MegaSquirt/Tuner Studio Tuning Theories/Concepts

Discussion about ECU Tuning Products and Theories
Kill3rwill
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

When i load up your tune is shows that boost control is activated, and that your running open loop. But the duty table shows nothing but 0's, so it isnt loading it correctly. would you mind taking a screen shot of your values, i know theyll be much higher i just want a starting point. Also i plan on running closed loop once open is well tuned, have you experimented that yet?
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

I will update with a new tune when I get a chance. I haven't played with closed loop enough to get any results. That will be happening soon though. I am tired of doing 4th gear pulls at night to see if I need to play with the map before running.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

I updated the tune. Please try and let me know.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

I got my idle stabled out. No more lopey-ness. I followed this guide: http://www.diyautotune.com/tech_article ... uning.html. Basically, my first x axis was 1000rpm. I split it down to 500, 800, 1200. In cell 800, made the idle stable with timing and fuel. In the 500rpm, increase timing 3* higher than 800 cell timing. When the engine starts to die, the ecu will increase timing to speed up the crank to keep it up. I only modded cell from 500 to 800 vs 20 to 60kpa. This is my idle/vacuum range. Hope this helps.

This is from yesterday.
https://youtu.be/lyY3C5PlDsw?list=UUHSV ... EnZcrlmaMA
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by cmj »

Supakat, Im using your suggestions to create a timing map. You state that at 100 kPa and 3000 rpm that timing should be at ~25* BTDC.. The .msq file you provided does not show this.

Clarification?

Thanks for the resource, lots of good reading!
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by cmj »

Image

Here is what I have come up with.. I used the values from RS-Enthalpy's stock ignition map, and did some work from ~3000 rpm @ 100 kpa and up. I'm looking for a very safe ignition map.. I'm looking for reliability over power. Let me know if this is a good start.

Thanks!
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

cmj wrote:Supakat, Im using your suggestions to create a timing map. You state that at 100 kPa and 3000 rpm that timing should be at ~25* BTDC.. The .msq file you provided does not show this.

Clarification?

Thanks for the resource, lots of good reading!
I am on e85 so I can run more advance timing without detonation. Glad this thread is helping everyone out.

Your map may be borderline on 93 pump. 19* at 10psi = 1:.65 reduction. Try doing 1:.75 = 17.5* @ 10lbs.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by BigLoukaT »

cmj wrote:Image

Here is what I have come up with.. I used the values from RS-Enthalpy's stock ignition map, and did some work from ~3000 rpm @ 100 kpa and up. I'm looking for a very safe ignition map.. I'm looking for reliability over power. Let me know if this is a good start.

Thanks!
I have a slightly different view for the shape of an ignition timing map, and read a response recently from a dude on msextra that I believe knows his stuff and explains it well.
elutionsdesign wrote:My only other comment on the table posted is the load axis "texture", over 2/3 of the cells are in boost (over 101 KPa). If that's where you're spending all your time, great, but if you want to drive this thing on the street and get the snappiest throttle response possible I'd make it the other way around with 2/3 of the load axis less than 101 KPa and 1/3 above. Boost retard is generally pretty linear anyway so you don't need very many cells while street driving experiences all levels of acceleration which needs more ignition resolution in the atmo part of the table. And the VE table load bins don't need to match the ignition bins either, they can be whatever gives you what you want in terms of driveability.
For your table specifically, you would command the same exact ignition advance if you only kept the 138 and 229 kpa rows and removed all the rows in between. Each load row between those two rows command a linear reduction in timing (0.5 degrees per psi), and by table interpolation, ignition timing at 183 kpa would still be 17.1
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

I agree with this concept as well. I will be changing my map to do the same so I can get better resolution on top. I hit 32psi with no ill effects so I want to increase boost map to 35psi incase I overboost timing will be retarded and my boost cut can be set higher to 35psi.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

