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  1. #1

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    Today, I ran 62# injectors on the stock ECM

    How would you like to be able to run any size high-impedence injector (up to 79 lb/hr available), be able to tune the fuel curve based on boost and rpm real-time with a laptop, be able to monitor and log boost pressure, rpm, and A/F ratio, and do this all for about $450?

    I got mine running today successfully with 62# injectors on the stock ECM, and ran up to 12 psi boost at 11/1 A/F ratio using an AEM F/IC. What amazed me about the whole deal is how easy it was to get started. I simply wired up the thing to the injectors and one sensor, put in the 62's, cut the fuel table by 40%, then started her right up. Not cough's, sneezes, or hiccups.

    I built my own plug-n-play harness because a) I didn't want to cut the stock harness, b) it all has to be waterproof, and c) we may be selling p-n-p harnesses so I wanted a prototype.

    The biggest hurdle I had was figuring out a weird loss of power at 10 psi boost. Apparently, the stock ECM will command the injectors to go static open and that's what limits the stock fuel system. The F/IC unit modifies the pulsewidth sent to the injector, so if the signal is static open, then the F/IC has nothing to modify. Luckily, the F/IC also has 2 analog inputs and outputs and so you can modify any constant voltage signal going to the ECM. All I had to do was clamp the stock MAP voltage to the equivalent of ~7 psi boost to make sure the ECM never sends a static signal to the injectors.

    Now, if I can ever get a prop tall enough to hold it down to 8000 rpm, I'm going to be running this thing at higher boost levels (hope to get to 15+ psi) and seeing just how fast I can go on the stock ECM.

    Mike


  2. #2
    Quote Originally Posted by engineermike View Post
    How would you like to be able to run any size high-impedence injector (up to 79 lb/hr available), be able to tune the fuel curve based on boost and rpm real-time with a laptop, be able to monitor and log boost pressure, rpm, and A/F ratio, and do this all for about $450?

    I got mine running today successfully with 62# injectors on the stock ECM, and ran up to 12 psi boost at 11/1 A/F ratio using an AEM F/IC. What amazed me about the whole deal is how easy it was to get started. I simply wired up the thing to the injectors and one sensor, put in the 62's, cut the fuel table by 40%, then started her right up. Not cough's, sneezes, or hiccups.

    I built my own plug-n-play harness because a) I didn't want to cut the stock harness, b) it all has to be waterproof, and c) we may be selling p-n-p harnesses so I wanted a prototype.

    The biggest hurdle I had was figuring out a weird loss of power at 10 psi boost. Apparently, the stock ECM will command the injectors to go static open and that's what limits the stock fuel system. The F/IC unit modifies the pulsewidth sent to the injector, so if the signal is static open, then the F/IC has nothing to modify. Luckily, the F/IC also has 2 analog inputs and outputs and so you can modify any constant voltage signal going to the ECM. All I had to do was clamp the stock MAP voltage to the equivalent of ~7 psi boost to make sure the ECM never sends a static signal to the injectors.

    Now, if I can ever get a prop tall enough to hold it down to 8000 rpm, I'm going to be running this thing at higher boost levels (hope to get to 15+ psi) and seeing just how fast I can go on the stock ECM.

    Mike

    WOW! No this is interesting! Great job!

  3. #3
    good job engineer mike
    Quote Originally Posted by engineermike View Post
    How would you like to be able to run any size high-impedence injector (up to 79 lb/hr available), be able to tune the fuel curve based on boost and rpm real-time with a laptop, be able to monitor and log boost pressure, rpm, and A/F ratio, and do this all for about $450?

    I got mine running today successfully with 62# injectors on the stock ECM, and ran up to 12 psi boost at 11/1 A/F ratio using an AEM F/IC. What amazed me about the whole deal is how easy it was to get started. I simply wired up the thing to the injectors and one sensor, put in the 62's, cut the fuel table by 40%, then started her right up. Not cough's, sneezes, or hiccups.

    I built my own plug-n-play harness because a) I didn't want to cut the stock harness, b) it all has to be waterproof, and c) we may be selling p-n-p harnesses so I wanted a prototype.

    The biggest hurdle I had was figuring out a weird loss of power at 10 psi boost. Apparently, the stock ECM will command the injectors to go static open and that's what limits the stock fuel system. The F/IC unit modifies the pulsewidth sent to the injector, so if the signal is static open, then the F/IC has nothing to modify. Luckily, the F/IC also has 2 analog inputs and outputs and so you can modify any constant voltage signal going to the ECM. All I had to do was clamp the stock MAP voltage to the equivalent of ~7 psi boost to make sure the ECM never sends a static signal to the injectors.

    Now, if I can ever get a prop tall enough to hold it down to 8000 rpm, I'm going to be running this thing at higher boost levels (hope to get to 15+ psi) and seeing just how fast I can go on the stock ECM.

    Mike

  4. #4

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    Thanks, guys. Me and my EE buddy had been talking over the details to build something like this for my ski, then I realized something was already available and it's better than anything we would have built.

    So, what's the interest level for a plug-n-play harness to make installing one of these as simple as 10 plugs and loading a base program?

    Mike

  5. #5

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    I also gave the AEM Universal/Generic Fuel/Ingnition controller a look for use on a 4tec motor, and also felt it could easily be adapted for this application. Although all I did was think about it Exellent work as always Mike. Sounds like a little boost in fuel pressure is all u need, Or some bigger injectors if you dont care how it idles, haha.

    Once again, thinking outside of the box, and comming up with low priced solutions for us cheapskates Thanks Mike!!

  6. #6

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    Quote Originally Posted by boostaholic View Post
    ...Or some bigger injectors if you dont care how it idles, haha...
    Actually, even with the 62's, it idles and responds just like stock. A/F ratio is the same too!

  7. #7
    bigdeez's Avatar
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    Keep us posted on your results i would like to see how this thing pans out.

  8. #8
    ctriverguy's Avatar
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    MIke, how is this working out?

  9. #9

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    Quote Originally Posted by ctriverguy View Post
    MIke, how is this working out?
    I've really put this through it's paces and it's still working great. Here's the latest. . .

    - I've raised the boost beyond 13 psi and ran 81.0 on the GPS and 80.0 at Mudbug, both in 90 deg heat and humidity. This is using a 15/20->15/24 and 81 mm nozzle, turning 8000-8100 rpm. The MAP sensor is clamped at 7.3 psi, so the stock ECU doesn't "see" anything beyond that. So, the F/IC is supplying all the additional fuel from 7 on up to 13+ psi successfully.

    - My O2 sensor crapped out a long time ago due to the humidity in the exhaust. I haven't checked the A/F ratio at anything over 10 psi (shame on me), but it runs good. The fuel tables in the F/IC were assembled purely by mathematics on my part and I haven't adjusted them any. I'm borrowing a 15.5/22.5 prop and will put a new O2 sensor on it then as I creep up the boost some more.

    - I sunk the ski a few weeks ago and the whole harness and F/IC (in the waterproof container) went under water. Apparently, the weatherpack connectors and container are doing their jobs because it has worked flawlessly before and after that event.

    The even better news is that AEM is developing an "F/IC All Terrain", which will be waterproof! Could it get any better for us?

    Mike

  10. #10
    kp04rxp's Avatar
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    Mike,

    Hands down this is some very impressive work you've done. Congratulations on your results and how well everything is working. Math never was my favorite subject so I find this quite interesting.

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