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Discussion Starter · #1 ·
I was reading through the gas mileage thread and early on someone posted a remark about it being nice to have a light/led signal that vtec economy mode was engaged. I have searched the forum but could not locate anything on the subject using my search criteria. That post was from 2007 (i think)- so it's been a while.

I would love to do this- If anyone has any thought on some way to trigger a light, I'd love to hear it.
 

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if you cant find it its actually pretty simple, heres the deal, buy yourself a 12V relay (well discuss type later), the LED and some wire

find the VTEC solenoid signal wire, the wire that the ECU sends signal through to tell the VTEC system to engage

once youve found it, tap it and run a wire from it to your relay, use pin 85 or 86 for it, then ground the one that you didnt use (i.e if you ran the solenoid to 85, ground 86 or vice versa)

now youre going to need to find a good source of power for the LED, a switched power wire would work, and so would a constant, so whatever you decide on will work, connect that to pin 30 on the relay

now run your LED to wherever you want, and run a wire from its POSITIVE terminal to the relay (pin input will change depending on app, we'll discuss this later), then ground the negative of your LED wherever you want that theres a solid metal-to-metal contact


then from there it gets to the good stuff, if you want it to act as an indicator that VTEC is ON, youll only need a simple SPST relay, connect LED positive to pin 87 and yore done


if you want this as a WARNING when VTEC is OFF, then youll need an SPDT relay, not too much more money though. . . from there connect LED positive to pin 87A, and then find a way to protect pin 87 from shorting out on anything, electrical tape or best that I would do is to get an unused connector and plug it in, that way its insulated and itll stay in place


LED can cost anything from 50 cents to 5 bucks-ish, Relay will range from about 5-10 dollars, and wire, well that all depends too much so youll have to figure that out on your own

now this is all on theory and all that, I havent done it on my car so I wont claim that itll WORK, but it should if it works the same sort of way my old car's VTEC did
 

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^sounds like you know what you are doing

but idk if the new ivtec that the r18 has will work with your idea

but if it does i want it done to my car...just a little green light like behind the steering wheel near the tach that tells me when vtec is on

it would be so cool
 

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Discussion Starter · #7 ·
^^
This is exactly the way I'm thinking about it. If I can locate the solenoid, then I can tap it to trigger the positive side of a LED. Given the low amp of LED's I bet you may not even need the relay (would not surprise me if the relay electro-switch needs more power to close the loop than the LED needs to light).

I have no idea where the solenoid is (never looked that close) but I'll do some research and see what I can come up with.

My goal is for the light to come on when I'm in vtec eco mode - kind of like the green vs blue indicator in the new insight. As I type that, it might be fun to have two lights- one that's telling you that you out of vtec (ie regular mode) and the other to tell you that you're in vtec(eco) mode.
 

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it doesnt take a rocket scientist to figure this sort of thing out, I was an ME major and I always hated the EE sections of intro to Engineering, but thats all the complex stuff, 12VDC electronics if easy by comparison


and from that pic of the solenoid, there will be a plug, usually with ONE wire coming off it, thats going to be the ECU signal wire
 

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^^
This is exactly the way I'm thinking about it. If I can locate the solenoid, then I can tap it to trigger the positive side of a LED. Given the low amp of LED's I bet you may not even need the relay (would not surprise me if the relay electro-switch needs more power to close the loop than the LED needs to light).

I have no idea where the solenoid is (never looked that close) but I'll do some research and see what I can come up with.

My goal is for the light to come on when I'm in vtec eco mode - kind of like the green vs blue indicator in the new insight. As I type that, it might be fun to have two lights- one that's telling you that you out of vtec (ie regular mode) and the other to tell you that you're in vtec(eco) mode.
for a 2 light setup it actually really simple. . . if you want to do that, heres how youll do it

basically take all the steps I did before and the LED and relay set that I said for the warning part, you take the before-mentioned LED as your Blue high-speed operation light, then take your green LED, put it's positive onto pin 87 that I previously said to cap off, ground that LED and done, green will be on the N/O circuit thatll be only on when the solenoid is engaged, and the blue will be on the N/C circuit thatll be on when the solenoid is disengaged

^sounds like you know what you are doing

but idk if the new ivtec that the r18 has will work with your idea

but if it does i want it done to my car...just a little green light like behind the steering wheel near the tach that tells me when vtec is on

it would be so cool
thing is regardless of how complicated the VTEC system is, itll always need a signal wire to/from the ECU so that the computer knows what the hell is going on
 

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Discussion Starter · #12 ·
Okay- did a bit more research. I also read most of the Fit thread I posted above. One thing some one did there was to build in an auto dimmer for day/night mode. This is pretty cool. I will likely hold off on that for the time being as it involves pulling the radio out and a couple addl parts.

I found a cool bi color LED (Green&Blue) Bicolor LED - Blue / Green LED N500TBG4D that I'm going to get (I wonder if my local RS will have these). Note that the picture in the link if of two diff LED's- not the one in the datasheet.

Using one of these, I can wire the LED change from blue (non vtec mode) to green (eco-vtec mode).
 

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From what I understand of the gas saving mechanism in the base civic it disengages at 3500rpm.

Now if you stomp the pedal, and you are still under 3500, does vtec go off?

My thinking is it will, which would be a good reason to have the light. If vtec is ON no matter what, as long as you are under 3500, i see no reason for this light. Just another light that will constantly be changing, and get annoying.

I was also under the impression that its not called vtec in the base civic because it works opposite that of in the past/current SI's
 

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Discussion Starter · #14 ·
The i in iVtec represents 'intelligent'. It's not on/off just based on rpm like the old vtec implementations. On the R18, the engine in std mode up to about 1000 rpms and above 3500rpms. From 1000rpms to 3500rpms it's possible for vtec to engage given the right inputs. When engaged the eco (my term) cam profiles are being used.
 

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i havent seen one, my focus had one for best mpg. it would be cool so im scibing for an answ er ha.
i remember reading on here somewhere were a guy wanted to or actually did it ( i cant remember) he hooked up his ambient floor lightning to the vtec solenoid. so when he would hit vtec the floor would light up red. (i think thats cool)
as for you xIMPULSEx check this article out. they already have what you were looking for.

Honda's color-changing speedometer to drive out bad driving habits
 

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Discussion Starter · #17 ·
"These are the VTEC solenoids. Yes, there are three. The R18 has every type of SOHC VTEC ever conceived all slapped into one package" ?
I read that. I'm guessing that all three activate together. I guess it's possible that two activate vtec and one disengages it. I'll have to do some testing with my VA meter.

Does anyone know for sure? I wish I had a FSM for stuff like this.
 

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our ivtec CAN work under 3500rpm but it not necessarily always on

it is activated when there is a light throttle input and other factors i think

this light would be useful for saving gas because you could see if you have the pedal down too far to be in vtec (to save gas)

and to make things clear THE R18 DOES NOT USE VTEC FOR PERFORMANCE...our vtec is for MPGS
 
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