quiz: exhaust collector/tailpipe assemblies for FFords

[Bill Manofsky]

As I recall, the Porsche 936's were the ones that used them. The reason why they had to route them sideways was because other cars kept running into them. You get a pressure drop when the additional elbow is added. I don't recall the 914's or any others.

The primary reason is that few drivers did the same research as Art and/or have the same access to a dyno. They trust the parts suppliers, engine builders, or just bolted on what was convenient so they can get out on the track and drive. Fine tuning for additional Hp through the exhaust was an after thought.

Most people think that as long as you put on any old header that you will get the best performance. This is not correct. Header design is engine specific and a black art.

In fact I am in favor of tuneable extensions that are then pre set to the proper harmonic sweet spot on the dyno.

I do agree that using a horn may be problematic at Laguna Seca or any track with db restrictions. The Supertrap I have on my 914 is essentially a horn, but the baffle plates that have to be added for sound attenuation significantly diminish any advantage from the horn.

[Art Smith]

Bill-

I agree "speed" through the air should help with exhaust flow through both the megaphones and the horn. that said, ALL of the real gains are being made on the acoustics side of the equation. recent testing confirmed that Kent's appreciate attention to detail when it comes to inverted pressure wave tuning, forming, shaping, and stretching. anticipating and dealing with the variability in the speed of sound (irreversible expansion, irreversible compression, & heat transfer) through the exhaust to get path lengths right is the real challenge. given the zero sum game nature of "acoustics" based designs, the other challenge is where in crankshaft degree space to "bet your money". surely the return-on-investment (aka: ROI) is NOT a constant across overlap and there's not enough chips to cover the board...........................!

Art
artesmith@earthlink.net

[Bill Manofsky]

yes, you are shooting at a moving target. Humidity, barometric pressure, ambient air temp on top of RPM and octane dependent burn rate will effect the acoustic sweet spot. Trying to then find the happy medium with a fixed exhaust config is a challenge. Your research efforts to resolve this are much appreciated.

[Tom Valet]

Art, seen at Daytona today, have you been messing around in DSR?

[Art Smith]

Tom-

funny you should ask, it just so happens I have been working with a local horn quartet (ie: only 4). haven't been able to find anyone to stand in for Herb Alpert so the thinking is a horn quartet might have a unique sound that would sell records/CD's/........ given it's a middle-of-nowhere pick-up group, none of the guys have modern horns so I'm now attempting to find them better instruments before their first concert. none of the music reviewed so far even begins to approach the originality and sound of "The Lonely Bull", but just imagine a piece of music written and orchestrated for a horn quartet with a Kent "accent"..................... even "muted", a horned quartet should provide serious music for the ears.

Herb Alpert & The Tijuana Brass "The Lonely Bull"
https://www.youtube.com/watch?v=B-5iwhbBd-I

Art
artesmith@earthlink.net

[John Merriman]

Art......Art......Are you okay?

[Art Smith]

John-

hope the delinquent reply brings a smile to your day!! it's finally getting warmer here in the desert which makes getting things done a great deal easier.

horn quartet - ie: a musical group with four horns! attached picture shows the middle-of-nowhere Kent "horn quartet". there's no solo artist; everyone plays the same music! as part of the upcoming exhaust trip to the dyno, the dyno version of the horn quartet will be tested. I'm anxious to quantify where the "horn quartet" is performance wise compared to my single horn solutions AND can hardly wait to hear the music!! all four horns are commercial 16ga megaphones configured for the group's needs. performance better than expected or a particularly sweet sound might be enough to get the supplier to finish the currently stalled full custom hydro-formed exponential horn (0.035" wall vs 0.063") project for the quartet ................

Art
artesmith@earthlink.net

ps: a local competitor has already been approached so after dyno testing there's an outside chance the group gets its first "gig" sometime later this year......

[stonebridge20]

Need......Want.......Must hear what that sounds like !

[HayesCages]

Will be interested to "hear" what the sound level is at full load. Have you tried adding a small dia. (1.5"), short section of tube in the end of, and centered in each mega? Held in place with a few strips of metal.

[LenFC11]

Art

That is just beautiful! A work of Art one might say!

Is it possible to post a sound clip?

[Art Smith]

Len-

working on it. the challenge is getting a recording in a format that can be uploaded AND widely enjoyed as I haven't done cell phones since retiring....

Lawrence-

"sound management", if required, is being left for a rainy day

Art
artesmith@earthlink.net

[LenFC11]

Art

Congratulations on retirement.

Look forward to hearing the quartet in all it's glory.

