Don Terrill’s Speed-Talk

hoffman900 wrote: ↑Tue Sep 26, 2023 5:06 pm Pretty sure they were like 4-6” expanding stubs

So something like 4 x 4-4.5" or 3 x 5.5-6" primary sections with each section stepping up a pipe size? And then old-F1 style 4-1 collector with a relatively small collector exit pipe diameter?

40-45cm wouldn't sound silly for this rpm range.

juuhanaa wrote: ↑Wed Sep 27, 2023 1:53 pm

ptuomov wrote: ↑Wed Sep 27, 2023 1:34 pm Also, what’s the best guess primary length for that rpm range and 4-1 system?

IMG_20210603_202332__01.jpg

-juhana

Does this system require a muffler? If so... Is there a sound test method and db maximum? No sound test, an object appearing like a muffler required on the pipe, plenty of space and slack weight to make any system appear like an open header to the exhaust flow if sound requirements ever come. So fo...

Also, what’s the best guess primary length for that rpm range and 4-1 system?

“I think that exhaust port is fine. We’ve put 190whp + through exhaust ports with that same area.”

I agree with free cams. But how about rules mandated short stock cams?

I’m thinking that the exhaust port at 31mm is a little small for trying to get the stock exhaust cam to hold up the 150hp+ power for the full 11-15k rpm range.

A pretty exhaust pipe photo here:

S measuring the engine internals for the 1D simulator:

It’s going to be nice enough no matter what in the 11-15k range, and that’s all that is ever needed with the gear box. 2-6 gears only use 12.5-15k.

That thread never reveals the super duper secret exhaust. What’s the best known exhaust?

What's the highest power exhaust for GSX-R750 L1 2011-2023?

The criterion is average power in the 11,000-15,000 rpm range and nothing below that matters. The shape of the torque curve doesn't matter and neither does the ground clearance so no need to do the 1-2&3-4 motorcycle 4-2-1s here.

Ha. Centre of gravity height is an advantage, yes. But not so much of an advantage that someone in a hire car that's down on power (and has zero experience in a car with this much, let alone what the rest of the field is running) should clean house on their first race. I mean the car isn't even pro...

If internal combustions engine car racing will continue for the next two decades, you'll likely see more of this driver:

Our driver is racing against grownups in his first race in the unrestricted class, the big leagues for this car. Unlike in the junior class, it is very hard to cheat in this class because there’s no artificially low rpm limit. He won the first heat with a huge margin and all the grownups are seethin...

Have you replaced/renewed the electrical connectors? Several years ago I replaced the Molex connectors, for example, (so new pins for male and female) in some stepper motors after carefully reading the engineering documents. There is a finite number of times they can be connected and disconnected w...

So did it have better midrange than the top cars given the header design? It's kind of silly. The car was competitive despite being being 100% legal (and it's obvious that not all cars are 100% legal) until about late June of this year, with the driver winning regularly and leading the series. Then...

This season, a number of wins and the second place in both the Nordic and Finnish (not certain, but virtually certain) series. In the last race in Sweden where all cars were tested on a dyno, our car was off almost 10 hp from the top two cars (and one of the top two cars drives like an unrestricted ...