Alright guys, spent the last few hours doing research, time to drop some knowledge bombs. As it turns out e85 is damn near completely knockblocking. lol. that word sounds funny. But as it turns out it is quite "pre-ignition" prone, compared to 93. What this means is that advanced timing can be pushed rather far without the flame front smacking the piston on the way up. Pre ignition on the other hand is latent heat in the cylinder/head/ spark plug causing the fuel to combust with-out spark. Basically auto igniting itself at whatever time in the engine cycle it occurs, often much sooner than knock. So this means that e85 can take less TEMPERATURE than 93, now that does't mean it cant handle heat, it actually absorbs is at a much greater rate than gasoline, but it cant take as high of a temperature before auto-ignition and therefore requires less PEAK TORQUE ignition timing than a comparative 93 tune. Less timing means more fuel/air mixture escaping out of the exhaust rather than being absorbed into the cylinder and thus cooler internal temperatures. After peak torque ve starts to drop off accordingly with rpm's, allowing more timing, and this is where e85 starts to show its magic. Attached is a timing map professionally tuned on a 2.0 evo 9, tuned on 91 and e85.
E85vs91_timing101208.gif
E85vs91_timing101208.gif (4.75 KiB) Viewed 10662 times
Granted this is not the same application but principles still apply. Keep in mind this is 91, not 93, and at peak torque the timing values are almost identical between the 2, i would imagine 93 to actually have a higher peak torque value. As you can also see with added rpm e85 can take exponentially more timing, ramping up 8 degrees at redline more than 91, and a ridiculous 16 degrees more than at peak torque. SUPAKAT's map and i are structured similarly and we only advance around 3 degres up from peak torque rpms. Now i don't know how close my map is a peak torque to knock or MBT( mean best torque) but SUPAKAT's map is actually 3 degrees or so more advanced, he runs without issue but neither of us have a working knock circuit. I'll be switching to e85 in a few days, I may keep peak around the same as my map, but will probably have a more aggressive ramp up with rpms as that seems to be a safer route. So in closing a max effort e85 tune should require slightly lower peak torque timing than a max effort 93 tune, but the e85 will take gobs more timing everywhere else, as well as being able to be run at a leaner afr all the while having cooler EGT's, so its still a miracle gas for 2$ a gallon!
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

Correct. One of the main reasons for cooler plugs is pre-ignition. After the spark and burn, on a hotter plug, the ground strap may still be glowing which may pre-ignite the incoming fuel which can cause detonation. Now when you say pre-igntion prone, this sounds like the fine line of having too much advance. Basically, you are trapping the flame inside the cylinder longer as compared to having the flame propagation peak at 14* ATDC. This will heat up everything and not give the motor enough time to cool down the internal components. This will probably peak water temps as well.

This is why you must have good head studs or it will lift the head. To make power, you are increasing combustion cylinder pressure and need good clamping force.

To tune e85, a dyno is needed to dial in on the tune. You will loose power before you ever hear any knock. But it is safer to street tune. I have a TurboXS Knocklite. I just don't have knock hooked up to my options port on ECU. I have been giving V8's a run for their money lately so I seem to be doing something good. I want to get my other manifold on so I can really let this baby breathe.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

To me pre ignition is heat related, like a glowing plug, whereas knock is obviously from too advanced of ignition and the piston fights the flame front. I'm running an ngk 7 iridium now, plan on switch to an 8 once I crank the e85. And I'm also giving v8's a run for their money! I'm on pump and meth at the moment 26 psi, virtual Dyno showing 470 hp and 465 tq. I lost to a supercharged new 5.0 with 600 whp by 1 length, but I was at 25 psi and 1 degree less timing. I should be right on him now. With e85, 3 degres more timing up top, leaner afr, and possibly 28-30 psi I should smoke him, hopefully be around 530-550. I am running the bigger 60mm hx40 compressor but still have the 35 hotside which may be holding me back. Also planning a bigger throttle body, possibly a 70mm for an SR with my tps as well as 3 inch after intercooler piping and a 3.5 inch exhaust. With all that and a Dyno I think 600 whp is doable with e85/meth.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

When the fuel pre ignites, do you still hear her ping? You may hear some back fire from the intake obviously but as soon as the intake valve closes and piston starts rising, do you think it still may knock?

I am running Q45 TB and it was a nice upgrade. I felt the difference down low and up top. I have a 3 inch dp all the way out but my manifold is holding me back. That is why I want to put on my other one. It will breathe nasty once it is on.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

Yea you'd still hear pre-ignition. It's fuel explaining after being sucked in through the intake valve, I would assume it could technically happen once the fuel becomes rich enough to combust, but I would think it would realistically combust after the valve has closed and whatever is hot has had time to hear the fuel mixture adjacent to it.

