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General gist for tuning with meth

Posted: Fri Dec 20, 2013 7:54 pm
by pilihp2
Well I've had meth on my current setup for close to a year running a system that my buddy had lying around. Not the best product out there, and the company that makes it is out of business. But It's better than nothing I guess.
Timing was increased by about a half a degree in I think 2 or 3 places on the timing table just for a tiny bit more power, and we didn't want to bump it up too much without any type of knock detection.
I'm wondering what the average timing increase is when running meth'd 91 tune over running a non meth'd 91 tune. I have a knock adapter tool on the way after I neglected to put mine together myself so I'll be listening when tuning.

Not sure what the nozzle size is. Was just a part of the setup that I grabbed.

Just increase timing till it knocks and then backoff a couple degrees? Hah :roll:



And I kind of have the same question for e85, but from my understanding the amount of boost and timing increase possible is even more? I feel like that's a whole other thread, and I'm pretty sure that one has been asked a couple different times.


Alright. Don't rip up the timing noob too much. :hide:

Re: General gist for tuning with meth

Posted: Fri Dec 20, 2013 9:03 pm
by audifreakjim
My take on Meth is this, treat it like a cool humid day. That is, don't make any tuning changes for it. Let the ECU sense the cool air charge vial the IAT and it will add timing for you, like it would on a chilly day. This basically gives you that turbo weather feel even when it is 90 degrees outside.

If you add timing separate from this model, you are asking for trouble even if you have fail safe systems in place. Things like uneven water distribution, intermittent pumps, leaks, clogged injectors, low fluid etc.

Re: General gist for tuning with meth

Posted: Sat Dec 21, 2013 12:38 am
by loxxrider
I really like Jim's idea on this (you can make your IAT map more aggressive if you want).

In general though, timing is pretty simple if you have the right tools. Increase until you see/hear the first signs of knock, then retard a few degrees. The best way to do it on the street would be to have some kind of knock listening and also read the plugs. The plugs will give you the first indication of det/knock via carbon deposits. You may or may not hear that on an audio-based knock detection setup. My advice is to it via plugs. That is pretty much the best way.