Re: headers (yet again)

[Iain Mannix <mannix@privateI.com>]

>>downpipes claim a +15 hp increase over other types. I just got my new
>
>However, TT refuses to guarantee ANY power gains over the stock 16v downpipe.
>
>>around a stock G60...oh heh forgot to mention my NOS too..should be
>>good for another +15 at least..hrm 180hp..saweeet!
>
>If only it were that easy...

No kidding...

>
>You've seen the latest "Project" 16v article?  On the dyno, the full TT
>stainless system from header to tailpipe, plus the Nology ignition parts
>gave a whopping 3hp.  There's obviously something wrong with that car, but
>even so I wouldn't call it a ringing endorsement of the TT exhaust.

I'm not sure there is anything wrong with the car, actually.  Quoted power
gains are always about twice what the manufacturer claims - TTs are
probably the most honest, and even theirs are a bit optimistic.  I read an
article in C&D or R&T recently about modifying a Mustang - they bought
heads, intake, cam(?), a bunch of other stuff costing well into the
thousands - the claim was for a gain of 120+ horsepower.  On their Vericom,
the noted a gain of 75hp.  Not bad, right?   Well, think of a claimed gain
of 12hp - you'd maybe only get 7.5.  Most of the exhaust ads claim a gain
of 7-10% - 7% of 90hp is 6.3hp.  That's assuming that a JH engine is really
making the when new claim of 90hp - what if it is down on power 10%?
That's 81hp, right?  So, a 7% gain would be 5.67hp.  That's assuming you
get 7%.  Lesse, if I added up all the claims on my engine, just for
giggles(yes, I am bored.  I called junkyards this morning looking for an
intake manifold to play with, they all wanted at least $50.  Umm, no, I am
not paying $50 for a frigging Rabbit intake - anyone have an 8v manifold
they want to get rid of?).  OK.

90hp JH(yeah right, it has 140k on it....)
K&N - do they make claims on power increases?  Neuspeed is claiming 3-4hp
for their foam filters.  Let's say 2% - 1.8hp
3" intake tube, PowerPipe does not claim #s, 1% for giggles - .9
Neuspeed TB - they claim something ridiculous, what, 8-10hp?  OK - 8hp
Ported intake, a la Bellview(but better, IMHO), they claim 21% flow, a gain
of 7-10hp(cough...bulls...cough), call it 8.5hp.
BMS header, I forget their claim over stock(oddly enough, they don't
advertise claims anymore on the header), lets call it 5% - 4.5hp
Good exhaust, let's call it "equivalent" to Eurosport's "Race" exhaust - 11hp

OK, those are the things which often get claims which are on my car.  My
engine had 150psi on all four cylinders last time I checked(5 months ago,
maybe).  It is a decent(not like new) example of a(140k) JH engine.  So, we
add up the claims and get....

34.7hp in "mods."  Sure, pal.  That equals 124.7hp at the crank.  Umm, no.
My car has 117 corrected(SAE) horsepower at the crank, from the last time
it was dynoed.  It also has timing at 12d btdc, which was good for 1-2 over
6d on the dyno, an aftermarket ignition which was good for about 3hp(that's
why it was dynoed - we put stock stuff on, ran it, put the aftermarket
stuff on, ran it, 3.5% gain), synthetic fluids and driveline greases(reduce
frictional losses), some injection tweaks to get better fuel delivery at
high rpms(although some of that was not in place at the dyno day).  This
7.7hp discrepancy is ridiculous - not only does my car have all the above,
but it has lots and lots of other little tweaks to make it run better.  No
cat, either.

As for TT claiming 15hp for their header, it was "over other street type
headers for 16vs."  This does not surprise me - 4-1 headers tend to make
more peak power than tri-y, which is the most common "street type" header
out there.  Plus, IMHO, the majority of "street type" headers out there are
junk, including the BMS header - I can't imagine it being worse than the
stock setup, probably a bit better, but the reason I bought it was because
a twin downpipe setup would have cost me a lot more than the header - the
BMS header was $159, twin downpipe was going to be a lot more for new
stuff, a little more for a new downpipe/used manifold, and I did not feel
like trying to find the right dual downpipe manifold.  I like the header,
and I am sorta looking for a truly tuned header, one that utilizes primary
lengths to maximize scavenging - the TT part is high on my list, but it
needs to have some sort of flex coupling incorporated.  We shall see.

As Shawn pointed out, EC did not do a dyno test before the exhaust - this
3hp gain shown on the "Project 16v" is assuming that the car really was
making 123hp.  I'd be surprised if it was actually making 123 - it has 110k
miles on it, which is not much as far as reliability, but I'd not expect a
car to be making the "new" level of power at 110k miles.  What if it lost
5% over the past few years?  116.85hp.  10%?  110.7hp.  I'd say a 5% loss
in power/efficiency over 8-10 years is not unreasonable.  If that is the
case, then the exhaust really added 10hp(just shy of).  Not too shabby.
What if it were only 2.5% down on power?  119.92hp?  126.6-119.9 = 6.7hp.
Again, IMHO, that's not a bad gain from an exhaust alone, claims be damned.
I basically refuse to believe without proof that an engine with 110k on it
is still producing 100% of its original power.  Maybe it is.  I _really_
doubt it, however.  EC should have done a test before and after if they
wanted to document gains accurately.  Oh well.

As far as I am concerned, the claims given are crap.  For a basic estimate
of power increases, take the lowest claim given, halve it, and you might
get that if you are lucky.  You have no way of knowing what else had been
done to the car that produced these claims - a bone stock 8v is going to
gain less than an 8v with intake work and a cam when the same exhaust is
fitted.  No surprise there, but how do you know what had been done to the
car in the first place?  You don't, for the most part, unless they tell
you(like the "Amazing Dyno Stories" TT put out a while back).

For this reason, when this ignition(finally) gets to market, it is going to
be advertised as showing a 3.5% gain on _my_ car, not an "84 Rabbit GTI."
I don't know how he is going to word it, something like "SCCA SoloII D
Street Prepared 84 Rabbit GTI."  Something like that, as the ignition may
or may not gain as much on a stock Rabbit.  We don't know, but those that
do have it on more stock cars than mine report a good seat of the pants
feel/similar improvements as mine.  Who knows.  I like the guy doing this
ignition - he is a racer, he knows that the claims are often crap, and if
he says "5%," well, it really did improve things by that amount on that
car, and he believes that it'll show similar gains on similar cars.  3.5%
does not seem like much, but it is surely noticable, and it really is
there.  Anyway.  Like everything in the popular press, it all has to be
taken with a grain of salt - exaggerated claims are nothing new, everyone
does it.  The ignition guy fully realizes that his numbers are conservative
in comparison to the others, but he is hoping that a reputation of real
gains and reliability will come out of his efforts.  We shall see - I like
the ignition, it makes the car run better, it revs better, and even if it
is only 3hp, it sure feels good!


I.Mannix


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