Tuning for meth...
Thread Starter
Racer
Joined: Jun 2006
Posts: 327
Likes: 12
From: Carlsbad California
Tuning for meth...
I have read several posts relating to tuning for meth. I am curious, precisely what does a tuner do to properly (safely) tune for the addition of meth to an already blown Vette? Is it simply a matter of tuning the car slightly aggressively without the meth, then just dumping meth into the equation, or is it a more complex proposition than that?
Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
We basically tune the car for max safe power with out meth. Then induce meth and keep track of additional timing. Then scale timing multipliers to remove timing if meth fails or runs out to put you back at you max safe power tune with out meth.
Sounds easy but takes a fair amount of time and understanding of exactly what is happening.
Sounds easy but takes a fair amount of time and understanding of exactly what is happening.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
A twin nozzle meth kit will be my next upgrade. I'm a pretty accomplished FI tuner (if I do say so myself 
) but meth tuning it still very mysterious.
I know you tune it without meth as you would a regular FI car, then move the IAT after the nozzle and add timing with the IAT table or add it to the HO spark table and remove timing using the IAT table. How much spark you can/should add I don't have a clue but what really stumps me is the target AFR. It would depend on how much meth you're spraying which increases linearly with boost based on whatever ramp rate you have the controller set to, and how the heck do you know what ramp rate to use anyway?
How do you know you're not spraying too much or not enough? 
I don't really expect to see tuners post these answers here. FI tuning is relatively easy IMO but this kind of stuff people keep in their back pocket.
) but meth tuning it still very mysterious.I know you tune it without meth as you would a regular FI car, then move the IAT after the nozzle and add timing with the IAT table or add it to the HO spark table and remove timing using the IAT table. How much spark you can/should add I don't have a clue but what really stumps me is the target AFR. It would depend on how much meth you're spraying which increases linearly with boost based on whatever ramp rate you have the controller set to, and how the heck do you know what ramp rate to use anyway?
How do you know you're not spraying too much or not enough? I don't really expect to see tuners post these answers here. FI tuning is relatively easy IMO but this kind of stuff people keep in their back pocket.
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
A twin nozzle meth kit will be my next upgrade. I'm a pretty accomplished FI tuner (if I do say so myself ) but meth tuning it still very mysterious.
I know you tune it without meth as you would a regular FI car, then move the IAT after the nozzle and add timing with the IAT table or add it to the HO spark table and remove timing using the IAT table. How much spark you can/should add I don't have a clue but what really stumps me is the target AFR. It would depend on how much meth you're spraying which increases linearly with boost based on whatever ramp rate you have the controller set to, and how the heck do you know what ramp rate to use anyway? How do you know you're not spraying too much or not enough?
I don't really expect to see tuners post these answers here. FI tuning is relatively easy IMO but this kind of stuff people keep in their back pocket.
) but meth tuning it still very mysterious.I know you tune it without meth as you would a regular FI car, then move the IAT after the nozzle and add timing with the IAT table or add it to the HO spark table and remove timing using the IAT table. How much spark you can/should add I don't have a clue but what really stumps me is the target AFR. It would depend on how much meth you're spraying which increases linearly with boost based on whatever ramp rate you have the controller set to, and how the heck do you know what ramp rate to use anyway?
How do you know you're not spraying too much or not enough? I don't really expect to see tuners post these answers here. FI tuning is relatively easy IMO but this kind of stuff people keep in their back pocket.
As for how much timing you can start really low and see what the dyno shows as you add small amounts. At a certain point you won't pick up any power. Back it off as much as you want for safety.
Target AFR is going to be the same as gas if you are using a wideband calibrated for gasoline. 11.5:1 in most cases.
As for ramp rates and how much meth, you would just have to experiment on the dyno where you can actually see the effects.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
I don't see too much point in tuning w/o the meth first. I just pull a ridiculous amount of timing if the IAT's get high enough that I'm convinced the meth is not spraying. I'm never going to run the car off meth on purpose, and I use the test button to make sure it is working before racing.
As for how much timing you can start really low and see what the dyno shows as you add small amounts. At a certain point you won't pick up any power. Back it off as much as you want for safety.
Target AFR is going to be the same as gas if you are using a wideband calibrated for gasoline. 11.5:1 in most cases.
As for ramp rates and how much meth, you would just have to experiment on the dyno where you can actually see the effects.
