Quote:
Originally Posted by Shawn D.
Well, how "low" are you and your passenger going to be? That's the frontal area issue, not the engine. If you put the engine upright behind you and your passenger, it will have a negligible effect on frontal area.
Even if your scheme was practical, there'd be no "pumping gains" to be had, really. Taking a few bends out of the exhaust is going to have a negligible effect. You'd be better off to fabricate a system with mandrel-bent curves instead -- gains from that are noticeable and well-documented.
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You just contradicted yourself... if you're taking the bends out, flow will have increased velocity and lower pressure than if there are (even smooth) bends.
You say that there are no measurable gains from "taking a few bends out of the exhaust", yet you claim that there are measurable gains from "mandrel-bent curves" in the exhaust.
So, given the OP's question, you're essentially telling him that more power can be had using a mandrel-bent, curvy exhaust, than a straight, bend-free, less restrictive exhaust, correct?
In the OP's representation, the "few bends" that are being removed are normally critical pressure points... They're the areas that commonly are re-worked for higher performance to begin with. Straight flow in that area would help prevent flow-reversion characteristics and the overall pressure drop compared to a "normal" head design might yield interesting effects.
I wouldn't be so quick to shoot it down, is all I'm saying.
Unfortunately, with respect to the angle of the valves in the head, a truly flat, straight exhaust would require the engine be mounted at an angle, as well. I believe it's approx 15*, but don't quote me on that.
So that would require the engine be mounted at least 15* from horizontal... which is great for draining oil away from the cylinders, as well. Dry sump the system, and there is no pooling issue.
Given the money and milling apparatus, it could be pulled off, I say.
I'm with Frank on this one though. Fun to discuss, but unlikely to occur.