Tom
It makes sense and out of 3 sets I just sold my best set- after reading your
out loud thinking, perhaps I should have sold the second best as I have at
least two more Tigers to complete and I could have done a check the first time
I had to remove the headers or stock exhaust- kind of my own dyno by driving
test.At least you saved the buyer some $$$ as I might have read your
"thoughts"- which make sense and ask more for the stock exhaust manifolds;.
EVERYONE on the LIST, Have a nice day and remember to tell your family you
care( Love is a good word to use) them,especially the younger ones.
TonytheTiger
--- On Tue, 6/8/10, Thomas Witt <atwittsend@verizon.net> wrote:
From: Thomas Witt <atwittsend@verizon.net>
Subject: Re: [Tigers] Headers versus Cast Iron Exhaust Manifolds
To: tigers@autox.team.net
Date: Tuesday, June 8, 2010, 1:23 PM
A bit late to reading this but I found an interesting article over on the
Mopar side of my life. They took a mildly prepared 360 and tried every
manifold/header possible that would fit the heads. The bottom line was that
$800 TTI headers added 10 HP over lowly 318 stock manifolds with 24" of open
pipe ( to 5,100 RPM test ). The lauded "340" manifolds (much like HiPo 289
manifolds) added only 4 HP. So, at least for the SB Mopar headers seem like a
lot of cost for very little gain.
The SB Fords are said to have a bad exhaust port design (size). So, I'm not
sure whether headers would help, or become even less relevant. The Tiger is
somewhat of an exception because it came with dual exhaust. But a lot of
people who say headers "woke up" their car typically had a single exhaust to
start. So, sure going to headers AND dual exhaust will make a difference. I'm
not down on headers, it just comes down to need, cost and added possible
troubles (leaks, dents, clearance etc.). Remember too that "Bigger is not
always better." Nor is there a desire to "have back pressure." What you want
is velocity. The exhaust piping size should be matched to a desired RPM
range.
Which brings me to the concept of variable exhaust. Just like there are multi
valve engines that allow for good intake velocity and the ability to meet an
added demand I'm surprised there aren't designs that follow a similar concept
on the exhaust side. I'm thinking of a smaller primary exhaust pipe with a
sprung flap that vents to a larger pipe secondary pipe on demand. Anyway,
just thinking out loud.
Tom _______________________________________________
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