93 civic si

[EG6ick]

hey guys i've been reading this board since the beginning of this summer, and i guess i should just register and talk to you guys. well my name is Gene and i've had my hatch for a year and a half now. i bought my car in california and drove it to illinois, the car is kinda banged up a little, but i got it for a good price. i experience the best gas mileage when i was cross country driving, i don't think you guys are going to believe me on this, but i got 40mpg. its a stock d16z6 engine, but now i'm looking into buying the vtec-e or the dual vtec motor, if they are the same here (d15b). i've been talking to one of the guys here (Danoronian, sorry if misspelled) in honda-tech and i'm encourage to get the motor soon early next year. i'm new so is there a thread here when i can read up the specs and the people results on the d15b and/or d15z1? i want to hit 50mpg soon cause i usually drive cross country with my friends.

[Danronian]

Glad to see you joined! Welcome to the board!

If you do some searched for d15z1 on here, you'll find lots of info. Probably the most popular swap motor on this board! And I doubt there is any forum where you'll find more vtec-e powered cars than here.

[Matt Timion]

Welcome EG6ick.

both of the engines you speak of have the same code, but the two-stage vtec costs a lot more, and there is not too much documentation on it as it is a JDM engine only. You'll have to get a JDM ECU for it, as well as some extra wiring.

If your main concern is FE, I'd get the d15z1. since your car is already wired for vtec, I believe you'll have to run about 3 or 4 wires to your engine bay to convert it to the p07 ECU. If you use the California p07 ECU, you can save yourself the hassle of getting a 5 wire o2 sensor and running an extra wire for that... but you'll also get a little bit worse FE.

You'll have to wire up the EGR control box, maybe the EGR (does the d16z6 have an EGR?), and that's about it.

Oh, get the Civic VX transmission too if you can. That transmission alone will give you 5mpg with highway driving... and if you're swapping the engine yourself, it's the perfect time.

[pizza dude]

I had a 92 SI and I was gettin 42 mpg, doing it consistantly too! never in vtec though

[EG6ick]

Originally Posted by Matt Timion

Welcome EG6ick.

both of the engines you speak of have the same code, but the two-stage vtec costs a lot more, and there is not too much documentation on it as it is a JDM engine only. You'll have to get a JDM ECU for it, as well as some extra wiring.

If your main concern is FE, I'd get the d15z1. since your car is already wired for vtec, I believe you'll have to run about 3 or 4 wires to your engine bay to convert it to the p07 ECU. If you use the California p07 ECU, you can save yourself the hassle of getting a 5 wire o2 sensor and running an extra wire for that... but you'll also get a little bit worse FE.

You'll have to wire up the EGR control box, maybe the EGR (does the d16z6 have an EGR?), and that's about it.

Oh, get the Civic VX transmission too if you can. That transmission alone will give you 5mpg with highway driving... and if you're swapping the engine yourself, it's the perfect time.

Aren't the cx and the vx tranny have the same ratio? I don't know if my Si is an EGR (I am hoping it does), if not is it a hassle to hook up the EGR box from the vx. Mainly the car is going to be daily driven and will probably have some preformance mods, not too rediculous. I've been seeing gas prices going up and I know its really going to hit $4.00 at least next year summer. So I'm kinda thinking for the future. I'm really looking forward for the swap next year spring or so, and post the mpg... btw how do you guys do the mpg thingy on the bottom of your s/n? Right now I'm reading some VX that TomO posted up. Thanks for the welcoming Welcome! Oh Danronian this is the same guy that pmed about the d15 questions at H-T.

[cfg83]

EG6ick -

Welcome to GS! I don't have anything interesting to say, the other Civic owners are already chiming in .

CarloSW2

[Danronian]

Your d16z6 doesn't have an EGR on it, but I doubt wiring up the "black box" for it should be too hard since it's only two wires. There are some people on here who converted older civics to work with the d15z1, so they should have good info to help you with the wiring too.

[EG6ick]

Well I've been reading the threads here and let me tell you that my eyes hurt from reading through all the info. I have the jest of things about d15z1 engines, but from the looks of almost all the swaps with the engine in, it seems like no one is running A/C in there cars. I kinda want to keep my A/C cause summers here get really hot. As for the block plate on the front grill is that a good upgrade once i get a d15z1? Also would it wise to replace the exhaust manifold on that engine or would i just loose precisious mpg (I read somewhere here in the forum, that the VX manifold is specially made for this engine)? Thanks in advance for the noobish questions!

[Danronian]

Originally Posted by EG6ick

Well I've been reading the threads here and let me tell you that my eyes hurt from reading through all the info. I have the jest of things about d15z1 engines, but from the looks of almost all the swaps with the engine in, it seems like no one is running A/C in there cars. I kinda want to keep my A/C cause summers here get really hot. As for the block plate on the front grill is that a good upgrade once i get a d15z1? Also would it wise to replace the exhaust manifold on that engine or would i just loose precisious mpg (I read somewhere here in the forum, that the VX manifold is specially made for this engine)? Thanks in advance for the noobish questions!

Some VXs actually did come with a/c from the factory, so the A/c in your current Si should work just fine with the VX motor. Just leave the system in-tact and bolt it onto the motor once it's in the engine bay.

For the grill block, since you are keeping a/c, you probably only want to block a little of the grill. I've heard the VX factory grill block only came on the non-A/c models, which does make sense since the a/c condensor NEEDS airflow in order to work. You could try blocking the center of the grill opening a bit just to decrease the amount of airflow through it.

As for the exhaust manifold, I think it was designed with the cat so close to the motor to keep the engine warm, and to keep the wideband warm and reading correctly, but I think you could get away with using the normal vtec manifold too. The wideband should work fine in the o2 hole on that manifold too.