2 Attachment(s)
A Brief History of QW Loop Engine Pipes
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
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No megaphones attached. The length includes the 2" female taper at the end. Tested for reference only.
GEN 1 (GEN = Generation)
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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")
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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".
GEN 3
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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
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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.
Frank
