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Alpha n/ itb's on m50b25/dme 403

 
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Tue Jul 18, 2017 1:45 pm    Post subject: Alpha n/ itb's on m50b25/dme 403 Reply with quote

Hi all,
My car ls a bmw e36 with a m50b25, 403 dme.
This week I put a set of individual throttle bodies from a 1000 gsxr.
I run with no maf (unplugged).
I have some problems of lean AFR in fast throttle : AFR reaches at 16/17, and then go down to 11 (I run E85, my wide band controller is a Zeitronix ZT-3, so AFR values I give are the displayed ones).
I think I think that the problem come from my TPS (I use the GSXR one), who gives incorrect values at low throttle and at idle: 1.2v instead of 0.5v). Does someone knows the correct range for these values, at Idle and WOT?
Because of that, I also have no Idle bevause I think that the ecu dont see th Idle state because of th wrong values from TPS.
I think I need To modify throttle dfinition table, I think I have find It in 6E4D, (31x1). I have converted th table values To airflow %, x axis in throttle % (I think in reality it is TPS voltage but dont know th conversion factor). See on this picture:


Can someone tell me if thats th good one and give le some advice about my setup?
Thank b'y advance
Charlie from France
[/img]
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Wed Jul 19, 2017 3:22 am    Post subject: Reply with quote

I would think you have 2 issues going on, whipping the throttles open quickly is resulting in the air getting to the chambers faster than it did with the single throttle and plenum set up, this is going to throw out your acceleration enrichment.

Second thing the acceleration enrichment is based on the change in TPS value, with the higher TPS voltage map sites getting less fuel.

Not using a M5x TPS sensor is really going to bugger things up as well, the ECU is expecting the TPS to be ~0.3-0.4v at idle and 4.2v+ at WOT, anything else is not going to play nice without having to change quite a bit of code.
In this case the correct M50 TPS is cheap and adapting one to the throttles should not be too hard, especially as you are relying on the TPS to give all the load data to the ECU.

You should be able to use a TPS from an M52, M54 or M60 as well, many BMW TPS sensors are the same electrically.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Wed Jul 19, 2017 4:41 am    Post subject: Reply with quote

Hi Hairyscreech, and thank you for your answer!
I see what you mean, I'll try To adapt the M50 TPS. Do you think that tuning the TPS définition table, To tell the ecu the higher airflow in low throttle opening, will solve the acceleration enrichment problem?
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Thu Jul 20, 2017 3:03 am    Post subject: Reply with quote

100% you will need to adjust the acceleration enrichment table, If your fuel tables were ok before adding the throttles then that may not be too tricky, otherwise it could become a bit of a circular task.

It is not the TPS transfer map you would need to adjust but the RPM vs change in TPS voltage map.
I can't see the correct map on your XDF or the 402,4 or 5 XDFs on here.

Take a look at the 506 ecu XDF and BIN, you will see there is an acceleration table that dictates the extra fuel the ECU needs to throw into the port to cope with the sudden gulp of air on a snap throttle opening.

I would expect there to be a similar map in the 402,3, or 5 software somewhere.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Thu Jul 20, 2017 5:33 am    Post subject: Reply with quote

Ok its a good idea, i had found the tps definition by looking at a 413 xdf and bin To recognize the same table in the 403.Thanks for thé idea!


I replaced the TPS from gsxr by the m50 one, the range is better but I have again less range than with the oem throttle. I think I will definitely have To change thé TPS definition but I dont know box To change axis.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Thu Jul 20, 2017 9:24 am    Post subject: Reply with quote

So I've take a look at the 506 xdf/bin. I've try to found the same table in my 403 bin but found nothing with the 3d viewer... I've try To do install the winols test version To take a look but my PC dont install it, nothing happens when I click on the .exe file...
I will try again tommorow to find it with Tunerpro on the 3D viewer, or must be a 4x6 table.
With the new tps its a little better, i've still problems in low rpm/low throttle opening but at faster rpm and fast opening AFR stay under 15, thats not optimal but a little better.
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aboutton



