Transient Throttle
 

EVERYTHING IS CORRECTED... Lets hope, that last manual was crap. My appologies for the horrible write up. This one is better. Promise. Please let me know if you see any errors (typo's or otherwise)

I have some edits to do after rereading it today. I never can write things well the first time through it seems...

that's what proof readers are for!

Updated!!

Has anybody with a turbo gotten the predictive map working? If you have, can you post a screen shot of your settings - thanks.

This is what I'm running. Gives me amazing response on my stock 1.6.

I know man, isn't that throttle response sick? It was never that good stock I know that for a fact.

I attempted to get Kpa points to fill in the table but it doesn't seem possible. How do you get to 6k rpm @ 2% or 5% tps or 2k rpm @100% tps, etc.?

its an educated guess. It will always be vacuum there.

can anyone else with good results post their data? i am still having a tough time getting things perfect.

I spent some time with it with so-so results. My map sensor has been getting flaky so that could have been part of the problem. Will try again after the new sensor is installed.

So you guys tried the map Neo posted and its so so?

it's a reasonable starting point. just do some normal driving and run a datalog the whole time and see if it's close enough and if it's not, fix it

Thanks for the tutorial, just set this up now. One thing though is that Rob_k over on the adaptronic forum recommends 80-100% for Async gain. Using it at 100% atm with good results, although havent tried 30% or less to compare...

Edit: Just re-read the v2.0 user manual, the 1-30 gain value is for the old transient throttle method.

Good info - mine is currently set to 30% for gain and 500ms transition time. Will have to try 100%.

Good discovery! Thank you! I will update the manual.

Is anyone still having problems with their transient throttle? I fine tuned my map using my data logs and neos map but got lean tip in. To resolve the issue I made it rich by increasing the kpa +20-30 in most cells but am now getting lean tip in and rich right off throttle. My gain is at 100% and trans time at 300 ms. Any advice?

I am having MAJOR problems this this. No matter what I do with the table it has INSANE lean tip in and then goes pig rich after like 1-2 seconds. So its fucking HORRIBLE.
I turned off the table and am trying to mess with it the old fashioned way, but have little luck with it.


If somone could chime in with a little more information on how to get rid of this shit I'd be very thankful

I re-read the tutorial for the 10th time and will try messing with the table 1 more time tomorrow. Wish me luck:D

Turned off "use map prediction", and it fixed most issues for me.

I did the same after trying to mess with it a few weeks ago, but while much better its still not perfect IMO.
I wanna try to get this whole prediction crap working cause it sounds like if done right it can completely get rid of the lean spike going back to light throttle/cruise after decel.

Just need to figure out EXACTLY what makes it spike like that then dip into rich:vash:
Tried increasing/decreasing transition time, no bueno. Tried raising/lowering asynch gain, no bueno. My maP values in the table are fairly accurate as well.
I mean without the prediction table its not HORRIBLE but I can't settle for anything less than great:D
Just don't know

I would but the base settings are worse than my predicted map settings.

I had the same issue with really light throttle and AFRs going full lean. Never could get it tuned out so I went back to the old method for now.

Have you tried increasing the MAP value for the lower TPS rows? (I haven't tried this, just an idea)

I did. still no bueno. The more I've been messing with it the more I can get it to go RICH right away, then it still leans out to like 15.5-16.5 AFR for a second or two and then goes to normal. I made sure my map isn't whats causing the lean condition and its not. My map is fairly rich.

I'm out of ideas

+1

At a certain point it goes rich right off throttle also. I feel like the predicted map just doesn't work or something is wrong with the gain and transition time values. I had my predicted map dead-on at one point but it never got rid of lean tip in.

+1, I messed around with it on a parking lot at least 5 hours. could never get it right. I did data log so value is correct. I believe there is an inherent issue with it. I got rid of predicted map, messed with other settings, and it was a lot better.

can you guys post your current settings?

Here are my current settings which are working well.

Attachment 200731

Attachment 200732

here is mine. it works 90%.

I guess SV650 and I have completely different base maps. as some of our settings are not even close.

wow they are WAY different. Different from mine too lol. I'll try each one of your guys' and see which is better. I'll try to snapshot my current ones too, but they are HORRIBLE just fyi

I'm on stock injectors. If you're not, you'll probably need to reduce the asynch values.

LOL. how can our Async be completely opposite !!!

same as the other thread. every base map is drastically different. I just took the base map, did dyno tune on it. so played with fuel and ignition map. other than that, not much else. I then had trasient throttle issue, really really bad, turned on map prediction, couldn't fix it forever. turned it off, was 50% better. than messed around with base setting, it is now 90% better.

well yours are wrong. should be tons at low RPM and almost none at high rpm.

thanks. I will fix it. guess I will go another second faster, LOL.

messed with it some more. no luck. going back to the old way til someone has a revelation and magically figures out how to get this shit to work.

