majinx4

I have a 94 Del Sol with a D15B7 Non-Vtec Block. I really want to get it converted to Vtec. So I was reading an article on the internet the other day about a D15B head that has 2 Vtec Switches hince the name 3-Stage Vtec. Stage 1 is 0-3000RPM using 12 valves, Stage 2 is the first switch 3000-6000RPM and it kicks to 16 valves, and Stage 3 is the second switch 6000RPM+ and it kicks in the wild rocker arms. after reading this i was thinkin that would kicks *** to hear 2 Vtec crossovers. So is this a good thing to go for or does it really suck? And if it does suck wuts the best setup i sould go for?

JDM_SOHC

Sounds kinda like the VX VTEC-E way of working... 12 valves until VTEC hits then the others open up... My friend has that on his VX hatchie, an it blows ***... Probably one of the slowest single cams i've ever raced before... I'd say http://www.jdmaddiction.com get urself a D15B thats what I have an I got it for 500 bucks cant beat that... If your looking for more power, your gonna have to spend more money obviously, but if you just want something decent, with availability to be a lot faster than it is stock, id say get the JDM sohc like I did.. I was impressed at how it responded to bolt ons an I dust plenty of cars around here so speed is there also.. good luck

majinx4

Do you think i could just swap my head w/ a JDM D15 Vtec head? would that be a lil cheaper or about the same price as an engine swap?

JDM_SOHC

yeah u could do that... that would work fine, u'd just have to run ur VTEC wires which isnt hard at all.. You'll need some factory Honda Pins for the ECU an about 4 foot of blue an red speaker wires... "colors dont matter i just did'm like that to make it easier an so i kno what was what"... But you could even swap a D16Y8 or Z6 head onto ur car.. Y8=96-00 EX Z6=92-95 EX but both would work fine an you'll probably have better luck finding a z6 or y8 head than a d15b head... But yeah any vtec head would work.... And for the wiring I could email u the diagram of what is what an such, or you could just search on here an find it...

majinx4

Aw, Dude that would be great, my email is magicbrianx4@yahoo.com. Thx!!

JDM_SOHC

Ight I sent you the link of everything you should need wiring wise, anything else you are trying to figure out...??

SVOboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">Sounds kinda like the VX VTEC-E way of working... 12 valves until VTEC hits then the others open up... My friend has that on his VX hatchie, an it blows ***... Probably one of the slowest single cams i've ever raced before... I'd say http://www.jdmaddiction.com get urself a D15B thats what I have an I got it for 500 bucks cant beat that... If your looking for more power, your gonna have to spend more money obviously, but if you just want something decent, with availability to be a lot faster than it is stock, id say get the JDM sohc like I did.. I was impressed at how it responded to bolt ons an I dust plenty of cars around here so speed is there also.. good luck </TD></TR></TABLE>

I wish you knew what you were talking about...Unfortunately, you do not.

The 3 stage is the obd2 jdm cross between the d15z1 (vtec-e) and d15b vtec engine. It gets 130 hp like the jdm vtec but also can get 45-50+ on the highway or easy driving because of the vtec-e capability.

schardbody

the d15b vtec head is the same as the z6 head, the only differance is minor changes to the cam, and i mean minor. you will also need a P28 ecu, etc... just search mini-me. and the 3stage vtec is differant than the vx vtec-e. its 12v to 3000 rpm 16valve low cam lobes to 6000rpm then vtec high lobes after 6000rpm. the vx only uses 12valve until 2400-3000rpm then switches to 16v, its still only a 16lobe cam.

JDM_SOHC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SVOboy &raquo;</TD></TR><TR><TD CLASS="quote">

I wish you knew what you were talking about...Unfortunately, you do not.

The 3 stage is the obd2 jdm cross between the d15z1 (vtec-e) and d15b vtec engine. It gets 130 hp like the jdm vtec but also can get 45-50+ on the highway or easy driving because of the vtec-e capability.</TD></TR></TABLE>

I didnt say I knew what 3 stage meant, oh intelligent one. I said the way it works sounded "SIMILAR" to the way one of my friends works. Dont try to flame people just because you believe your opionion/facts are better than theirs. Unfortunately you've not quite inherited the ability to be a discusser/helper but more likely the lines of an *******/degenerate. Sorry to hear you're so poorly desized in you choices of lending a helping hand, good day.

SVOboy

Well, for thinking it's similar and not knowing what it really is, you sure led him down a path that was totally different from his intended one.

You should at least attempt to make it clear if you don't know what something really is and you're just offering a guess.

