. Now, if I can find a longer extension cord, maybe George can finally get some speed out of that old airplane.

[GAHorn]

Driving by a yard sale noticed that there was an old red Electrolux sitting there. Grabbed it, went down to Austin while George is out of town and hooked the Electrolux up to the exhaust on that old slow red B. Now, if I can find a longer extension cord, maybe George can finally get some speed out of that old airplane.

That story just doesn't fly, Joe. In fact, it sucks! (Bruce and I will both agree on that, I'm sure.) You're just trying to give us all a "hose job".