Joined: 09 Mar 2011
Posts: 168
Location: Lebanon

PostPosted: Thu Jul 20, 2017 1:44 pm    Post subject: Reply with quote

0x6F84 - 4 X 6 Acceleration Enrichment

enjoy
_________________
HyperBoost Tuning
Tony Ouneissy
Lebanon


Last edited by aboutton on Fri Jul 21, 2017 2:30 am; edited 1 time in total
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Thu Jul 20, 2017 5:21 pm    Post subject: Reply with quote

Thanks Aboutton, I'll try it as soon as im back from work 😉
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Fri Jul 21, 2017 3:04 am    Post subject: Reply with quote

Huge thanks To Aboutton for the enrichment table, now I will be able To do some work on this ITB setup.
The enrichment table is already at top value at low opening, but I have To solve the TPS problem and Perfect my fueling before doing anything else!
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Sat Jul 22, 2017 2:15 pm    Post subject: Reply with quote

Little update:
My TPS had a little clearance with the throttles shaft, solved with a better adaptatif with no clearance. Now voltage changes as soon as throttles move, and response on acceleration is better.
I'll receive my Ostrich 2.0 soon, more update when it will be there.
I'm thinking about wiring the TPS on the maf plug, because the alpha n table is only 6x7... with that done, and with the maf table modified I think I could tune the partial throttle tables for idle/PT and wot, the idle and wot tables unused because of the reduced TPS range.
Am I right with with it? If someone has ideas about it he's welcomed 😉
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Mon Jul 24, 2017 2:57 am    Post subject: Reply with quote

From what I know of these ECUs (sure someone can correct me if I am wrong) you will need to give the ECU a normal TPS input as well as giving the MAF input the TPS voltage.

Both are being used by the ECU so giving it the TPS voltage on the MAF input and running no TPS is also going to put it into limp mode.

I suspect you could get some joy by giving the MAF input a signal from the TPS in parallel with the normal TPS signal.

The MAF table would need to be setup specific to that engine as the signal would not be a measure of airflow and just throttle angle.
Two ways of solving this I guess, 1 would be to get the throttles on a flow bench and find the flow at various angels and derive a transfer function from the measured flow.

Other option is calculate the theoretical flow mathematically which would not be strictly correct to real life and then tune around it using the fuel map.

Is this a road car? If so then an air box with a MAF on the end like the M3 uses would be a lot better long term.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Mon Jul 24, 2017 6:48 am    Post subject: Reply with quote

You're absolutely right, thats what I meaned by wiring the TPS signal on thé MAF plug: TPS signal will be use for both TPS and MAF in parrallel.
For the airbox + MAF, maybe I could do it in the future, but I have to build the airbox, it will ask a bit of work so I want first To make this setup work fine 😉
I'm also reflecting about speed/density (MAP sensor instead of MAF), with a "vacuum manifold". This solution is apparently a little complicated with ITB's, I will see what's better.
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aboutton



Joined: 09 Mar 2011
Posts: 168
Location: Lebanon

PostPosted: Tue Jul 25, 2017 8:55 pm    Post subject: Reply with quote

1- Did you make sure that the TPS voltage is ascending not descending when you step the throttle ? cause on M50 with M3 throttle bodies it will be flipped so you need to flip the positive and negative wires together to fix that issue.

2- Its true that the AlfaN table is 6 x 7 but it is not a fuel table, the ECU uses this table to calculate load so you can use the table to enrich fuel on ITB opening and you can still use the part throttle table to tune your fuel.

3- If you are gonna use the ITB's with no air-box you will loose low end torque.

4- If you want to use a MAP sensor instead of the MAF you need to alter only the MAF table and make it linear cause that is the only difference between the 2 signals, but i don't recommend MAP sensor on ITB's its not gonna work good because you will loose 90% vacuum on 10% throttle.

contact me for questions. good luck
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Tue Jul 25, 2017 10:20 pm    Post subject: Reply with quote

Hi Aboutton 😉
1. Yes I have switched wires 1 and 3 on the TPS plug .

