jonward786

by all means, keep talking about this. im learning a lot.

Norm Peterson

That is exactly how I read it. What you're looking for is a point at which wave reflection can take place. And I think this applies to H and X pipe location as well, though probably to a lesser extent.


Norm

JMD

IMO, for the most part, when we are discussing certain issues that by using "the best solution" "is supposed" to make a difference of perhaps a couple of percent (or often much less than this) in one aspect or another..

We always need to consider;

1. Does the difference really even matter?
a Is having 508 HP instead of 501 HP worth the $250.00 cost?
b Does that $600.00 MSD Billet distributor do a damn thing for that stock 302?

2. Have we done other modifications that are required for the "solution" to actually work?
a That is one bitchin custom Holley carb!!!.. Will it even make a difference on that stock intake manifold?

3. Are we sure that we even want the all of the effects that the "solution" brings?
a That new single plane intake, Super comp headers, and 3" exhaust are great for your top end power,,, too bad you never get to use this top end on your daily driver, and now your low end torque sucks now...

4. When looking at the "best solution" to an issue, have we maximized other more cost or time effective fixes first?
a That $2,600.00 custom built, low friction, street/strip C-4 tranny "freed up" 12 HP!!! that is great! ,,,,,, but a set of undrdrive pulleys will "free up" 18 HP for $129.00....

My point is that while discussing the "best solution" for a situation is fun, informative, and useful, the opinions and the accompanying emotions can often become rediculius.... (not saying it happened on this thread but I see it all the time, this is one of the things that bugs me on forums sometimes...) The "best" solution is not always best,, sometimes "the best solution" sucks...... context matters, and looking at "the whole package" is probably the most important..

So in short.... "H Pipe", "X Pipe", "No Pipe", Giant Collectors, "Big Primaries" - might matter,,,, might not...

eZ

I completely agree with JMD...when it came time to do my exhaust the x pipe was an extra $300. And for probably the same amount of hp increase as racing stripes. That $300 could be better spent on underdrive pulleys, intake etc.

here an interesting link. engineers try to tackle the subject
http://www.eng-tips.com/viewthread.c...=189289&page=8

Norm Peterson

I wouldn't spend $250 - $300 for one either, or even the $140-ish that FRPP wants for their S197 version. Not for what's essentially a pair of mandrel bends siamesed together. And certainly not for what's worth perhaps a percent or two power. But at the price point represented by a couple of mandrel bends and a little of your own cutting and welding time on a system that you're building up from scratch anyway, it gets a whole lot more reasonable assuming that you have the necessary clearances to fit it.


Norm

JMD

I was talking in very general terms,,, My comments don't really address the speciffics of this discussion except as it might touch the edges of the discussion by chance... (I was hi-jacking the thread.)

Norm Peterson

Odd that you should post a link to the very thread I was thinking of. Since strictly speaking the topic was not a problem that somebody was up against in their work, it tended to get lighter weight responses. There's a hint in patprimmer's first reply that's likely unintentional.

Here's a thumbnail chart I put together a while back that shows more or less what's happening in your exhaust system. It most certainly is not steady flow, and the instantaneous backpressure associated with those spikes is quite a bit higher than what an "overall average" might be and hurt you by more than the brief zero-flow periods help. BTW, that one is for completely separate duals, with the red and blue traces being for the left and right banks. The spreadsheet that generates that plot and a couple others is 700k or so if anybody is interested (edit - I've just cleaned it up a bit, so the charts have a slightly different appearance than the thumbnail - PM me and ask for V8ExhaustPulsing11.xls).


Norm