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Discussion Starter #1 (Edited)
I had this weird thought a few days ago...if our hemi's are rated around that range of 400-ish hp, how well would it survive doing that at a 80-90% duty cycle on an oval track for however many laps would make up 300 mi, instead of just occasionally hitting that mark as it would be driven on the street in typical ownership of these cars? Say if you were to drive it like the wind (not recommending anybody do this AT ALL) at 120-140 mph (just guessing that it would end up there in 3rd/4th gear) with WOT on the straightaways, varying degrees of engine braking entering the curves, and moderate throttle on through the curves, how would the engine make out?

Would the coolant temp gradually rise until it overheats after x amount of laps? (wondering if the stock cooling system can accommodate the demands of short moments that hit full engine power, but is completely out of its element if called to spend sustained and recurring periods at full engine power)

Would the oil temp gradually rise in a like manner described above?

Would some internal part break under so many recurring cycles of high stress?

Would the probability of a cylinder breach or cracked head be very high, if not, imminent?

Would it keep running for the entirety of the race, but most likely need a complete rebuild before it could do another race like that (or even be reasonably drivable on regular streets)?

Would it just shrug it off as just another 300 mi on the tach (albeit abusive miles) in a typical heavy-use lifespan that will last 100k-150k?

I'm just curious about this hypothetical. Anybody who has experience running these modern hemi's in race situations have wisdom to share on what sort of things/outcomes/failures to expect?
 

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If you stay under the redline, I'd bet the engine would last a long time. If the circle track is a mile or less around, You'd likely have brake overheating if you're really pushing it.
 

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Discussion Starter #3
This is true, and my scenario certainly does fall apart when we get down to this level of detail. I hope we don't get mired in it, as I am admittedly shuffling conditions about inconsistently in order to focus down specifically on what will happen to an utterly stock engine with such an aggressive duty cycle. I fully grant that there is no way stock brakes could survive the race, and likely will dictate the car coming to the pits well before the engine can be put into a position where limitations are observable. So please indulge me in the notion that the brakes are not stock and are able to keep the car running in the race indefinitely (ok, and the tires, too...for the sake of having to re-stipulate this same condition).

If the engine can run full-out to its heart's content for sustained periods with typical pits for race-application brakes and tires, will it survive? Let's say the typical rpm range being utilized is from 5000 to wherever redline is (6200-ish?)...
 

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We're talking about a car that Ralph Gilles piloted in the 2008 Newfoundland Targa road rally race (3000km over 5 days). I'd say it can handle it just fine.

Ralph Gilles tells the tale of Challenger at Targa Newfoundland

And that's with the Mopar Crate engine. I'd imagine the production engines have even better durability.
Other mods included StopTech brakes, stronger suspension (rally races incur many jumps), and better cooling for the power steering. Not all of those mods would be necessary for a shorter 300mi oval race.
 

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Discussion Starter #5
Tnx, I'm downloading it now...

So the engine simply lives to race another day? Nothing needs to be rebuilt (even a little)?
 

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Discussion Starter #6
The video titles him [Ralph Gilles] as VP of Design at Chrysler. He gets my respect for being badass enough to be racing these cars (instead of just being a guy in a suit)! :D I feel confident that persons like him are working in the design labs to make these cars what they are.
 

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Ralph is also the CEO of the Dodge brand and if you aren't familiar with him, he is definitely a car guy and a professional driver. He races in the Viper Cup series under different names, and always finishes near the top.
 

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Well, running one of these cars on an oval track for any length of time would very likely starve the engine of oil and end the day abruptly. You'd also destroy tires in a hurry - goodbye right front!

But, ignorning that and focusing on the thermal issues, I think you'd be okay coolant-wise, but everything else would overheat fairly quickly (power steering, transmission, differentialy, engine oil). There is not enough cooling capacity on any of those systems to manage temperatures at sustained high-RPM driving.
 

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Discussion Starter #9
Interesting!...I had not imagined all these other peripheral systems would be involved to put the clamp-down before the engine is ever in danger.
 

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Well, running one of these cars on an oval track for any length of time would very likely starve the engine of oil and end the day abruptly. You'd also destroy tires in a hurry - goodbye right front!

But, ignorning that and focusing on the thermal issues, I think you'd be okay coolant-wise, but everything else would overheat fairly quickly (power steering, transmission, differentialy, engine oil). There is not enough cooling capacity on any of those systems to manage temperatures at sustained high-RPM driving.
Exactly.

Circle track is relentless high rpm operation. Maybe a better oil pump, dry sump with a large capacity and cooling. Also your wheel hubs/bearings would not stand up to the punishment. Valve springs might have something to say too. Keep money in the budget for rubber obvoiusly, But you could always get by once but any continued punishment would surface real fast.

FYI,
Marion
 

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Discussion Starter #12
So I'm getting it that the oval track scenario is largely a moot point as far as the engine, due to pretty much all other sub-systems apart from the engine are simply not up to it in their stock state. Aside from all of that, the weakest link on the engine, itself, is simply the oil system...specifically, not having the oil control of a dry sump system, being able to operate at punishing temps for longterm w/o failing, and just being able to keep the oil acceptably cool given the bigtime heating that will occur in use?

The actual block and moving components should be quite up to the task of delivering all the engine is worth over and over??
 
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