Deceleration

busterhax · **Joined:** Wed Jan 22, 2014 10:54 pm **Posts:** 1774

Enabled wrote:

328ijunkie wrote:

Messed with 411 on the way home tonight to try to trim some of 411's 'tip out hang' that is extremely annoying and apparent when adding S52 cams and throwing a stock 412 ECU in there negates it completely. I got it to improve slightly on heavy throttle lift when shifting but cant seem to affect 'light lifting' if you will between shifts. I basically cut and pasted 412 values into the 411 maps. Ill update tomorrow which changes exactly i made.

I'm not familiar what you mean by tip out hang? Now I'll have something to look for while driving my car. I'm with S52 cams on MS41.1, tuned, but not for cams specifically, it was for M50 manifold and boltons at the time of tune. I'll have to look through your VANOS tuning tips to figure out what else I can do to maximize power from cams as well.

If you drive a M3 you will notice the difference. When you clutch in, the RPMs shoot down to idle. With the 328s, when clutching in, it seems the RPMs will bump a tad/hang, then slowly fall to idle. The lower compression may be part of the reason the RPMs don't fall as quickly.

busterhax · **Joined:** Wed Jan 22, 2014 10:54 pm **Posts:** 1774

mrf582 wrote:

BTW, there is a clearer need now than ever to start logging and sharing your datalogs during these discussions. Things are getting advanced enough that we can't just go off subjective reports from the field anymore. I had downloaded a development copy of the RomRaider Logger but that link seems to be dead now. I'll work with Dale to see what we can do to get it going again. I know he is in the middle of some pretty substantial changes to more gracefully integrate the MS41 stuff into RR.

But we should all be datalogging before/after every modification and posting the results.

BMW Logger logs OK until I get the RR logger setup? :oops:

mrf582 · **Posted:** Wed Jan 21, 2015 7:25 pm

It's not ideal but it should be good enough to get an idea of what the Load, RPM, Injector pulsewidth, and Ignition Timing are doing.

mrf582 · **Posted:** Wed Jan 21, 2015 7:27 pm

busterhax wrote:

Enabled wrote:

328ijunkie wrote:

Messed with 411 on the way home tonight to try to trim some of 411's 'tip out hang' that is extremely annoying and apparent when adding S52 cams and throwing a stock 412 ECU in there negates it completely. I got it to improve slightly on heavy throttle lift when shifting but cant seem to affect 'light lifting' if you will between shifts. I basically cut and pasted 412 values into the 411 maps. Ill update tomorrow which changes exactly i made.

I'm not familiar what you mean by tip out hang? Now I'll have something to look for while driving my car. I'm with S52 cams on MS41.1, tuned, but not for cams specifically, it was for M50 manifold and boltons at the time of tune. I'll have to look through your VANOS tuning tips to figure out what else I can do to maximize power from cams as well.

If you drive a M3 you will notice the difference. When you clutch in, the RPMs shoot down to idle. With the 328s, when clutching in, it seems the RPMs will bump a tad/hang, then slowly fall to idle. The lower compression may be part of the reason the RPMs don't fall as quickly.

The noticeable difference is all in the tune.

Enabled · **Posted:** Wed Jan 21, 2015 8:59 pm

busterhax wrote:

Enabled wrote:

328ijunkie wrote:

Messed with 411 on the way home tonight to try to trim some of 411's 'tip out hang' that is extremely annoying and apparent when adding S52 cams and throwing a stock 412 ECU in there negates it completely. I got it to improve slightly on heavy throttle lift when shifting but cant seem to affect 'light lifting' if you will between shifts. I basically cut and pasted 412 values into the 411 maps. Ill update tomorrow which changes exactly i made.

I'm not familiar what you mean by tip out hang? Now I'll have something to look for while driving my car. I'm with S52 cams on MS41.1, tuned, but not for cams specifically, it was for M50 manifold and boltons at the time of tune. I'll have to look through your VANOS tuning tips to figure out what else I can do to maximize power from cams as well.

If you drive a M3 you will notice the difference. When you clutch in, the RPMs shoot down to idle. With the 328s, when clutching in, it seems the RPMs will bump a tad/hang, then slowly fall to idle. The lower compression may be part of the reason the RPMs don't fall as quickly.

