Mustang Evolution Forum banner
1 - 20 of 27 Posts

1,435 Posts
Discussion Starter · #1 ·

Campbell X-PipeTM Acoustic Super ChargerTM what is it?
How does it work?

Please take a moment to understand why the Acoustic Super ChargerTM powered Campbell X-Pipe TM is such a powerful and profitable invention. The Campbell X-PipeTM is the most cost effective and simplest way to make real horsepower on any engine.

Background. To better understand the Campbell X-PipeTM, first look at the extremely successful 4into1. The 1940 era 4into1 was "tuned" (timed) by joining multiple equal length head pipes into a single, larger diameter collector to communicate and maintain momentarily, a periodically produced scavenge (suction) pulse generated by the high velocity exhaust gasses alternately exiting each head pipe. The collector allows this scavenge to 1. reduce atmospheric pressure in the non-exiting pipes, and 2. exist slightly longer within the exiting pipe to help extract residual exhaust gasses from that cylinder. When introduced, the 4into1 was a remarkable improvement over the log manifold used on the poor flowing flat head engines of the day.

However, 4into1 limitations became apparent over the years as engines, but not 4into1s, evolved;

1. 4into1 tuning is static and limited. Modern engines lose low rpm torque. The fixed head pipe length creates a minimum rpm torque range because atmospheric air has time to push hot exhaust gasses back into the head pipe between exhaust pulses, filling the cylinder and even the intake manifold, reducing power.

2. The power band drops off at high rpm. Exhaust pulses are slowed down and stack up as they enter the larger collector cross sectional area, creating excessive back pressure. (As a result of these constraints (1 & 2), a highly tuned 4into1 will usually have a very narrow power band.)

3. As engine cylinder head design improves air flow, scavenge becomes over-scavenge (as unburned air/fuel from the intake manifold can more easily loop through intake and exhaust valves during overlap, to be sucked out the tail pipe as unburned air/fuel; HC emissions).

4. Air/fuel mixture varies radically depending upon rpm; at low and high rpm, the mixture has full strength, but at the tuned rpm over-scavenge removes unburned air/fuel, weakening the mixture and reducing dynamic cylinder pressure.

5. *High compression pistons are used to improve reduced dynamic cylinder pressures at tuned rpms.

6. *High octane fuel is used to prevent detonation during un-tuned periods of normal dynamic cylinder pressure.

7. Special cam shafts are used to improve the high rpm power. Long duration exhaust cams open the exhaust valves earlier, cutting into the power stroke, to dump additional combustion energy into the head pipes (robbing combustion energy from the power stroke) to increase exhaust gas pressure to overcome top end back pressure. Because the power stroke event duration is decreased, the engine loses thermodynamic efficiency.

Enter the Campbell X-PipeTM! It changes everything. 1. Tuning is not based upon head pipe length and can be dynamic. 2. The power band is much broader because scavenge is not lost at low rpm and back pressure is not produced at high rpm. 3. A high performance engine will not be over-scavenged because the Campbell X-PipeTM Acoustic Super ChargerTM does not need to create and maintain suction to work. 4. Without over-scavenge, engine mixture does not vary between too rich and too lean and back to too rich as rpm increases. 5. High compression pistons are not needed because dynamic cylinder pressure is not lost. 6. High octane fuel is not needed because high compression pistons are not needed. 7. Special 4into1 cam shafts are not needed because additional exhaust duration is unneeded and wasteful.

(* #5 & 6 Although not needed, these items can be added to the Campbell X-PipeTM for improved performance.)

So, where does the HP come from, with the Campbell X-PipeTM? The engine is more thermodynamically efficient (it generates a greater dynamic cylinder pressure while using a longer, more efficient power stroke), it is more fuel efficient (due to reduced over-scavenge) and it works with fewer engine modifications. As a bonus, since the Campbell X-PipeTM can work with a short duration exhaust cam (allowing a longer power stroke) exhaust gas temperatures (EGTs) are cooler. Cooler EGTs can allow the tuner to lean the mixture to make even more power, on less fuel!

