Notices
MEGAsquirt A place to collectively sort out this megasquirt gizmo

Acceleration enrichments - I want to eat my cake too

Thread Tools
 
Search this Thread
 
Old Sep 9, 2008 | 12:54 AM
  #1  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default Acceleration enrichments - I want to eat my cake too

I've been struggling with this minor issue for a while, tried a few things, but I haven't cured it yet. Figured I'd get some opinions.

When I am at low RPM, let's say 2000, and I smack the throttle open, the AEs are perfect and the car flies forward. If I smack the throttle at 5000rpm in 2nd, though, the boost shoots up REALLY quickly and the AEs can't keep up. If I increase the AE, then I get ideal fuel delivery under high-RPM throttle openings, but then my low-end gets these huge bogs when I open the throttle.

So what do I do? The only way I can see to avoid this is to go back to MAP-based enrichments which means a loss in throttle response. :( I know MSII can do a mixture of the two but I don't have that :(
Old Sep 9, 2008 | 08:15 AM
  #2  
Matt Cramer's Avatar
Supporting Vendor
 
Joined: Sep 2006
Posts: 2,332
Total Cats: 67
Default

Try using the RPM based acceleration enrichment. This lets you specify four RPM bands and put in different amounts of enrichment at different RPM.
__________________
Matt Cramer
www.diyautotune.com
Old Sep 9, 2008 | 05:51 PM
  #3  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default

Holy crap, I didn't even know that existed. Matt, does it extrapolate between the bands/values? Also, from what I see, activating the RPM-based AEs turns off the TPS-based AEs. Any way to keep both and have the RPMs just augment the TPS-based stuff?
Old Sep 10, 2008 | 06:07 AM
  #4  
Laur3ns's Avatar
Elite Member
 
Joined: Mar 2008
Posts: 2,054
Total Cats: 14
From: Enschede, NL
Default

From what I see in MegaTune, with MS1-extra. It triggers with TPS or MAP but the actual AE is only RPM based.

Last edited by Laur3ns; Sep 11, 2008 at 03:11 PM.
Old Sep 10, 2008 | 09:17 AM
  #5  
Matt Cramer's Avatar
Supporting Vendor
 
Joined: Sep 2006
Posts: 2,332
Total Cats: 67
Default

Spookyfish is right: It can be triggered off TPS or MAP, but the amount added is dependent on RPM instead of the rate of TPS change. Here's the coverage in the manual:

http://www.msextra.com/manuals/MS_Ex...nual.htm#rpmae

Although the manual claims a lot of installs don't need this option, a stock Miata is already pretty close to a "high strung small displacement motor."
__________________
Matt Cramer
www.diyautotune.com
Old Sep 10, 2008 | 12:20 PM
  #6  
The_Pipefather's Avatar
Senior Member
iTrader: (5)
 
Joined: Nov 2007
Posts: 854
Total Cats: 15
From: Troy, MI
Default

have you tried setting the accel timer to "cycles" instead of "sec"? That changes the "accel time(s)" in the wizard to ignition pulses instead of time, thereby making the AE RPM dependent. I tuned out the same problem you mention by changing this one parameter and re-tuning the TPS-based numbers.
Old Sep 11, 2008 | 01:08 PM
  #7  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default

Originally Posted by The_Pipefather
have you tried setting the accel timer to "cycles" instead of "sec"? That changes the "accel time(s)" in the wizard to ignition pulses instead of time, thereby making the AE RPM dependent. I tuned out the same problem you mention by changing this one parameter and re-tuning the TPS-based numbers.
From the Manual:
"The Accel Timer can be changed from Seconds to Engine Cycle counts. Note that a value of 0.3 could mean 0.3 seconds or 3 ignition pulses. The Cycles option is useful because the enrichment will reduce at higher rpms"

Can you explain further?
Old Sep 11, 2008 | 03:06 PM
  #8  
The_Pipefather's Avatar
Senior Member
iTrader: (5)
 
Joined: Nov 2007
Posts: 854
Total Cats: 15
From: Troy, MI
Default

what part?
Old Sep 11, 2008 | 03:09 PM
  #9  
Laur3ns's Avatar
Elite Member
 
Joined: Mar 2008
Posts: 2,054
Total Cats: 14
From: Enschede, NL
Default

I think he wants more enrich at higher rpm not less? That was what his last post said before editting
Old Sep 11, 2008 | 03:12 PM
  #10  
Laur3ns's Avatar
Elite Member
 
Joined: Mar 2008
Posts: 2,054
Total Cats: 14
From: Enschede, NL
Default

Sav: i think rpm based, time based is you best shot. Did you experiment yet?

Last edited by Laur3ns; Sep 12, 2008 at 04:25 AM.
Old Sep 11, 2008 | 03:58 PM
  #11  
Saml01's Avatar
Elite Member
iTrader: (9)
 
Joined: Jul 2007
Posts: 5,710
Total Cats: 3
From: NYC
Default

You shouldnt be having any problems with your enrichments savington, if im not having any at any rpm, then you shouldnt either.

