SiMateoAko

As some of you may remember, my big schtick is gas mileage. I want my car to have efficient gas mileage, etc. etc. My whole point of owning a honda is to get good gas mielage. Any modifications I make will be to accomplish this goal.

So, I was reading today and I read that the D15B VTEC actually gets like 50mpg on the highway, and between 37-42 on the street. All of this with 128 hp. I couldn't believe it.

So, my engine is on it's way out. I probably screwed it over after my overheating incident a few months ago. While it only has 146k miles on it (an 89) it might just be more wise for me to swap it out.

So now I'm starting to consider the D15B VTEC.

Who has it? Pros/cons? Do you really get the level of gas mileage that I've read about?

How much can I expect to pay for a mechanic to do the swap? What else do I need besides the motor/ECU? Will I need a new tranny as well?

FYI, I have a 1989 Civic LX.

And yes, I've already performed a search, but couldn't find exactly the info I wanted.

Magick211

You can use your current tranny. If you're car is already mpfi than your ecu will work and you can engage vtec with a rpm activated switch (however your best bet would be to upgrade to obd1 ecu)


Not sure what kinda labor prices a mechanic would give you since ive always done my swaps myself

knwldge54

One thing to consider is that the JDM D15B is an OBD-1 engine. You'll need a harness or you'll have to do a whole lot of wiring.

Timmah!!

Convert to OBD1 and run a stock P28 ECU... Then just keep your foot off the gas.

slywfbpsi

I converted to odb1 via a conversion harness and a p08 ecu with an si tranny on my d15b. I paid the installer 400 + a gsr armrest. I used to get 284 a tank when I had a bad o2 sensor. Now, I only get 234-254 a tank.

SVOboy

To use the d15b vtec most efficiently you have to make sure you keep the rpms down so that it will only run on 12 valves (vtec-e). It is a good good engine, and I have been thinking about it myself. As for the fuel efficiency, it is best in a light car, and since I can't find an exact weight on yours, it will just suffice to say that a crx hf would be much better cuz they only weight 1819 stock, but you can always strip yours for better gas preformance.

d15civ

these engines are horrible on gas.
even with shifting at 4k each time, you'll still only get around 300kms/tank.
fun little engines though.

Chronicsinners

I will try and throw my two cents in about my swap:

Firstly if you are considering a d15b go with a d16z6 instead, especially if you arent familiar with cars that much. (It is much easier to have a service manual to turn to when things go sour)

Secondly run OBD1, get a harness adapter and a p28 ecu. And if you arent competent doing the wiring pay someone else to do it.

The cable trans you have now will be ok, so dont worry about picking up a trans with the swap. It isnt necessary and in fact wont work.

The only thing that you need for mounts is to transfer your driver side mount from the old motor to the new one.

As for gas milage last tank i got 38.8 mpg and i generally get about 300-335 miles to the tank. Its good on gas, but you have to make sure that you really lay off it otherwise you get shitty gas milage (obviously)

In retrospect with my swap i probably wouldnt have done the d15b. It is cool to have some oddball jdm motor, but what i should have done was either B18b or d16z6. Thanks for reading...

d15civ

is there any advantages to switching to obd1.
i'm still running obd0.


i kept track off all the mileage and such for about a month, the best i could pull off was 29MPG.

Chronicsinners

The reason that i switched to obd1 is because i was told that the fuel curves are better because the ecu is designed for that particular engine. Personally i think the whole vafc or rpm activated switch idea is mertely a bandaid for running vtec.
My mentality was that i should use the ideal ecu for the motor ie odb1 P08

Jonathan_ED3

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d15civ &raquo;</TD></TR><TR><TD CLASS="quote">these engines are horrible on gas.
even with shifting at 4k each time, you'll still only get around 300kms/tank.
fun little engines though.

</TD></TR></TABLE>

Holy crap.....you're talking like that's a low RPM to shift at.

I generally shift at around 1500-1700 RPM. I found that combined with gently accelerating yields leaps and bounds better gas mileage than any other combo.

