Dyno results from today

[Bob_H]

Sorry for the delay about the methanol injection. This will validate what has already been said and provide you with the method to tune if you change the percentage of Meth injection. It is important to determine exactly what percentage meth you are injecting vs pump gas because it has a fairly significant difference in the target A/F ratio.

 

The stoich A/F ratio for pure methanol is 6.5/1, Premium gas, (pump gas) is around 14.7/1

 

The difference between those two is 8.2

 

To figure out your target A/F ratio, multiply the percentage of either one and add or subtract it to the other.

 

For example, if you are running 10% methanol - multiply the difference of 8.2 by .9 and add it to 6.5,(or multiply it by .1 and subtract it from 14.7)

 

Net result:

10% Meth A/F target ratio for stoich,(NOT max power): 13.88 or rounded to 13.9

For best power on a turbo setup for regular fuel, (NO Meth), you are shooting for about 11.5 A/F,(12.7 for NA setups).

 

To convert it over, it is easier and simpler to use what is called Lambda. Basically Lambda is a universal number for any fuel. Lambda of 1.0 is stoich for that fuel. So for premium gas,(pump gas), 14.7 = 1.0 lambda

 

Best power for a supercharged/turbocharged setup is lambda of .78, (.88 for NA).

 

If your setup won't show lambda, multiply your stoich point for the 10% meth by .78 to get your target A/F ratio. The nice thing about lambda is it doesn't care what fuel you put in or what ratio you are mixing - .78 will always be your best power tuning point and 1.0 will always be your idle/cruise/light part throttle point.

 

Best power 10% meth = 10.8 A/F ratio

 

I put the math so you can scale this equation for any fuel or varying percentages.

I stated above that you need to be sure of what percentage meth you are injecting as a small change shifts your target a/f significantly. For example, 5% meth injection best power is about 11.1 and for 15% meth is 10.5.

 

Another example, pure ethanol has a stoich of 9.0 A/F, E85 is 85% ethanol, so the stoich point or Lambda 1.0 is 85% of the difference between 9.0 and 14.7 or 9.9 A/F for stoich, and 7.7 for best power on a turbo application. Pretty low eh?

Anyways, just wanted to provide the method to change what your tuning for. If you can switch your wideband to display lambda, you eliminate all the guess work and just tune for 1.0 and .78,(well the higher throttle settings will be in the .9 to .95 range).

-Bob

[jgkurz]

Great write-up Bob. Thanks for taking the time.

[ktm]

Edit: Read too fast. Thanks!

[wigenOut-S30]

edit.. did the same heh..

[big-phil]

Sorry for the delay about the methanol injection. This will validate what has already been said and provide you with the method to tune if you change the percentage of Meth injection. It is important to determine exactly what percentage meth you are injecting vs pump gas because it has a fairly significant difference in the target A/F ratio.

 

The stoich A/F ratio for pure methanol is 6.5/1, Premium gas, (pump gas) is around 14.7/1

 

The difference between those two is 8.2

 

To figure out your target A/F ratio, multiply the percentage of either one and add or subtract it to the other.

 

For example, if you are running 10% methanol - multiply the difference of 8.2 by .9 and add it to 6.5,(or multiply it by .1 and subtract it from 14.7)

 

Net result:

10% Meth A/F target ratio for stoich,(NOT max power): 13.88 or rounded to 13.9

That is now your target A/F for cruise/part throttle/idle.

For best power on a turbo setup for regular fuel, (NO Meth), you are shooting for about 11.5 A/F,(12.7 for NA setups).

 

To convert it over, it is easier and simpler to use what is called Lambda. Basically Lambda is a universal number for any fuel. Lambda of 1.0 is stoich for that fuel. So for premium gas,(pump gas), 14.7 = 1.0 lambda

 

Best power for a supercharged/turbocharged setup is lambda of .78, (.88 for NA).

 

If your setup won't show lambda, multiply your stoich point for the 10% meth by .78 to get your target A/F ratio. The nice thing about lambda is it doesn't care what fuel you put in or what ratio you are mixing - .78 will always be your best power tuning point and 1.0 will always be your idle/cruise/light part throttle point.

 

Best power 10% meth = 10.8 A/F ratio

 

I put the math so you can scale this equation for any fuel or varying percentages.

I stated above that you need to be sure of what percentage meth you are injecting as a small change shifts your target a/f significantly. For example, 5% meth injection best power is about 11.1 and for 15% meth is 10.5.

