# 16V MS2 tuning for smoothest throttle lift and tip in



## still_a_G (Jun 23, 2008)

Hey yall. Long term build in progress here. I'm in NA mode right now but using a G60 throttle body (wedge removed from primary plate). The controller is MS2 extra controlling a Ford EDIS coil and receiving a 36-1 trigger wheel. My tune is finally turning into something that doesn't feel like a science project. Aside from a sticking ISV, my biggest gripe is the bucking felt during throttle lift and tip in. I can get it smooth on some spots in the map but it varies based on speed of lift, rpm, load, etc. Should I go for a lot of advance at the bottom of the map or retard it to make it smoother? I'll get some screen shots up later.


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## still_a_G (Jun 23, 2008)

All suggestions appreciated.

VE Table:










Timing Table:


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## wrbusa (Jun 13, 2007)

Bucking is tricky because there isn't a magic formula to say that timing or fuel should be relatively high or relatively low--It really has to do with getting timing and fuel *right* for the part of the map that you're in, then using AE to dial in the removal or addition of fuel based on the throttle input.

It looks like you may be compensating for accel enrichment and decel enleanment in your VE table, which is not going to give you good results. You need to first tune for steady state in each cell, then use some kind of AE to smooth out the transients. If your table is far off, autotune may not be able to correct it properly due to misfires, so as you go you'll want to smooth out the values in adjacent cells manually--the fuel table shouldn't have large jumps cell to cell.

Also, when you are tuning low RPM/low load areas, it is very important that your injector timing has been measured or fuel delivery may never be calculated well enough to have good drive-ability. Because this affects all fuel calculations, do this first if you haven't already. :thumbup:


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## still_a_G (Jun 23, 2008)

Hmmm, I haven't messed with injector timing yet. Maybe that's my next step. The biggest improvement so far has been in decreasing the TPS and RPM lag factors from 50% to 95%. Felt waayyy different when I changed that.


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## still_a_G (Jun 23, 2008)

I enabled the semi-sequential injection option. Had to go from 2 squirts alternating to 2 squirts simultaneous because I can't remember how I have my injectors wired. It solved a misfire that I had while under steady state so that's good news. It also feels a little more "free revving", which is good too. The VE table still needs work, this is after an hour of driving around with VEAL active. 

But it still bucks at throttle lift and tip in. I really need to solve this. I don't want to put the charger on until I have an engine that feels stock.

You can see the RPM bounce around in this datalog. This is 4th gear. 











Here's the timing table. I have dual exhaust cams, btw. Advanced a couple degrees.


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## still_a_G (Jun 23, 2008)

wrbusa said:


> It looks like you may be compensating for accel enrichment and decel enleanment in your VE table, which is not going to give you good results. You need to first tune for steady state in each cell, then use some kind of AE to smooth out the transients. If your table is far off, autotune may not be able to correct it properly due to misfires, so as you go you'll want to smooth out the values in adjacent cells manually--the fuel table shouldn't have large jumps cell to cell.



You were right. :thumbup: I turned off accel enrichment and fattened up the bottom rows. So far it feels much improved. Shifting is smoother for sure. I was relying too much on AE going in and out of throttle. I got some more tuning to do then I'll post up the maps.


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## sdezego (Apr 23, 2004)

Here are a couple of quick comments (outside of what was mentioned with AE).

1.) you probably know this, but you no longer (as of quite a few years ago), need to turn off AE, Fuel Decel Cut (although I do tend to turn this off so I can tune those low bins just for the sake of my table looking nice LOL) or EGO correction during Log Analyze or VEAL. Just figured I would mention it just in case.
2.) I know some people use the low RPM bins to try and keep from stalling, but I don't like this (I am a stickler for rock steady idle and have no ISV currently). Doing so, can cause erratic idle since (based on your map) normal idle will likely be between column 1 and 2. So, timing is constantly fluctuating. I usually go with a straight 12* BTDC for first 2 cols (700 and 900 rpm)
3.) I would add another column or two of resolution between 900 and 1500 rpm (more like your VE map)
4.) You don't have near enough timing at tip in at lower kpa. This will cause your motor to fall on it's face during tip in ..or up to 2500 rpm at lower kpa for that matter.
5.) any timing changes, will require VE retune (but you know that).

Your first 3 timing cols are actually inverted at low kpa. If anything you want to increase timing slightly at those low bins. Even if you never see them, MS is still using those values for interpolation.

as an example, from low kpa to 100, in the first 3 cols from low kpa(left to right) I have:

Col1 - 700
all 12*

Col2 - 950
all 12*

Col3 - 1200
all 14*

Col4 - 1400
20, 19, 18, 17, 17, 16, 16 (rest is above 100kpa for boosted map)

Col5 - 1600
22, 22, 22, 21, 20, 19, 18


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## still_a_G (Jun 23, 2008)

Thanks Shawn. 

#1 - Yeah, fuel cut is off but AE is bypassed by a very high TPSdot threshold.
#2 - I think once I get the perfect idle, I won't need to advance timing to prevent stalling. It rarely requires requires that bounce back and I think it contributes to fluctuation so I agree.
#3 - I'll try that but it seems like the first few columns are most useful for starting and launching. 
#4 - Those bins started out higher but I kept reducing them because I thought the bucking was a lean surge. I'll see if advancing it helps it get smoother.

