Since we have a couple of months with nothing to do, I'd like to revisit this.
I've had a chance to talk to a couple of fuel drivers and crew chiefs about swapping a complete fresh motor into cars between rounds and was told that the motors take a "set" and need to be rebuilt using info from the previous round to adjust parameters (jetting, compression etc.) But, if you grenade a motor you are starting from ground zero.

My idea? Build a dyno with a full set of sensors that will simulate an actual race pass. Don't tell me this can't be done - it can.
Then (if you are a multiple car team) run a dozen complete motors through a pass, make adjustments from the telemetry, bolt a fresh clutch pack to each and button em up. And don't tell me that DSR, JFR and Kalitta don't have enough parts to do this. I realize that that atmospheric and traction conditions will change at the track, but there are a lot of adjustments available to crew chiefs to compensate.
If you haven't noticed, there are a number of experienced fuel people signing on - I'd love to hear from some of you why this wouldn't work.

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"The Counterfeiter"

I heard the reason that nitro motors aren't dyno'ed is because they're simply way to voilent, otherwise it would have been done already.

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7/20/08 - T-bone's first win.
HEMI's and LS-series motors rock!
Hoosier, Hoosier daddy?

Think about it for a minute. Devising a test stand capable of withstanding 7/8,000 hp, pull after pull after pull? It COULD be done, but it would be incredibly expensive, both in terms of structural considerations, investment in measuring instrumentation, and sound proofing. You'd have to figure that while people like us might not mind the noise, the surrounding neighborhood sure would. Throw in the amount of money on the fuel used, (You'd have to use nitro, anything else and the results are meaningless.) crew time, etc, and I think the costs start to outweigh the benefits. PLUS, what about situations like the western swing, when there's only a week between races. The teams are doing good enough to get the operation from one track to another, much less stop at the shop and pick up another batch of fresh bullets. You could ship them, but once again, we're talking more money.

It could be done I suppose, and the teams that could do it would have a huge advantage over the single car teams that can't afford to do it. We're still talking about a huge outlay of time and effort and, most important, cash. That's the bottom line.

Another question. Would teams that DO engineer and build such a dyno be willing, at the end of a season and in the hunt for a championship be willing rent time to non dyno-equipped teams that might eliminate them from the championship hunt the following weekend? I think not.

I seem to remember a couple of teams did try swapping a fresh bullet between rounds, and quickly dropped the practice.

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AKA DrRocket

There are several teams that swap engines after each round on Sunday due to parts fatigue. That is one of the gripes about 85%, they have to pump up the compression and fuel volume so high, they are only getting one run out of a set of rods and 2-3 runs from a crank.

As far as having a complete motor ready to go, head gasket thickness is a major factor in the tuning of a fuel motor and is one of the last decisions made. Also, in having a clutch pack all bolted up and ready to go, the flywheel and clutch are all behind the motor plate which does not come out with the engine. Not to mention the weight of all the components behind the motor plate is pretty heavy. It's hard enough lifting the short block out, if you added the weight of the heads and clutch assembly, the crew probably couldn't "safely" pick it up.

Believe me, when they cut the turn around time to 75 minutes, everyone looked at what could be done to make the servicing between rounds faster.

no dyno out there for a 7-10,000 powerplant is the main reason. Even Force does not have a fuel engine dyno.
Dean

I don't think you could get a reading on a fuel motor before it expired anyway. They last about 5 seconds at WOT on average, I doubt the dyno would get a stable reading before you had motor sprayed around the dyno room.

I don't think there is anyway you could simulate the progressive drag/load on the motor to get an accurate reading. Even if you did, could you imagine what would happen if the drag brake broke and the engine over wound?? Ka boom. I don't think the dyno operator could act fast enough.

I know for a fact there has been a blower explosion on a blower dyno. Not that it exactly exploded in a ball of fire, but something in the breaking, or the dyno drive shaft came apart, and things got out of hand to say the least.

One more thing, blocks and heads, new and old, are going to be different one to the next. Deck height, and combustion chamber volume also play into the compression of the motor. It's not like a p/s engine where all the same parts and pieces stay on the motor run after run.

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Go Hight!!!----4.63
Prock Rocket 2008 Style

Right on the money. First off you would use up the life expectancy of the parts trying to set them up and then it doesn't matter what happens in a dyno cell, when you get to the track each motor is difference and has it's own personality. Just not practical.

jim

Our "Go-Power" dyno would handle 10,000 HP but would only turn 3,000 RPM TOPS, Too big and bulky to spin any faster AND handle the Horsepower too.