To the thread starter, I'd say look for a d16z6. The D15b has different fuel maps than the d16z6, and unless you get the proper ECU to go with that d15b, a p28 (d16z6) ecu isn't going to be proper for that d15.

Since you're all about gas mileage, something I'm also interested in, I'd say get a d16z6, get a p28 since that's the proper ECU for the engine, and convert to OBDI.

I've also got an '89 LX and I'm currently swapping in a '92 D16z6. I bought it locally for like $225, and it's only got 121K miles on it. Good deals are out there...just look for one!

dr_latino999

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">I've also got an '89 LX and I'm currently swapping in a '92 D16z6. I bought it locally for like $225, and it's only got 121K miles on it. Good deals are out there...just look for one! </TD></TR></TABLE> 1990 LX and swapping a D16Z6 into, and I got mine for $200

Voodooboy520

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">
I generally shift at around 1500-1700 RPM. I found that combined with gently accelerating yields leaps and bounds better gas mileage than any other combo.
</TD></TR></TABLE>

How do you make it up hills? I drive my friends 91 accord, and it wont go anywhere unless you shift at 2500 rpm

djsire

if i try to shift at 1700. my clutch wont grab!!!! and when it does ill bog out and shut off the car

Jonathan_ED3

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Voodooboy520 &raquo;</TD></TR><TR><TD CLASS="quote">

How do you make it up hills? I drive my friends 91 accord, and it wont go anywhere unless you shift at 2500 rpm</TD></TR></TABLE>

Come on man. You're taking me too literally. If I'm accelerating up a hill from a redlight, of course I won't shift at 1500.

If I'm a flat road under normal driving circumstances, I shift at around 1500 rpm.

To the last poster, why would your clutch not grab at 1700 rpm????

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dr_latino999 &raquo;</TD></TR><TR><TD CLASS="quote"> 1990 LX and swapping a D16Z6 into, and I got mine for $200 </TD></TR></TABLE>

I thought you ended up with a HB? Or was that another member? If it was you, glad to see you're back in the sedan squad

SVOboy

Toyotas I have driven will shift at 1700, but won't cruise around less than 1250. And my cousin can drive his dsm 5 speed at 25 mph giving like 1100 rpms just fine. Crazy stuff.

SiMateoAko

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chronicsinners &raquo;</TD></TR><TR><TD CLASS="quote">I will try and throw my two cents in about my swap:

Firstly if you are considering a d15b go with a d16z6 instead, especially if you arent familiar with cars that much. (It is much easier to have a service manual to turn to when things go sour)

Secondly run OBD1, get a harness adapter and a p28 ecu. And if you arent competent doing the wiring pay someone else to do it.

The cable trans you have now will be ok, so dont worry about picking up a trans with the swap. It isnt necessary and in fact wont work.

The only thing that you need for mounts is to transfer your driver side mount from the old motor to the new one.

As for gas milage last tank i got 38.8 mpg and i generally get about 300-335 miles to the tank. Its good on gas, but you have to make sure that you really lay off it otherwise you get shitty gas milage (obviously)

In retrospect with my swap i probably wouldnt have done the d15b. It is cool to have some oddball jdm motor, but what i should have done was either B18b or d16z6. Thanks for reading...</TD></TR></TABLE>

I was actually planning on getting a p08 ECU for it if I do get it. I found a good deal on the ECU. if not I can get one from hmo for $100. Right now I get abour 34 mpg in the city. When I drove down to CA a few months ago I got 45mpg on the way down. On the way back up I blew the head gasket, overheated WAAAY past the red mark, etc. I havn't gotten more than 35mpg since then. Hence I think that something is wrong with the motor.

The only reason I am considering the D15B VTEC is because it offers superior gas mileage (under the right conditions) and tons of power. It would be nice to have a car that can accelerate like a mad man, and yet get around 40 mpg around the city. I'm sure if I keep my tranny that can only help with the mileage (as opposed to getting a SI tranny).

I've heard that in order for this thing to get the best mileage (Ie, "lean burn" mode or something like that) it has to stay under 3k RPM. With this much horse power, I'm guessing that wouldn't be too much of a problem. I really have no plan to speed like a madman all over Salt Lake City (especially since the cops here are so happy to ticket you).

