eddie7978

ive been doing a lot of research on how to get my 2000 obd2? civic to pass emissions with a 98+ jdm b18c r motor from hmotors
my main question is will it run rich or lean with the usdm b18c5 ecu because i know the compression is different so the mapping must be different from the ecus
i don't want to have cel on and in trying to do this the right way
i know i'm going to need the usdm manifold, oil pump with ckf sensor and gear, the vtec solinoid and purge valve and ecu of coarse and i was talking to somone about putting a dummy chip for the immobilizer, but with all of that out of the way i just want it to run right.. or will i have to get it tuned because of the different ecu? will that still be safe for the obd2 emissions testing?

JRCivic1

The compression difference is only .4 of a full point... 10.6 USDM to 11.0 JDM. I would suggest a simple adjustable FPR and increase the fuel pressure 4 psi static.

eddie7978

ok so the jdm motor with the usdm ecu would cause it to run lean (too much air) therefore i should get a fuel pressure regulator to give it more fuel to even it out.. so is that somthing i can do myself with a simple air fuel ratio gauge?

would the .4 throw a lean code? or cause it to not run right?

JRCivic1

AFR gauge will not be helpful on a stock ECU. It will not likely throw a lean code, but understand that prolonged lean full throttle operation is dangerous to the engine. Yes, the fuel pressure regulator will be able to add fuel so that the full throttle operation is safe. Ideally, you will want to go to a dyno and verify the A/F under wide open throttle.

eddie7978

ok so i will need to get it tuned but can that be done on a usdm itr ecu?
and still be emission scan tool friendly?

JRCivic1

Yes.

eddie7978

is the 96,97 jdm itr 11.1 ? or only the 98+?

eddie7978

should i just buy a b18c5 or buy a 98+ b18c type r and converting it to usdm specs

pros of usdm
i dont have to convert anything to usdm specs
have all vin tags
have correct ecu intake manifold vtec solinoid purge valve knock sensor oil pump ect

cons higher mileage 4.4 final drive

pros of jdm
higher compression
4.7 final drive
lower milage
better exhaust manifold
cons
have to buy usdm intake manifold vtec solinoid purge valve knock sensor ecu ect
might not run right with 11.1 compression on usdm ecu

Matt8314

Where are you trying to get this to pass? California? If so, the fact that you have possibly put an older motor into a newer car could cause you more problems than anything else.

As for the ECU, I wouldn't worry too much about the AFR. You would get better detonation resistance from a richer mixture. But the .4 point increase in compression in the JDM motor is nothing huge. I don't think it will make kichbdifference. If you feel uncomfortable with this, simply use the USDM ECU for smog and swap back to the JDM ECU afterwards.

As for the knock sensor, the JDM motor uses a knock sensor, too.

As for the transmission, keep in mind that only the 1999+ JDM engines had the 4.785 final drive transmissions. The 1996-1998 JDM engines used the same exact transmission as the USDM engines. Also keep in mind that the 4.785 transmission is no different in overall ratio from the 4.4 transmission in fourth and fifth gears. These gears are actually taller in the 4.785 transmission vs the 4.4 transmission (1.034:1 vs 1.107:1 and .787:1 vs .848:1), and the overall ratio comes out pretty much the same. Gears 1-3 have the same ratios in both transmissions, so the 4.785 transmission IS shorter overall. This can help with racing, but will result in a greater gap between third and fourth gears.

eddie7978

do i need the usdm intake manifold to pass inspection with the jdm motor? i know it has the purge valve nipple on the usdm one

eddie7978

is the jdm itr b18c intake manifold the same as the usdm b18c5 intake manifold with the exception of the nipple on the back for the purge valve??
will i throw an evap code with a usdm computer with the jdm manifold??