Oh, I may have not noticed it too well when comparing to my S52 Z3M Coupe because my 328 has a lightweight flywheel, so I assumed differences are due to that. I'll keep a good high suspicion next time I drive them.

mrf582 · **Posted:** Wed Jan 21, 2015 9:16 pm

A lightened flywheel will have a faster engine speed drop.

mrf582 · **Posted:** Thu Jan 22, 2015 7:04 am

UPDATE

Alec found the tables that directly deal with Fuel Cut that we had been looking for a few weeks now! I updated my 3rd post of this thread accordingly

Basically, all we have to do to keep the injectors on and get that sweet exhaust crackle during throttle off deceleration is to increase the values in the "Fuel Restore - Engine Speed" tables to our preference. Then, you can tune the amount of 'rev hang' you want and the sound by playing with the Ignition Retard tables.

Cloudforce · **Joined:** Wed Aug 27, 2014 11:57 am **Posts:** 259

mrf582 wrote:

UPDATE

Alec found the tables that directly deal with Fuel Cut that we had been looking for a few weeks now! I updated my 3rd post of this thread accordingly

Basically, all we have to do to keep the injectors on and get that sweet exhaust crackle during throttle off deceleration is to increase the values in the "Fuel Restore - Engine Speed" tables to our preference. Then, you can tune the amount of 'rev hang' you want and the sound by playing with the Ignition Retard tables.

Very good find :!:

Do you know what those maps are called in the siemens calibration description?

mrf582 · **Posted:** Thu Jan 22, 2015 9:56 am

Why don't you read the table descriptions in RR?

Cloudforce · **Joined:** Wed Aug 27, 2014 11:57 am **Posts:** 259

Well, i would do so, unfortunally i have massive problems installing RomRaider on Win7 64bit. I´ll try it on a Win XP system later.

busterhax · **Joined:** Wed Jan 22, 2014 10:54 pm **Posts:** 1774

I have RR on win 7 x64...

d_munter · **Posted:** Thu Jan 22, 2015 1:44 pm

IP_N_ACCIN_MIN_PUC__TCO_byte_CAL_11D76
IP_N_MIN_PUC__TCO_byte_CAL_11D7E values in N/32 = 1600, 1344, 1152, 1056, 1056, 704 rpm

in MS41.1 they are:
IP_N_ACCIN_MIN_PUC__TCO_byte_11EAA
IP_N_MIN_PUC__TCO_byte_11EB2

can someone test to increase limit to, say, 2500 - 3000 rpm at last value (engine warmed up)?

328ijunkie · **Joined:** Mon Apr 15, 2013 11:04 am **Posts:** 101

After some more driving/testing the rev hang when shifting is basically gone. One thing to note im pretty sure the scaling factor is different between 411 and 412 because now when lifting off throttle say at 3k in third (clutch still engaged) there is a noticable 'bump' when the engine goes into overrun mode if you will, so copying the 412 values directly into 411 maps may have overdone the decel.

Before and after pics below. You can see ing retard neg throttle is completely different between the two. ANd slow throttle is pretty different too.

mrf582 · **Posted:** Thu Jan 22, 2015 3:03 pm

328ijunkie wrote:

After some more driving/testing the rev hang when shifting is basically gone. One thing to note im pretty sure the scaling factor is different between 411 and 412 because now when lifting off throttle say at 3k in third (clutch still engaged) there is a noticable 'bump' when the engine goes into overrun mode if you will, so copying the 412 values directly into 411 maps may have overdone the decel.

Before and after pics below. You can see ing retard neg throttle is completely different between the two. ANd slow throttle is pretty different too.

Are those the only 4 tables you copied over? There are a few other tables that govern this behavior. Look at the screenshots posted by Enabled and compare them to the ones I posted to gauge all the differences.

Also, I doubt there is any difference in logic or scaling between the two but I haven't personally verified that.

328ijunkie · **Joined:** Mon Apr 15, 2013 11:04 am **Posts:** 101

Those are the only ones I copied over initally. I want to see what tables change the most/how

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