 

Another example, pure ethanol has a stoich of 9.0 A/F, E85 is 85% ethanol, so the stoich point or Lambda 1.0 is 85% of the difference between 9.0 and 14.7 or 9.9 A/F for stoich, and 7.7 for best power on a turbo application. Pretty low eh?

Anyways, just wanted to provide the method to change what your tuning for. If you can switch your wideband to display lambda, you eliminate all the guess work and just tune for 1.0 and .78,(well the higher throttle settings will be in the .9 to .95 range).

-Bob

I have no idea how to figure out what % of meth i'm injecting. I figured it out to be about a 350/380cc nozzle pumped with a 150psi pump its about 5/6 gph. my car has 720cc injectors and the meth comes on at 14 lbs of boost running a max of 25 lbs of boost.

 

So, whats my meth %? I don't no?

[ktm]

Phil, you are running a Coolingmist setup, correct? If so, see if you can get their flow information from them.

 

Secondly, you can back calculate what your meth flow rate is based on the changes to your AFRs that you logged.

 

Saying that, it is my understanding that you do not have a means of adjusting your methanol flow rate with the Coolingmist system. You can change the nozzle size, but it is a "digital" system is that it is all or nothing.

 

When tuning for meth injection, you still tune with AFRs. Do not get wrapped up in calculating what your meth flow rate is, simply tune your car for AFRs. Your calculations are theoretical at best. You still need to tune.

[X64v]

Phil, as Bob_H said in the last sentence of his post, just use lambda. Forget the specific AFR, switch megatune to display/log lambda instead of AFR, and tune for .78, regardless of how much meth you're injecting.

[Garrett76Zt]

I'm afraid I have to disagree with Bob H's suggestion. Please bare in mind that I dont know everything there is to know about this subject but . . .

 

1) The following sentence does not make any sense:

 

"10% Meth A/F target ratio for stoich,(NOT max power): 13.88 or rounded to 13.9

That is now your target A/F for cruise/part throttle/idle."

 

We are talking about methanol injection which is only injected when in boost. Your target AFR's for cruising will remain the same.

 

2) Consider this, isnt the reason for a turbo motor to run richer 11.5 afr as opposed to 12.5 afr in an NA application due to the fact that cylinder temps are increased from the pressurized air entering it? If that is true then you must also consider the role that the methanol is playing in reducing those temperatures. Also consider that the more meth you spray the more cooling effect it will have. Yes if all things were equal between gasoline and methanol aside from their stoich values, Bob's suggestion would be the way to do it.

 

Speaking for myself and others that are running more like 20% methanol (scottieGNZ), if I plug those numbers in I get a target AFR of 10.1, I can tell you from experience that my motor doesnt like that, haha.

[ktm]

Speaking for myself and others that are running more like 20% methanol (scottieGNZ), if I plug those numbers in I get a target AFR of 10.1, I can tell you from experience that my motor doesnt like that, haha.

 

Garrett, I know that the RX7, Evo and Buick crowd run around 20% meth as well. There is a great thread on RX7club.com (under Auxiliary Injection sub forum, its a sticky) about meth injection. Have you found that an AFR around 10.8 to 11 is ideal for your car?

[Garrett76Zt]

Garrett, I know that the RX7, Evo and Buick crowd run around 20% meth as well. There is a great thread on RX7club.com (under Auxiliary Injection sub forum, its a sticky) about meth injection. Have you found that an AFR around 10.8 to 11 is ideal for your car?

 

I currently tune my car around 11.2 right now.

[madmatt48]

Has anybody out there tried running t3/t4 turbo charger through a blow through Demon 4-barrel carburator mounted on a clifford 4-barrel manifold on an L-28? If so, how were the results in hp and torque? If there is a past thread on this, could you all help direct me to it? A lot of the domestics are running Demons with big single and twin t3/t4 turbines with powerful results. Figured it should flow well due to the large inlet area and how the Demon compensates with extra fuel for every pound of boost blowing through it. This is the combination I will try first before attempting to run a supercharger tandum with it. Any info on this would be apprieciated.

[Garrett76Zt]

Has anybody out there tried running t3/t4 turbo charger through a blow through Demon 4-barrel carburator mounted on a clifford 4-barrel manifold on an L-28? If so, how were the results in hp and torque? If there is a past thread on this, could you all help direct me to it? A lot of the domestics are running Demons with big single and twin t3/t4 turbines with powerful results. Figured it should flow well due to the large inlet area and how the Demon compensates with extra fuel for every pound of boost blowing through it. This is the combination I will try first before attempting to run a supercharger tandum with it. Any info on this would be apprieciated.

