Just finished my tune, low numbers?

[StevenW]

Originally Posted by Awal Your K04 just might be on it's way out if you're feeling such a substantial loss in power. Also, it's time to check your compression (which will also give u a look at your plugs), and for any boost/vacuum leaks. I also don't know how your tires were at the start of this all, but it might just be that you've worn them down to a point where they give you more dry weather traction. You can shave a DOT legal street tire into pretty much a full slick with the proper tools or frequent rotation plus time/wear. Also, not sure when you started this thread exactly, but maybe the higher summer temps are keeping your tires closer to the optimal warmth for traction, and u might be losing some power to higher BATs. At this point, start checking some of these things. I hope you can sort it out.

My car's only got 36k miles with new plugs at around 20 when I got tuned initially. And the car pulls well in 3rd and 4th. The only problem I have is what feels like boost dropping a few PSI in 1st gear. I also completely forgot about that log...maybe the streets will clear up this evening.

[Awal]

Maybe, my turbo went at 17k kms (10-11k miles), so low mileage cars are not immune.

I doubt this is your issue, as it's very rare, but it's not completely out of the question. Just watch for smoke.

gl w/ troubleshooting.

[StevenW]

Can someone explain why you would use meth but not as an alternative fueling source? I would like to run meth for its cooling effects and NOT rely on it for fuel as I'm always paranoid bad things will happen but then again aren't you in a sense "tuning" for it?

You get meth to cool BAT's, which means you can run higher timing and more boost...but where is the line where meth crosses over from cooling effect and becomes an alternative fuel that you're tuning for? I may be completely backwards on this so feel free to let me know.

[MD1032]

Originally Posted by StevenW Can someone explain why you would use meth but not as an alternative fueling source? I would like to run meth for its cooling effects and NOT rely on it for fuel as I'm always paranoid bad things will happen but then again aren't you in a sense "tuning" for it?

Happy to explain this, because I am currently using methanol, but I am not spraying it, I am running a mix in my fuel tank, therefore I'm doing exactly what you're referencing.

Methanol has a some huge advantages over gasoline in that 1) it has a much higher octane rating than gasoline, even using the (R+M)/2 method (98.65) and 2) because it has a higher enthalpy (heat) of vaporization, which is the amount of energy required to change it from a liquid to a gas state, than gasoline and many other fuels, this causes it to have an even higher "effective" octane rating. Technically running methanol in-tank is actually better than spraying it (assuming the same amount) for cooling purposes, because the methanol is being injected directly into the cylinder and isn't losing heat capacity by coming into contact with the intake manifold, cylinder head, and technically the cylinder itself (since GDI systems inject the fuel after the intake valve closes) prior to detonation.

You might ask, why do we even care about how cold the charge (air+fuel mixture) is in the cylinder? Well, our engines are pretty high compression for a turbo vehicle already, and compressing (heating) already hot air with the gasoline in the cylinder causes autoignition/detonation.

Then I'd imagine you'd ask, well, why not just inject a lot more gasoline to absorb the excess heat if cooling is the problem? I'm not the best at explaining this one, but I'll try. First off, it's not the only problem. Adding methanol does increase the knock resistance of the charge because, again, its octane rating is significantly higher. Secondly, running the car really rich causes other problems like fuel dilution in the oil, it covers your car in soot, and it also slows down the rate of combustion, which works against you in the long run for developing power.

Now no matter what you do, either spraying the methanol or running it in-tank, you will most likely need to tune for it for the following reasons:

1) In-tank: Mixing methanol with gasoline in the tank causes the overall air-to-fuel stoichiometric ratio of the fuel to drop since Methanol is like 9:1 and E10 (pump gas) is like 14:1. To compensate for this, you must scale the injector pulse width and fuel density so the ECU injects more fuel to compensate.

2) Spraying: The ECU injects the amount of fuel that corresponds to the amount of air it sees from the MAF sensor, and corrects for any differences using the AFR sensor in the exhaust. The problem is that the methanol you're spraying is effectively "stealing" some of this measured air and reacting with it. When the ECU looks at the exhaust stream exiting the cylinder, it will see that is is very rich because there is more fuel than it expected. The difference may be too great for the ECU to compensate, therefore you must actually scale the MAF curve to compensate. What you actually end up doing is changing the values at each voltage where you're spraying methanol to correspond to only the amount of air that will react with the E10/gasoline. There are calculators on the forums here that you can use to estimate what numbers to use thanks to the MSF gearheads.

