Honda Car Forum

Like my subject says, I'd like to swap a D15B2 USDM with a D15B JDM
motor. From what little I've found, this JDM motor can go into my 91
Civic DX, but I must use my throttle body, intake and exhaust
manifolds.

All I want is a replacement motor. I don't care about going fast and
furious, I just want to take out my blown original and get my car
back.

There's conflicting info about the D15B that causes me to be a bit
wary, however. Some say it is a VTEC motor with substantially more hp
than my D15B2 (90hp vs 130hp). If it is VTEC, how will my ECU be able
to run this motor. It's also supposedly MPFI, whereas my current
motor is DPFI. These differences are pretty steep in my book and I'm
trying to figure out if these motors are similar enough for a direct
drop-in.

If anyone has any information I'd really appreciate it!

btw - the following link is the company I'm considering buying the
motor from:

http://www.nippon-motors.com/honda.htm

larson.joshua@gmail.com wrote:
> Like my subject says, I'd like to swap a D15B2 USDM with a D15B JDM
> motor. From what little I've found, this JDM motor can go into my 91
> Civic DX, but I must use my throttle body, intake and exhaust
> manifolds.
>
> All I want is a replacement motor. I don't care about going fast and
> furious, I just want to take out my blown original and get my car
> back.
>
> There's conflicting info about the D15B that causes me to be a bit
> wary, however. Some say it is a VTEC motor with substantially more hp
> than my D15B2 (90hp vs 130hp). If it is VTEC, how will my ECU be able
> to run this motor. It's also supposedly MPFI, whereas my current
> motor is DPFI. These differences are pretty steep in my book and I'm
> trying to figure out if these motors are similar enough for a direct
> drop-in.
>
> If anyone has any information I'd really appreciate it!
>
> btw - the following link is the company I'm considering buying the
> motor from:
>
> http://www.nippon-motors.com/honda.htm
>
just call and make sure you order one that's year appropriate if you
want stock replacement. the vtec will disappoint if you're not going to
connect the gear to run it since the cam will be in "low performance"
mode all the time. if you /do/ want to run the vtec, the electrical
conversion is doable with the help of the folks at boomslang, but imo,
it's still non-trivial. but the motor drops right in.

so, just a few questions.

1 - running the vtec is possible, but do you think i'll need a
different ECU?

2 - does the vtec require MPFI?

3 - is converting to MPFI a pain?

4 - so the D15B JDM will drop right in (if i decide on a simple swap),
using my intake, exhaust, throttle body and ECU?

i really appreciate your help!

larson.joshua@gmail.com wrote:
> so, just a few questions.
>
> 1 - running the vtec is possible, but do you think i'll need a
> different ECU?

to do it "properly", yes. there is an aftermarket vtec kit out there
that will allow you to get around that - it will operate a simple vtec
on/off solenoid independent of the ecu based on rpm's, but i've not used
one so can't endorse. i'm also not sure if the odbI ecu's shift their
cam timing around or whether that motor has multiple more than 2 cam
profiles, but if yes to either, factory ecu conversion is the way to go.

>
> 2 - does the vtec require MPFI?

for maximum advantage, yes.

>
> 3 - is converting to MPFI a pain?

yes! the mechanicals are easy - it's the wiring that's the pain. go to
boomslang.com for the least brain damage solution.

it's going to cost you a fair bit more to do the conversion. vtec ecu's
aren't cheap. the conversion wiring kits aren't cheap. the 4pfi
manifolds, throttle bodies, plumbing, etc. aren't cheap, even if you get
them from a junk yard. you'll also be best advised to get the factory
shop manuals for the patient and donor vehicles too.

>
> 4 - so the D15B JDM will drop right in (if i decide on a simple swap),
> using my intake, exhaust, throttle body and ECU?

yes. some of the motors have blanking plugs on some widgets that the
japanese use that we don't, but other than that, they're identical. you
don't mind japanese stickers on your engine do you?

>
> i really appreciate your help!

call your vendor - they'll advise best.

my advice is that if you want this car for transport and it's your daily
driver, just do the straight swap. if this is a second car, it's a
science experiment, you're good at jigsaw puzzles, and you're good with
wiring diagrams, it's fun to go down the 4pfi road.