+1 I tried some of the others' settings and it made the lean worse. I went back to the predicted map. It sucks not being able to mash the throttle cause these settings aren't worked out yet.

you still get a big lean spike with the normal settings? cause it shouldn't be that bad. I can definitely mash throttle without leaning out with the old settings. They work fairly decent actually. I was just hoping the new map prediction table would be EVEN better.

If you're still leaning out badly using the old method then something is wrong with either your map or settings.

Are you on stock injetors?

Mine is almost there after getting the predicted MAP table dialed in on the dyno:

http://sites.google.com/site/timkent...p-settings.png

Transition time is 500ms and asynch gain is 100%. You can pretty much hammer the thing at any RPM and it behaves. The bit that sucks is transitioning between 0% and any throttle, slow moving traffic is painful.

EDIT: On the Adaptronic site they suggest ticking the DBW tickbox (even without DBW) if you are having light throttle sensitivity problems - http://www.adaptronic.com.au/forum/i...p?topic=1075.0

It's leaning to about 17 afr with these settings. It's way conservative. 600cc injectors and afr are fine at steady rpms.

http://farm5.static.flickr.com/4016/...d98076d0_o.jpg

This was on the adaptronic forum, might be of some help:

YouTube Link

The only difference to most settings seem to be the enrichment percentage which is set to 150%. The car is a stock miata btw. Have to wonder if its only good for n/a models as atmospheric "boost" is instant, whereas real boost will take a a certain length of time to build. I would imagine you would hit 100kpa very quickly and then from there to your positive boost is going to take a while longer which could account for the rich-lean-normal AFRs people are seeing with this.

Thanks for the link. I fixed much of my lean tip in this week by lowering my spark plug gap to .035. It was left at the stock gap since I installed them a month before the turbo install. noob mistake... Now I have to lower the predicted map to where it should be and hopefully it won't lean back out.

I'll try those this weekend and report back

Isn't the standard spec 0.030" ? How does spark plug gap affect afr conditions - bigger gap = lower afr?

saw the thread on the adaptronic forums suggesting that now instead of suggesting the async gain should be set to 150% as a default. prior to that it was 100%. and prior to that there were posts suggesting like 30-50%!

sounds like there is no real answer yet. people just guessing

here is a dumb question. how do you set async gain to 150% ? every time I done that, it defaults back to 100%.

I thought it was .040. I might still have to bring it down to .030. The AFR completely changed after changing the gap. At lower map it slightly leaned out some sections and at higher map it became too rich (partly due to the conservative predicted map). I still haven't changed to ve tuning though. I'm not sure how much of an affect that would have.

i can set it to 150%, save the file, reopen, and it's still 150.

dont know if that holds true for loading the map. too much snow.

found the reason
https://www.miataturbo.net/forum/t44108/

win-F "wariv1.exe" ctrl-A del

download 2.000 and use. heh.

I reduced my transition time to 150ms and set the asynch gain to 200%, seems to work quite well on my JRSC setup.

I have a question/point based on watching the youtube video and a little lightbulb gong off in my head...

The whole point of all this is to compensate for delays in the MAP sensor response. Makes sense to me. The MAP value lags the actual condition in the manifold and thus this feature compensates by momentarily applying a table based 'predicted' MAP value, increasing fuel flow and improving throttle response. Great idea. It is significant to 'accelerator pump' style enrichment, except more sophisticated.

Question: So, where is that MAP response delay coming from in the first place? It should not be the electronics in the MAP, or anything in the Adaptronic. Both should respond instantaneously, relatively speaking. Therefore the delay, I suspect, is mostly due to the mechanics of the transient gas flows. That is, system characteristics like the air volume between the manifold and the MAP, the volume in the MAP, and the flow resistance in the vacuum line, are creating the delay. It is the same reason why the BOV line should be short and unrestricted; the BOV responds faster. These delays would seem to be trivial, but they are most certainly there (basic fluid dynamics) and we are only talking about milliseconds of lag here.

So here is my point. Perhaps one of the reasons everyone here (and on the Adaptronic board) is coming up with different settings is because everyone has slight differences in their MAP installations that change the volume and the flow resistance. Different line diameters, different lengths, where it is teed into the manifold, what else it teed into the same connection point, etc. would all change the behavior. They create variations in the transient response profile, and thus require different settings to compensate properly.

One thing to try might be to have a dedicated and very short vacuum line to the intake manifold. Minimize the line volume/length so that it becomes insignificant (using a very small diameter line could be problematic though since it would create flow resistance. A really short line would be better IMO). This would minimize the magnitude of the MAP delay, and thus minimize the amount of correction required. In turn, since the correction is minimized, then the criticality of having it exactly right would also be reduced, and thus it should be easier to tune.

Now I know there is also the transient response of the intake manifold volume to consider as well. But, loosely speaking here, the pressure at the end of the runner should be very closely tied to this response, and in that sense it really is the same actual condition.

