believer

I purchased a d15b vtec-e to replace my d15z1. My goal was to achieve at least thet same gas mileage if not better since the d15b has 40K miles as opposed to the d15z1 with 258K.

I swapped it out but the d15b sucks on gas. I'm getting 32mpg versus the 40+ I used to get on the d15z1.

I'm stuck with the motor so I was wondering if I could swap out parts from the d15z1 into the d15b to achieve the same gas mileage as before or is it a lost cause.

Thanx in advance for your help.

Car:
94 Civic VX

Relic1

which ECU are you using?
which exhaust?
cat?
getting any CELs?

johnnylaw

dude if it was getting 40mpg then why change? thats awesome and i wouldnt imagine that you could get much better unless you went with a hybrid car

Relic1

because the VX is capabable of higher numbers than that, and 258k is a good number of miles.

believer

I used everything original on the car:
- P07 ECU
- Same cat
- Same exhaust, it bolted on real easy

And right now I am getting a CEL. Its throwing a code 07 - TPS voltage signal low. But I already replaced it and it's doing the same thing.


Car:
94 Civic vx

Relic1

throwing that CEL will make you run in limp home mode which will get really poor mileage.

troubleshoot that, fix it, reset the ECU and your mileage will be back to where it should be.

93CX

Sounds like you replaced a d15z1 vx motor with a JDM D15B vtec motor. No suprise you lost mileage, the D15B motor is much stronger. I would look into a P28 ecu because it might still be trying to engage 3 stage vx vtec which you dont want.

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93CX &raquo;</TD></TR><TR><TD CLASS="quote">Sounds like you replaced a d15z1 vx motor with a JDM D15B vtec motor. No suprise you lost mileage, the D15B motor is much stronger. I would look into a P28 ecu because it might still be trying to engage 3 stage vx vtec which you dont want.</TD></TR></TABLE>
I just learned this myself.... there were actually three different D15B engines produced. One is the 130hp P08 driven (much like our D16Z6/P28). The other is a dual VTEC setup (two VTEC solinoids) in the later civics, and last but not least was the VTEC-E version that believer is talking about. It's the D15B block with everything else from the VX(D15Z1/P07)

BTW the VX has a normal VTEC setup, it's not a 3-stage.

believer

Relic1 is correct. I've just learned the same thing. And that is my case.

I'm currently troubleshooting the TPS (voltage signal) and after that's fixed are there any other parts I could switch over like the tb from d15z1?

Relic1

the TB should be same from the D15B VTEC-E to the D15Z1. So there is no need to switch.
From what I can tell the D15B you have has all the Z1 parts so everything should be identical.

here is someone else that's playing with a D15B VTEC-E swap. https://honda-tech.com/zerothread?id=1371838

Jizzmaster Zero

The D15b is not a vtec-e engine, it's just your regular vtec. Not built for economy.

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jizzmaster Zero &raquo;</TD></TR><TR><TD CLASS="quote">The D15b is not a vtec-e engine, it's just your regular vtec. Not built for economy.</TD></TR></TABLE>
reading &gt; you
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">I just learned this myself.... there were actually three different D15B engines produced. One is the 130hp P08 driven (much like our D16Z6/P28). The other is a dual VTEC setup (two VTEC solinoids) in the later civics, and last but not least was the VTEC-E version that believer is talking about. It's the D15B block with everything else from the VX(D15Z1/P07)</TD></TR></TABLE>

Jizzmaster Zero

Nah

der Weinerschnitzel

Well, I'm not sure if I'm counting funny tonight, but I put the count at four, possibly five different D15B engines. It's kind of like one of those 'ZC' things.
1) SOHC D15B VTEC-E (92-95 Civic ETi) - 94HP
2) SOHC D15B non-VTEC carbed (92-95 Civic MX) - 100HP
3) SOHC D15B VTEC (97- Domani) - 105HP
4) SOHC D15B VTEC (92-95 Civic VTi, 96-00 Civic Vi)* - 130HP

*I'm not sure whether the 92-95 VTi had the three stage VTEC, but if it doesn't have it then that would be five types of D15B's ; )

I'm in the same position...swapping in a D15B (my D16A6 died a horrible death) to get both power and fuel economy. I think it is worth a look to see if you have two or three stage VTEC. Three would be nice (both the economy of the -E 12-valve operation as well as the 'wild' 130HP from a 1.5L), and I'm hoping that's the case for both of us. My engine gets here next week.

Relic1

here is some really good info about the D15B engine... http://asia.vtec.net/article/d15b/

D16z6BoostedEK

y does it matter there just sohc

believer

So i tried swapping the tb's but no luck because the bolt patters are different.

I'm just trying to get the best mpg but I guess i'm stuck with what I have.

thanx all.

believer

i swapped out the air intakes (d15z1 and d15b vtec-e) and here are the results:
- check engine light went away
- 3 mpg more
- the car hesitates when i give it gas initially but eventually picks up

i think i'm gonna slap my old d15z1 back in.

HabitualOffender

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by believer &raquo;</TD></TR><TR><TD CLASS="quote">- the car hesitates when i give it gas initially but eventually picks up...</TD></TR></TABLE>

Has or Does anyone experience this symptom with the stock D15z1? Just picked up a freshly tuned 92 VX H/B w/ 96,000 miles. ****, motor is still new, but I have random hesitation under 2.5K. It pulls real hard when it catches, but stammers bad when it dosen't. No codes, CLEAN car, one owner. VERY HAPPY OTHERWISE!Any ideas/recommendations?

brickinthewall

Did you get it fixed?

brickinthewall

Looking at doing the same thing you did.
What was your final result?
Did you get near 55mpg?

deschlong

iTrader: (8)

I don't think the users 'believer' or 'HabitualOffender' have been to this site in ~ 9 years. I doubt you're going to get an answer from them.

If you have questions I suggest you start a new thread.

/Old thread closed.