flip switch for different fuel map? - 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 12-20-2008, 09:09 PM   #1
N3v
Junior Member
Thread Starter
 
Join Date: May 2008
Location: Nashville/Knoxville, TN
Posts: 318
Total Cats: 1
Default flip switch for different fuel map?

While I've got my MS torn apart, I wanted to ask another potentially stupid question. I know that MS can alternate to a second fuel map, obviously, and I wanted to implement a switch to change my fuel map. I want to do this for two reasons. First, it would act as a switch now to simply switch between an economical tune and a 'race' one for the track. Later I might use the switch for nitrous control, if I decide to go that route. Either way, I just have my ms out of the car and out of the case, and I'd rather do this now than have to pull it all out again down the road.

So, looking in megatune it says there's an option to switch to a second fuel map if 'JP1 is low'. I see no JP1 anywhere on my board, its all JS# not JP#
N3v is offline   Reply With Quote
Old 12-20-2008, 09:40 PM   #2
Trackspeed Engineering
iTrader: (9)
 
Join Date: Jan 2008
Location: Bay Area, California
Posts: 937
Total Cats: 10
Default

Not answering your question, but a single good tune will work well on the track and be economical. When you are being economical, you will be in vacuum and you have those cells tuned for 14.5-15.5 or so.... what they should be tuned for either way. When you aren't being so economical, you are in boost, those cells are tuned richer depending on how much boost.

Basically, unless you are changing octane level, or adding nitrous or water/meth or something along those lines, you only need one map.
crashnscar is offline   Reply With Quote
Old 12-20-2008, 09:41 PM   #3
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,367
Total Cats: 1,331
Default

^^^+1. My car gets 28-30mpg on the highway and makes 230whp on the same fuel map.
Savington is offline   Reply With Quote
Old 12-20-2008, 10:05 PM   #4
N3v
Junior Member
Thread Starter
 
Join Date: May 2008
Location: Nashville/Knoxville, TN
Posts: 318
Total Cats: 1
Default

yeah I guess I just need to mess with my tune a little, itbs can be kinda tough to nail down cruising a little lean and then being rich enough during track driving. Either way though, thats not really what the switch is for. I'd probably load in a richer tune for the fuel map when I don't have nitrous, just for a limp-style fuel map.
N3v is offline   Reply With Quote
Old 12-20-2008, 10:57 PM   #5
Trackspeed Engineering
iTrader: (9)
 
Join Date: Jan 2008
Location: Bay Area, California
Posts: 937
Total Cats: 10
Default

Sounds like you need to learn how to tune a car.
crashnscar is offline   Reply With Quote
Old 12-20-2008, 11:31 PM   #6
N3v
Junior Member
Thread Starter
 
Join Date: May 2008
Location: Nashville/Knoxville, TN
Posts: 318
Total Cats: 1
Default

congratulations on posting twice and still contributing nothing.
N3v is offline   Reply With Quote
Old 12-21-2008, 12:04 AM   #7
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,892
Total Cats: 1,792
Default

Quote:
Originally Posted by N3v View Post

So, looking in megatune it says there's an option to switch to a second fuel map if 'JP1 is low'. I see no JP1 anywhere on my board, its all JS# not JP#
JP1 is on the v2.2 board. JS9 is the v3.0 board spot.


super easy. js9 to switch to ground. the end. I really see no reason for table switching.
Braineack is offline   Reply With Quote
Old 12-21-2008, 01:54 AM   #8
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,326
Total Cats: 1,926
Default

Certainly not for econ / power. By definition, those two operating conditions occur in different cell ranges, thus one single table can easily accommodate both.

The only valid reason to use map switching, IMO, is if it's part of some failsafe mechanism. On my car, for example, the Spark1 map is heavily retarded in the boosted cells. When the WI system comes on and the pressure switch closes, it flips to Spark2, which has an aggressive timing map in boost. If the WI fails to come up to pressure, the spark map remains in the retarded mode (and the boost controller remains bypassed) which both saves the engine from exploding and lets me know something has gone wrong.
Joe Perez is offline   Reply With Quote
Old 12-21-2008, 06:28 PM   #9
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 407
Default

the megasquirt already has a built in "race/economy" switch. it's called the gas pedal. if you dont press it, the table cells will be "economy", and if you do, it'll be "race".
y8s is offline   Reply With Quote
Old 12-21-2008, 10:09 PM   #10
N3v
Junior Member
Thread Starter
 
Join Date: May 2008
Location: Nashville/Knoxville, TN
Posts: 318
Total Cats: 1
Default

well I got it working just fine (thanks braineack) I know the econ/power tunes is pretty much useless, but I wanted to wire this up while I had my megasquirt out of the case just so I wouldn't have to do it later if i decide to run nitrous. Right now I just have a slightly richer tune loaded as a limp setup, which again, i know, isn't really infinately useful.

Originally I was thinking that before I have nitrous I could simply use it for an agressive tune, as I run 15.5-16 AFR while cruising, and my car showed a charming tendancy to lean out during heat-soaked track condition. My ITB's are used to seeing IAT temperatures at only about 8 degrees hotter than ambient temps, and it starts to get flaky when the engine bay gets heat soaked. I know though, that I could probably hammer this out mostly by just messing with my tune.

However, I did what I wanted to do, so thanks.
N3v is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
Someone help me with AE ihiryu MEGAsquirt 33 10-08-2015 05:56 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
"Chimney Ethanol" E100 MiataGarage Engine Performance 5 09-30-2015 12:04 AM
In need of base map for stock 1997 brandonbkd MEGAsquirt 0 09-29-2015 12:52 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 01:43 AM.