Makes sense?

Yea makes sense. Although I believe the majority of the delay is electronically induced. The speed of sound would be 1125 ft/s in semi normal conditions of the manifold, and so at 200ms delay that some people use would be 225 feet worth of travel. The actual time it takes the plenum and the runners to pressurize should be around 1ms (2ft).

What they are trying to do with an electronic delay is to mitigate the pulses caused by the cylinders and get an average plenum reading that correlates more with throttle position and cylinder filling.

The rubber hoses might have more significant effects though because it does dampen pulses due to its elastic cross section, and its fairly small area to volume ratio. From a speed of sound point of view we're talking 1 ms per 2 feet of hose. Even if it takes twice that long or 4 times that long to fill the tube the change is pretty nugatory compared to the delay and setting differences we're seeing.

What I attribute to the differences comes from all the other variables that change the dynamic reaction of the motor. Camshafts, turbochargers, headwork, intake manifolds, throttle bodies, intake tubing, helmoholtz resonators, even headers to some extent(reversion, scavaging... etc).

So as you change all these things the instantaneous fuel demands will change, and the calculations to figure out what it should be based on a difference of any of the variables above would probably earn you a Nobel prize in fluid dynamics.

Regardless of all this crap, I have thought about standardizing the install process more. Providing tubing for the map, and an exact place for everyone to mount it. Elimination of variables is the first step to making this transient tip in tuning a more standardized process and I am right there with you on knocking a few more of the variables out so we can concentrate on just the differences in engines and not have to worry about these secondary variables that can be all over the map.

Yes I thought about it some more today and agree that the delay in the MAP pressure drop is probably just one of many dynamics leading to the measured delay.

One thing though, and no offense Travis, but I do not agree with the part about how the pressure signal travels at the speed of sound. For pressure to drop in a volume (constant volume, constant temp) the air has to be evacuated from the volume via flow. So I do not think one can conclude that the MAP signal response happens as fast as you described.

Think of it this way. Allow me to illustrate by extremes. Say I have a large volume (manifold) connected to a small volume (MAP sensor) with a hose. The pressure in both volumes and the connecting hose are all equal (steady-state pressure).

Now, think of two different experiments that use two different size interconnecting hoses. One is large, say 3/8" i.d. and one is small, say 1/8" i.d.. Everything else stays the same (volume sizes, and hose length). For this illustration assume the volume of the hoses is relatively negligible.
- Test #1, Connect the two volumes with the large hose. Suddenly raise the pressure in the larger volume (open the throttle), and measure (versus time) the relative pressure difference between the large volume and small volume. The pressure rise in the small volume will slightly lag the pressure rise in the large volume.
- Test #2, do everything the same as Test #1 but replace the large hose with the small one. The pressure rise in the small volume will lag farther behind the large volume than it did with Test #1. There is significantly more flow restriction with the smaller diameter hose and therefore the small volume does not pressurize as quickly, and the pressure lags farther behind.

This is illustrated by the fact that a small restrictor in the MAP vacuum line can be used to make a MAP sensor (or a vacuum gauge) have a quieter (less noisy) response. The restriction slows down the flow between the manifold and the MAP sensor (increasing the lag time) and thus dampens out the small transients from the intake pulses. Same deal.

I agree, my idea about pressure moving at the speed of sound is pretty dramatic, but all I was getting at is if pressure movement was limited by cross section versus volume problems then even if it takes it 5 or 10X the time that it would take the speed of sound, the difference still would not compensate for the delay times we have to use in the transient throttle system.

I have also heard of this system you were talking about with long vacuum tubes being used to dampen pulses. For instance in ITB systems I've heard that its pretty advantageous to equip the car with 30-40 inches of vacuum hose that is coiled up because generally you only connect to one cylinder and using such a long length of hose deadens in the pulses from the cylinder that are more evident in an ITB system. So I know for a fact you're spot on, but I've never done the experimental to know the exact time delay per foot of hose(if its even linear like that).

OK so I finally started playing around with Predicted MAP and it is working for me. I logged some drives, did some spreadsheet analysis (Openoffice calc), and plugged best-guess values into the table. I am really pleased so far. 100% gain, 300 ms.

This is a freshly rebuilt motor so my wastegate is wired open right now until I get everything dialed in. There is no boost except at very high RPMs. Point being that there is no point in posting my table because it will be wrong for most others, and I will be retuning it when the wastegate actuator is reconnected.

has anyone had any luck with this? i am having a hard time with getting transient throttle response in the low rpm 5% range and pretty much all transient throttle above 5000 rpm

I'm not 100% happy with mine either, I'm trying the old method to see if I can get things to be any better.

I switched back to the non-predicted MAP method and I think I like it better. For one, you can set separate enrichments for MAP and TPS... because sometimes MAP increases without TPS increasing.