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#

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.

^^^+1. My car gets 28-30mpg on the highway and makes 230whp on the same fuel map.

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.

Sounds like you need to learn how to tune a car.

congratulations on posting twice and still contributing nothing.

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.

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.

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".

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.