"dual vtec" "3 stage vtec" please share what you know!

[vrmouseyd15b]

hmmmm. I don't run and egr valve, and I have a 4 wire o2 sensor, upper and lower (but I believe I only need a single wire, and only and upper) I've been running around, give me a little bit for more pics.

[Cobb]

Ever notice the vtec screens clogged up? A lot of gen 1 owners have found that on their vehicle.

Why dont you use a egr? Thats the poor mans VCM. I tried to hack my egr and got a code, lost auto stop, ev mode and a few other fuel saving features.

Ever consider getting the cam reground for more performance, more economy and more mid? I had a machine shop mention to me they could do that if I bring them my cam, then I would need to adjust my valves to make it work.

[vrmouseyd15b]

This is the best bit of info ever related to a dual vtec setup! (should be all P2J ECU's at least), and this dude explains the "no egr thing" on my setup..



Hence my econo light "smiley light":

this stuff took me forever to dig up from around the interweb, I'll gladly share it with you here

The other big trick, at least for my setup was getting the right ECU. It ran like dog poop, either at idle, or at high or low rpm's or all the above until i got the dual vtec ecu.

I run a 37820-P2J-J62 (jdm dual vtec lean burn cvt ecu). the trick is that this ecu is independent of the traction control module! I don't have one. What I do have is the one thing all automatic hondas of this generation have, a 3 wire idle air control valve on my manual car. I pinned that thing to the ecu just like the stock 96 civic lx would, and viola!

thanks,
victor

[Chrysler kid]

Just went through a long article published in 1999, but basically the car needs to have a 5 wire 02 sensor to engage lean burn. The 3 stage VTEC contains the VTEC E cam settings that are used when the engine is up to operating temperature.

On the hx and vx the egr valve is used to quickly make the car go up to operating temperature so the car can run optimally under the vtec-e cam settings. If the egr valve is not functional the idle control valve makes the car idle higher so the car doesn't misfire at idle from the cam settings

Essentially your lean burn indicator is a stage 1 VTEC cam setting indicator for when the vehicle can operate at the vtec-e can settings. Otherwise the car operates in its second stage.

Apologize in advance if I read it wrong. But it does specifically mention a 5 pin 02 wire is needed in order for the computer to stay in advanced closed loop settings


My head hurts. There is no definition of sources on Any of this stuff.

So my last quest, lean burn operates when only one valve is open to reduce consumption. So technically my hx has 3 cam settings. High horse power VTEC, normal cam operation idling, and full max hp VTEC?

[vrmouseyd15b]

cobb, check the first pic - he explains it for the jdm ecu. nothing in the vtec screens over the last 20k, might want to check since you mentioned it, though

[vrmouseyd15b]

Originally Posted by Chrysler kid

Just went through a long article published in 1999, but basically the car needs to have a 5 wire 02 sensor to engage lean burn. The 3 stage VTEC contains the VTEC E cam settings that are used when the engine is up to operating temperature.

On the hx and vx the egr valve is used to quickly make the car go up to operating temperature so the car can run optimally under the vtec-e cam settings. If the egr valve is not functional the idle control valve makes the car idle higher so the car doesn't misfire at idle from the cam settings

Essentially your lean burn indicator is a stage 1 VTEC cam setting indicator for when the vehicle can operate at the vtec-e can settings. Otherwise the car operates in its second stage

Apologize in advance if I read it wrong

no prob, I'm here to learn too. but I'm pretty sure the indicator is as described. I don't hit second stage vtec until about 5200 rpm!

I have at least 5 stages of operation:

12v lean burn (no vtec) low rpm - not enough oil press. for vtec to engage cam anyway
12v non lean burn (full throttle)
16v lean burn (1st stage vtec 2.5k- ? rpm)
16v (vtec non lean burn about 3k-5k rpm)
16v WILD CAM (both vtec engaged 5k rpm - redline) I've had the motor "run away from me" while redline shifting and testing the vx tranny - rev limit was about 8k (jdm ecu) - first gear went to about 50, second to about 85, and then I chickened out

[Chrysler kid]

Alright apologize for muddying up your thread, VTEC e is just the opposite of VTEC.

But still wouldn't that in itself be considered 3 stages of valve timing?

[vrmouseyd15b]

Originally Posted by Chrysler kid

Alright apologize for muddying up your thread, VTEC e is just the opposite of VTEC.

But still wouldn't that in itself be considered 3 stages of valve timing?

I would say yes on a d15z1. standard vtec-e (full throttle), vtec-e lean burn, and vtec "full power".


no apologies necessary, like I said this info is so hard to find in the first place, and I only seem to be able to find bits and pieces... any input would help

and that's where the having cake and eating it too came from - this motor setup is crazy either way you want it! economy or go!




hey, whatever happend to 379Kcivic anyway? Oh well, the info will be here.....

[Chrysler kid]

Awesome article
55 Miles Per Gallon: How Honda Did It - Businessweek

[Chrysler kid]

Well in my insomnia fueled learning binge I still have questions

Do only VTEC models run on 12 valves then switch to 16 valve operation under high throttle? I would think there would be more of a difference in mileage without VTEC if that was the case

Lean burn refers to the way the head is designed to let air ignite with fuel directly at the plug. Technically the car is always using the lean burn intake valve design but only restricts fuel during ideal conditions. It sounds like a very early form of direct injection which would explain why the cars are still viable today

No answer on egr valves however I believe it has to do with the lean burn and emissions. The intake manifold design cause the car to always run slightly lean and to meet emissions standards they included that on US lean burn models.

The d15b sounded Like it was the completion of the primary engineers design. He began working on it in 1988 to build it in the 1.5 and after all the logging for fuel maps was able to run the d15b on a 4 wire 02 sensor with ore programmed throttle settings stored in the ecm where as the 1.6 needed the 5 wire to program settings on the go.

My assumption is that Honda killed the 1.5 motor and the cost to develop the 1.6 into a 3 stage VTEC was too great to adapt to the large us market as it was mentioned several times the project was nearly killed before nearing completion in 1991