Everything you always wanted to know about HP, break in, and oil changes
- Thread starter BadBatsuMaru
- 44 comments
- 15,283 views
- 24,120
- Midlantic Area
- GTP_Duke
Port and polish shouldn't be regular maintenance. You don't really do it more than once unless you're in the kind of racing team that throws away every engine after every race.
Porting means the intake and exhaust openings (ports) in the head are enlarged and reshaped to perfectly match the runners on the intake manifold and exhaust manifold/header. The head flow is improved by removing material in some places and adding it in others throughout the galleries leading to the valve openings, to smooth the air path as much as possible. The shape of the valve seats is often changed a bit to reduce turbulence at the lip of the valve. The whole path is then ground smooth and polished to improve flow yet further.
But if it's done right the first time, it doesn't need to be done again. There shouldn't be any real wear on these surfaces. Yes, if you had the head off to do something else, you might make sure the paths are still shiny, but you'd never take the head off on a regular basis just to do that.
- 1,203
- Nottingham, England
I agree with you. Maybe you would be able to change the oil in a pit stop, although you might lose several laps or more doing it, or should! Definatly need to be able to re-fuel during pit stops and the car should be slower due to the added weight than when you are coming in for a pit stop. What about the option of being able to change tyre type, ie if you find that your rear tyres are being worn away too quickly being able to change them for a slightly harder model, or even a much harder model.Majin SSJ Eric
- 1,795
Well, the weight of 22 gallons is like 180 pounds... on a 3400 pound car... that don't make too much of a difference. Maybe the car will get tighter as the fuel burns off.
I'd like to see fuel depletion, but when you factor in the numbers of cars in GT3/4, and how certain modifications (say, a Stage 4 turbo or overbore) affect the car's fuel consumption, you'd understand how tough it would be to get accurate fuel mileage for each and every car and each and every modification. I rest my case
I'd like to see fuel depletion, but when you factor in the numbers of cars in GT3/4, and how certain modifications (say, a Stage 4 turbo or overbore) affect the car's fuel consumption, you'd understand how tough it would be to get accurate fuel mileage for each and every car and each and every modification. I rest my case
- 1,203
- Nottingham, England
It could make a difference to the accleration & stopping distance with the weight transference and the way the car handles in corners. After all PD have made engine wear and oil consumption make a difference in races.Victor VanceWell, the weight of 22 gallons is like 180 pounds... on a 3400 pound car... that don't make too much of a difference. Maybe the car will get tighter as the fuel burns off.
I'd like to see fuel depletion, but when you factor in the numbers of cars in GT3/4, and how certain modifications (say, a Stage 4 turbo or overbore) affect the car's fuel consumption, you'd understand how tough it would be to get accurate fuel mileage for each and every car and each and every modification. I rest my case
PD could generalise, that's what they seem to have done with GT2 & 3 and will probably do with GT4.
I have created several graphs that show the engine wear and oil consumption, however I am having a problem uploading them. When trying to add an attachment it ask's for a HTML address which I don't have. I am also working on idea to show all the information in the same graph, I tried before but it hid most of the info behind each line and proved worthless.
TMM
Host them on http://www.imageshack.us.
Doesn't all this discussion of fuel consumption etc. belong on the GT4 board?
- 1,979
- Toronto, Ontario, Canada
- MastrGT
It would be nice if TMM could add picture dimensions to the URL, so the image doesn't overflow most browser windows. Make it: width="800" height="475".
I also think that, unless I somehow missed this info, that this thread is missing the milage limit for changing oil in new cars. If oil is not changed before 80 miles, permanent power loss results. If changed beforehand, the maximum power can always be achieved, before the milage adds up to its limit.
Cheers,
MasterGT
I also think that, unless I somehow missed this info, that this thread is missing the milage limit for changing oil in new cars. If oil is not changed before 80 miles, permanent power loss results. If changed beforehand, the maximum power can always be achieved, before the milage adds up to its limit.
Cheers,
MasterGT
- 51
what do you mean by modifier? i having trouble making sense of any of this
- 84,365
- Rule 12
- GTP_Famine
Each car has a "BASE" power output.
When you first buy a car, it doesn't have "BASE" power. The power is "modified" by a given percentage because the engine has not yet been run-in. Once the car HAS been run-in, it no longer has this "percentage modifier", so it will be running at peak power, with suitable oil changes. This applies to all cars - from a Daihatsu Cuore to a Lister Storm.
This section of BBM's post was key:
"When you buy a car at the dealer, it has a 3% HP penalty for not being broken in. As you drive it, this penalty goes down gradually over the first 300km (189mi). After you have driven 300km, your car is at its peak HP. It remains at its peak HP until you have driven another 500km (800km total). After you have gone 800km (504mi), your car loses power over the next 100km. Once you reach 900km (567mi), your car has the full 2% old engine penalty. This penalty never goes away or changes. If you run your car at redline for 1,000,000 miles, you will still just have a 2% old engine penalty."
So:
0 miles - Purchase car. Car is running at 3% UNDER base power.
0-186 miles - Car is being broken in. Still running at between 0-3% under base power, decreasing as mileage increases.
186 miles - Car is running at base power.
186-504 miles - Car is running at base power.
504 miles - Car is at the end of its run-in engine life
504-567 miles - Car is past its best. Runs at between 0-2% under base power, increasing as mileage increases.
567 miles - Car is running at 2% UNDER base power.
567 miles to infinity (or 2.4 billion miles, actually) - Car runs at 2% under base power.
Fresh oil merely helps keep the engine ticking over nicely. Dirty oil subtracts up to 5% from your engine's power.
When you first buy a car, it doesn't have "BASE" power. The power is "modified" by a given percentage because the engine has not yet been run-in. Once the car HAS been run-in, it no longer has this "percentage modifier", so it will be running at peak power, with suitable oil changes. This applies to all cars - from a Daihatsu Cuore to a Lister Storm.
This section of BBM's post was key:
"When you buy a car at the dealer, it has a 3% HP penalty for not being broken in. As you drive it, this penalty goes down gradually over the first 300km (189mi). After you have driven 300km, your car is at its peak HP. It remains at its peak HP until you have driven another 500km (800km total). After you have gone 800km (504mi), your car loses power over the next 100km. Once you reach 900km (567mi), your car has the full 2% old engine penalty. This penalty never goes away or changes. If you run your car at redline for 1,000,000 miles, you will still just have a 2% old engine penalty."
So:
0 miles - Purchase car. Car is running at 3% UNDER base power.
0-186 miles - Car is being broken in. Still running at between 0-3% under base power, decreasing as mileage increases.
186 miles - Car is running at base power.
186-504 miles - Car is running at base power.
504 miles - Car is at the end of its run-in engine life
504-567 miles - Car is past its best. Runs at between 0-2% under base power, increasing as mileage increases.
567 miles - Car is running at 2% UNDER base power.
567 miles to infinity (or 2.4 billion miles, actually) - Car runs at 2% under base power.
Fresh oil merely helps keep the engine ticking over nicely. Dirty oil subtracts up to 5% from your engine's power.
- 51
oh, ok. thanks for helping me with that.
- 498
- Jujubean14
This is kind of ridiculous, but I wonder what would happen if you put so many miles on your car that the odometer would roll back over to 0. I am not at my PS2 right now so I don't know how many digits the odometer has, but if I had 999,999 miles on say the R391 GTR, and then drove one more mile, do you think the odometer would reset to 0, and if so, would you regain your lost power (as a glitch)?
