Is Engine Wear The Same Across the Board?

[kennythebomb]

One note to fuel consumption: In A-Spec fuel consumtion is lower than B-Spec (at least in La Sarthe 24h). You easily can go one more lap than your buddy. I guess the reason might be different driving styles (B-Spec likes to accelerate with full throttle out of every corner) or an advantage given by PD to make us more competitive.

That's very interesting - I have noticed that my B -spec driver is much easier on the throttle than I am. B - Spec is very smooth. Combine this with not ever reaching the full potential of the car and he usually outlasts me by a lap or so.

 

[Tornado]

That's very interesting - I have noticed that my B -spec driver is much easier on the throttle than I am. B - Spec is very smooth. Combine this with not ever reaching the full potential of the car and he usually outlasts me by a lap or so.

Yeah, but that's usually on tires. I have noticed that he does use a little more fuel than I do.

Also, regarding the fuel milage to revs issue, compare Sarthe II to the 'Ring, or even to Sarthe I (although the differences aren't as drastic). Sarthe II, the Chapparal 2J can go 9 laps on fuel. On the 'Ring, he can go at least 6 laps (tires went red). The 'Ring is 13 miles long, and Sarthe II is (I believe) 6 miles. 9X6=54 miles. 6X13=78 miles. B-Spec Roberto maxes revs out far more on Sarthe II than on the 'Ring.

 

[Epinionator89]

The following tests are not "scientific" and should not be considered the concrete answer to the question "Is engine wear based on just mileage alone?" I am doing this out of curiosity. There still needs to be a lot more testing done due to numerous variables such as gas pedal position, RPMs, A-spec or B-Spec, gearing etc.

Test 1:

I bought two Mercedes-Benz SL65 AMGs because they're generally fast and I love driving the cars in the game. Both did not get oil changes and ASM/TCS were switched off. There were no modifications to them at all. I wanted to keep them the same just so I don't have to wonder if modifications affect engine performance.

The Hypothesis: If engine wear is only determined by mileage of the vehicle, then it doesn't matter if you're redlining constantly or allowing the car to mainly coast at a low RPM.

I used the "Mega Turbo" code on my Action Replay Max to rack up the miles as fast as possible, in hopes that 1) I don't become bored driving really slowly around the Test Course, and 2) I can get some results in a short amount of time. With the Mega Turbo code activated, I can propel the car to a high velocity (I've managed 32,000 MPH) once I press the R3 button and hold it there. The engine does not propel the car, but the car suddenly rockets to high speeds as if something hit you in the rear end and you're just coasting to those speeds.

I bought a green SL65 AMG to represent the vehicle that's used without revving the engine, and a red one to represent a car that redlines multiple times. I went into Gran Turismo (Simulation) mode, and clicked on "Practice" when selecting the Test Course. I did this test using A-Spec since the B-spec driver is tuned to race and I want to keep RPMs low on one of the cars. I don't believe in A-speccing one car and B-speccing the other because it wouldn't give good results. Plus, the B-Spec driver tries to go as fast as possible but I want to stay at redline constantly.

Pre-test specifications when viewing said car at "Home": 604 horespower at 5500 RPM, and 722.68 lb/ft. of torque at 2000-4000 RPM.

Here are my results:

Green
Oil Light at 3080 miles.
Before Oil Change: 592 HP; 722.64 lb/ft.
After Oil Change: 622 HP; 759.09 lb/ft.

Red
Oil Light at 2890 miles.
Before Oil Change: 592 HP; 722.57 lb/ft.
After Oil Change: 622 HP; 759.09 lb/ft.

After the oil changes, both cars have identical power figures despite the two different ways of using two different engines.

Conclusion: After the oil changes, it proves to me that it doesn't matter how you use your car. Mileage determines engine wear, not how you use the engine.

----------Test 2:

I have decided to do another test. I am not using the Mega Turbo code this time and I've bought two more Mercedes-Benz SL65 AMGs of the same colors.

Note that I'm using Practice mode. I cannot measure gas mileage though I may do a test after I finish this one.

The Questions: Does torque and horespower figures go down at a steady rate? When does power actually start to go down? How long will it take both cars before the oil change light illuminates?

The Hypothesises (is that a word?): If engine wear is based on just mileage alone, then both cars should have identical power figures after an oil change. If oil changes depend on RPMs, then the red car should need an oil change quicker than the green car.

What I'm doing: Every 100 miles I'll check to see how much the engine has lost power. The green car is driven at a low RPM and the red car is being driven constantly at redline.

