Can megasquirt be used to achieve better fuel economy???

[Compaq888]

I don't know if this question came up, because most guys here want most hp, not fuel economy.

So my question is can the megasquirt be used to get better fuel economy??

Here is some backround info on my car. I have a 1999 nissan altima, auto. It is stock. It has Internal coil and it's ODB-2. It has a stock 2.4L KA24DE motor that has 4 cylenders.

If the system can be used to improve fuel economy then which one would be best to buy, because there are a couple of them.

I mainly want to change the 1000-2500rpm fuel consumption while keeping a good A/F ratio. I also want to to lower fuel consumption 3000-6100rpm because Nissans run rich in that area and kills performance.

So this is what I mainly want...
1000-2500rpm better fuel economy
3000-6100rpm more power and better A/F ratio.

Also is the megasquirt a piggyback or standalone?

[78Spit1500Fed]

...So this is what I mainly want...
1000-2500rpm better fuel economy
3000-6100rpm more power and better A/F ratio.

With goals as specific as these, you're likely to be successfull in acheiving them...

The MegaSquirt (any version) gives you direct access to the Volumetric Efficiency table, which directly controls fueling and therefore consumption.

To tune for maximum efficiency, you'll need a wideband oxygen sensor/controller to closely monitor your AFR.

Most, if not all, carb to EFI conversions will see a marked increase in efficiency and power both. EFI to EFI installs can see the same effect, especially older systems.

Newer EFI systems, like yours, are likely sequential and have timed injection for low-load/low-RPM and idle situations whereby fueling can be tightly controlled during the time the intake valve is open. Some discount the power improvements in such an injection scheme, but none will argue over it's inherent ability to improve economy and emissions. In these situations, MegaSquirt may not acheive better economy, but it's not unreasonable to acheive the same economy.

The one important factor in considering any stock EFI system is that one ECU is interchangeble with any number of the same engine/car combinations... that is they tune the fueling/spark requirements for an ideal engine and then provide sensors for adjustment of that mixture away from that ideal. This is obviously far from ideal. No two engines will run the same with the same tune, nor will any two engines react the same to a custom tune.

[78Spit1500Fed]

Sorry, pressed submit before I was done!

MS can be used in stand-alone or piggyback depending on the requirements from the car of the ECU. An ODBII vehicle is likely to have transmission control, communication with a body/brake computer and gauge/accessory control that MS would not support. In these cases, MS can handle fueling/spark/other control and let the stock ecu do it's deal.

As far as a version reccomendation; I would have to suggest MSII in your case, in a fuel-only setup. The MSII's processor is capable of controlling the injector pulsewidth on a higher resolution, a hundred times that of the original MegaSquirt. Also, the VE table in MSII is 12x12, whereas the MegaSquirt with standard code is only 8x8.

When you've gone as far as you can with fueling, then you can add spark control and go even farther...

-Brian

[Compaq888]

So basically you're saying It will be a piggyback because the car is an automatic and that the one I need only controls the fuel supply???

Now if I get the one you're recommending I need a wideband so I can control my A/F ratios??

Is the MegaSquirt able to control fuel 0-6100rpm, or only a specific portion of the rpm???

[Bernard Fife]

So my question is can the megasquirt be used to get better fuel economy??

Compaq888,

Maybe. It depends on your ability to tune, and how good a job your manufacturer did balancing emissions, etc., against efficiency.

Read this for a bit more on tuning for efficiency:

http://www.megasquirt.info/v22manual/mtune.htm#economy

However, I would not convert an otherwise stock vehicle soley for efficiency purposes, the gains are likely to be samall and the investment in time large.

Lance.

[Compaq888]

So my question is can the megasquirt be used to get better fuel economy??

Compaq888,

Maybe. It depends on your ability to tune, and how good a job your manufacturer did balancing emissions, etc., against efficiency.

Read this for a bit more on tuning for efficiency:

http://www.megasquirt.info/v22manual/mtune.htm#economy

However, I would not convert an otherwise stock vehicle soley for efficiency purposes, the gains are likely to be samall and the investment in time large.

Lance.

I read it, very interesting. I know the SAFC2 would be perfect for me but the problem is that it only has 12 points at 200rpm increments of tuning. I need something from Idle to redline to tune my car.

The timing right now is perfect for fuel economy I just need to tune the fuel.

[78Spit1500Fed]

So basically you're saying It will be a piggyback because the car is an automatic and that the one I need only controls the fuel supply???

Yes, and no. Yes the MS would be used in a piggyback configuration. No, the MS doesn't ONLY control fuel supply. It can be configured for spark as well.

Now if I get the one you're recommending I need a wideband so I can control my A/F ratios??

Yes. Without a wideband, you only know you're lean of stochiometric. Not by how much.

Is the MegaSquirt able to control fuel 0-6100rpm, or only a specific portion of the rpm???

The VE table in MegaSquirt-II can be configured for any RPM range you like. There are 12 bins and they are user-configureable. (Not in 200 RPM steps, but in whatever increment you want, and not neccessarily the same increment between any two points.)

For instance, in the SAFC2 product, the bins are:
200
400
600...

In a MegaSquirt, you can do:
500
1000
1250
1500
2000
2500
3000
3125
3500
4500
5500
6500

Or whatever you like for each of those values. (The same applies to MAP values)

[78Spit1500Fed]

...However, I would not convert an otherwise stock vehicle soley for efficiency purposes, the gains are likely to be samall and the investment in time large...

I agree with Lance, here... if all you're looking for is improved economy, and you're not the type of person who likes to "tweak" on things until they're perfect, the MS may not be the right solution.

I'm a borderline obsesive-compulsive and a total data geek, so tuning will be my glory. (It's like an EQ for my car's engine... ROCK ON!) If, however, I didn't really care, and just wanted better "X" I would look for another car! ("X" could be power, economy, comfort, looks, whatever) The time you spend will be significant... mostly on learning.

[boost junkie]

If all you are after is better gas mileage get an LC-1 wideband and configure the simulated "narrow band" sensor output to switch at 15.5:1 - 16.5:1 air/fuel rather than 14.7:1. The engine will run leaner durning closed loop only. The emissions wont be as good, but you'll get better gas milage.

[Spenser309]

and fry the cats