Could you imagine following a car with that exhaust sticking out the back?!?!

[Jnovak]

Art, seen at Daytona today, have you been messing around in DSR?

this car has a flat 6 cylinder 2 stroke engine

[Jnovak]

Thanks a ton for all your effort Art!!!

[Art Smith]

Friday the Middle-of-Nowhere Horn Quartet performed their first public gig (invitation only) at
an up and coming club in Orange County (Southern California); as the group's sound
engineer and unofficial manager I had the opportunity to attend. time was short due to the club's
busy schedule so the Quartet only had time for one number even thou they traveled with sheet music
for three additional tunes. keeping in mind the biased nature of my position and love of all music
from Kent, the group's sound was pure music to my ears !! security was tight as you might
imagine/expect, but I did manage to get a small inexpensive Nikon digital camera into the gig.
although the camera's video sound quality clearly isn't up to that from my studio microphone and
doesn't do the group's sound justice, the video has the potential to be a priceless recording of the
group's first small steps toward stardom..........

https://www.dropbox.com/s/spsw706p0r...N0004.MOV?dl=0

Mr. Dyno (didn't get his first name or business card), the club's resident music critic was impressed
with the group's sound and shared on the way out that he thought the Quartet's sound was slightly
better than the single horn act that took the fall classic by storm in 2018. he wouldn't speculate about
the potential impact of modern horns on the group's sound or the impact of arrangements to improve
the group's mid-range harmony...........................

Art
artesmith@earthlink.net

[Bill Manofsky]

https://www.dropbox.com/s/spsw706p0r...N0004.MOV?dl=0



Wow... a symphony!

Sounds like throaty big bore.

[marshall9]

Holy Moly ! That is awesome !
Now for my Pinto?

[stonebridge20]

That's awesome!

[Joefisherff]

They would look great poking out of the back of my Swift Art!

[Daryl DeArman]

Interested to see how this experiment plays out. Does the area under the more peaky curve create enough advantage at certain tracks, to overcome the packaging/aero issues?

I love the always thinking outside the box.

[Art Smith]

Mr. Phelps:

this post is intended to serve as your official two week notice that your "forecasting
services" are no longer needed by the firm. your contributions historically have been
very helpful but the firm elected to pursue digital engine simulation technology over
five years ago. after three years of intermittent development work on the project, the
firm finally has a digital engine simulation that provides excellent correlation with dyno
test results of our historic exhaust system designs. after the current collection of
intake and exhaust hardware awaiting dyno test is tested, the bulk (not all) of the
firm's design and performance testing will be done in the digital domain. thanks
again for your years of forecasting services and best wishes to you going forward!

Arthur E. (Art) Smith
artesmith@earthlink.net

[steve zemke]

Mr. Phelps:

this post is intended to serve as your official two week notice that your "forecasting
services" are no longer needed by the firm. your contributions historically have been
very helpful but the firm elected to pursue digital engine simulation technology over
five years ago. after three years of intermittent development work on the project, the
firm finally has a digital engine simulation that provides excellent correlation with dyno
test results of our historic exhaust system designs. after the current collection of
intake and exhaust hardware awaiting dyno test is tested, the bulk (not all) of the
firm's design and performance testing will be done in the digital domain. thanks
again for your years of forecasting services and best wishes to you going forward!

Arthur E. (Art) Smith
artesmith@earthlink.net

Art, Say it ain't so

[Art Smith]

Steve-

think of it as a simple TQM exercise; quicker more accurate "forecasts", experimental hardware fabrication and testing cost reduced by at least 70-80%, AND NO politics. using a vintage 2005 exhaust design and period dyno data to calibrate the digital engine simulation, the simulation is already providing "forecasts" on the order of ±2%. with better input data, particularly cylinder head flow test data, ±1% may be achievable for the Kent. the digital engine simulation as currently configured can be used to "forecast" engine performance resulting from exhaust system design changes, camshaft timing changes, ignition timing changes, lubrication system changes, cylinder head configuration changes, and intake system configuration changes. as good as Mr. Phelps was, he didn't have the speed, accuracy, breath of forecasting capability, or clinical objectivity provided by the digital engine simulation.

Art
artesmith@earthlink.net

ps: as a result of previous day jobs, I appreciate feeding simulations more and better data isn't free.....................

[steve zemke]

Intersting to learn how much simulation has improved since your first post in this thread.

[Art Smith]

Steve-

what's changed is the price of poker!! digital engine simulations with significant capability/functionality are now in the financial reach of normal people (given interest in Formula Ford (ie: not FF) is normal).

Art
artesmith@earthlink.net