So far:

Because I've only started to see a change in figures after 700 miles, I have decided to drive both to 700 miles and then check 100 after that from then on. I'll start with the green car first, and then do the red car second.

Green
700 miles=No change in power
800 miles=603 HP, 736.6 lb/ft.
900 miles=735.95 lb/ft.
1000 miles=602 HP, 735.37 lb/ft.
1100 miles=734.72 lb/ft.
1200 miles=601 HP, 734.14 lb/ft.
1300 miles=601 HP, 733.49 lb/ft.

Notice how every 200 miles the horsepower drops 1. Also notice that torque is dropping at a steady rate, too. Each time I drive another 100 miles, torque reduces either by .65 or .58 lb/ft in a "take turns" pattern. Therefore, results should look like this (Edit: here are the official results)

1400 miles=600 HP, 732.91 lb/ft.
1500 miles=732.26 lb/ft.
1600 miles=599 HP, 731.68 lb/ft.
1700 miles=731.03 lb/ft.
1800 miles=598 HP, 730.45 lb/ft.
1900 miles=729.8 lb/ft.
2000 miles=597 HP, 729.22 lb/ft.
2100 miles=728.57 lb/ft
2200 miles=596 HP, 727.99 lb/ft
2300 miles=727.34 lb/ft.
2400 miles=595 HP, 726.76 lb/ft
2500 miles=726.11 lb/ft.
2600 miles=594 HP, 725.53 lb/ft.
2700 miles=724.88 lb/ft.
2800 miles=593 HP, 724.3 lb/ft.
2900 miles=723.65 lb/ft.
3000 miles=592 HP, 723.07 lb/ft.

(Oil light illuminated at 3070 miles, dropping horsepower to 591 and torque to 721.06 lb/ft., dropping 1 each.)

Now I'll be doing the red car.

Red
700 miles=604 HP, 738.82 lb/ft.
800 miles=603 HP, 736.24 lb/ft.
900 miles=735.59 lb/ft

Note the 900-mile result is .65 lb/ft. lower than the 800-mile result, so I assume the red car will lower torque and horsepower in the same fashion as the green car. If so, and if the results are similar to that of my last "test", then this would confirm, yet again, that engine wear only depends on mileage--not how you use the car's engine.

 

[Ezz777]

Crikey, i skip out for a few days, and every man and his AMG SL joins on in. Great to see the responses. I kind of feel sorry for the guy doing this A-spec - primarily because it will take bloody ages and be extremely boring - but also because i somehow feel that whatever his results are, someone will say that he should have done it B-spec to take out the human element.

As for running around on taller gearing, and comparing resultant power loss to running the same distance at the same speed but higher revs, this will give false results if engine wear is related to throttle position. More throttle, more wear. So driving flat out at 3000RPM may cause similar wear to driving flat out at 7000RPM.

I guess while it may not rule out the throttle position issue - it WILL rule out engine revs as a contributor to engine wear - which is the primary goal.

My theory on throttle position (which conveniently links to the B-spec fuel consumption question) is that it is all about the duration of time with ANY throttle application. I also get slightly better mileage than Bazza, and reckon it is due to our different cornering styles - particularly in the longer sweepers. I tend to brake -> coast (no throttle/brake) -> accelerate. Bazza - brakes -> then with partial throttle maintains a more constant speed -> then accelerates. Hence will have more throttle time in any given lap.

 

[JTSnooks]

Awesome, great info. Not quite a perfect test, but it should help clear things up Wonder if the non A/R test will end up the same as the A/R test...

 

[niky]

At least Epinionator's test confirms some of my feelings about engine wear... that constant redlining... no matter what the mileage, brings the oil change light on faster... I still don't have time to test this myself, but re: what was said regarding my previous post... the number of races extra in the long series you run past the test course (in GT3) if you skip it without the light coming on... it's often more than the amount of mileage you get on the test course... it's been a long time, but I'm pretty sure of this. Having the difference at about 5-10% of miles racked up seems right for my previous observations.

 

[Alfaholic]

I guess while it may not rule out the throttle position issue - it WILL rule out engine revs as a contributor to engine wear - which is the primary goal.

Since Epinionator is running standard road cars, the gears are not adjustable to allow for driving flat out but not on the redline. To be touring as he is at under 4000rpm he must be using a partial throttle, so his tests will not conclusively show a link between the redline and oil degradation wear. They may instead show a link between throttle position, fuel consumption (perhaps?) and oil degradation.

