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! :w00t:

[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...

[ferocity02]

Ah I see. Thanks for the explanation and examples. I have been using AFR because it seems like so many other people use it even though lambda makes more sense.

So I had my tune dialed into 0.793 lambda, and then sprayed 67/33 water/meth today and it dropped it down to ~0.73, but it was more inconsistent than I'd like to see. Unfortunately I don't have a progressive boost controller, maybe that is the issue. At 7psi it switches on at full flow and then it takes about half second for the wideband to register a drop in AFR. So I'm going to drop it to 5psi tomorrow to test. I still want to have a street boost setting of 4-5psi w/o spraying.

I also filled it up with a 50/50 mix to try tomorrow.

And instead of modding the VE table for methanol I may try using the COS5 nitrous trigger to pull fuel once the injection is turned on. However I'm worried about the delay between the fuel being pulled and the methanol entering the engine. Perhaps this isn't the best idea now that I think about it. Maybe I'll have to mod the boost VE table.

And the boost timing table says it can only pull timing in boost, not add it. So I guess I'll have to use the high-octane spark table?

The drop in IAT's when spraying isn't as sudden or as significant as I would have hoped, so I don't think using the IAT tables for spark or fuel will work very well.

[ferocity02]

Tried 50/50 this morning and lambda was down to 0.70-0.73. It looks like I will have to mod the boost VE table for methanol injection. Is modding the high-octane spark table the only way to add spark? It appears I can't use the boost timing table to add spark, and my IAT change/drop isn't significant enough to use the IAT table to add timing. I may set the baseline IAT to about what I'm getting when spraying, and then pull timing at higher IAT's. Is this a reasonable approach?

[Chevy366]

Is modding the high-octane spark table the only way to add spark?
Can't you use B5908?

[ferocity02]

Can't you use B5908?

Hmm I suppose I could, good idea. I guess a better question would be, is there a reason to not use the high-octane table.

[IJ.]

What happens when you run out of Water/Methanol?

[ferocity02]

What happens when you run out of Water/Methanol?

Well I have a level sensor so I know when it's running low. But the idea would be to tune it so it can run safely w/o spraying, at least for long enough for me to notice and let off the throttle. I'm not sure what the best way to go about this is.

[BLK02WS6]

I would use the boost VE to pull the fuel to compensate for the meth. You can use the HO timing table to add spark - make it the highest value that you want to see - and then use the boost timing table to pull timing in the areas where you want it lower... I personally would never use the IAT method to pull/add timing - not consistent enough for me...

[IJ.]

Well I have a level sensor so I know when it's running low. But the idea would be to tune it so it can run safely w/o spraying, at least for long enough for me to notice and let off the throttle. I'm not sure what the best way to go about this is.

Had mine set up last time using MoTeC gear to drop it down to a "safe" setting if it ran out or there was no flow under power, biggest concern for me was if I tuned for optimum advance and fuel while on the Meth and the pump died or something else failed I'd lose an engine, ended up just using straight water injection in the end as knock suppression to simplify things as the afr's were never consistent with the Methanol.