Max RPM in a Veloce

[velocedoc]

I was just wondering what has been achieved in maximum running rpm in a Veloce motor with out exploding? The tach freely swings to 8K on the guage, but what about 9K or more? What were the Conrero motors able to achieve? Were needle bearing motors ever built? Is there any documentation?

[divotandtralee]

Don't know what drives your question but I have two points to ponder. Revs above 6500-7000 are really more destructive than a positive gain in performance other than a few MPH at the top end. I am not a mechanical engineer but performance is best delivered by how quickly one can get to this range rather than how far above it one can go. The other point is the tach on the old cars is pretty optimistic. I can rev mine to 7000 indicated but know it's probably closer to 6000 than 7000. It's fun to watch it climb, though.

[velocedoc]

lets throw another log on the fire so to speak. If NASCAR and F1 cars use RPM above 8K, then there must be a benefit. Having a "square" bore and stroke, lends itself to revving higher rpm. I was wondering if Alfa used needle bearings in the race engines and what if that was ever used in 1300 racing applications. I agree with your thought of finding the best torque to power range, and using that to its full potential.

[velocealfa]

Ask Mike Besic...

[velocedoc]

Good idea!

[genericwood]

Quote:

Originally Posted by velocedoc lets throw another log on the fire so to speak. If NASCAR and F1 cars use RPM above 8K, then there must be a benefit. Having a "square" bore and stroke, lends itself to revving higher rpm. I was wondering if Alfa used needle bearings in the race engines and what if that was ever used in 1300 racing applications. I agree with your thought of finding the best torque to power range, and using that to its full potential.

[velocedoc]

Erik, I wasn't thinking of anything over 1300 cc. Just keeping the discussion to 1300 cc and what the engine is capable of doing. This is only for discussion, as I am not contemplating what I could do, only what has been done. My 1750 with synthetic oil and blueprinted would love to rev up to redline. Unfortunately the old style rod bolts were not up to the task and I spun a bearing. My 164Q loves to bounce off the rev limiter if I push it that far, but engines typically don't last long if you do this often unless you build it to do it.
Jim K ought to weigh in on this one.

[Alfa-Jerone]

Revs above 9K will cause difficulties to the valves as well. They just can't follow the speed. That's why formula 1 cars have pneumatic operates valves.

Jerone

[genericwood]

Quote:

Originally Posted by velocedoc Erik, I wasn't thinking of anything over 1300 cc. Just keeping the discussion to 1300 cc and what the engine is capable of doing. This is only for discussion, as I am not contemplating what I could do, only what has been done. My 1750 with synthetic oil and blueprinted would love to rev up to redline. Unfortunately the old style rod bolts were not up to the task and I spun a bearing. My 164Q loves to bounce off the rev limiter if I push it that far, but engines typically don't last long if you do this often unless you build it to do it. Jim K ought to weigh in on this one.

[velocedoc]

All of this discussion revolves around using a 1300 Veloce engine in a boat. Since there is no transmission and the prop is direct drive off the nose of the crank, then power/speed is related to engine rpm coupled with the pitch of the prop. If you can get the boat to plane correctly then the minimum hull will be in the water for stability with the prop in the water driving the boat. If one was to drive the engine at 8,000 rpm that would equal a particular top speed. If the rpm range was on the order of 9K or 10K, that would result theoretically in more speed. Hence, the question...what is a 1300 capable of producing with out destroying itself. I was hoping to take the short cut in the way I posed the question, but a round about discussion led me open up. With new technology available, then any thing is the limit, as long as the wallet can support it.

[Andrew]

Giulietta race cars in the Bay Area rev to 7500/8000. HP comes from a formula, involving torque, a constant, and RPM, so the higher the RPM you run, the higher HP you'll have, it you can achieve and maintain it.

By "needle bearings" do you mean roller bearings on the con rods? Porsche tried those on the 356 Carreras and eventually gave up. If you mean something else I'm not sure what. I don't think that's the limiting factor on RPM though.

Andrew

[velocedoc]

roller bearings...my coinage for needle bearings. Used in place of bearing shells to achieve a higher rpm. Rods and oiling of the bearings would be the mitigating factor in how high one can turn an engine. If you look at the 1300 Veloce engine, they use castle nuts and cotter keys to keep the rod nuts in place, hence the rod breaks above the crankshaft. If you look inside a Conrero or prepped engine you will find shot peened, polished and balance rods to get the max out of them. I was taught that a 1300 Veloce could outrun a 1600 and I didn't believe it until I was given a few laps around Sears point at speed where the tach was at 7-8K most of the time. The engine was at home at that rpm. The "square" engine lends itself to running 9-10K with prep.

[divotandtralee]

Conrero's technology is 50 years old. It's gee whiz stuff that any of today's builders far outrank. The casselated bolts are the first to go to the junk bin.

[genericwood]

Quote:

Originally Posted by Andrew Giulietta race cars in the Bay Area rev to 7500/8000. HP comes from a formula, involving torque, a constant, and RPM, so the higher the RPM you run, the higher HP you'll have, it you can achieve and maintain it.

[raelorance]

From a high-performance point of view, the standard forged connecting rods don't 'look right' and, once these engines are tuned to produce more power and run to higher revs, the connecting rods break regularly. True, the connecting rods will turn high rpm 8000rpm and more for a very short length of time, but this is hardly the reliability needed for high performance applications. Constantly changing connecting rods to preclude failure and even then not really knowing whether or not the rods are going to break is not normal race engine practice.
The reliability of this connecting rod is improved by approximately 300 rpm maximum rpm 7000 if the small end boss is lightened and a lightweight forged piston and piston pin used. The forging flash on the I-beams is not removed or touched in any way so that the maximum amount of material is kept.
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Alfa Romeo Car Lease