Bottom line is that so far they seem to indicate that the harder you drive, the faster your oil degrades - though the fact that it seems to change at exactly 200 miles suggests a simple constant or straight line graph is at work and not a complex formula. I await the red car results with anticipation.

Thanks for running the tests Epinionator!!

 

[Ezz777]

Since Epinionator is running standard road cars, the gears are not adjustable to allow for driving flat out but not on the redline.

Unless PD have for some reason thrown customizable gearboxes into their engine wear calculations - i see no reason why a test along these lines could not be run.

Also, Niky, i may be a doubter - but i don't see this "confirmation" that driving hard has any effect on engine degradation. So far the results I am looking at would suggest that there is no significant difference at all. Namely his prelim testing (including some whiz-bang-turbo-thingy-magingy) had a 'whopping' ~0.05% difference in torque and zero difference in power between a car being driven hard - and one not being 'driven' at all. All of this difference was recovered upon changing the oil - hence no observable difference in engine wear.

Futhermore - the 6% difference in oil useage when comparing 100% full throttle with 100% zero throttle doesn't seem to support any of your theories relating to oil consumption. On any given race track, i am guessing you would be at full throttle for about 80% of the time (anyone who has worked this out for a few tracks in GT3/4 is welcome to add in concrete data). Now the big assumption - that there is some correspondance between throttle and oil consumption - then there should be about a 1.2% difference in observed oil consumption. This, i am afraid is not going to be significant given the much greater variation in actual race distances in a series.

The whole green/red test he is currently running at the moment - should give a better indication on the revs side of things, but as has been pointed out - won't rule out throttle position being a contributor. Hence the custom tranny would be a good idea (next time i guess).

 

[niky]

My observation had to do with how long the oil lasts... power degradation is nearly always the same... and I'm surprised there was actually a torque difference. Yah, but let's wait for further testing.

 

[Epinionator89]

i don't see this "confirmation" that driving hard has any effect on engine degradation. So far the results I am looking at would suggest that there is no significant difference at all. Namely his prelim testing (including some whiz-bang-turbo-thingy-magingy) had a 'whopping' ~0.05% difference in torque and zero difference in power between a car being driven hard - and one not being 'driven' at all. All of this difference was recovered upon changing the oil - hence no observable difference in engine wear.

I was not surprised when both engines, after an oil change, were identical in power and torque. Since this is a racing game, where almost 100% of people who own it will use their cars the same (overrev, hit redline, race the vehicles etc.) I doubted that PD would add a feature that slowed engine wear the less you push your car's engine. Basically, the only reason why power before an oil change would matter is if you didn't have enough money to get an oil change (which is next to impossible unless you buy a whole ton of 1,000,000 credit race cars).

The whole green/red test he is currently running at the moment - should give a better indication on the revs side of things, but as has been pointed out - won't rule out throttle position being a contributor. Hence the custom tranny would be a good idea (next time i guess).

The only thing I'm trying to test is whether or not RPMs affect engine wear and/or oil usage. If someone else wants to do a throttle test, or any other test for that matter, go ahead and do it . I'm getting pretty exhausted doing this test as it is (in fact my right arm got sore this afternoon ). So far, the red vehicle (at 800 miles) has less torque than that of the green vehicle when at 800 miles (I'll update in a few minutes). Not by much, but noticable. I'm only doing this out of curiosity and by no means do I consider this a real hardcore "scientific" test. From my results in the last test (Action Replay's website), both cars had identical power figures. I expect a similar result in this test, especially since it looks like the red car's horsepower and torque are lowering at the same rate the green vehicle's figures were.

Hopefully my testing will bring us one step closer to whether or not how you use a vehicle's engine affects performance. It's a small step, but a step nonetheless

 

[Ezz777]

The only thing I'm trying to test is whether or not RPMs affect engine wear and/or oil usage.

That is why i suggested using b-spec and the custom trannies. My understanding is that you are running a car at either full-throttle high-revs, or part-throttle low-revs (bloody hard a spec). This means there are (at least) two possible variables. I don't want to discredit your testing because you have been very generous doing it, but i am suggesting that it could have been done better - in hopes of getting more conclusive results.

N.B. "noticeable" and "measureable" are two very different things when it comes to this thread. given that it all started by some fellow stating that he noticed his elise becoming a dog after a few hundred miles and suggesting it was due to engine wear. The measureable differences you speak of would NOT be 'noticeable'.

 

[kennythebomb]

Good work Epinionator, keep going