I'm running a extra think cx racing manifold, the ports don't even line up, I ported it as best I could, but there is still a bit of wall on the way that the exhaust hits. I'm running 2.25 Intercooler piping so I know that could use an upgrade.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

Hey supa, did you have a pump gas tune before you went e85? If so I'm curious what all was necessary to scale when you made the switch. Looks like just add around 35% more injector scaling and crank the startup fueling way up.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

I had pump when I had chipped ecu with emanage blue. I switched to corn on this setup then brung in the mspnp. You could add 35% instead of messing with the req fuel. After that, than either deduct or add fuel to the whole table to get close to your original afr's. Then ve live it.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by BigLoukaT »

I would consider adding the additional fuel into the required fuel field (either by changing injector size or stoich ratio) instead of the ve table. This way, all of the scalar maps that depend on required fuel (warm up enrichment, afterstart enrich, cranking pulse, etc) have the extra 30% of fuel built right in as a starting point.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

+2.4 :werd:
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

I punched in 9.7 afr under the required fuel and then just used the value it generated and put the afr back to 14.7. It ended up being around 35% exactly. That ended up being too much as the tank had a few gallons of 93 left. I just dropped the req fuel till I idled back at 14.7 and then used ve live. 20 mins later my map was smooth. Easy transition. BTW for anyone interested, just switching fuel alone and keeping afr the same, no added timing or boost, virtual Dyno went from 467 to 484, all on 25 psi. Since then I leaned it out to around 11.8 afr and added 2 degres of timing and jumped way up to 535! Can't wait to add more boost
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

Sounds good man...keep up the good work.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

I added another tune. Basically, it is the same as the others just increased the resolution to 40psi. I also increased fuel at 30+psi by increasing values by 6% from 30 psi to 40psi at every 2 psi. This will make sure I have adequate fuel when I begin to tune. I also increased by boost cut to 40psi. I don't plan on going to 40psi. I mostly did this because I have open loop boost control. On cold days, I can spike to 32psi and hit boost cut. So why not increase the map since I can hit 31psi safely and if it crosses to 35psi, I will just fly past whomever I am racing.
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Image of fuel and timing map.
Image of fuel and timing map.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

Let me know how high you take the boost on that bad boy. We have pretty much the same setup. I'm curious how far the 10mm headstuds can hold on for. I've been running 26-27 psi for awhile with no issues now. Getting a 3.5 inch turbo back made, that should help out with the back pressure these turbos love to make.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by supakat »

Kedbmx made 800 on 10mm studs before lifting. I know my car hit 30psi and up to 32psi. Tuning done after making the changes.
https://www.youtube.com/watch?v=ib2k6pRmaAw
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by Kill3rwill »

Yea but his turbo came online super late. I think he made like 550 torque and 800 hp. No he's not putting crazy amounts of stress at low rpms like these holsets have the potential to.
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Re: MegaSquirt/Tuner Studio Tuning Theories/Concepts

Post by scoobydo »

book marking :-)
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MAT density table discussion

Post by NukeKS14 »

This thread has been dormant for a while but still has super relevant info for the MS beginner. I used some of these approaches when tuning my MS2, and thanks to all of the contributors for sharing their knowledge with the community. I didn't see anything about MAT density tuning and just dealt with it in my tune so here goes;

In revision 3.3.0, MS changed the air-density compensation scheme from using a combination of MAT/CLT and MAP density, to a consolidated table where MAT density does all of the lifting now. Good idea and makes it a lot easier to tune a single table. Problem is, they leaned on Boyle's law a little too hard for their graph. Air density isn't entirely linear with temperature, as they tried to make it.
Image
Pv=constant graph for illustration of what I'm talking about. Link to good explanation if you want to know more about this topic.

The shortcoming in their application here, is that this all assumes a FIXED volume of air, and all of the other factors that affect air density are being taken out of the equation as well. So you wind up with the default plot they have here;
Image

What does this table to do? It's just like any other fuel modifier table in Megasquirt. Under the conditions you specify, it's going to add or remove fuel, in this case, based on air density which it is deriving from your IAT sensor readings. IAT placement really affects this as well. I've got my IAT installed about 6" after the outlet of my intercooler in the cold-pipe to avoid heatsoak in the engine bay and am running an open element GM IAT sensor.