2. Ok I see what you mean.

3. I know that no airbox will affect a low end torque, but thats an option that I dont neglect, maybe I will come To it with a bigger MAF when the actual setup will work fine.

4.you're right, it seems that MAP with itb will only work fine on idle and very low loads. With all the renseignments I had from all of you I think that things will gonna be fine. Thanks for your help!
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Tue Aug 01, 2017 12:20 pm    Post subject: Reply with quote

Last Two days I made some tests with the ostrich.
WOT is now good, PT are better (not perfect but I have To work on it again), but I have some problems with idle which is verry erratum (sometimes rich, sometimes lean), but I think that's because injectors are biggers (270cc).
I had To lean a lot at wot (was under 10), but in PT and idle i had To enrich (I was at 17 in very low load).
I dont understand how to tune acceleration enrichment, it seems that nothing i do on this table has effect, i always have big hesitations when pressing the throttle... the y descriptor of this table is D3 but no idea of what it is on a 403 dme.
If someone has ideas about all that he's welcomed 😉
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Wed Aug 02, 2017 3:23 am    Post subject: Reply with quote

I know the Axis descriptors are a little different from the 413 ECU but the enrichment table is TPS volts vs RPM, 6 wide 4 high.

It has a noticeable effect on the 413 ECU, reducing the enrichment does drop the initial AFR when you change throttle position.

As you say you have changed injectors do you have the injector latency set right.

I just posted the M50 and M20 values on the other thread (http://tunerpro.net/forum/viewtopic.php?t=4403)

I have noticed the motronic is very sensitive to changes of injector without the lag being set right. Until I adjusted mine it was all over the place.

Did you need to go up to the 270cc injectors? Quite a bit bigger than the stock ones if all you did was add throttle bodies.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Wed Aug 02, 2017 6:24 am    Post subject: Reply with quote

Yes 270cc are a bit too much, but I couldnt use the m50 one because I run e85 now .
I tried To adjust the latency but I dont know what need these injectors, it seems To be better with higher values. I will try more on it .
For the accel enrichment, descriptors are rpm and D3, but TPS is CB, maybe is there a calculation? Maybe D3 is throttle change rate but I dont know 🤔
Thanks for the precision because I was thinking that high value was higher enrichment, so I think I was doing it wrong 😅 I will look at that too, thank you very much!
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Wed Aug 02, 2017 6:56 am    Post subject: Reply with quote

It seems to behave as an additional enrichment on top of the values in the VE table.

Makes sense as the VE table is already working off load, which increases with acceleration...

The acceleration enrichment is intended to compensate for the wetting of the walls of the inlet port and the delay in the time it takes between the air beginning to flow into the cylinder and the flow increase being detected by the ECU.
In theory if it was set up ideally then you should see the AFR hit the required value as soon as you open the throttle and stay steady after that, too little and it will go lean for an instant, too much and a glut of fuel will be added and an instant of over rich will happen.

It is a fine adjustment on all ECUs but one that life would suck without.
Think the feeling you get from a carb with a broken accelerator pump function. The accelerator pump is doing the same job, dumping a bit of fuel in instantly to keep up with the air flow change until the depression at the carb increases enough to up the fuel flow.

You might be able to find the injector lag values on the web, whats the part number for them?
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Wed Aug 02, 2017 8:59 am    Post subject: Reply with quote

Thanks for thé explanation, I knew the principe about accel enrichment but the matter was I thought I had To increase values to enrich more. I have tried by lowering and its better but there's still a "lean hole". The enrichment seems To be "retarded": when I Press throttle it goes lean, then too rich and then runs normal afr. Also when I releases throttle, AFR goes very rich for a second and then injection cuts as it should. Its like there was a delay between throttle action and enrichment or cutoff.
Anyway, its quite more driveable than before and I begin To ses the benefits of itb's, little decrease of low end torque but a full engine until 7200rpm. Maybe the runners are a little too shorts, will try To increase lenght and see what it does
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Wed Aug 02, 2017 9:01 am    Post subject: Reply with quote

For thé 270cc injectors: there is no ref on them, they are from the gsxr, I'll search more To see if I find their latency.
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Thu Aug 03, 2017 1:45 am    Post subject: Reply with quote

The table should be higher number for more enrichment, certainly that it the response I get from the M3.3.1 ECU.

