View Full Version : A Brief History of QW Loop Engine Pipes

Frank Volker
12-24-2004, 01:27 PM
The hp plots below show the 3 main generations of pipes developed at QW from 1964-1972 for the loop engines, as well as one experimental expansion chamber. The hp curve for each system is based on data I recorded at the QW dyno as part of my MS thesis research in late '71. I used a very early FA with low ports, and a very low compression head to minimize vibration problems. I also wanted a setup that would not break in the middle of my research, so the performance was purposely degraded, but good enough for my exhaust pulse studies. The same elbow set was used in all tests--9" from ex port to beginning of first flare section.

Edited: Removed external URL reference. 04/25/05 - fav

Elbow 11in
No megaphones attached. The length includes the 2" female taper at the end. Tested for reference only.

GEN 1 (GEN = Generation)
These were used in the early (64-66) work and were probably close to the old deflector engine tapers. There was no dyno during early development, so all testing was done in a test tank with a test wheel that was (I think) about 5 1/4 in. dia. Often, the engine would tend to hang at 6000-6500 RPM. Entries in the test book contained phrases like "....slight hang at 6000, then good acceleration to 8600-8650" or "can't get thru 6000". On a good day, it might read: "pulls well thru 6000 / rapid accel to 8700". Also, our on-water testing was with a runabout. You can see that things were truly biased toward a fat low-end. The FB's would sometimes run these pipes at 1" off.

GEN 2 ( 12", 11", 10")
I'm a little hazy on the exact date of these pipes. I'm sure we had the dyno, because that GEN2 10" would'nt stand a prayer of making it thru the dreaded "6000 RPM wall" in a test tank setup. Probably mid/late '66. Things really took off then. I recall rolling up a piece of aluminum and tig'ing it to the GEN 1 small-end tapers. They worked well first time out and became our new pipes. They were usually run at full length or 1" off. I think it was in '67 when I stuck a set of GEN2 11-inchers on an FB on a SidCraft hydro at Rice Lake, WI. In a real rush to make the heat, I grabbed a Cary wheel and stuck it on what I think was a 12:15 Konig unit. Running this mongrel setup, I swept wide thru the first turn and then went thru the pack like I was the only guy on the lake not tied to a stump. During the testing shown here, I dyno'd them at 12", 11", and 10".

These are sometimes called "bells" or "flared-end pipes". They were created as part of the thesis work. I was so damned happy that I not only gathered enough info to make a 70-page thesis, but actually spun off a pipe that helped the horsepower cause. It is extremely difficult to gain top-end hp with a slow peak rolloff while maintaining lo/mid-range.

Exp Ch
The dimensions for the expansion chamber were determined after I viewed the pressure trace photos of the open pipes. This was a one-shot deal--no time for hacksaw engineering to tweak the setup, because I had to get back to Mizzou and begin writing my paper.

It was so good of Chris to let me use the dyno for my research. Aside from the fact that I always regarded him as a working genius, he was a great father-in-law, a mentor, and the best friend you could ever have.


Seagull 170
12-25-2004, 05:03 AM
It's not often you ask a question, to get an answer that's that comprehensive. That's worth a cold one.
I can almost see the smile on your face when the pipes on that Sidcraft started singing.
Oh to know then what we know now!

01-08-2005, 05:48 PM
Frank, do you have any recall of how much more power a high ported, high compression FA would have made?

What about late FB's?

Frank Volker
01-09-2005, 05:42 AM
Sam - I can't recall the exact numbers, but I believe that in '72/'73 the FA was pulling around 55hp and the FB about 66hp. This was about the last stage of the engines based on the merc crank/rods. Also, my thesis work was done with the full divider setup. The later engines used the short, milled-in divider and (IIRC) no divider in the pipe.


01-24-2005, 06:17 AM
In 1968 my C Looper showed 95 hp on the Quincy Welding dyno. The D was between 115 and 120 hp. At that time with 2-blade props and a 13 foot conventional hydro we ran about 103-105mph with the D. That was a quantum leap over our earlier 60's speeds of 73-76mph with a D Quincy Merc. Today my 44xs with a 3 blade cleaver on a B&H is running a very consistent 81mph with a race setup.

02-08-2005, 04:07 AM
Hp seems lot diff. than kanuck said?
Just curios. I do read a bit. So keep talkin,i,m old wife says so anyhow.

Is water hole #3 still alive? Was jus' past de park.

If a fella look hard west , bout a hour to I-5.? Nixon whithouse

05-02-2005, 03:23 PM
When did you start adding the exhaust dividers? What did you find out about the effect of varying the length of those dividers?

Mark Crabtree
04-14-2007, 10:40 AM

I found this chamber you spoke about. I believe this chamber was only Franks test chamber. There is another chamber that was the final design for cross flows. We used it at Eufaula, Oklahoma.

By the way Frank, nice to hear you are still alive and kicking. I remember the input you had at the shop. Do you remember the piston ring expansion test in the good ole oven??? What memories.

I went by the oven, going back to the dyno and thought something was cooking to eat. I opened the oven to see and what I didn't see, was OF Christner right behind me. Well, and you thought he was always a nice guy. He chewed me out, all the way out....of the shop. Must of been the pressures of the day. He said this was the third time he was trying to get this done. :]


05-04-2007, 08:32 AM
I just purchased one of the Loopers from Tim Burden who has them posted on eBay from the estate of Phil Crown. I got motor FD-67. I will need three (have 1) of the 12" Gen 2 megaphones to restore the motor. Any leads would greatly be appreciated.

Roger Hinsdale
Spring City TN