Oil change vs. horsepower?

[MacBaby]

Hello folks.

I have searched the forum for this answer, but I couldn't find it anywhere, and I won't add it to the bugs thread, as I'm not sure, that it's a bug yet.

Whenever I buy a factory new car, the first time I change the oil on it, I get a little tweak in horsepower, I calculated it to about 5% more. Even though the oil (of couse) is brand new, when the car comes directly from the factory.

Now the other strange thing comes: The horsepower tweak is only visible in the garage. When I finish a race, and the replay blackscreen comes up, it says for example: "Toyota Supra RZ '97 600 PS SM/SM" even though the car apparently has 630 PS in my garage.

It doesn't happen on used cars, when i change oil on them, they just get their stock horsepower back, as the old oil was bad.

Has anyone else experienced this "bug", or can it has anything to do with the fact, that I'm using PS instead of HP? Is there a reasonable explanation for this?

 

[Terronium-12]

Well, here's my theory...

When you purchase a new vehicle from the mfr and you do an oil change, I figure you're either enriching the mixture, or leaning it out.

As for the replay stats, whether it be in PS, KW, or otherwise I think the rating shown for the car is measured through the rear wheels (BHP).

I could be right, or I could be totally wrong.

If you notice, if you've ever brought a vehicle in GT3 (for example) that you could receive for free, the available horses would be lower and would increase as you race with it; whether you did an oil change or not.

 

[Parnelli Bone]

Hello folks.

I have searched the forum for this answer, but I couldn't find it anywhere, and I won't add it to the bugs thread, as I'm not sure, that it's a bug yet.

Whenever I buy a factory new car, the first time I change the oil on it, I get a little tweak in horsepower, I calculated it to about 5% more. Even though the oil (of couse) is brand new, when the car comes directly from the factory.

This is somewhat realistic in some ways, and not realistic at all in others.

It is possible to change oil in a real-life car to a blend that uses additives which allow for maximum performance; in effect, creates less friction at higher revs for slightly more power available. I don't know if this adds the highish amount of power that GT4 simulates, tho.

The part where PD gets it wrong is that if a car's engine is brand-new, there should be some sort of break-in period where horsepower slowly increases as the engine gets its first early miles. GT3 actually simulates this because if you buy a car in GT3 and don't change its oil, power will increase slightly and slowly over the first 180 miles or so, before starting to decrease. GT4 simulates only the decrease part after many miles have passed, but (for whatever reason) doesn't simulate the engine break-in part. 👎

Not entirely realistic in GT3 (engine break-in usually takes many more miles than 180), but at least the thought is there. Perhaps PD is trying to simulate (in GT3) the engine gaining power as it breaks in, but then power decreasing after 180 miles since most of the time, we're running that engine to its maximum performance, and the oil is therefore losing viscosity alot faster than it would in a normal production car which rarely revs over 3,000 rpms. Assuming the driver is an everyday Joe or Jane.

There's an interesting thread about this very subject (oil, breakdown and such) somewhere here in the GT4 forums. I think it's in the FAQ section. You should go and try to look it up (I'm too lazy).

Now the other strange thing comes: The horsepower tweak is only visible in the garage. When I finish a race, and the replay blackscreen comes up, it says for example: "Toyota Supra RZ '97 600 PS SM/SM" even though the car apparently has 630 PS in my garage.

The screen that shows up during the replay is showing false information. Ignore it. I think it shows how much power your car is supposed to have when stock or tuned a certain way or something. But it's false information. Ignore. it. 👎

Switching to PS or KW or HP or whatever won't matter...this always seems to be false, misleading information. Perhaps somebody here at GT Planet has a good explanation as to why it does this.

It IS possible, however, to use the replay system to find out how much power the Ai cars you'll be up against have in various races. Whenever you're about to enter a race...don't enter the race itself..instead, enter the PREVIEW of the race. Wait several seconds. When the preview starts, it'll show the last-place car. It'll also show how much power that particular car has, as well as which tires it's been shod with (usually S2 or R3 for sprint races, or R2s for endurance races). This seems 100% reliable, too.

It doesn't happen on used cars, when i change oil on them, they just get their stock horsepower back, as the old oil was bad.

True. This is well-simulated.

Has anyone else experienced this "bug", or can it has anything to do with the fact, that I'm using PS instead of HP? Is there a reasonable explanation for this?

What's the bug now? The replay screen or the added power after oil change? You lost me.

 

[MacBaby]

Thanks for your answers. I didn't realize the break-in thingy, but it actually makes good sense.

About your last question, I meant that the "bug" was the whole added-horsepower-because-of-oil-change thing

About the decreasing horsepower you mentioned. I've only experienced this with one of my used cars, a 420 HP Lancer Evolution GSR '92. Everytime, after just a few races, it began losing horsepower one by one, but an oil change always brought it back to it's supposed amount of horsepower. I have a few other used cars now, including a heavily tuned 860 HP Supra RZ '97, which I haven't changed oil on yet (except for the first time of couse), and after lots of races, it's not losing horsepower, and it still has a nice light-yellow oil gauge. They had both run about 25,000 miles.. weird

To be honest, I still don't realize what the difference in mileage of the used cars, makes purely performance-wise, and why the "10k" cars are so attractive?

 

[PF]

With a 10km car you're getting a new car, most of which can't be bought new or won as a prize car. And they're comparatively cheap, particularly the Jaguar, the NSXs and other high-priced ones.

Cars lose 5% hp every 20,000 miles (or km?) and the chassis becomes distorted quite quickly, often requiring a chassis-refresh.

