can you guys look at my Megasquirt timing table

[mobythevan]

This is my base timing table with megasquirt, it is what I started with using the general rule of thumb given to me by other turbo guys, basically ramp up to full advance by 3000rpm under no boost and remove 1 degree of timing per pound of boost.

It is running very well for me, but I am only at 13.5psi and I am ready to start moving up, so I just wanted to make sure there are no HUGE areas I should be concerned with.

I am planning to remove 1degree per pound up to 13psi then remove 1.5 degree per pound above that(the table does not reflect this yet). I have FMIC and will also be running water injection above 16psi becuase I can only get 91 octane. I have the injection kit but need to install it.

Because I am at high altitude my atmospheric pressure is 77kpa, so 13psi right now is putting me around 165kpa on the table and that gives me about 22 degrees timing.

Once I update the table 16psi put me around 185kpa on the table and give me about 18 degrees timing.

Does that sound reasonable? I have a wideband and I tune AFR to stay right at low 11's under boost.

Also, since I'm at high altitude, a sea level guy would start pulling timing under boost from 100kpa up, should I start pulling timing under boost from 77kpa up since that is my atmo pressure?

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[blueman803]

Do you have a logger and knock sensor still in the car? I will post my table up later tonight when I get home for comparison. One thing, your column for 400 is useless, you will never idle under 400 rpm. You can get rid of the 400 column and add one to the end going however high you plan to rev it.

 

[GVR4592]

One thing, your column for 400 is useless, you will never idle under 400 rpm. You can get rid of the 400 column and add one to the end going however high you plan to rev it.

I agree, I usually just set one rpm breakpoint around 1000 rpms for idle. If the EMS system you are using is any good, it will just interpolate the values and it'll run fine.

There are a few things I would change but it might not apply to your setup. If you were able to view the volumetric efficiency of your engine in a chart it would look something like this

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That is similar to what the VE is a of a stock 4g63(it's based on a fuel map and not applicable for every vehicle). Now look at the big plateau in the middle, that is where the engine is at peak VE. Peak VE makes the most torque, it also requires the most amount of fuel and the least amount of timing, than other VE points. You want your timing and fuel tables to reflect this. Most tuners shoot for flat timing advance and flat A/F from full boost to redline. They do that because it's much safer, but it's not good for power under the curve. By pulling fuel and adding timing(in small increments), before and after the torque peak there will be noticeable increases in the range of the powerband. A car that used to start pulling hard at 4000, will start pulling hard at 3500. Or a car that falls flat on it's face at 6000 rpms, will pull harder all the way to redline. This is just a generalization, the actual numbers will vary from vehicle to vehicle.

The only way to accurately dial in ignition timing is with a load holding dyno. Most people don't have access to that type of dyno so in those case street tuning will have to do. But if you have access to that type of dyno, that should be next on your agenda.

There are other things that will affect ignition timing as well, (without taking detonation into consideration) a larger engine, a higher compression ratio, a more efficient combustion chamber, will all require less advance to make optimum power.


When I tune on the street I initally set ignition timing fairly low. I tune the A/F first, then I tune ignition timing, then I go back and touch up the fuel. So if you plan on running high boost you will probably want to pull a little more timing just to be safe, you can always add it back in later.

 

[blueman803]

I just noticed thats a huge amount of advance at idle. Stock the car idles around 10 degrees. It shouldn't cause any problems, but I noticed it quited the exhaust down considerable if the timing was lower. A high advance can make your exhaust louder.

GVR4592, Megasquirt does interpolate between the advance and fuel points. After peak torque, you are suggesting to add advance and pull fuel? Any idea how much advance to add per RPM? Is it just a trial and error thing using a knock sensor and feel of the car if you don't have access to a dyno? What AFR do you suggest leaning out to?

 

[wishihadatalon]

woot another ms user. Did you build your table from scratch?

 

[mobythevan]

ok,

GVR4592,

That is exactly what I was hoping for, thanks for the response. I have not been tuning to match the VE of the engine, that is a new direction I will take now and see what I can figure out.