As for how much timing you can start really low and see what the dyno shows as you add small amounts. At a certain point you won't pick up any power. Back it off as much as you want for safety.
Target AFR is going to be the same as gas if you are using a wideband calibrated for gasoline. 11.5:1 in most cases.
As for ramp rates and how much meth, you would just have to experiment on the dyno where you can actually see the effects.
You still shoot for 11.5:1?!? If thats the case how is that "safe"? Seems like my boost VE table will likely go downhill instead of uphill so if the meth fails my AFR would go super lean, even if the timing gets cut I'm still in big trouble.
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
I guess thats true. I was going to say it's so you know the MAF or SD tables are right prior to adding the meth but you're just going to change them when you tune for the meth.
You still shoot for 11.5:1?!? If thats the case how is that "safe"? Seems like my boost VE table will likely go downhill instead of uphill so if the meth fails my AFR would go super lean, even if the timing gets cut I'm still in big trouble.
You still shoot for 11.5:1?!? If thats the case how is that "safe"? Seems like my boost VE table will likely go downhill instead of uphill so if the meth fails my AFR would go super lean, even if the timing gets cut I'm still in big trouble.
The VE table here is choppy. The AFR was 11.4-11.5 the entire run on the final run.
If the wideband is calibrated for gasoline 11.5 on meth is as safe as 11.5 on gasoline assuming a safe power level.
There is an add vs iat PE table you could experiment with.
The chances of the meth kit failing right at the wrong time are VERY slim. It's much more likely human error will kick in. I top mine off before racing and check often even though there is a sensor. I also hit the test button and watch the wideband show it go rich. People worry too much imo.
Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
If you don't tune it for max safe power with out meth first. You will never know what your fueling requirements are if the meth fails. So if the meth does fail you are very lean and hopefully it survives...
I personally feel that is just being lazy. Especially because it gives me a good working base and so I know at what safe point I can start from.
Target A/F is tricky. You would be a fool not to work in lambda targets since you are mixing fuels with completely different stoich points. 11.5:1 could be rich or lean depending on how much of the total fuel composition is methanol, nitro, or ethanol depending on your meth blend of choice and pump gas quality.
I personally feel that is just being lazy. Especially because it gives me a good working base and so I know at what safe point I can start from.
Target A/F is tricky. You would be a fool not to work in lambda targets since you are mixing fuels with completely different stoich points. 11.5:1 could be rich or lean depending on how much of the total fuel composition is methanol, nitro, or ethanol depending on your meth blend of choice and pump gas quality.
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Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
So Taylor, with your method your MAF or VE tables, PE and/or BE are all tuned for non-meth and you're using the IFR VS: IAT table to reach your target meth AFR when the IAT temps drop due to the meth?
Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
Taylor@DallasPerformance;1571221810]If you don't tune it for max safe power with out meth first. You will never know what your fueling requirements are if the meth fails. So if the meth does fail you are very lean and hopefully it survives...
I personally feel that is just being lazy. Especially because it gives me a good working base and so I know at what safe point I can start from.
I personally feel that is just being lazy. Especially because it gives me a good working base and so I know at what safe point I can start from.
Target A/F is tricky. You would be a fool not to work in lambda targets since you are mixing fuels with completely different stoich points. 11.5:1 could be rich or lean depending on how much of the total fuel composition is methanol, nitro, or ethanol depending on your meth blend of choice and pump gas quality.
Ok, I straight up stole this from blownbluez06 on here. He worded it much better than me.
Originally Posted by BLOWNBLUEZ06 View Post
What many people fail to understand is how the UEGO's actually work. They take a given input voltage from the sensor and convert it to a # based on that voltage. (I'm sure there's no misunderstanding on that part) Where the misunderstanding comes in is that 14.7 (the stoich value for gasoline) = 2.5volts on the sensor output an a lambda value of 1. If you took your sensor and put it on a perfectly tuned pure methanol car, when that car is at a stoich fuel value, your sensor will still read 14.7. Are you still with me? Ok the reason for this is because it takes X amount of any fuel to reach X amount of voltage on the sensor output. That X amount of fuel will vary to achieve that 2.5 volts. In the case of methanol, you will have to pump in fuel at a 6.4:1 ratio to achieve a lambda value of 1 and achieve 2.5 volts on the sensor output, yet your gauge will still read 14.7 as it is programmed to do. The true AFR value is lost in translation between the sensor input voltage. If we tuned based on a lambda value, this would be much easier. Look at the chart I have supplied and maybe it will shed some light on what I'm saying.
