More Acceleration enrichments - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 09-09-2008, 09:42 PM   #1
Junior Member
Thread Starter
 
Join Date: Oct 2007
Location: AC, NJ
Posts: 346
Total Cats: 0
Default More Acceleration enrichments

I had a question about the AE's and MT doesn't appear to have a help topic on them...

I pretty much understand the basics about the TPS-Based system, it see's how fast the TP voltage changes, and opens the injectors X milliseconds according to the table.

But my question is... Since I have a 2001, and this is from a 94-95 PnP, are these rates the same? Is the fastest I could hit the pedal make the voltage change 8.0V ? Is there any way to figure this one out?

Also, what is the TPSdot Threshold and how to I obtain it?

I figure understanding these would help me tune the AE's much better.
compy is offline   Reply With Quote
Old 09-09-2008, 09:45 PM   #2
Junior Member
Thread Starter
 
Join Date: Oct 2007
Location: AC, NJ
Posts: 346
Total Cats: 0
Default

Just thinking... If I measured the volts of the TP with it all the way open, is that what the max voltage per second could be?
compy is offline   Reply With Quote
Old 09-09-2008, 10:32 PM   #3
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,323
Total Cats: 1,920
Default

Quote:
Originally Posted by compy View Post
But my question is... Since I have a 2001, and this is from a 94-95 PnP, are these rates the same? Is the fastest I could hit the pedal make the voltage change 8.0V ? Is there any way to figure this one out?
Should be. Both devices are potentiometer voltage dividers, fed with 5v.

Quote:
Also, what is the TPSdot Threshold and how to I obtain it?
"The TPS/MAPdot threshold setting determines the rate at which acceleration enrichment begins. If you set it too high, no accel enrichments will be applied, and the engine may respond poorly, backfiring or coughing under sudden throttle movements. If you set it too low, however, you may have inadvertent enrichment triggered by noise on the TPS signal."

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

Quote:
Originally Posted by compy View Post
Just thinking... If I measured the volts of the TP with it all the way open, is that what the max voltage per second could be?
Nope. Let's say the minimum voltage is 0.5v, and the max voltage is 4.5v (which is pretty close to what it will in fact be). If you depress the pedal fully from closed over 1/2 second, then the rate is 8 v/sec. If you mash it open in 1/4 sec, then it's 16 v/sec. Etc...

For some reason, reality seems to differ from the software settings slightly.
Joe Perez is offline   Reply With Quote
Old 09-09-2008, 11:07 PM   #4
Junior Member
Thread Starter
 
Join Date: Oct 2007
Location: AC, NJ
Posts: 346
Total Cats: 0
Default

Quote:
Originally Posted by Joe Perez View Post
Nope. Let's say the minimum voltage is 0.5v, and the max voltage is 4.5v (which is pretty close to what it will in fact be). If you depress the pedal fully from closed over 1/2 second, then the rate is 8 v/sec. If you mash it open in 1/4 sec, then it's 16 v/sec. Etc...
I guess I don't understand this. I measured it and it was about .6 at 0% and 3.78 at 100%. So how could you produce more than 3.78 volts per second no matter how hard you hit the pedal?

I guess I'm missing something since I think that 3 volts/sec would be max acceleration, 1.5 volts/sec would be half acceleration, and so forth.

So my question is, how could it be more voltage per second than what the TPS provides? Without hitting the pedal more than once in a second.
compy is offline   Reply With Quote
Old 09-09-2008, 11:21 PM   #5
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,323
Total Cats: 1,920
Default

Forget the actual maximum value, we're talking rate of change, which is relative.

First off, your delta is only going to be ~3.2v, since your minimum is 0.6 and your max is 3.78 (which I'll round to 3.8).

If you go from mix to max, and it takes four seconds, that's 0.8 v/sec. If you take two seconds, then that's 1.6 v/sec. If you do it in one second, that's 3.2 v/sec. With me so far?

Ok, so given that, what do you call it when you do it in 1/2 sec? IOW, 3.2v/half-second.

Maybe we step back to elementary school math for a second, and express these as fractions. We all agree that 2 / 4 is the same as 1 / 2, right? And that 1 / 2 is the same as 0.5 / 1, yes? So that's the same as 0.25 / 0.5. It doesn't matter how far we break this down, so long as both the numerator and the denominator are scaled by the same factor.

Ok, so we'll now do it with your numbers. 3.2 / 0.5 is what happens if you mash the throttle from closed to open in a half second. But MS needs us to enter data in volts per second, not volts per half-second. So we just scale the fraction up so that the denominator becomes one, which gives us 6.4 / 1.
Joe Perez is offline   Reply With Quote
Old 09-09-2008, 11:23 PM   #6
Elite Member
iTrader: (21)
 
paul's Avatar
 
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
Default

Didn't I just explain this to you last week?
paul is offline   Reply With Quote
Old 09-09-2008, 11:34 PM   #7
Junior Member
Thread Starter
 
Join Date: Oct 2007
Location: AC, NJ
Posts: 346
Total Cats: 0
Default

Gotcha now. And No Paul.

Thanks for clearing that up.
compy is offline   Reply With Quote
Old 09-10-2008, 08:53 AM   #8
Elite Member
iTrader: (21)
 
paul's Avatar
 
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
Default

Must've been Artie. Which means I'll probably have to explain it a few more times.
paul is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Well tuned naturally aspirated example project? asmasm MEGAsquirt 21 09-23-2015 11:53 AM
In what world... curly MEGAsquirt 11 09-22-2015 12:54 PM
VE values too low? compuw22c MEGAsquirt 4 09-12-2015 08:42 PM
ME221 Now has Autotune and Long Term Fuel Trim Tables Motorsport-Electronics ECUs and Tuning 0 09-05-2015 09:02 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:42 AM.