The Campbell X-PipeTM is not a something for nothing device. Rather, it gives you what you thought your 4into1 promised: More Power, Everywhere! In addition, the Campbell X-PipeTM gives you a broader power band and greater fuel economy.

We are gonna get some test data and then I am going to grind some
special cam(s) for this system. There is so much more to it than the
website mentions, Monty (Dr. Campbell) told me the actual concepts
that govern the system and how to take advantage of the concept
with camshaft specifications. It gets more exhaust flow from the same
cam duration, and opening the exhaust valve later keeps the power
stroke doing its work and the chamber still gets fully evacuated due
to the superior ASC tuning. It is a self-tuning (adjustable) dynamic
device. Torque peaks on a V6 are 3000, 6000, and 9000 RPM and
while the last one is very high, the first two are very useful!
The power will not just be at those RPM's, it will be good useful
torque at all RPM's between, those peaks are just "bonus" points
of extra torque, caused by the system's resonance.

OK, I'll answer the Q's as best I can now...

1,435 Posts
Discussion Starter · #2 · (Edited)

That is the original thread, I moved it here since the old threads
are not returning emails now.
The system is avail. in any size, most V6's would need 2.25" which is
special order. Strokers would use the standard 2.5" so that is preferable.

Cams are avail. FOR LESS (discounted prices) on an R&D basis, also
anyone willing to try this system can purchase it at discounted prices!

I BELIEVE in this system, or I would not show it.
I WILL do one for myself, when I get another car this year.
Had to sell my Stang because of my own personal hardships,
so these good projects have to wait :cry:

1,435 Posts
Discussion Starter · #4 ·
Well, your camming and NOS bias kind of works against the
system as a whole, it was not suitable for the overall setup.

It could be setup as a combination system, but the bias
would have to be set towards NA torque, with occasional
nitrous use, and I never discussed the requirements with
the inventor, Dr. Monty Campbell.

The camming for the exhaust side is the exact opposite of
what conventional NOS camming theory calls for. But so is
the conventional NA camming too :) Opposite of conventional.

This system loves really short exhaust timing and lots of overlap.
the exhaust valve, in conjunction with the additional overlap, acts
a a secondary "intake system" as the ASC introduces fresh air thru
the exhaust tubing back into the chamber! It is that good...

1,435 Posts
Discussion Starter · #6 ·
No dual exhaust system bolts up to stock cats...
I presume one could be ordered that is off-rod, and
would bolt to stock shorty headers...

1,435 Posts
Discussion Starter · #8 ·
I get no kickback from Campbell, but can do cams that match.
He said it works well with stock cams in the sense that short
stock exhaust timing works well with the system, but also told
me what kind of timing parameters worked best, and hi-flow
exhaust ports (ported) and short duration exh. lobes with
appropriate lift (disimilar to stock) helped too. He claims
40#-ft on a stock 4.6 and the gains can be bigger with a
fully tuned system.

Mostly science at this point, but if someone wants to try it
I can make them a special deal on a cam/spring setup. I'm
trying to get a gineau pig in other words :D

2,381 Posts
rgr, i can't do this now, but i will need at least 2.5" piping for the 2.2 autorotor and built 3.8 i'm doing. you had told me 3" would be better, but isnt' that overkill? if i went above 2.5" i'd need custom headers. i just would like to get my priorities in line. either way, whether it is 2.5/2.75/3", can he custom up one for my 6 banger in months to come?

1,435 Posts
Discussion Starter · #10 ·
tire said:
...I will need at least 2.5" piping for the 2.2 autorotor and built 3.8 i'm doing. you had told me 3" would be better, but isnt' that overkill?...
The 3" comment was in the context of a conventional system,
2.5" duals are good to 400 BHP before beconing a restricion at
all on a conventional setup. If your big Autorotor deal comes thru,
it might be going over 400 BHP.