 

Wrong place for these questions, you probably wanna start a new thread.

[Bob_H]

1) The following sentence does not make any sense:

 

"10% Meth A/F target ratio for stoich,(NOT max power): 13.88 or rounded to 13.9

That is now your target A/F for cruise/part throttle/idle."

 

We are talking about methanol injection which is only injected when in boost. Your target AFR's for cruising will remain the same.

 

 

Shoot,

I got all wrapped up in showing the math, I completely forgot that we don't need a stioch value for meth while cruising/etc...... But it is important to know what it is so you can use it for the math.

Your right - cruise, idle, etc.. use gas stoich - 14.7/1

I'm going to edit the first post to reflect that and make it more clear.

 

In the end, you will greatly simplify your life if you can read and log Lambda - it takes all the guesswork out of what AFR to run and how much your injecting.

To answer your question #2 if you run pure methanol - you would have to tune for a stoich ratio of 6.47:1, (or Lambda of 1.0 - hint, hint guys, get the picture? ). That takes into account its different burn effect.

What you are doing by injecting meth or ethanol or whatever into your mixture is changing the octane of the gas - effectively giving it a higher octane rating, and a higher resistence to knock. In the end, if your motor can produce max power on pump gas,(i.e. its not knock limited), meth injection, higher octane fuel, etc.. won't make squat of difference.

In our L6 motors, they are almost always knock limited - so higher octane gas, meth injection, water injection, etc.. all raise the knock tolerance and raise the ceiling on max power.

What you are asking in that second question is way beyond the scope of what we can account for w/o some serious guessing.

[Bernardd]

This link has a chart in it showing the lamda values vs stoich values for a couple of different fuels.

http://www.turbobuick.com/forums/alcohol-nitrous-propane-tech/191893-how-does-methanol-affect-wideband-readings.html?highlight=methanol+effect+wideband

[Garrett76Zt]

Bob, I agree with you on tuning via lambda, and probably that this whole conversation should be condensed to that.

 

As far as your math goes for calculating AFR's when using meth injection, its just not that simple. There is more going on than just a difference in stoich values. Tuning via the method you suggest would probably result in a safe tune, but I contest that it would result in tune that is much too rich, sacrificing power.

[Clifton]

You are down an easy 60 HP. It's not the meth and I don't think it's afr if his tune is anything like this graph starting at 1653.58, looks like third or forth gear. 10.1 is as low as it goes on the graph. As the revs increase it leans quite a bit, atleast to mid 11's. His dyno would show power picking up, not dropping so much as the revs increase and it leans. Plus his peak toruqe is on par for the boost.

 

I would look at cam timing. Maybe you degreed it since, but last I saw you had problems making power after a cam swap. I would print the paper wheel on hybrid and check it.

[Bob_H]

I couldn't formulate an adequate answer to the meth cooling effect,(or any alcohol for that matter) I did what any sane person would do - I asked the smartest person I know. He is an OEM calibrator and was responsible for the Dodge SRT4 tuning and is currently responsible for driveability and fuel mileage on the upcoming Chevy Volt,(which will likely re-define what we think is good gas mileage).

Anyways, here is his response as I can't encapsulate it as well. If any of this is not clear - just ask and I'll clarify. It is important to note his last few comments about ensuring that you only have less base fuel and more timing if you are sure you have meth flowing. If it runs out - and your table is leaned out to compensate for the meth - that's a good way to toast an engine.

added some edit at the end.

 

Bobby,

 

We run richer ratios with boost primarily to control burn temp, rate, and knock. With alcohol blends that naturally burn cooler and slower than gasoline, you may not need as much safety margin for these reasons. This may allow you to run closer to LBT ratios like we do N/A.

 

If you run meth injection, I would recommend first tuning without it if at all possible. This will give you a good failsafe mode.

 

Then you have to remember that meth is fuel, so adding that in does several things: it blends the stoich point, blends the average octane, and cools the charge/burn temps.

 

I would still look at lambda (not AFR) when using alcohol blends. As you add meth (without increasing airflow), you will probably see a drop in lambda. If you artificially lean out the base (non-meth assisted) fuel delivery target, you should really have some safety check to avoid an overly lean condition if the meth runs out to avoid damage. The same goes for spark advance. Hopefully, you are only leaning the mix and adding timing when the meth is actually flowing.

 

Once you have confirmed that you have meth contribution, it is desirable to run more lead (to get closer to MBT timing) and perhaps a leaner lambda that gets closer to LBT since temp control is less of a concern.