So has anyone experienced the 50mpg this thing is claiming? Assume I use the p08 ECU, DX Tranny, and convert to ODB1. Does higher than normal gas mileage seem likely?

i'm plannin an engine swap sometime this year ANYWAY. It would probably cost me the same to have the stock engine dropped in, so I figure I might as well take advantage of the opportunity.

SVOboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiMateoAko &raquo;</TD></TR><TR><TD CLASS="quote">
I've heard that in order for this thing to get the best mileage (Ie, "lean burn" mode or something like that) it has to stay under 3k RPM. </TD></TR></TABLE>
The lean burn that you are thinking about is called vtec-e. The neat thing about the d15b vtec in my opinion is that it is three stages, meaning vtec-e (which runs at 12 instead of 16 valves), normal, and then vtec.
So really, if you can keep it running 12 most of the time (low rpms), that will rock for gas mileage. And the longer gearing is always the best. You could prolly even looking into swapping your fifth gear into something even longer so that you'll cruise in 5th at lower rpms.

slywfbpsi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SVOboy &raquo;</TD></TR><TR><TD CLASS="quote">
The lean burn that you are thinking about is called vtec-e. The neat thing about the d15b vtec in my opinion is that it is three stages, meaning vtec-e (which runs at 12 instead of 16 valves), normal, and then vtec.
So really, if you can keep it running 12 most of the time (low rpms), that will rock for gas mileage. And the longer gearing is always the best. You could prolly even looking into swapping your fifth gear into something even longer so that you'll cruise in 5th at lower rpms.</TD></TR></TABLE>vtec-e is only on the 96-98 vti's, or jdm d15b's. The 92-95 vti jdm d15b have regular vtec, which is what is normally sold from different vendors like hmo.

SiMateoAko

How is the 12 valve any different than the 12 valve motor I have now? It seems that vtec-e claims better gas mileage than the d15b2 stock motor I'm running.

Please don't hate if my questions are stupid. I'm eagerly trying to learn.

I've thought about building a hyrbid tranny in the past. Maybe I can get a 89 DX tranny and add the 89HF 5th gear in there before I end up doing the swap. Could provide the right stuff to get me a kick *** car. Fuel efficient, but super kick *** over 3000 RPM.

Timmah!!

Umm... my D15b isnt a 3 stage vtec.... its just like a Z6

SiMateoAko

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slywfbpsi &raquo;</TD></TR><TR><TD CLASS="quote">vtec-e is only on the 96-98 vti's, or jdm d15b's. The 92-95 vti jdm d15b have regular vtec, which is what is normally sold from different vendors like hmo.</TD></TR></TABLE>

So I guess the question is, where do I find a jdm d15b vtec?

d15civ

they started doing the 3stage vtec thing halfway thru 95. at least thats what i read on temple of vtec. then they came in 96 in every vti. in 95 it was kind of a mismatch thing. some did, some didnt.

SiMateoAko

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d15civ &raquo;</TD></TR><TR><TD CLASS="quote">they started doing the 3stage vtec thing halfway thru 95. at least thats what i read on temple of vtec. then they came in 96 in every vti. in 95 it was kind of a mismatch thing. some did, some didnt.</TD></TR></TABLE>

Or if Gas Mileage is my game, would Ijust be better off with an engine from a Civic VX? I would have no idea where/how to find one, but I'm sure it's possible.

SVOboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SiMateoAko &raquo;</TD></TR><TR><TD CLASS="quote">So I guess the question is, where do I find a jdm d15b vtec?</TD></TR></TABLE>

I'm foolish, because when I was thinking and engine swapped I assumed it would be jdm. Sorry about that that slywfbpsi, I have seen people who sell them for 300 bucks or something on this site.

http://hondamarketplace.com/zerothread?id=1270092

Searching for something and found this:
http://auto.howstuffworks.com/....html (haha)
And here is not what I'm looking for (it was a good explanation of vtec in general) but it defends my saying jdm d15b is 3 stage vtec:
http://www.leecao.com/honda/vtec/3stagevtec.html