The Campbell ASC can flow more air thru the 2.5" twin-acoustic
supercharger setup, as it is pretty much perfectly tuned for that
size piping, so a 2.5" system in the ASC could probably handle
a good bit more BHP than a conventional 2.5" setup. IMO you
can probably make more HP with a small blower and an ASC
with mild camming, and easier, cheaper, than all teh trouble for
a huge blower and all that. The ASC, if it works as advertised,
would add gobs of torque at 6K and most supercoupes are done
at ~ 5000 RPM, so major gains can be made thru the proper
application of camming and breathing, and valvespring technology.
All these things are now coming together, I just got a brand NEW
valvespring (conical) that does everything anyone wants in a conical
these days! Tomorrow's valvespring is here today!

A Campbell ASC system is velocity based, and on a V6 it has a
resonance point at 3000, 6000, and 9000 RPM's. The first 2
are quite usable, and I suspect there is another harmonic down
around 1500 RPM. This one would kick in at cruise speeds, but that
is still debatable and I will have to ask Dr. Campbell more Q's but
all resonant systems like this have sub-harmonics that are mathematically
related to the ones that show up on a dyno. (A V8 has 2000, 4000,
and 6000 RPM resonance points, and also at 8000, those V8 guys are
so lucky in many ways :D)

The thing here is, as you make your SC setup "less streetable"
(as in higher boost) it reduces the effectiveness of the ASC
because you need more exhaust timing (or WAY more exhaust flow
thru the valve) to make the SC work, and the LCA's need to be tight
for the ASC, and wide for the SC, so those 2 things fight each other.

If you settle on a boost limit, and stick to it, I can design a system
that works all around with the ASC and a 2.5" (or 3") system, the 3"
would definitely be all you would ever need, but if U use the ASC then
I strongly suggest bigger exhaust valves and properly matched parts
all the way thru, and we can probably use a 2.5" system if you keep it
realistic. A semi-wild supercoupe spec cam, lots of lift, and a proper LCA
will work wonders for a setup like you want. I'd just drive the M-90 full-blast
and then maybe later, get an Autorotor just to increase efficiency, not to
up the boost alot. The ASC really makes a difference with the right cam,
you just gotta get the LCA and flow right, and if you get these things right,
it will be a real BEAST in the designed RPM ranges. Then you could tinker
with the boost levels a bit.

2,327 Posts
So doesn't this guy make X pipes with Hi flow Cats in them? Oh, and if so, what sort of prices, these in Stainless steel usually run in the range of around 400 or so....

1,435 Posts
Discussion Starter · #13 ·
This is not an "X" as such, but it uses 2 of them
in some arrangement to generate the effect of the ASC.
The concept was first patented in 1916 for diesel engines...
This is a different arrangement for overall torque increases
for gasoline engine applications.

1,435 Posts
Discussion Starter · #16 ·
For the ASC?

I have talked to Dr. Campbell for several hours now, and
I've had lots of scientific reading and science classes, it
makes sense but we are going to get a tester and some
hard data on a V6... I also have worked out some cams
that will work awesomely well even without this system,
but great with it, provided the concept works well. I also
got my new cam catalog of lobes in and there are some
really great new lobes! I have full data now from 3 grinders
so I have lots of flexibility in cam selection.

1,385 Posts
Well, the claims in his patents make sense to me, HOWEVER, I do not see how the claims made in his patents can be realized in a cat back system. In fact the drawings in his patent, used to illustrate the concept, do not use a cat, much less four of them like in our exhausts. Be interesting to see how his exhaust stacks up against another "performance" exhaust and stock.


1,435 Posts
Discussion Starter · #19 · (Edited)
I even had questions about that aspect, I believe that
the "effect" of the ASC could work thru cats, but his own
statements about pipe sizes and taper, would lead me to believe
that Stock Cats (with reducers before and after) would reduce
the "effect" somewhat. His testing showed +18 RWHP over
something (let's assume worst case, STOCK, but it may have
been over your run of the mill catback system) so that is a good
gain. I've never seen #'s like that from any other cat-back.
Total systems, yes, but not a catback.

High Flow cats without reducers would work best in a system
like this, according my interpretation of our conversations.
Like anything, optimizing can give greater results!
1 - 20 of 27 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.