So we finally get to the issue I was having along with other MS users running the 3.3.x firmware or above. The issue I've been chasing my tail on, was consistency in my AFRs. I'd get my VE table dialed in, then go out a different day when it was hotter/colder and I was running too rich when it was cold, and too lean when it was hot. Digging through the manual, MS forums, and the Miata MS forums, I figured what was going on.

So what SHOULD the values look like? Well there isn't a blanket answer. Just like there isn't a blanket VE table or spark table that is going to work for every car. They've done a good job here simplifying it for the end user but elevation, humidity, IAT sensor placement, and some other factors are going to play a part.

How to apply this to your tune? When tuning your VE table, set the values to 100% for a 10-15 degree range of temperature starting where your IAT reads when you fire your engine up before you go tune. That way, this table won't be modifying your fueling and you can do a more pure tune for VE for those conditions. Go get your VE table all tuned in. THEN, as you drive the car in different weather conditions, pay attention to what your EGOC % is. If it's having to add a ton of fuel when your IATS are well below the temperature you tuned at, you need to increase your MAT correction at that temperature range, vice versa if it's pulling a lot of fuel. Pay attention to what it's doing across your table, not just one area of cells. It's easy to get zoned in on cruise and just assume that's what's going to happen everywhere. The important part here is to get your VE table tuned in, finalized, for one fixed set of weather conditions and THEN and only then, adjust\tune your MAT density correction table as you drive in different conditions. datalogging on cruises is IMMENSELY useful when you're doing this.

Image
I ended up with something like this. This was lifted from miataturbo.net. They're a good source of MS tuning info, the theories and application are same. Apologies, I don't have my actual graph to post right now but the hotter temperatures aren't far off from this, save mine is nearly flat from 85-95F and at 100% since this is where I tuned in my VE table.

So far so good, I drove a little last night and a storm was moving in. My IATs ranged from about 97F when I started to around 81F when I got to some cool spots outside of town. My EGO correction never got above 105% or below 98% peaks, riding mostly between 100-102.%. I'll call that a win knowing I'll need to dial in my lower temperature values in the winter.

I know that graph goes way beyond what a majority of us will ever see. I'll pull my actual graph this weekend if anyone actually wants to see it. A completely separate discussion, but, mine only goes up to, I think, 140F. At 120F IATs I start pulling pretty heavy timing. I'm on pump gas (93 octane) and I REALLY don't think it's that safe to tolerate IATs much higher than 120F on that alone. Lots of factors at play like, again, IAT sensor location/heatsoak, humidity, compressor efficiency, etc... I feel like, with my IAT sensor where it is, I'm getting a pretty accurate picture of what is going into the engine. At lower velocities, I'm sure I'm getting a little saturation from intake manifold heat, but I've got a Sikky phenolic spacer I'm planning to install to cut down on that. At WOT and higher loads this is not much of a factor, if any.

If anyone wants to get into the meat of heat transfer and fluid flow discussions, I've been a student-in-practice for a little over a decade now. I'm all about the science behind the application here. Probably why I prefer tooling with a Megasquirt over something more expensive like a Haltech or Link.


*edit* We're actually on to firmware version 3.4.x now. I'm running 3.4.3 and the MAT density approach is unchanged. Yeah, EGO control CAN tune out things to a degree but, I REALLY don't like seeing EGOC constantly having to do much with my AFRs over a percent or two. To me, that means my tune needs work. Any time you're leaning on your EGOC to fix your issues with a tune, you're inducing a lag into the process that I feel is inefficient. I set my max authority to 9% FWIW.




*Second edit!*

Almost forgot. It isn't hard to find but, for those interested, here's the link to Megasquirt's page for all of the active released firmware versions. A word of warning;

IF YOUR TUNE IS RUNNING JUST FINE AND YOU'RE NOT HAVING ISSUES, YOU ARE TAKING A RISK BY UPDATING YOUR FIRMWARE. THE INTENDED PURPOSE IS TO ADD ENHANCED FEATURES OR POSSIBLY FIX ISSUES THAT HADN'T BEEN ADDRESSED IN THE PREVIOUS FIRMWARE RELEASE. UPDATE AT YOUR OWN RISK

Ok you've been duly warned about reflashing firmware for no good reason. >Megasquirt firmware downloads here.< The currently released version is downloadable directly there. If you're drilling down to another link instead of downloading a file from that page, you're going for an old version or a beta release.
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