MEGAsquirt A place to collectively sort out this megasquirt gizmo

Randomly richer than normal?

Thread Tools
 
Search this Thread
 
Old 04-16-2015, 11:37 AM
  #1  
Junior Member
Thread Starter
 
ihiryu's Avatar
 
Join Date: Jul 2013
Location: TX
Posts: 319
Total Cats: -11
Default Randomly richer than normal?

Hey guys, so a little more hand holding. I've noticed that as it gets warmer (I'm here in TX, so the weather is always wonky) the car runs a bit richer than expected.

I'm assuming it has an issue with the MAT tables. Could someone explain them to me?
Attached Thumbnails Randomly richer than normal?-mat-table.png  
ihiryu is offline  
Old 04-16-2015, 11:54 AM
  #2  
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
Default

That doesn't look terribly dramatic to me.

When you view a log in MegaLogViewer, you can look at the individual modifiers which alter the requested fuel. Collectively, they are represented as the GammaE value. I believe that the one which deals specifically with air density (based on manifold temperature) is expressed as Air_Corr.
Joe Perez is offline  
Old 04-16-2015, 11:57 AM
  #3  
Junior Member
Thread Starter
 
ihiryu's Avatar
 
Join Date: Jul 2013
Location: TX
Posts: 319
Total Cats: -11
Default

That's Joe, I'll take a look at it.

Yeah it's actually not that bad, when it's cold I cruise 16.5, but when it's warm it's like 16.2. Not bad, but it is a little annoying. Guess I've got wideband OCD.
ihiryu is offline  
Old 04-16-2015, 12:05 PM
  #4  
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago. (The less-murder part.)
Posts: 33,026
Total Cats: 6,592
Default

Originally Posted by ihiryu
Guess I've got wideband OCD.
Uhm, yeah, I'd say you do.

The difference between 16.2 and 16.5 is so miniscule that I'd typically attribute it to measurement error, particularly in a system which is designed to oscillate under normal conditions.

It's also weirdly lean. Are you trying to hypermile this vehicle?
Joe Perez is offline  
Old 04-16-2015, 12:13 PM
  #5  
Junior Member
Thread Starter
 
ihiryu's Avatar
 
Join Date: Jul 2013
Location: TX
Posts: 319
Total Cats: -11
Default

Yes it only hits that on super low loads, or less than 10% throttle. If i drive it like a normal human being, it'll cruise 15.2-15.5. And when I go WOT, it'll richen up with boost.

So even on the highway cruising 3500 rpm's, I'm at 15.8-16, and if I go to WOT, it'll richen up to 13-12.8 then all the way to 11. Of course just depending on the load.

Just trying to achieve 300 miles to the tank. Since I'm using MS2E from Rev, it's got map switching, when I go road racing, I plan to use the secondary map for more fueling when I'm racing, since MPG's aren't really a concern at that point.
ihiryu is offline  
Old 04-16-2015, 01:07 PM
  #6  
Elite Member
iTrader: (3)
 
deezums's Avatar
 
Join Date: May 2014
Location: Kansas
Posts: 3,146
Total Cats: 201
Default

There's a point where too lean is actually less economical than running a fatter AFR. For a time I was trying to cruise 16.2, but I believe I get better miles running 15.5-15.8, and it also seemed to run closer to target more often.

I haven't played with timing much, which I expect is pretty critical when you try to run so lean.
deezums is offline  
Old 04-16-2015, 03:09 PM
  #7  
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 10,917
Total Cats: 2,201
Default

I ran the last turbo car in the low to mid 16s on the highway. Was rewarded with 35.3mpg best tank. Typically 32-33mpg combined.

Most of my tanks were well over 300.
concealer404 is offline  
Old 04-16-2015, 03:44 PM
  #8  
Retired Mech Design Engr
iTrader: (3)
 
DNMakinson's Avatar
 
Join Date: Jan 2013
Location: Seneca, SC
Posts: 5,009
Total Cats: 856
Default

Hustler (back when he drove instead of riding) published a long time ago, and had support, that 15.7 was more economical than 16.2 at cruise.

Concealor, that is indeed impressive.
DNMakinson is offline  
Old 04-16-2015, 05:23 PM
  #9  
Elite Member
iTrader: (5)
 
Erat's Avatar
 
Join Date: Oct 2011
Location: Detroit (the part with no rules or laws)
Posts: 5,677
Total Cats: 800
Default

I was around 38mpg with a passenger and a trunk full of stuff. 15.7:1 cruising 65mph, 40psi in the tires. Though, this was my attempt at trying to hypermile it. Oh and i think my timing was somewhere around 36*.
Erat is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bigmackloud
Miata parts for sale/trade
19
01-08-2021 11:24 AM
shooterschmidty
Engine Performance
8
09-30-2015 10:28 PM
viriiguy
General Miata Chat
5
09-28-2015 07:39 PM
psyber_0ptix
MEGAsquirt
4
09-22-2015 09:35 AM



Quick Reply: Randomly richer than normal?



All times are GMT -4. The time now is 01:21 PM.