Also, I find it easier to tune a car with the extra 5% rather than add parts to get the extra hp. Once I got to the point of not worrying about credits I started collecting 10km specials in case they're needed. After choosing a car for TCv5 I found 3 10km specials in the garage, allowing me to experiment with different setup configurations with the irreversable mods like weight reduction, Port Polish, rollcage and even oil change.

 

[Rotary Junkie]

@ Parnelli, you're almost correct, however unchanged oil in GT3 does not EVER lose power and if you do use the wear in period you pick up a good bit of power more with freshened oil than if you would've just thrown fresh oil at a car.

 

[Parnelli Bone]

@ Parnelli, you're almost correct, however unchanged oil in GT3 does not EVER lose power and if you do use the wear in period you pick up a good bit of power more with freshened oil than if you would've just thrown fresh oil at a car.

Oh I see.

Yea, I always used to drive a car thru its wear mode in GT3. I thought it was a pretty cool feature.

MacBaby
New Member

Yesterday, 11:29 PM #4

Thanks for your answers. I didn't realize the break-in thingy, but it actually makes good sense.

About your last question, I meant that the "bug" was the whole added-horsepower-because-of-oil-change thing

That aint a bug. LIke I said, PD is obviously trying to simulate a superior blend of oil being added, which allows for better performance. But in some cars, this adds (what seems) an unrealistic amount of power. The BMW M3 is a great example--which gains an incredible 18 horsepower just after an oil change. But then, I'm not an expert here. Perhaps there's some real-life basis for this huge power bump, but I doubt it.

About the decreasing horsepower you mentioned. I've only experienced this with one of my used cars, a 420 HP Lancer Evolution GSR '92. Everytime, after just a few races, it began losing horsepower one by one, but an oil change always brought it back to it's supposed amount of horsepower. I have a few other used cars now, including a heavily tuned 860 HP Supra RZ '97, which I haven't changed oil on yet (except for the first time of couse), and after lots of races, it's not losing horsepower, and it still has a nice light-yellow oil gauge. They had both run about 25,000 miles.. weird

If you haven't changed oil in the Supra, it's not gonna lose power, as Rotary Junky pointed out up above.

You might wanna check out this thread, it sort of explains why some cars wear oil faster than others:

https://www.gtplanet.net/forum/showthread.php?t=101688

It's the one I didn't look up last nite as I was being lazy. Somebody long ago made a detailed study about all this that explains it all better than I can. Basically, all cars have the ability to wear out their power-bump (caused from oil changes). Some do so faster than others.

Also, if you're in the habit of redlining cars all the time, so that the tach-needle meets its RPM limit, it is possible to find yourself permanently destroying that car's max-perfomance mark. So that if you could make 650 horsepower after oil change before you "destroyed" it, you'll now be making 642 max or whatever. This sort of plays into your next question...

To be honest, I still don't realize what the difference in mileage of the used cars, makes purely performance-wise, and why the "10k" cars are so attractive?

...again, check that thread out....

Low mileage vehicles in GT4 have greater capabilities than ones that are older, which is PD attempting to simulate the fact that the car with lower miles has newer parts (piston rings, valves, cams, etc that aren't worn as much). I'm hoping GT5 will simulate all of this even further...like the way it is in ToCA, but I doubt that'll happen.

 

[mafia_boy]

Yeah, you beat me to it Parnelli.

Car-Less's story is great reading and got me even more deeply involved in getting more power for longer myself as evidenced with the debating I do with him through the thread. It helped me afterwards with learning other things I felt I had previously mastered with maintaining power in the cars. I since have tested and found other stuff that confirms 95% of what he's got there and my own research has discovered other interesting facts regarding the effects on various cars and their various states of tunes with and without GT Oil.

I'm not like him though, I couldn't be bothered with providing a full dissertation and getting back onto that train wreck again.

 

[Parnelli Bone]

Yeah, you beat me to it Parnelli.

Car-Less's story is great reading and got me even more deeply involved in getting more power for longer myself as evidenced with the debating I do with him through the thread. It helped me afterwards with learning other things I felt I had previously mastered with maintaining power in the cars. I since have tested and found other stuff that confirms 95% of what he's got there and my own research has discovered other interesting facts regarding the effects on various cars and their various states of tunes with and without GT Oil.

I'm not like him though, I couldn't be bothered with providing a full dissertation and getting back onto that train wreck again.

He's kind of like Sucahyo, who did tons of testing in GT2 (and some for GT3 and 4, too). A guy who's willing to slog thru lots of tedious testing for some results, know what I mean? I couldn't be bothered, either. I just wanna race goshdarnit!

 

[a112]

As for the replay stats, whether it be in PS, KW, or otherwise I think the rating shown for the car is measured through the rear wheels (BHP).

Only thing is,BHP are brake horsepower,on the crankshaft,whp would be through the wheels,but there is no whp in GT4 AFAIK.

 

[mafia_boy]

He's kind of like Sucahyo, who did tons of testing in GT2 (and some for GT3 and 4, too). A guy who's willing to slog thru lots of tedious testing for some results, know what I mean? I couldn't be bothered, either. I just wanna race goshdarnit!

There's a select echelon that I consider great in all areas....those are two names on that list. 👍 There's only about 5-6 drivers on that list too.

I've done the testing, I just couldn't be :censored:ed typing up all of the results. That's what I consider too tedious. I've gone a lot deeper into this based from my initial thread 'I lost 32hp' and hopefully after the move I have the time to dedicate sometime into writing it. 👍

 

[Kingofweasles]

The BMW M3 is a great example--which gains an incredible 18 horsepower just after an oil change.

Dude, my Supercar entry that i'm working on for TCv5 gained 26 Horsepower after an oil change!