Top Fuel factoids??

[Ghoste]

Some time back somebody had sent me an e-mail with a whole bunch of little facts about Top Fuel cars in it.  I'm sure it even came up on here and somebody was debating the truthfulness of some of the "facts"?  In any case, now I can't find the e-mail, I can't find it on here and a Goggle didn't turn it up either.  I wanted to show it to a co-worker and I figured that there had to be a bunch of people on here that had so if someone does, could you post it?
It had about 20 little Top Fuel quickie facts on it and the last one was something about racing a bike.

[Troy]

http://www.dodgecharger.com/forum/index.php/topic,44895.0.html
http://www.dodgecharger.com/forum/index.php/topic,486.msg7823.html#msg7823

Troy

[John_Kunkel]

I'm one of the ones who usually bebunk some of the "facts", the current version making the rounds is nowhere near as "factless" as the original version.

[Ghoste]

Thank you Troy.  Now out of curiousity, what parts of that have been debunked?

[bakerhillpins]

Thank you Troy.  Now out of curiousity, what parts of that have been debunked?

Yea, I'm interested in that info too! 

[captnsim]

Me to...

[John_Kunkel]

Some of the myths:

Spark plug electrodes are totally consumed during a pass. After halfway, the engine is dieseling from compression, plus the glow of exhaust valves at 1,400 deg F. The engine can only be shut down by cutting the fuel flow.

Total nonsense, electrodes are occasionally melted away but anybody who watches the after-run pit thrashing on TV will occasionally notice the rack containing 16 perfectly intact plugs.

The fuel valve shutdown because of dieseling claim is also total nonsense, the engine is shut off with the fuel valve to prevent residual fuel from "cooking off" and causing injury as heat builds up in the shutdown engine.

If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.

Anybody who has watched a top fuel run knows that it's very common for a cylinder(s) to quit firing very early in the run, it's called "dropping a cylinder" and the raw fuel spewing from the pipe for that cylinder is quite obvious...no big deal and seldom does any damage.

Top fuel engines turn approximately 540 revolutions from light to light! Including the burnout, the engine must only survive 900 revolutions under load.

Do the math, especially using the claimed redline below and consider that the engine runs near wide open from the hit of the throttle pulling down slightly at each stage of clutch engagement.

The redline is actually quite high at 9,500 rpm

There is no redline on a top fuel engine and certainly nowhere near 9,500; before the NHRA mandated rpm rollbacks the target rpm was in the 8,000-8,000 range...as one crew chief was quoted as saying "much over that and they start to eat themmselves up".

The original version of the "factoids" claimed that tires only lasted one run (sometimes but not always), and that the clutch discs were welded together at the end of the run and the entire clutch is thrown away and replaced 100% which isn't true as proven by the fact that the clutch slips as the car is towed back to the pits after a run.

[mauve66]

i still like the one with the calloway corvette and the top fuel dragster though, stupid corvetes anyway.............

[FJMG]

 I seem to remember that at the nationals in brainerd someone telling me that the clutch had a multitude (can't remember the nunber) of fingers that were set up to gradually engage with the last one applied at the 1320. If all fingers locked at the startline everything is tirespin.

[John_Kunkel]

There are several fingers on the pressure plate and there are changeable weights on the fingers to vary the centrifugal force that applies the clutch. The throwout bearing limits the travel of the fingers and is released in stages by a CO2 powered cylinder, a variable timer chip energizes a solenoid valve that feeds the cylinder.

The electronic controlled lockup is based on time rather than distance, a switch under the throttle starts the timers for clutch application and ignition timing, so the lockup doesn't occur at any certain place on the track unless the crewchief has guessed correctly. That's why things get crazy if the driver has to lift the throttle for some reason (tire spin/shake), the throttle switch cancels the timing and things go awry.

I would imagine the crewchief sets it up for lockup at mid-track, full lockup at track end wouldn't accomplish much.