Also, you mention starting with less timing if I plan to run higher boost, what would you suggest, pulling 3 degrees everywhere under boost? or more?


blueman,
I thought the factory ECU idle was higher than 10degrees because 10 was just a base setting with the ECU disabled, then it would add more when it was enabled. I haven't made time to set down and change timing at idle because I still have to swap the TB and then I will do it.

wishihadatalon,
This table was taken from my L28ET engine and then I modded it for the 4G63. I was running a little more timing with the L28ET because it only had 7.3 CR

 

[wishihadatalon]

ok,

GVR4592,

That is exactly what I was hoping for, thanks for the response. I have not been tuning to match the VE of the engine, that is a new direction I will take now and see what I can figure out.

Also, you mention starting with less timing if I plan to run higher boost, what would you suggest, pulling 3 degrees everywhere under boost? or more?


blueman,
I thought the factory ECU idle was higher than 10degrees because 10 was just a base setting with the ECU disabled, then it would add more when it was enabled. I haven't made time to set down and change timing at idle because I still have to swap the TB and then I will do it.

wishihadatalon,
This table was taken from my L28ET engine and then I modded it for the 4G63. I was running a little more timing with the L28ET because it only had 7.3 CR

Interesting. If you would like a base map from diesel geek let me know. I could send it over anytime.

Also my timing is way down at 8 degrees right now at idle. I run right around 18-19 through the power band at 20 psi with a 11.3-11.5 afr on pump. Everyday I play with it I learn more about it. It was very very difficult to understand and it still is hard when you get people talking about ve maps and stuff like that. I have a lot to learn still

 

[mobythevan]

That table looks really flat IMHO, let me setup a picture of what the stock map looks like for you.

Yeah, that was my starting point until I understood more about the 4G63 engine. Thanks for posting the stock type map, that will help a ton.

 

[wishihadatalon]

That table looks really flat IMHO, let me setup a picture of what the stock map looks like for you.

This is taken directly from the stock E931 ecu.

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That is really cool. I am gonna compare that to the map I have now to see where I am at.

what about after 7k though? Does it just stay in the last table there?

 

[wishihadatalon]

Anything past 7k rpm, it takes the last number, and applies it to more RPM.

ex:
@264 and 8,000rpm its still 18*
@120 and 20,000rpm its still 35*

Which is exactly how it works if it calculates more than 264, it goes down instead. Which is mainly why a lot of street guys really like the extended maps for their daily drivers.

That's how the stock ecu worked.

I see. What exactly is extneded maps? Sorry if that seems noobish.

 

[GVR4592]

I just noticed thats a huge amount of advance at idle. Stock the car idles around 10 degrees. It shouldn't cause any problems, but I noticed it quited the exhaust down considerable if the timing was lower. A high advance can make your exhaust louder.

GVR4592, Megasquirt does interpolate between the advance and fuel points. After peak torque, you are suggesting to add advance and pull fuel? Any idea how much advance to add per RPM? Is it just a trial and error thing using a knock sensor and feel of the car if you don't have access to a dyno? What AFR do you suggest leaning out to?

It all depends on what the engine likes. You'll have to experiement.

That is exactly what I was hoping for, thanks for the response. I have not been tuning to match the VE of the engine, that is a new direction I will take now and see what I can figure out.

Also, you mention starting with less timing if I plan to run higher boost, what would you suggest, pulling 3 degrees everywhere under boost? or more?

Just by tuning up to 15 psi you should get an idea of how much timing you will need to pull in the higher boost area's. 3-4 degrees is a good place to start. Just take your time until you get the hang of it.

 

[wishihadatalon]

The extended maps is basically what it sounds like, you extend the map further, so you have more tunable area for your car.

ex:
You extend the load map up to 30ish psi, so you can still control timing from vacuum to a full 30psi range, instead of up to 15psi, which is stock.
Then you can extend the rpm, to adjust the timing across that as well.

the ecu project im envolved with (dsmap) already has basically extended maps for the bar level lookup.

so your tables don't get larger but you just change the values of the cells on the x and y axis?