I realize this is probably a dumb question, but as a guy who is looking for the right used C7... how do you interpret the lifetime rev data into information that can help you understand the abuse (or not) a car has taken?

For example, I found a car with 4,718 miles, 1217 rs (lifetime revs), and 118.4 engine hours. I have no idea if this is good or bad.

Can you guys explain how this works? Not only for the specific car above, but for others I may look at?

Thanks!

 

It's generally useless to try to make anything from typical counts. The numbers could probably be useful in extreme circumstances but that is likely to be rare on street driven cars.

Just as an example, here's a discussion from last year with many opinions:

https://www.corvetteforum.com/forums...v-counter.html

 

Engine hours between rebuilds are an important measure when a vehicle does not have an odometer, like planes and boats, but I have no idea how many are considered too many.

Lifetime revs could possibly tell you if the car was driven easy or hard, but again, I have no idea how many revs per mile would be considered high.

Long story short, these stats probably don't tell you anything useful as a practical matter.

 

More here:

https://www.corvetteforum.com/forums...en-driven.html

 

time will tell how these are used when it comes time to sell used cars on the forums. Engine hours are nice for vehicles like police cars that might not put a lot of miles, but idle many hours...

 

So with the hour meter that means the average rpm is 1700ish? Doesn't sound bad but I have no clue...

 

@Dwim - 2 cars can travel the same distance. One can redline the whole way and the other can cruise. It is possible for one car to travel 10 miles @1800 RPM, and it is possible to travel that same distance @ 6000 RPM.

The Rev counter x 10000 is telling you your engine has completed 1217 x 10,000 engine revolutions or 12,170,000 Total.

12,170,000 Revolutions / 4718 Miles = 2579 Average Revolutions per Mile.

It it ok. 1500 is low like a grandmother driving, my number is well over 3000.

Currently the best method to determine engine wear is the odometer, which tells you nothing more than how far the vehicle has travelled. It does not tell you ANYTHING about how the engine was used.

One can sit in Neutral and redline the engine for seconds, minutes or even hours... and nothing detects this abuse. This is a MAJOR problem. That means two cars with 10k miles ARE NOT the same. I credit Chevy for trying to establish a better method.

At 800 RPM, an engine rotates about 13 times a second, but @ 6000 RPM, the engine rotates 100 times a second! We need a way to figure out when this extra wear and tear has happened.

Average RPM is okay. But Average RPM can be manipulated. The logic is... If you run it at high RPM for a period of time, and then let the car idle for the same amount of time, you will ultimately reduce your average RPM in half. But did we actually reduce the wear on the engine by half? No.

Average RPM not only is inaccurate but also potentially encourages adding more engine wear in an attempt to offset the ratio.

THE SOLUTION:

If you take your total engine revolutions and divided by distance traveled, now you get Average Revolutions per Mile. (ARM) This is a better metric, because in the above example, you can idle it for as long as you want... the average engine revolutions per mile will only go up because the car is not adding more distance.

Example:
6000 RPM x 1 minute = 6000 Engine Revolutions
6000 Engine Revolutions / 1 Mile = 6000 Average Revolutions per Mile.

If we idle the car for 5 more minutes, at 800 RPM we get:
800 RPM x 5 minutes = 4000 Engine Revolutions
4000 Engine Revolutions + 6000 Engine Revolutions = 10,000 engine revolutions.

But since the car didn't move, 10,000 engine revolutions divided by 1 mile gives us 10,000 Average Revolutions per Mile. We can still see this engine has had extra wear and tear. The same applies to someone attempting to disconnect the Odometer. Without Miles being added to the ratio, the ARM continues to rise making it obvious that someone has tampered with the vehicle raising a red flag.

It would be nice if Chevy would calculate this for us so we could quickly know the difference between two vehicles side by side. The downfall is it is still just an overall representation. The ONLY way to REALLY know what has happened to an engine would be to record this information with timestamps, so it can be exported and displayed in a timeline history graph. Plus, since engine revolutions and distance traveled are recorded against Time, it's possible to determine speed by using the formula [Distance = Rate X Time] for any period of time in history.

I have attached graphs showing how valuable this information is. RPM displayed on left. Speed displayed on right. Distance is on bottom. One example shows what normal driving looks like, one example shows how idling averages out quickly, one example shows moderate racing, and the last chart shows burnouts, over revving, drop shifting, downshifting and other driving actions that could be considered abusive putting the ARM to a ridiculous number. No one wants to buy that car!

Credit to http://kenometer.com for their work in this area.