http://www.techedge.com.au/vehicle/wbo2/wblambda.htm
What many people fail to understand is how the UEGO's actually work. They take a given input voltage from the sensor and convert it to a # based on that voltage. (I'm sure there's no misunderstanding on that part) Where the misunderstanding comes in is that 14.7 (the stoich value for gasoline) = 2.5volts on the sensor output an a lambda value of 1. If you took your sensor and put it on a perfectly tuned pure methanol car, when that car is at a stoich fuel value, your sensor will still read 14.7. Are you still with me? Ok the reason for this is because it takes X amount of any fuel to reach X amount of voltage on the sensor output. That X amount of fuel will vary to achieve that 2.5 volts. In the case of methanol, you will have to pump in fuel at a 6.4:1 ratio to achieve a lambda value of 1 and achieve 2.5 volts on the sensor output, yet your gauge will still read 14.7 as it is programmed to do. The true AFR value is lost in translation between the sensor input voltage. If we tuned based on a lambda value, this would be much easier. Look at the chart I have supplied and maybe it will shed some light on what I'm saying.
http://www.techedge.com.au/vehicle/wbo2/wblambda.htm
Melting Slicks
Joined: Feb 2006
Posts: 3,191
Likes: 43
From: Scottsdale Az
This is what not to do IMO. That pump fails and pop goes something. Too much risk for that few extra ponies. Just my .02
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
You are the resident meth kit hater though, right?
You wouldn't it for an extra 500rwhp from the sound of it.
Melting Slicks
Joined: Feb 2006
Posts: 3,191
Likes: 43
From: Scottsdale Az
With a nitrous kit your motor pops when a fuel solenoid fails or a nitrous solenoid sticks. If 1 injector fails your motor is toast too. I test the system before I race real quick with the test button. The risk is there but minimal.
You are the resident meth kit hater though, right? You wouldn't it for an extra 500rwhp from the sound of it.
You are the resident meth kit hater though, right?
You wouldn't it for an extra 500rwhp from the sound of it.Also and injector can fail with either kit and have terrible results. That's the risk you take.
This isn't a N20 Vs. Meth thread. This is a "give the best advice" thread. Following your model isn't the best advice IMO. I didn't say not to run it, I said be safer than you.
Yes I hate Meth. It would have to give me elevently billion hp for me to consider it.
Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
If setup properly, you can completly run out of meth and you will just notice a significant drop in power. Several of my customers have done this test on accident. I don't consider it luck, I consider it proper homework when setting up the tune...
BTW, when an injector fails - 99% of the time they stick OPEN (grounding issue). However if an injector did stick closed from a straght mechanical failure or weak pintle, you should have ZERO damage. It would act just like a fuel cut in one cylinder.
I think that is a common misconception.
BTW, when an injector fails - 99% of the time they stick OPEN (grounding issue). However if an injector did stick closed from a straght mechanical failure or weak pintle, you should have ZERO damage. It would act just like a fuel cut in one cylinder.
I think that is a common misconception.
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
If setup properly, you can completly run out of meth and you will just notice a significant drop in power. Several of my customers have done this test on accident. I don't consider it luck, I consider it proper homework when setting up the tune...
BTW, when an injector fails - 99% of the time they stick OPEN (grounding issue). However if an injector did stick closed from a straght mechanical failure or weak pintle, you should have ZERO damage. It would act just like a fuel cut in one cylinder.
I think that is a common misconception.
BTW, when an injector fails - 99% of the time they stick OPEN (grounding issue). However if an injector did stick closed from a straght mechanical failure or weak pintle, you should have ZERO damage. It would act just like a fuel cut in one cylinder.
I think that is a common misconception.
Never really thought about that on the injectors.
My point is that the risk is not generally that high. A better example would be those who have an extra fuel pump that kicks on under boost. If the hobbs switch fails or the pump you still see the boost.
A BAP can fail w/o anyone noticing as well, and a ton of people run them. Some of us take more risks that other I suppose. I think the perception of risk on the meth kits is way to high is all.
Thread Starter
Racer
Joined: Jun 2006
Posts: 327
Likes: 12
From: Carlsbad California
Thank you for your replies, gents. I already have meth, but I was always curious as to how tuning works with the addition of meth.
Special thanks to Taylor for being a stand-up guy and providing some details.
Special thanks to Taylor for being a stand-up guy and providing some details.
