By "correctly set up" I meant using mechanical components appropriate for your motor, and tuning correctly.
There are a number of good choices in aftermarket EMSs, of which Megasquirt is certainly the most popular, presumably primarily because of its price. When Megasquirt entered the market there were very few EMSs offered, and those that were available were rather pricey. Megasquirt literally brought programmable EMSs to the masses. There are quite a few more options now, so it's much easier to find something that meets your specific goals. FWIW, the Autronic units look to be very interesting, although they are significantly more expensive than Megasquirt.
Just to clarify, the X1/9 EFI (Bosch L-Jetronics) uses an airflow meter (AFM), not a mass airflow meter (MAF). AFM is old technology, but MAF is used on virtually every injected car made today, including most of the top line exotics. IMO it is an excellent means of measuring airflow, although most DIYers seem to use MAP (Manifold Absolute Pressure).
Some Xwebers are running 40/80 or wilder cams with the stock AFM, although most of them will admit it's not ideal. AFM uses a spring loaded plate to measure airflow. That plate pulsates with the intake reversion caused by a high-overlap cam, which presents a number of problems at lower RPM.
On top of that, the AFM literally presents a "barn door" to the column of air moving through the intake tract. This interruption of the intake charge inertia has a large detrimental effect on power output, particularly torque-- the engine is not only being strangled, but much of the "inertial supercharging" effect of intake resonances is negated. IMO, that is the single biggest drawback of the stock injection system.
It is entirely possible to use the original injection components in conjunction with an aftermarket controller, but the AFM would obviate most of the advantages offered by the programmable EMS.
However, you could either replace the AFM with a MAF (my preferred solution) or remove it and use a MAP or other means of measuring airflow, but still retain the rest of the original components (other than perhaps injectors), and integrate that with the aftermarket EMS of your choice. This would remove the intake obstruction presented by the AFM, which would result in instant power gains all by itself. It would also solve many of the problems presented by a more aggressive camshaft, at least with regard to the EMS.
My own plan is to do just that initially, in order to create a good, simple base mechanical installation so we can test out and become familiar with the particular EMS we'll be using. Once I'm comfortable with how it all works I hope to move to an individual throttle body (ITB) arrangement, both for the extra power and for the sound. I intend to use a MAF for both arrangements because I prefer the advantages it offers.
I have no data to support the following statement, so take it with a rather large grain of salt, but I suspect that a well tuned aftermarket EMS using MAF and running through a nicely ported, port matched, and polished stock plenum/runners would probably yield roughly as much power as the average DCNF setup. A well tuned DCNF installation or, better yet, a pair of DCOEs, would likely make a decent amount more power. But that's why my ultimate plan includes ITBs.
I almost hesitate to include the above paragraph since it's unsupported and presumably controversial, but I do so to illustrate my belief that the limitations in the stock injection system are not as great as they might seem, at least with regard to lower RPM street engines.
Hope that helps.
Regards,
///Mike
- seriously sucks.