JDM_SOHC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SVOboy &raquo;</TD></TR><TR><TD CLASS="quote">Well, for thinking it's similar and not knowing what it really is, you sure led him down a path that was totally different from his intended one.

You should at least attempt to make it clear if you don't know what something really is and you're just offering a guess.</TD></TR></TABLE>

My inquisition of it being "similar" to a friends states clearly that I dont know what it is, I just know my friends car works somewhat like that. I was just plainly saying that it's kinda rude to degrade somebody just trying to hint some evidence into the picture.

SVOboy

I wasn't degrading you, just saying you didn't know what the 3 stage was and that it was unfortunate the OP had his opinion shifted from that (great engine) to the regular old jdm d15b vtec (not so great).

Bense

the only real advantage that this has over a hx conversion is like 3000-4500rpm midrange. Honda didn't make this for long because they realized it wasn't really necessary.

3stage is too complex to make and the gains are minimal, that's why the accord ex 94-02, civic hx, civic hx/ex 01-05, fit vtec all use the same 12/16valve design for vtec.

JDM_SOHC

i figured maybe by throwin my 2 cents out there someone else would have picked up on it an taught me some too.. that's all im sayin, no need to bash just for statin an opinion, but i'd appreciate it if you could include me in on what exactly makes stage 3 vtec better than the jdm single cam??

schardbody

3 stage vtec is only better because it only runs 12valves until the first vtec solenoid kicks in, giving better fuel ecomomy as well as off idle torque. after 3000rpm they are identical.

JDM_SOHC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by schardbody &raquo;</TD></TR><TR><TD CLASS="quote">3 stage vtec is only better because it only runs 12valves until the first vtec solenoid kicks in, giving better fuel ecomomy as well as off idle torque. after 3000rpm they are identical.</TD></TR></TABLE>

so un-economically is my motor better power wise..?? it seems like the VTEC-E is only ever messed with for economical reasons, not many people down here in South FLA have VTEC-E's as swapped engines.. an also, didnt they only come sohc..??

schardbody

dude you are way to confused for me. the 3stage just combines vtec-e w/ conventional vtec. so you get lean burn 12valve mode below 3000rpm and regular non vtec 16valve mode from 3000-5600 then regular vtec high cam from 5700up to 7200rpm. so you get the best of everything. power wise its identical to a z6 or zc sohc vtec, and the JDM d15b vtec.

dpkelly

Everyone has forgotten how expensive the O2 sensor is for the vtec-e engine. The '92 vx civic uses a much more expensive O2 sensor than the other engine types of the same vintage. It is several hundred dollars.

CoffeeBurner

I'm hoping to do the 3 stage Vtec conversion to my 95 Sol sometime in the future...couple things I've learned....

vtec "E"... that second E stands for ecomony, all about upping the MPG

the 3 stage is a combination of the vtec E and regular vtec... so you get that rare combination of good mileage and 130 or so HP

Bense

typing a huge write up about this, give me a little while

dpkelly

Basically going from 8 valves to 16 valves on the old VTEC-E increases the size of the valve. In fact, the new Honda Fit uses this technology along with roller style rocker arms.

brmiddle

btw, the main reason a vx is soo slow is the nice long gears in the tranny. it's an economy car...wow, most hondas are as a matter of fact.

schardbody

basically bense spoke of the obd0 gas station passer byer. move to obd1 and thats where vtec e came in, 12valve normal operation for low rpm cruising efficiency, w/ low rpm geared trans and ultra light chassis made more MPG than the older HF, but still not fast enough for most. thats where the vtec e kicks in the other 4 intake valves and zip goes the motor into another "Better" powerband. low sales seize the building of the z1 after 95 so they came up w/ the HX D16y5, same consept just more power, in J-land the Y5 equivelant was the obd2 "3stage" vtec. hmmm, everything is better in J-land. basically you get the low rpm MPG, tranny geared for frillful driving, and then when the foot gets heavy and the RPM soar the regular vtec takes over, wow, whats not too love??? HP equivalent to any other Dseries motor, plus HF mpg. well, im not a fan of the 3stage just because of tuning and parts reasons, but it really is the best designed honda motor ever built IMO. "bense" your up.

Bense

Here's the deal. Anyone correct me if I'm wrong, although I doubt I am (not to sound arrogant, just that I have given this a lot of thought.


Most of our honda motors have 4 valves per cylinder. Two intake valves and two exhaust valves. VTEC, by design serves one purpose and only one purpose, that is having two engine profiles for the cylinder head.

You have an entire rpm range, and engines by design have an area where they make the most torque.