Hope this helps.

[StevenW]

Originally Posted by MD1032 Happy to explain this, because I am currently using methanol, but I am not spraying it, I am running a mix in my fuel tank, therefore I'm doing exactly what you're referencing. Methanol has a some huge advantages over gasoline in that 1) it has a much higher octane rating than gasoline, even using the (R+M)/2 method (98.65) and 2) because it has a higher enthalpy (heat) of vaporization, which is the amount of energy required to change it from a liquid to a gas state, than gasoline and many other fuels, this causes it to have an even higher "effective" octane rating. Technically running methanol in-tank is actually better than spraying it (assuming the same amount) for cooling purposes, because the methanol is being injected directly into the cylinder and isn't losing heat capacity by coming into contact with the intake manifold, cylinder head, and technically the cylinder itself (since GDI systems inject the fuel after the intake valve closes) prior to detonation. You might ask, why do we even care about how cold the charge (air+fuel mixture) is in the cylinder? Well, our engines are pretty high compression for a turbo vehicle already, and compressing (heating) already hot air with the gasoline in the cylinder causes autoignition/detonation. Then I'd imagine you'd ask, well, why not just inject a lot more gasoline to absorb the excess heat if cooling is the problem? I'm not the best at explaining this one, but I'll try. First off, it's not the only problem. Adding methanol does increase the knock resistance of the charge because, again, its octane rating is significantly higher. Secondly, running the car really rich causes other problems like fuel dilution in the oil, it covers your car in soot, and it also slows down the rate of combustion, which works against you in the long run for developing power. Now no matter what you do, either spraying the methanol or running it in-tank, you will need to tune for it for the following reasons: 1) In-tank: Mixing methanol with gasoline in the tank causes the overall air-to-fuel stoichiometric ratio of the fuel to drop since Methanol is like 9:1 and E10 (pump gas) is like 14:1. To compensate for this, you must scale the injector pulse width and fuel density so the ECU injects more fuel to compensate. 2) Spraying: The ECU injects the amount of fuel that corresponds to the amount of air it sees from the MAF sensor, and corrects for any differences using the AFR sensor in the exhaust. The problem is that the methanol you're spraying is effectively "stealing" some of this measured air and reacting with it. When the ECU looks at the exhaust stream exiting the cylinder, it will see that is is very rich because there is more fuel than it expected. The difference is too great for the ECU to compensate, therefore you must actually scale the MAF curve to compensate. What you actually end up doing is changing the values at each voltage where you're spraying methanol to correspond to only the amount of air that will react with the gas. There are calculators on the forums here that you can use to estimate what numbers to use thanks to the MSF gearheads. Hope this helps.

So from what I understand..if you spray meth you'll basically lower your AFR's and HAVE to tune it as fuel?

[MD1032]

Originally Posted by StevenW So from what I understand..if you spray meth you'll basically lower your AFR's and HAVE to tune it as fuel?

Most likely, because methanol IS fuel. To clarify why it can "lower your AFRs", if the amount of fuel that spraying methanol contributes to the charge comprises more than 10% of the total fuel, it will throw the AFR's off, otherwise the Gen2 ECU can compensate for it. In that case you simply scale the MAF curve like I said. It is really not as complicated as it sounds.

[Mike@Stratified]

Originally Posted by MD1032 Yes, because methanol IS fuel. To clarify why it "lowers your AFRs", it's because the amount of fuel that spraying methanol contributes to the charge comprises more than 10% of the total fuel, otherwise the Gen2 ECU would be able to compensate for it. Since it can't, you simply scale the MAF curve like I said. It is really not as complicated as it sounds.

Only if you are spraying a lot of meth. With a D07 or smaller the ECU can usually compensate just fine and not require a retune.

Sent while Stratified.

[StevenW]

I think the plan right now is to probably go AEM starting with a #3 nozle. Once everything starts running correctly I may end up tuning for it and actually making noticable power along with a failsafe or GA.