Shoot me a IM, and ill send you my AE table.
Old Sep 11, 2008 | 04:59 PM
  #12  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default

Originally Posted by Saml01
You shouldnt be having any problems with your enrichments savington, if im not having any at any rpm, then you shouldnt either.

Shoot me a IM, and ill send you my AE table.
If you aren't running a Knocksense you'd never know you had this problem. The car runs and acts totally, fine, but on high-load high RPM acceleration (5000rpm+ in 4th, 5th, and 6th) I get a single detonation event.

I'm going to experiment a bit this weekend. I'm worried about a loss of throttle response if I move away from TPS-based accels, though. Pipefather, switching over to ignition-based would give me less AE at high RPM, not more like I need.
Old Sep 12, 2008 | 11:17 AM
  #13  
Saml01's Avatar
Elite Member
iTrader: (9)
 
Joined: Jul 2007
Posts: 5,710
Total Cats: 3
From: NYC
Default

^ You didnt mention any of this in your OP. All I got was that you were losing throttle response, not that you have knock as well.

Are you sure it isnt mechanical noise? Especially for 1 knock event, it maybe be a fluke.
Old Sep 12, 2008 | 01:36 PM
  #14  
chucker's Avatar
Junior Member
iTrader: (4)
 
Joined: Oct 2007
Posts: 245
Total Cats: 1
From: santa cruz
Default

Originally Posted by Savington
I'm going to experiment a bit this weekend.
Please post your results as soon as you have something useful to report. I'd be very curious to see what you end up with.
Old Sep 12, 2008 | 01:40 PM
  #15  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default

Originally Posted by Saml01
^ You didnt mention any of this in your OP. All I got was that you were losing throttle response, not that you have knock as well.

Are you sure it isnt mechanical noise? Especially for 1 knock event, it maybe be a fluke.
I was hoping, but I checked the logs and the event always correlates with a lean spike, like a 12.2-12.3:1 AFR and 12-14psi. I run the car pretty close to ragged edge on timing, but my AFRs are 11.4-11.6:1 so when it goes that lean, it obviously detonates.
Old Sep 12, 2008 | 08:41 PM
  #16  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default

Played around with it a bit, no improvement. Still detonates when I apply partial throttle to 1-2psi, and then snap the throttle open. It happens at 4500 in 5th, 5000 in 5th, and 5500 in 4th.

My internet is on the fritz, so i will post more later. I included a zip file of the datalog I took; I put a marker in after every knock event. I can post a datalog of what it used to do with the TPS-based stuff (basically the same)
Attached Files
File Type: zip
map1.zip (136.9 KB, 57 views)
Old Sep 12, 2008 | 09:52 PM
  #17  
Saml01's Avatar
Elite Member
iTrader: (9)
 
Joined: Jul 2007
Posts: 5,710
Total Cats: 3
From: NYC
Default

Back off the timing, its not worth the power vs engine life. Besides its not THAT much you would lose.
Old Sep 13, 2008 | 04:09 AM
  #18  
Savington's Avatar
Thread Starter
Former Vendor
iTrader: (31)
 
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Default

A small aside: I really do enjoy it when my computer decides to randomly corrupt various MSQs, so when I try to load my "last map saved" after a failed experiment my car runs like I've loaded an MM9093 basemap. One set of plugs and a session later...
Old Sep 13, 2008 | 01:21 PM
  #19  
JasonC SBB's Avatar
Elite Member
 
Joined: Jul 2005
Posts: 6,420
Total Cats: 84
Default

If you look around timestamp 5940 in your datalog for example, after tip-in, your TPS has pretty much stopped increasing, but MAP is increasing (turbo is spooling).

This is why on a turbo motor one ideally needs BOTH TPS AND MAP based enrichment.
And why I still like my AEM over an MS...
Old Sep 20, 2008 | 07:09 PM
  #20  
patsmx5's Avatar
Elite Member
iTrader: (16)
 
Joined: Aug 2007
Posts: 9,406
Total Cats: 559
From: Houston, TX
Default

Well, my acceleration settings were off forever, and it sucked. Car had LOTS of hesitation everywhere, especially when cold. Then I made one that was TPS based and it helped a little bit, but it still sucked. Anyways, I just spent an hour and a half making this one. Works soooo good compared to before. The car is a lot smoother when shifting. It makes it a lot easier to drive. And when I punch the gas it lurches forward. Never done that before without first falling on its face. MS2 FTW. I mainly tuned the MAP based cells, as it seemed more important. The TPS ones are probably way off. But it's running better than ever so I'm happy for now. If anyone else with MS2 wants to post theres, that would be acceptable...

Name:  accelerationsettings.jpg
Views: 153
Size:  101.1 KB
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
asmasm
MEGAsquirt
21
Sep 23, 2015 10:53 AM
curly
MEGAsquirt
11
Sep 22, 2015 11:54 AM
BlackBandit
Local Meets, Events and Tech Days
5
Sep 18, 2015 09:10 AM
compuw22c
MEGAsquirt
4
Sep 12, 2015 07:42 PM
Motorsport-Electronics
ECUs and Tuning
0
Sep 5, 2015 08:02 AM




All times are GMT -4. The time now is 06:36 PM.