Stand alone engine management

ricar

True Classic
I guess this is not X specific but since many of us are interested in engine swaps I figured it might fly...

I have heard in many cases factory engine management will negate hop up parts. I have heard (mostly from Honda guys but I guess it's probably across the board) that the addition of CAIs and exhaust systems even lightened pulleys have limited gains because the ECU "corrects" for the upgrades. One guy commented on his butterfly only opening 3/4 after his bolt on mods so now he's looking for a new throttle controller. I know from my experience what a CR125F is capable of but my wife's CBR125 was a slug with only 13Hp. What is the bulk of the difference? I can't see much more that engine management.

So if this is the case how much of a difference can a standalone like Micro Squirt add?
 

kmead

Glutton for punishment
The factory Bosch FI isn’t that smart, it won’t correct for anything, it only responds to airflow. It will respond to mods pretty well. The biggest issue you will have with the OE injection system is it can’t deal with ’radical’ camshafts due to the backward pulses from the overlap of a hot cam to the vane type air metering system Bosch used. So if you go for HC pistons, a warmer cam (the Euro cam works well), larger valves, a better header and exhaust you will see notable gains.

If you go to MicroSquirt you will be able to use a more radical cam as it approaches the air metering using an entirely different technique. You will be able to eek out a bit more hp with micro than you would with the Bosch system if you used the same cam as the Bosch setup. With a more radical cam you can take better advantage of all the other changes and therefor get more power out of it. If you went to Megasquirt (or similar) you could get a bit more still due to being able to go to sequential injection versus batch fire (which is what both Micro and the Bosch system use), this won’t make a big difference but will be yet another increment on the diminishing return game as you max out the capability of a motor.

Clearly the easiest way to get lots of power out of an engine is carburetors, preferably DCNFs though others prefer other alternatives. The trade off here is fuel economy and drivability along with maintenance issues. Carl will dispute some of this but he likes to putter in any case :) Perhaps IDFs are different…

As for modern cars, they are designed to adjust to deliver economy and emissions. Most will respond to changes but often times the reality is bolt on features are rarely much if any better than the OE version and many times they are worse. Cold air intakes often do anything but pull in cold air… Other things like underdrive pulley gains would only be reflected at very high rpm where a street car spends very little time.

In regards to your Honda experience, if you are comparing an old one and a new one that meets modern emissions, they likely have adjusted the cams, valve sizes and compression etc compared to your older one. Yes unfettered engines could deliver more power by wasting fuel at the top end. It was designed to deliver 13hp which means there were many choices which brought this to pass…
 

Dr.Jeff

True Classic
As Karl said, the Bosch system on the X is very old technology. Therefore it really isn't very efficient compared to more modern designs, like a current standalone ECU will offer. Things like idle quality, acceleration and transition smoothness, peak torque and power, fuel economy, emissions, and overall drivability will improve.

Plus you will be ditching the air flow meter (AFM) from the Bosch system. That is a major air flow restriction that limits the engine's performance capability. By eliminating it you could realize a definite increase if the rest of the engine is built up, as Karl described.

Basically you are moving into a newer technology for both the fuel and ignition management systems, with far greater efficiency. That being said you will still be somewhat limited by the design of the intake manifold as a whole. So to really see gains you would need to replace more than just the ECU. But the ECU will offer the single biggest gain (particularly since it removes the AFM).
 

lookforjoe

True Classic
I guess this is not X specific but since many of us are interested in engine swaps I figured it might fly...

I have heard in many cases factory engine management will negate hop up parts. I have heard (mostly from Honda guys but I guess it's probably across the board) that the addition of CAIs and exhaust systems even lightened pulleys have limited gains because the ECU "corrects" for the upgrades. One guy commented on his butterfly only opening 3/4 after his bolt on mods so now he's looking for a new throttle controller. I know from my experience what a CR125F is capable of but my wife's CBR125 was a slug with only 13Hp. What is the bulk of the difference? I can't see much more that engine management.

So if this is the case how much of a difference can a standalone like Micro Squirt add?

With most newer (2010 or so on) EMS, there is not much you can do for performance unless have the ability to modify the factory maps to either bypass limiting software or change parameters so the system doesn't try to pull it back.

I'm surprised Honda guys were complaining, as that is one market with much aftermarket (software - Hondata, K-Tuner, etc.,) support covering pretty much any setup adding superchargers, turbos, etc. That's one of the main reasons for using the K-series Honda drivetrain (in pretty much ANY chassis).
 

ricar

True Classic
The diminutive L15A does not have much aftermarket support. A very compact engine but not capable of what most people want.
 
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