Tuning for methanol/water injection?

[ferocity02]

I am running COS5 2bar SOLSD at the moment working on getting the VE tables dialed in with a safe tune. The most boost I've run so far is 9.5psi at which I'm about 10.8-11 AFR and ~14 deg of timing, I'm running on 91 pump gas but assuming I'm getting E10 out of the pump.

Once everything is dialed in, I'd like to start spraying methanol/water while adding timing and AFR. I will be spraying a 33/67 or 50/50 mix of meth/water at 15.5gph with dual nozzles. How should I go about adjusting the tune for the methanol? My plan is to have a street boost setting of 5-7psi w/o injection, and then a spirited boost setting of 12-15psi w/ injection. I'll be using my boost controller to turn on the injection at probably around 8psi or so.

One idea I had was to use the nitrous trigger in COS5 to modify the fueling when injection is on. Anyone do this?

I'd like to think of the meth/water injection as a safety net since this is my daily driver, it will never see the track.

Thanks!

[joecar]

You're going to surprise any street racer that takes you on...

[BLK02WS6]

Personally, I would spray it under any boost - invest in a good progressive meth injection system. You will benifit from the meth even under low boost... If you do it the way you are talking, you will just have to add timing and pull fuel in the higher boost areas where the meth is spraying. You can use the boost timing table to add the timing and just adjust the boost VE table to get the fueling right. The only way to find out how much timing it will want and how much it will want to be leaned out is on the dyno...

[johnv]

As BLK02WS6 said much easier to use a progressive controller, I start mine at around 3 psi and is at 100 % by 12 psi (straight meth)
A 50/50 mix won't have such a great effect on AFRs , use boost VE to control fueling, and boost timing tables for timing ,or you can add xtra timing with the IAT spark table at the cooler intake temp zones the meth spray will give you. This adds somewhat of a fail safe if meth fails to spray and intake temps dont drop xtra timing will not be added.
Unfortunatly the nitrous tables are designed to pull timing and add fuel which is the opposite function meth inj would require.

[BLK02WS6]

It should be noted that the method of adding timing via the IAT spark table only works if your meth is sprayed before the IAT sensor - many sensors are in the MAF and the meth nozzle is installed downstream of that (close to the TB) - in that case, it won't work unless you add a sensor outside of the MAF...

[ferocity02]

Unfortunatly the nitrous tables are designed to pull timing and add fuel which is the opposite function meth inj would require.

In the nitrous VE table I could use a value less than 1.0 to remove fueling. Or maybe use the IAT VE Multiplier table to pull fuel when the IAT's drop as meth is injected? At the moment, my IAT VE multiplier is setup to pull fuel at lower IAT's.

But for the nitrous timing table the minimum allowed value is 0.0, so wouldn't be able to use it to add timing. I guess I would need to use the Spark IAT Table.

It should be noted that the method of adding timing via the IAT spark table only works if your meth is sprayed before the IAT sensor - many sensors are in the MAF and the meth nozzle is installed downstream of that (close to the TB) - in that case, it won't work unless you add a sensor outside of the MAF...

My IAT sensor is in the front of the manifold, it sticks out into the flow path a little bit so it should be able to detect the cooler temps from the injection.

[ferocity02]

So lets say my tune is dialed in on 91 octane up to 11.5psi, 11.3 AFR and 10-12 deg of timing. Can I just start spraying with this tune and then adjust accordingly, or should I adjust the tune first and then spray? I feel like I'm at the limit of 91 now so I'm hesitant to lean it out or add timing w/o spraying. The plan is to use 50/50 water/meth at 15.5gph total.

[BLK02WS6]

You can make a baseline pull on that tune with the meth... It will be way rich though and you will see the power pick up as soon as you start to lean it out. After you get the fueling were it is optimum, work on the timing...

[ferocity02]

You can make a baseline pull on that tune with the meth... It will be way rich though and you will see the power pick up as soon as you start to lean it out. After you get the fueling were it is optimum, work on the timing...

When you say get the fueling where it is optimum... how do I know when it's optimum? One person told me to aim for 11.0 AFR, but I'm not sure if he meant spraying 100% meth or a 50/50 combo or what.

[BLK02WS6]

The only way to know when timing and fuel are optimized is to put it on a dyno and make small changes until you get the max torque and horsepower throughout the RPM range. There is no other way to do it - even track times won't show you how it is doing throughout the RPM range. Every combination is different...

I recently tuned a procharged 383 and a magnacharged 408 - both on 50/50 meth - and the fueling was pretty close to the same with both at .80 to .82 lambda - which brings me to the point that you really should be using lambda with blended fuels! You can't speak AFR with blended fuels - a safe AFR for gas is way different than a safe AFR for methanol - and blended is different still... AFR is fuel dependent and lambda is not. I would say that it is generally accepted that 20% rich (i.e. .80 lambda) is a good safe point for forced induction.

However, the timing was a totally different story because of compression, boost, cylinder head, and cam differences... the two above engines were vastly different in what timing they wanted. There are no shortcuts to doing it right...