Tuning Meth with Boost
01-24-2014, 04:01 PM
#21
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same problem happened to a friend of mine, and I told him it would happen... A flow gauge wont help much either because if you're car has even a modest amount of power you wont be starring at the flow gauge. A shift light would be nice because those are frickin bright though.
01-24-2014, 04:10 PM
#24
I have an AEM failsafe wideband that flashes bright red when my AFR goes out of the programmed range. Saved my motor once already when my external Walbro 255 failed in the middle of a 4th gear pull. I was able to let off in time before it went boom.
01-24-2014, 04:15 PM
#25
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The problem with tuning a fuel mixture where both fuels have different AFR stoich values is the fact that AFR becomes sort of meaningless unless you know for sure the ratio of pump gas going into the motor vs meth and calculate accordingly. Stoich for meth is something like 6.5 AFR.
You can tune your car with meth and pump gas spraying simultaneously, youd initially have to decide how much meth you want to spray and adjust the controller, then tune the car's ECU until you hit the desired Lambda number.
You can tune your car with meth and pump gas spraying simultaneously, youd initially have to decide how much meth you want to spray and adjust the controller, then tune the car's ECU until you hit the desired Lambda number.
01-24-2014, 06:13 PM
#28
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01-25-2014, 08:24 AM
#32
Here is my strategy to tuning with meth water injection. Leave it turned off and log afr and IAT's. See what a normal IAT profile is and what your targeted pe afr is. For the sake of arguments, lets call it 11.5:1, and you see after a full run that your iat's go up to 145 degrees.
Now add in your meth/water injection and get your afr's back to the targeted 11.5:1 or slightly richer to 11.2:1 and look at your IAT's again, they should be dramatically lower.
Now, the added safety factor is in the PE adder vs IAT table.
Engine > Fuel > Power Enrichment.
Find the max temp of your run with the meth/water on, and above that value, add in enough of a pe adder (0.2-0.5) to pull your afr back down to 11.2-11.5 in case your meth/water cuts out. It's not fool proof, but it's an added layer of protection in case you have a failure. Granted, that's a sliding scale that will need to be changed from summer to winter, but lets be honest, at least here up in the north east, there's not too many people driving boosted cars in the winter.
Now add in your meth/water injection and get your afr's back to the targeted 11.5:1 or slightly richer to 11.2:1 and look at your IAT's again, they should be dramatically lower.
Now, the added safety factor is in the PE adder vs IAT table.
Engine > Fuel > Power Enrichment.
Find the max temp of your run with the meth/water on, and above that value, add in enough of a pe adder (0.2-0.5) to pull your afr back down to 11.2-11.5 in case your meth/water cuts out. It's not fool proof, but it's an added layer of protection in case you have a failure. Granted, that's a sliding scale that will need to be changed from summer to winter, but lets be honest, at least here up in the north east, there's not too many people driving boosted cars in the winter.
01-25-2014, 09:02 AM
#34
I've been thinking about this and have found that I could pull all the timing out if my second pump fails during a WOT run by way of the AFR vs Timing table. I worry more about WOT situations than part throttle/crushing conditions because you can't burn down your engine at those times. You have anymore suggestions?
Last edited by Monte4ever; 01-25-2014 at 09:14 AM.
01-25-2014, 10:12 AM
#35
Here is my strategy to tuning with meth water injection. Leave it turned off and log afr and IAT's. See what a normal IAT profile is and what your targeted pe afr is. For the sake of arguments, lets call it 11.5:1, and you see after a full run that your iat's go up to 145 degrees.
Now add in your meth/water injection and get your afr's back to the targeted 11.5:1 or slightly richer to 11.2:1 and look at your IAT's again, they should be dramatically lower.
Now, the added safety factor is in the PE adder vs IAT table.
Engine > Fuel > Power Enrichment.
Find the max temp of your run with the meth/water on, and above that value, add in enough of a pe adder (0.2-0.5) to pull your afr back down to 11.2-11.5 in case your meth/water cuts out. It's not fool proof, but it's an added layer of protection in case you have a failure. Granted, that's a sliding scale that will need to be changed from summer to winter, but lets be honest, at least here up in the north east, there's not too many people driving boosted cars in the winter.
Now add in your meth/water injection and get your afr's back to the targeted 11.5:1 or slightly richer to 11.2:1 and look at your IAT's again, they should be dramatically lower.
Now, the added safety factor is in the PE adder vs IAT table.
Engine > Fuel > Power Enrichment.
Find the max temp of your run with the meth/water on, and above that value, add in enough of a pe adder (0.2-0.5) to pull your afr back down to 11.2-11.5 in case your meth/water cuts out. It's not fool proof, but it's an added layer of protection in case you have a failure. Granted, that's a sliding scale that will need to be changed from summer to winter, but lets be honest, at least here up in the north east, there's not too many people driving boosted cars in the winter.
01-25-2014, 12:58 PM
#37
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Thanks of all of the responses, this thread is covering a lot of great information. I have an appointment Tuesday to get the car on the dyno to start the new tune. I intent to approach the meth injection tune as The Alchemist has posted. I hope to end up with a meth enhanced tune not a meth dependent tune.
01-25-2014, 01:27 PM
#38
Yeah, I forget to mention the IAT spark advance tab. I only pull timing when the IAT's get higher, but that was because I had a crappy IAT sensor that was very slow to respond. Having meth spray on it, it wouldn't change temps at all. Now that I replaced it with a fast response sensor, I may add some timing when it goes really cold, but it'll depend on the difference between the IAT's with and without meth. If I see that without meth, it goes up 5-10 degrees above ambient, then I'll only add when the temp drops a fair bit below ambient.
01-28-2014, 02:23 AM
#40
Yeah, I forget to mention the IAT spark advance tab. I only pull timing when the IAT's get higher, but that was because I had a crappy IAT sensor that was very slow to respond. Having meth spray on it, it wouldn't change temps at all. Now that I replaced it with a fast response sensor, I may add some timing when it goes really cold, but it'll depend on the difference between the IAT's with and without meth. If I see that without meth, it goes up 5-10 degrees above ambient, then I'll only add when the temp drops a fair bit below ambient.