SI Engine Swap into Sedan

[blade34609]

Hi,

I have the 1990 Civic LX sedan with the 1.5 liter 92hp engine.
I am planning to save up for a 1.6 liter engine that came with the SI 108hp. I cant really afford a ZC or B16 even though they would be nice.
But also I want a engine that i can bolt directly into my civic with relaitvely no problems.
If I went to scrapyard and got a Si engine out of the HB would it bolt directly in?
Will I have rewire the ECU?
ALso can I keep my LX 5 speed tranny or should I use a SI tranny?

thanks,
Owen

[sastanley]

Yes - an Si engine (d16a6) or a ZC will bolt in directly...The b16a requires a mount kit ($3-400)

The LX sedan has the same DPFI system as the DX sedan and the DX & STD Civics. You will need to convert to MPFI for any motor above the 1.5L.

Personally, I think the HP to $$ ratio is best with a ZC....although I certainly can understand not being able to afford one. I saved for over a year, and spent another year buying parts a little at a time to rebuild my ZC.

You probably would have better luck finding an Si engine (d16a6) from somone else (think partstrader.com or ebay) that has done a ZC or b16 swap in their Si. Si's are pretty rare at junkyards these days.

Also, on the tranny - yes you can keep the LX tranny, however, it has a different final drive then the Si and is geared for better fuel economy (but same actual gears as an Si) so you'll sacrifice some acceleration characteristics. The only exception to this is a b16a requires a b-series tranny (more $$). The d15b2 (92HP), d16a6 (108HP) and ZC (130HP) are all d-series motors, so any d-series tranny (L3) will bolt to them. Again, there are issues with axles, etc. if you had a ZC tranny, so most people pick the Si tranny.

Personally, I think you can get a ZC motor, and bolt its 130 HP to your LX tranny, for about the same price as an Si motor and Si tranny.

You'll need to REPLACE your ECU, with an Si ECU (PM-6) or if you get a ZC, either a ZC ECU (PM-7) or an 89 Integra 5-speed (PG-7) also works. Hey other 4G peeps, did I get those codes right? - I have heard of people running a ZC with a PM-6 ECU, but it is designed to run a SOHC motor, so I wouldn't personally bother..you can probably find an Integra ECU for the same price as an Si ECU.

Check out this reference for more info - it is where I started a couple of years ago when I was in your shoes..I ultimately chose a ZC w/ Si tranny and Zdyne ECU which I bought as a package deal from another guy on this board & then completely rebuilt the engine. - http://hybrid2.honda-perf.org/tech/4gtech.html

[amy@af]

to be honest....you can just upgrade from DPFI to MPFI and it will be just as good with half the effort and $$$ of getting a 1.6.....you could also swap in the Si/ EX tranny but it isn't required

[nemo_wolf]

since everyone obviously refers to the DOHC zc when they say "ZC" ... i might add that you can get the SOHC ZC for a bit less then you can the Si engine im sure ... and it puts out about the same HP with maybe a bit more torque ??? there is hardly any info on the net on the SOHC so its hard to be sure ... i know the compression is a bit higher but other then that ... anyways ...


i think i got my SOHC ZC for a little over 200 or so ... so i would check into maybe picking one of those up.

[4-Door Flunky]

As always, it depends on how you want to use your car.
If you want to autocross, or race from stoplight to stoplight, use the SI tranny.
If you're not into getting lots of tickets and tearing up equipment (like me), and just want to do hundreds of thousands of miles at highway speeds, 80MPH interstate cruises (while getting good MPG) stick with the LX tranny. It was made to operate at higher speeds with lower RPMs for better mileage.
Flunky

[91civicDXdude]

I race from stoplight to stoplight every day and im using a DX tranny :P

[sastanley]

Originally posted by 91civicDXdude
I race from stoplight to stoplight every day and im using a DX tranny :P

LOL - you'd prolly beat a few more cars with an Si tranny

[4-Door Flunky]

Having said that, I do indeed wind it up to 6 grand in every gear at every light on my way to the interstate...
Flunky

[blade34609]

Hi,

Aiight so one of you said that I could just convert it MPFI and save some money? Is it easier than swapping an engine? Stupid Question... lol.
I will need a SI intake manifold, SI ECU, and SI distributor right?
How long will it take to complete?
How much hp gains will i see?
Better acceleration?
Will I get the 108hp that the Si engine puts out?
Also will my short ram intake still fit on the conversion?
Can I keep my LX tranny for this conversion or would having the SI be better?

Thanks,
Owen

[GScivic7]

replacing the lx tranny with an si tranny would benefit you even if you didn't do the MPFI conversion cause it has a shorter final. Don't expect huge gains, but you'll definetely see the difference. It's not going to give you the 108 hp, but you'll be close, and i don't think you're intake will work with it

[91civicDXdude]

LOL - you'd prolly beat a few more cars with an Si tranny

sure but i'll beat your car with my DX tranny :P

[sastanley]

Originally posted by 91civicDXdude
sure but i'll beat your car with my DX tranny :P

\

Yup currently you would. I ran it at the track last year and it ran 18.08 @ 74

As for the intake - i think it should work. I have a CAI on my DPFI throttle body that was made for an d16a6. Actually, my intake rubs my strut bar a little bit, and I think once I have the MPFI setup with the ZC in there, it should sit a little lower and stob rubbing

[91civicDXdude]

heh

as for intakes, most honda intakes are made the same.. i have a 99-00 Si intake on my 91, had to move the battery for it to fit, but as far as lengthwise, and fitting into the fender hole, it fit fine.

[D15Bitch]

I had the D15B3 motor (single carb, South Africa, but exactly the same horsepower as the D15B2, basically our version of your DX) in my sedan for 13 years, took it out when it had 225 000 miles on it.

I planted in a ZC SOHC dual Carb from a '93 Tegra into my sedan. The HP reading were 108 with a Cat converter. Guess what? No cat converter, so my ZC pushes 112HP. The motor is stock for now, I only have a CAI and a brospeed freeflow exhaust system.

From 92HP to 112HP and 121 torque to 139 torque is a pleasure. I get challenged quite often, and I beat most of them. With a stock DX tranny...