[cecil98]

my bet is, that if you took two identical ford escorts, put them in neutral and threw a brick on one gas pedal and took the second one through an rpm range from 2000 to max every 20 secs, that the one that is matted would blow long before the one you're breathing every 20sec. it's the physics of it.

[Stagger]

I have to say they would both blow up because they are Fords. :rolling:

I think when you put the pedal to the floor and keep it there, the motor will start to find a happy place and keep running till it floats a valve or breaks or gets to hot and blows up. might be awhile. The on and off puts a lot more stress on a lot of critical parts that can cause premature Failure.

If you are talking a stock motor..... I would still by a used car with heavy highway mileage than a start and stop city car. But then again if it was a ford I would not be buying it. LOL J/K

[Joe Snyder]

Originally Posted by Bubzilla My observations are that it would be a track that you're constantly on and off the throttle, not one that you run flat out the whole lap. Most motors I've seen start to blow up get hurt initially due to the sudden RPM changes. The ever changing stresses and harmonics with varying the engine RPM's is extremely hard on the rods, rollers, and piston wrist pin areas, not to mention the cam gear drive backlash lag on deceleration offering the valves an opportunity to kiss the piston a few times.

I agree with what he said but to add, its multiple sudden RPM changes while under heavy load that is tough on engines.

Even 3/8th banked dirt tracks when tacky, can be killer on engines. When guys back them in hard, the engine is under extreme load trying to pull the car out of the corner considering the moisture in the track and how hard the driver threw it in there. This happens twice a lap, over and over again in a short amount of time.

Its the same reasoning why when you watch a Nascar race at Martinsville, they say time and time again its one of the toughest tracks on engines, yet one of the smallest tracks. Many more engine probs at Martinsville than Daytona usually.


You might say, well, if that on/off the throttle theory is correct, then why wasnt the old Kokomo, when it was dry slick, an engine killer becuase drivers are really playing with the throttle there. Its because that situation is totally different, they arent putting much of a load on the engine in that situation.



I could be wrong here, as its been a good while since I worked on engines but...

It depends on the perfection of the balance, the weight of the rotating weight, and the max of the RPM range, they both take a toll, so its probably 50/50 guys, if not its really close.

JEFF SAC ENGINES

[rhamilton91]

from experience with a wing at salem the track can be held flatout pretty easily

[cecil98]

Ok guys. Charlie Fisher (Fisher Racing Engines Plain City, OH) is our engine builder. I just called Charlie and asked him about our little debate here. I used Eldora and Williams Grove as an example but also asked about any "flat-foot track" vs. a track where you breathe the motor. Charlie said "by far" Eldora would be tougher on a motor than Williams Grove. He said by shutting the motor down in the turns you are allowing a cooling period. Parts that move faster for longer periods of time create more friction and heat than parts that get a reprieve from time to time (ala in the turns). As well, high banked tracks put a much greater load on the motor and drivetrain than flat or semi-banked tracks with similar surfaces. He also said that if he put two identical motors on his dyno and set one at a constant 8500rpm and took the other from 2000 to 8500rpm every 20 seconds, the one running continously at 8500 would wear out much quicker than the one being shut down. This guy has built World 100 winners, Kings Royal winners etc. Maybe your engine builder will tell you different but, I have a lot of confidence in Charlie. It would be interesting to hear how other top flight engine builders would weigh-in on this topic.

[petey]

So by that rationale could it be possible that a track like Pevely, Mo. be harder on an engine than The Grove? The WoO could run pretty much wide open there all the time if they had to.

[smith19]

Cecil, You Cheater...lol

[cecil98]

Originally Posted by petey So by that rationale could it be possible that a track like Pevely, Mo. be harder on an engine than The Grove? The WoO could run pretty much wide open there all the time if they had to.

Lawrenceburg with a little moisture in it would be tougher than the Grove. You don't lift at Lawrenceburg. You can hear 900HP motors bogging down in the turns. Tell me that's not putting a major strain on the drivetrain and motor.

[rhamilton91]

Originally Posted by cecil98 Lawrenceburg with a little moisture in it would be tougher than the Grove. You don't lift at Lawrenceburg. You can hear 900HP motors bogging down in the turns. Tell me that's not putting a major strain on the drivetrain and motor.

ill agree with that especially the last few races at the berg very heavy track hard on the gas and good racing