 

 

On edit - I should clarify some of the terms as they are not likely universally known. LBT = Lean Best Torque, which is ~.92 Lambda depending on engine. We tune to richer than that for a safety margin and to ensure under all condtions, you won't go leaner than that, (the .88 NA and .78 boosted). MBT = Maximum Brake Torque - which is the maximum power at that given rpm/load and once you have the fueling set, you tune via timing to achieve that. The end statement of tuning with more lead - means more advance.

[ktm]

Bringing this back to make a correction to Bob H's statements. You can tune with gasoline AFR's when using meth. It does not matter that the stoich has changed. I was wrong before and have since seen the light. The AFR is just a representation of your lamba in terms of your fuels stoich. O2 sensors output lamba and this value, regardless of stoich, does not change.

 

Now, AFR gauges report your AFR based on gasoline (unless you can change it) which has a stoich of 14.7. Regardless of how much methanol you run, you can still tune using gasoline AFRs since it is a number we are all familiar with. The key point to remember is that your lamba value will not change and that your AFR is simply stoich times lamba. Your AFR value is simply a conversion value and should not be taken as an absolute. Your true AFR will not be reported if you are running a blend since the stoich value is not correct, but you do not care about your true AFR. Regardless if your true stoich is 12.0, 11.0 or 10.0, selecting and tuning with stoich as 14.7 will still give you in the correct lamba.

 

Please read the following link and the others it references: http://www.rx7club.com/showthread.php?t=582856

[Bob_H]

I had forgotten about this thread. Some very good points - I'll clarify a few, but fundamentally, what your saying is correct and thanks for pointing that out.

 

 

You can tune with gasoline AFR's when using meth.

 

Absolutely, I agree 100%.

 

 

It does not matter that the stoich has changed.

 

I wouldn't say it doesnt' matter at all, but for tuning if you adjust what your targeting appropriately, it doesn't matter.

 

 

The AFR is just a representation of your lamba in terms of your fuels stoich. O2 sensors output lamba and this value(my bolding), regardless of stoich, does not change.

 

Minor point: O2 sensors(the actual sensor) output Lambda only,(technically just a voltage corresponding to Lambda). Its the controller/Gauge that then converts it to Stoich for gasoline,(or whatever you have programged it to put for stoich).

 

 

Now, AFR gauges report your AFR based on gasoline (unless you can change it) which has a stoich of 14.7.

 

Which dovetails with what you said above - I just wanted to clear up for others that the sensor itself only reads and outputs voltage for Lambda.

 

 

 

Regardless of how much methanol you run, you can still tune using gasoline AFRs since it is a number we are all familiar with. The key point to remember is that your lamba value will not change and that your AFR is simply stoich times lamba. Your AFR value is simply a conversion value and should not be taken as an absolute. Your true AFR will not be reported if you are running a blend since the stoich value is not correct, but you do not care about your true AFR.

 

That's the key point.

 

The info I gave is to compute true AFR. If you can convert your tuning midset to Lambda - its a moot point, just tune to the Lambda. However, as you pointed out, if you have a gauges setup that will only display Gasoline AFR,(or you can't change it), then you need to change what your target is.

 

First, you need to know your target, such as 20% rich, or .80 Lambda - then multiply it by the stoich for whatever your gauge is setup for,(Gasoline of 14.7 in 99% of the cases, remember, Diesel is 14.5, etc..). If your not sure, assume Gasoline at 14.7.

After multiplying your target Lambda by the stoich, you have your target AFR, (11.76 in this case). That is where there was some good confusion created above by mine and other posts.

 

 

If you have tuned your car w/a meth/water injection for 10.5:1 on your gasoline referenced AFR gauge, your running very rich, (.71 Lambda), which is much, much richer than you should target for even just boosted applications. The biggest advantage of running Meth/water mix is you can run closer to a NA Lambda max power setup - because of the cooling effect of the meth and water.

 

Here was a great set of posts about exactly what's going on and how to use what ktm said and what I've expanded on:

 

http://forum.mazda6club.com/index.php?showtopic=105601

 

Heres a great post about what to target and what to do w/meth injection. Specifically post #91

 

http://forum.mazda6club.com/index.php?showtopic=105546&st=80&p=1461761entry1461761

 

Realize that post #96 that the poster from #91 acknowledges as a great post is not correct - there is one big incorrect assumption in his post I can clarify if requried - but its already clarified in the first link post #7, (the poster in #91 posted the same thing in the first link and was wrong both times).

 

ktm, great job clarifying how people can use gasoline AFR gauges - I did a terrible job and certainly confused the issue.

-Bob