I had a streak of insanity. I'm in my garage about 30 min away from the test drive. I have the relay, rpm switch, and rocker arm solenoid just about wired up. I'm quite stoked. Probably about to try 4500 rpm vtec activation. Wish me luck. I'll report in later with the results. Might even write a diy.

 

The only negatives I see is the cam phasing you can not adjust for, that along with fuel and ignition changes that would be needed. Even the old, rude Spoon VTEC controller of yore was not a very good adaption of VTEC control. Now with iVTEC, you shouldn't just lower the VTEC activation as so much more is going on today.

 

Hmm test drive not so good. The ecu seems to be upset with me for disconnecting it from the vtec solenoid. Going to try a work around. Right now it won't let me go over 3700 rpms.

 

Work around successful. However, it seems to now be ignoring my attempts to engage the solenoid.

 

Agh WTF? Force vtec lobes at idle and the engine doesn't even care. Are the vtec lobes made with like .0000000001 extra lift? The vtec solenoid is definitely engaging.

 

Murphys law. Rpm switch is broken/not picking up the injector pulse. Momentary switch anyone?

 

I swear, there is nothing that does not piss the ecu off. Got it to activate at 4000 with a manual switch and felt and appreciable difference. But when 5300 swung around and ecu tried to engage vtec that was already engaged she went into limp home mode.

 

I am victorious I now have a vtec switch that allows me to force vtec to engage. Diy to come.

 

wtf...diy please!

 

Sorry about my broken English posts. iPhone posting sucks. But this thing is pretty cool. I used the same switch I used for nitrous before i took it out for the winter, so it gives me lols to use it. Problem is that there are a million ways to screw up. Turn it on too early and you will go slower. Turn it on early under heavy load and you will go lean and force the engine into limp home mode which will require you to shut off the engine to go over 3700 rpms. Turn it on when you are not at wot and you will also get limp mode. Turn it on at idle and engine hardly reacts, but you guessed it, limp home mode. Look at this shit I am forced to do when hondata ignores us. All and all it is a death switch. But boy is it fun to play with.

 

got to love winter... and it isn't that cold out yet.
definite A+ reps for effort
manage to steal a snap shot and boy have got some explaining to do...

 

Why would you want to force vtec earlier? Without the proper air/fuel ratios when you force vtec you are going to start damaging your motor. Neither variation of the L15 have vtec that enhances performance, this is dumb.

 

Modern engines have many means of compensating for additional air flow. It has the MAF and MAP sensors to trigger a higher injector cycle. It has a wideband o2 sensor to detect a lean condition and when all else fails a knock sensor to pull timing. It's not gonna blow up. Plus, l15a7 engines are cheap as a budget computer nowadays. The vtec lobes are very very mild on this cam anyway. If they were even moderate lobes I would expect a loppy idle when I engage the solenoid. The esm also indicates a very mild profile.

 

Correct me if I'm wrong. I thought the vtec on these engines doesn't increase lift of the cam, but opens another intake valve.

The Truly Amazing Honda Fit/Jazz

Read here under L15A VTEC technology overview.

 

You're correct, however I believe the OP has a GE which uses ivtec.

 

No, neither ge8 nor ge6 ever uses one valve. Vtec is simply a switch between two cam profiles. That's it. Ivtec is vtec + vtc. Some of the dohc engines do use the swirl effect but not the l15a7 or a8.

Sorry about the mixup. The Esm does in fact show 3valve operation on the gd3 gd1

 

That's the first iteration of the L15. At 3000 or whatever RPM (in that region) it allows the the other 4 intake valves to operate, so either a 12V or 16V setup. The first L15 is definitely an economy type of VTEC, not so for the 2nd model of L15. It is more of a performance type of VTEC as it comes on at 5400 rpms on a slightly higher lobe of the cam and all 16V are engaged at all times.

 

Love the ingenuity! Even if it doesn't work, what you are doing will def lead to more understanding of how these engines work. I remember when peeps would only roll stock wheels on hondas...everyone freaked when someone ran 16's! It takes people like you to bust things wide open. Great work Lyon!

 

If I'm reading right it looks like the old school l15 also has the vtec lobes.

 

um, yes...?

As far as I've been reading in the past how many months, the old and new L15 always had VTEC lobes, it was just WHAT the lobes did. That was affected by the rocker arm.

The Truly Amazing Honda Fit/Jazz (repost of the link above)

Honda L-Series SOHC i-VTEC Engines for the new GD Honda Fit/Jazz (from the same site of the "2nd Gen" engine)

So, according to those two links, the difference is, 1st gen did the 12/16 thing, where 12 valves open up at low RPMs and the last four open up after the threshold is hit ("variable" in this case being number of valves). While the 2nd gen did more like "some and more air" thing with all 8 intake valves (sorry, incorrectly put 16), where at low RPMs, they open at a specific time and amount to let air in, and at higher RPMs, open up sooner and more to try to get as much air in, in the less amount of time given. Both using the same cam, as indicated by the second link. <-- scratch that.

edit: another thing... if you look at the L15 chart in the second link and compare it to the L15 chart in the first link, then include his comment from the same first link:

I would guess the 2nd gen is also opening up at 3500 rpm.

or maybe not... https://www.fitfreak.net/forums/1st-...tml#post636266

incidentally, both links were provided in this thread https://www.fitfreak.net/forums/2nd-...ec-engage.html where you posted too. btw, I kinda disagree with 555 about the 5400rpm... that is, assuming the chart in the second link from "temple" is correct, there's a noticeable change around 3k to 4k, not at 5400 (unless you want to count leveling out).

um... this is what I've been thinking (more or less) since you started the thread.