When I say reducing the numbers lowers the AFR I should have been more specific, Reducing the numbers should reduce the fuel, which means the numerical value of the AFR would increase.
Should probably stick to talking in lambda Mad

I won't profess to be an expert in these ECUs and I am sure there are some on here that could give a lot more details.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Thu Aug 03, 2017 3:39 am    Post subject: Reply with quote

No problem hairyscreech 😉
Now its clear: higher the value = higher the enrichment.
This confirms there is a problem 😅 with all values at 255 enrichment is not better... I'll check if I dont have fuel pressure problems, I dont think because my fuel pump is a 255l/h and its far enough for 270cc injectors.
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Thu Aug 03, 2017 4:44 am    Post subject: Reply with quote

I would start by either finding those injector dead times or swapping in a known set, these ECUs really need to know how fast the injectors open to work right.

Without getting that table set up right any other adjustment is going to be guess work or a work around.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Tue Aug 08, 2017 9:44 am    Post subject: Reply with quote

After many research I didnt found dead time value of my injectors.
I have tried To adjust Injector constant and dead time but with no satisfying results... ls the injector constant just a factor, or is there an "interpretation" To read the value? In the original bin the value is 54953 . Original injectors are 180cc. So for 270cc injectors I put 36635? (54953*(180/270))? For e85 do I need To change this value to decrease AFR or just tune the fuel tables?
Unfortunately my acceleration enrichment problems are still here, It seems that values on the tables are not big enough ... I really dont know if the problem comes from my injectors caracteristics not tuned properly, or if its a problem of tuning the alpha n table...

I found some other maps with same descriptors than the accel enrichment table, maybe are they related, I'll do some screenshots and post it here


Last edited by Evil on Tue Aug 08, 2017 10:46 pm; edited 1 time in total
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Tue Aug 08, 2017 10:26 am    Post subject: Reply with quote


6x6 table, adress 7053
Descriptors CD (rpm) and D3 (dont know what it is, maybe related with CB/throttle signal), same that acceleration enrichment table


6x6 table, adress 7618, same descriptors


4x4 table, adress 7251, same descriptors.
All these maps are on a dme 403.

I dont know if they are related To acceleration or decceleration enrichment, the first table is not traced with the ostrich but the 2 others are traced, if someone knows anything about it he's welcomed.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Fri Aug 11, 2017 5:55 am    Post subject: Reply with quote

After a bit of reflexion I think I have 2 problems that cause my lack of acceleration enrichment and also deccel enleanment:
-my "manifold " between head and throttle bodies is stainless steel, and I think it involves condensation because he's always cold when engine is hot.
-injectors are further from the intake valve than with the stock manifold (5cm further) because they are on the throttle bodies.

So I think that both causes wall wetting more important (more surface To wet + condensation), more fuel is used for that instead of going into cylinders, and the accel enrich table dont allow To reach a sufficient amount of fuel.
Same problem for deccel enleanment: the wall film is more important and after fuel cut-off in decceleration the wall film goes into cylinders and causes a drop of AFR, so the decceleration is not instantaneous, mostly at low rpm.

Maybe is there a factor somewhere that could permit To increase the possibilities of acceleration enrichment? I think there is also a deccel table so I will search about that, maybe is it one of the maps I have found. Anyway I think Iwill have To weld injector ports on the manifold closer of the valves, but It would be nice To be able To first solve the problem with tuning.

What do you guys think about it?
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Sun Aug 27, 2017 2:19 pm    Post subject: Reply with quote

Am I right in thinking you thread about making the tables bigger may have something to do with this thread?

Are you thinking of making the limp mode table bigger?