Shift the torque curve into the higher rpms and you lose power in the lower rpms. However this makes the car accelerate faster, because we take it to redline, shift and take it to redline again (keeping it in the higher rpms).

Shift the torque curve to the lower rpms and you get more grunt off the line, but the engine chokes when it gets in the higher rpms.

The solution is put the peak torque right in the middle of the rpm range. That is, for non-vtec motors. However, honda had a solution. Since it was the camshaft profile that dictated where the engine made it's peak torque, they said "hey, lets figure out a way to have TWO profiles!!!" "This will allow us to give it cam profile that gives us low end grunt in the lower rpms, and high-rpm screaming horsepower in the higher rpms!" Oh the excitement of the engineers when they created it, and oh the excitement of the stockholders once sales shot up.

There are two ways of doing this. The first idea was to use one camshaft spec (lobe) that both of the valves followed in the low rpms. Then switch to a larger (high-rpm optimized) camshaft lobe for the higher rpms. This is what we know as Regular VTEC.

Now lets take a back to 1988 (I don't know much about the 84-87 crx hf) but the CRX HF was honda's fuel sipper car. It was a d15, but it only had a 8 valve head (2valves per cylinder) It also used roller rockers because they're more efficient. Now, realize that it takes energy to open a valve (depressing that valve spring, etc.) So if this is a fuel sipping car, the people that are going to be buying it are going to be concerned with paying for gas, so obviously they're not going trying to race it, so they're not going to take it to the high RPMs (oh the irony of this with young males trying to make these hondas fast in the later years) The solution being, only use 8valves because in low rpms, the car doesn't NEED that much intake charge, because the engine isn't pulling air in as fast as it would at 7000rpm. So there you have it, 8 valve head + roller rockers + tranny geared for low rpms = fuel sipper (kinda like your mom huffin' gas)

As time progressed, people complained that the HF was too slow, so honda came up with another idea for having two engine profiles. A 16valve engine that disabled one of the two intake valves (per cylinder) in the lower RPMs. This allowed it to have the benefit of less air being drawn in, more efficiency, as well as a unique "swirl" in the combustion chamber because that one operating valve is in the "corner" The vtec-e design also utilized roller rockers for more efficency.

So on this vtec-e motor, the torque starts to drop as one intake valve isn't allowing enough cfm that the higher rpms need. So where 1valve drops off, the 2nd valve is engaged to keep the engine from choking. So basically the rpm range is now broader than a 8valve design. This is how the d15z1 gave us 92hp instead of the 70ish hp that the HF offered. However, the ports on the d15z1 head are small, so it loses power in the higher rpms. Not only are the ports small, but the valves are small due to the uniquely shaped combustion chamber. Without getting too in depth (although I think it's too late for that) The d15z1 makes power in the low rpm, and the midrange, but loses in the high rpms.

Now obviously, it would be ideal if the d15z1 had a 3rd stage like the d16z6, and this is exactly what the 3-stage d15b is, the two stages of the d15z1, but with also a wild lobe that both of the valves follow. However, it has to use larger ports/valves to give it the 130hp or whatever it makes.

Now here's where my project shines. the vtec-e design = 1 intake valve in low rpms, 2 intake valves in higher rpms. Why not give that head larger ports and larger valves like a d16z6/d16y8. Okay, done. We'll put it in a 96-00 hx and call it a d16y5. Okay so now we have a large port / large valve vtec-e head with the beloved roller rockers. Okay, so lets get a custom cam with a HUGGGEEEE lobe. Not to worry about wearing out the rockers with the huge lobes, cause we got roller rockers So okay, custom cam from crower. Now with that large lobe, we simply raise the vtec engagement (stock is near 2800) Because it will open the single valve further and for a greater duration. Yes we may lose a few mpgs here (who cares, it will get at least 35-40 anyways) But we will gain a lot of power in the higher rpms. Midrange won't be as good as a 3stage could be. But again, the difference will be so minute. Another issue of having a huge cam is usually the choppy intake. Well, we'll just cut that intake charge in half by only opening 1valve. No big deal cause we have vtec to work for us!

So there you have it. Basically, just shift more. higher rpms when you're getting on it. lower rpms when you're cruising.

termi

to the guy that started this thread....
im not sure what youre budget is exactly (prolly very low as you mentioned) but seriously. D15b7 is simply an *** engine. I drive one now and then in my coupe and I have trouble making it up certan hills. This engine is something you dont want to put money into. Save up, buy a helms and attempt a b16 engine swap or somehting. The way I see it, any money put into a b7 is wasted money. The decision, however, is yours.