Again, I appreciate the advice. It's funny how you can keep plugging away at the tuning then all of a sudden it looks nothing like it's supposed to. I need help snapping back to reality sometimes. :laugh:


Edit: I think this is how I started my map, it's supposedly for the 1.8 16V


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## wrbusa (Jun 13, 2007)

Nice! So once you get your steady state VE table sorted and working reasonably well, then you can get back into TPS based AE tuning. 

In your datalog, it looks like the AFR goes from full lean (normal on decel) to 11:1 or so after the throttle press, which may be causing some of the surging you're experiencing due to rich misfire. On my engine, anything richer than 11.8:1 won't catch. There is no magic AFR number to shoot for though, and since it's usually behind what's actually happening, it can give you bad information--so I find it best to ignore what the AFR is telling you and tune AE by feel.

Start with a flat AE table and slowly add enrichment while trying to repeat the same throttle press. I would add just 0.1 at a time for small throttle presses and 0.2 for medium/fast stabs until the bucking and hesitation stops. You can do this all in an empty parking lot to get the basic AE tuned. Smooth out the curve at the ends, and it should be pretty drivable.

After that, while driving you can work out the RPM taper which i find impacts fuel economy more than drivability (unless it's way off). Then when you still want to tinker there's the enhanced AE, which has a steep learning curve but rewards you with stock-like drivability and crazy AFR control :thumbup:


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## sdezego (Apr 23, 2004)

How's it going? LMK if you would like to see the maps I have (8v but it is aggressive and would probably be fine for 16v). A lot of work went into them, but I don't mind. The VE map is of no use really though (other than observation) as I have found MS3 later code (forget which revision) completely changed my map. It may be a linear scaling, but I went from uppers of 100-110 to uppers of ~85


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## need_a_VR6 (May 19, 1999)

You probably turned on include afr into fuel calc. Common change.


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## sdezego (Apr 23, 2004)

need_a_VR6 said:


> You probably turned on include afr into fuel calc. Common change.


 Interesting. Not knowingly, but possibly  Going to check that out for curiosity factor.


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## sdezego (Apr 23, 2004)

sdezego said:


> Interesting. Not knowingly, but possibly  Going to check that out for curiosity factor.


actually, no. Just checked.


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## still_a_G (Jun 23, 2008)

It's getting better. I recently made the switch to 89 octane from 91. So far I like it but I did have to pull back timing in some areas. I don't really have high compression anyways. It's supposed to be 9.5:1 so I'll take the cheaper gas. It really doesn't like being advanced in the the lower bins. I get lean surging at cruise. When you guys are decelerating off-throttle, do you get any wideband reading? Mine is way too lean to provide a reading, even with these numbers.


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## sdezego (Apr 23, 2004)

I am using Fuel Cut on decel, so my WB goes immediately to 20.9 when conditions for Fuel Cut are met.


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## still_a_G (Jun 23, 2008)

After driving a co-worker's NC Miata on Friday I had an epiphany. The Mazda engineers tuned in extra fuel at throttle lift to keep rpms up during shifting, dampening the transition. But just the right amount of fuel and air to prevent rich surge. That tune was so smooth, sporty throttle so you know what you're in but not abrupt. 

So how do I dampen the the volumetric transition? 

I mulled it over. I can give it even more fuel but I feel the rich surge kicking in. So I thought about how to dampen the air change. The throttle plates close tight on the g60 and the idle screw is in no way going to provide enough air to burn.

OH YEAH.

A few years ago I adjusted the idle valve to close super tight. Between Megasquirt and the adjustment screw on the valve body, I keep it completely closed when moving. This was to prevent leaks while under boost.

So to dampen throttle lift all I had to do was change the idle valve settings. Effectively causing a leak through the valve so that when I lift off and get back on the throttle, there's already a small amount of air being sucked into the intake manifold. I can see that it doesn't pull as much vacuum at decel. It would dip all the way down to 15 mpa but now it only gets down to 20. 

Clearly, this is not ideal when under boost. I wonder if I can get some code to close the valve completely when boosting but go to leak position while cruising. I gotta tune some more then I'll update with screen shots.


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## turboSlap (Feb 5, 2009)

Maybe a purge valve to bleed in a little air below 100kpa or whatever MAP you want?


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## still_a_G (Jun 23, 2008)

That's a good idea, just a small EGR valve routed back to the intake. Much easier than modifying the code. :thumbup:


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## turboSlap (Feb 5, 2009)

The purge valves are pwm if you wanted more control.


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## still_a_G (Jun 23, 2008)

model or link?


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## turboSlap (Feb 5, 2009)

Most cars use them on the EVAP vapor canister lines to burn off fuel vapors. They have two ports and 2 wire
Here's a VW one > 0280142308


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## turboSlap (Feb 5, 2009)

Maybe we are talking about the same thing


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## turboSlap (Feb 5, 2009)

I tried using it (n80) as an idle valve today untill I get my fittings to use a real iac valve. 
My idle is fine with it, it's a bit noisy and slow to react but I have to use one for a/c as the wierd AEB idle motor/throttle flap combo is horrible in normal driving on standalone, so I'm gonna do away with it to run a bosch 2wire (I usually use the stock iac in the aeb tb just for warmup, then when CLT temps go above 65c it's not used )


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