It is possible you are correct about wetting out the walls of your manifold.
Is your manifold a smooth polished surface inside? If so the trick of roughening the surface with ~300 grit may help, the V8 lot with wet manifolds have issues of fuel condensation on smooth polished manifolds.

It might explain your lean-super rich-normal. It is because most of the fuel is collecting on the walls making it lean, then trickling into the cylinder causing the over rich and then back to normal once this is resolved by greater air flow through the manifold. Exactly the same as the US V8 lot get with carbs and wet manifolds.
Do you have pictures of the setup you are running?


R.e. Injectors, we absolutely have to get those set up right. You are correct about the way to adjust the injector constant, however you also need to adjust the load values of all the tables as well to match that scaling.
Your injectors are 1.5x bigger but just dividing the injector constant by 1.5 will mean the ECUs base load calculation will also be 1.5x too low. You will never get past the bottom 2/3rds of the fuel table.
You have to move the tables load values down to match the new calculated loads which will be smaller to suit the smaller pulse widths needed from the new injectors.
I sound like a stuck record on here the last few visits but to do this right you have to understand the way motronic table headers work.
i just wrote a spread sheet to calculate the new table headers for any given injector scaling. I can do a bit more programming on it and post it up if your not sure about how to scale the table headers.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Mon Aug 28, 2017 12:53 am    Post subject: Reply with quote

You're right about extending the limp mode table, thats exactly what I want To do. I've done another thread about it to make it easy To ses for other people.

I have some photos of the setup i will post them today.

I polished the manifold up To 400, maybe its too much as you say.
But the bignproblem I think, ls that injectors spray directly on the wall (thats it with the original position on these throttle bodies), I will modify that by welding injector ports with better angle directly on the manifold, To make them spray on the valves.

For thé injectors constant: for the moment I run without change on the constant, I just tuned the injectors latency, and fueling is not so bad,, just had To enlean a lot at wot and enrich at idle . One things I have maybe not tell is that I run e85, and by decreasing a little fuel pressure I think I'm not bad for the constant.

The 2 problems now are acceleration enrichment and little variations of AFR at very low loads (first 3 columns at low rpm).
Thanks again for your help, I really ppreciate it.
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Hairyscreech



Joined: 20 Jun 2017
Posts: 78

PostPosted: Mon Aug 28, 2017 8:12 am    Post subject: Reply with quote

Evil wrote:
You're right about extending the limp mode table, thats exactly what I want To do. I've done another thread about it to make it easy To ses for other people.

I have some photos of the setup i will post them today.

I polished the manifold up To 400, maybe its too much as you say.
But the bignproblem I think, ls that injectors spray directly on the wall (thats it with the original position on these throttle bodies), I will modify that by welding injector ports with better angle directly on the manifold, To make them spray on the valves.

For thé injectors constant: for the moment I run without change on the constant, I just tuned the injectors latency, and fueling is not so bad,, just had To enlean a lot at wot and enrich at idle . One things I have maybe not tell is that I run e85, and by decreasing a little fuel pressure I think I'm not bad for the constant.

The 2 problems now are acceleration enrichment and little variations of AFR at very low loads (first 3 columns at low rpm).
Thanks again for your help, I really ppreciate it.


Yep, ethanol makes a difference as the energy density/different AFR for stoich will come into it.
Having done the math I think the 270cc injectors are not far off the stock injectors for size when you account for the extra liquid you need to inject.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Mon Aug 28, 2017 9:33 am    Post subject: Reply with quote

Yeah thats what I found too after calculating.
In some cells i had To enlean for about 7-8% but I think my alpha n table need again some fine adjustments
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Wed Aug 30, 2017 11:40 am    Post subject: Reply with quote

Can someone confirm that D0 is IAT descriptor for a 403? I need to adjust a little the IAT compensation. I found several tables with this descriptor but I'd like To be sure these are the good ones.
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Evil



Joined: 18 Jul 2017
Posts: 74
Location: France

PostPosted: Fri Sep 01, 2017 9:16 am    Post subject: Reply with quote

Nobody?
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