Ok got some ZC engine questions!

[doug294]

Ok I am so hyped about getting a new engine but not sure if I want to get a new one or rebuild my A6. I found a non-vtec DOHC ZC with 5 speed tranny for $785 shipped. Is this a good deal? Or should I just invest the money in my A6? Also I heard that the D16A6 Si tranny that I already have is better than the ZC tranny. Especially for turbo apps. Is this true? Without the tranny it's $730 shipped. So I don't know. Just let me know what you guys think. Oh also isn't the ZC a direct drop in, like no aftermarket motor mounts needed?

[cyberfelon]

zc tranny has shorter gearing, so i guess it would be better in boosted applications. ive found a zc just long block for 595 here in town so i guess shipped with tranny and such is pretty good price. and yes it is a direct drop in, no mounts or anything, but if you get the zc tranny you will have to go buy driveshafts from an integra, unless it comes with them. i think 84-87 teg shafts are the ones that work.

[sastanley]

Yes..the ZC is a direct drop in.

I'd still get the ZC tranny...you should be able to sell it for way more than the $50 you will save if you don't get it....and $785 shipped with tranny seems very reasonable.

Don't forget to budget roughly $100 for misc. parts once the motor arrives...you should plan to replace the timing belt, water pump, other belts, and possibly some sensors if they are broken...you'll also need a few hoses (radiator, etc..) to make it all fit, and don't forget an ECU. If you can get a ZC ECU great...otherwise, the most common substitute is the US 88-89 Integra ECU.

Edit - And as I come back to clean up my post I see Problem Si has cleared up a few things...I was too lazy to type forever - thanks dude - The ZC has shorter gearing than the Si tranny, but a tall final drive...so for max acceleration, the Si final drive into the ZC tranny case will give you the best acceleration

[Problem_Si]

Two things...

First, you have it backwards cyberfelon. The Zc trans has longer gearing, theoretically making it better for a turbo application. The Stock Si trans is the best trans you can use on a D series or Zc motor.

If you choose to use the Zc trans, you will need 90-93 Integra axles. If you plan to do this, make sure the Zc comes with the trans half-shaft. Im not sure if the integra one will work.

There are two things good about the Zc trans. First, equal length axles is always a good thing. Second, the Zc trans has a taller final drive than the Si final drive. Other than those 2 things, the Si trans is a much better choice. If you want the best of both worlds, take the Si gearing, and put it in the Zc trans case. Then you have good gearing, better final drive, and better traction with equal length axles.

But if you're just looking to put the motor in and drive, or dont have the money to fool with taking transmissions apart or buying new axles....the better choice is the Si trans...hands down.

I've driven both, and can honestly say that the difference is very noticeable, especially on 0-60.

I think $730 shipped is reasonable, for a motor thats not been yet been beaten to shit by some kid in the states. I paid about $800 for my Zc, but that was about 4 years ago, when no one around here really knew about them.

I would seriously think about replacing timing belt/w pump and headgasket before you put the motor in. Yes the motor is probably low mileage, but most of these motors are about 12+ years old. Better to do it now, then to have something happen later. My t belt broke on my Zc last year, luckily no valves or anything else were damaged.

Anyways, good luck.

[Problem_Si]

yes, i believe the bottom rad hose is from an 88-89 integra.

You dont need to get an ecu if your car is an Si, the pm6 Si ecu will do just fine with the zc. Your ecu options are as follows.

Pm6 - 88-91 Si (good)
Pg7 - 88-89 Integra (better)
Pm7 - Jdm Zc ecu (best)

Ive had all three, and the pg7 integra is a cheap and effective ugrade, but not absolutely necessary. Like I said, If you have an Si, your needed parts list should be very short.

[doug294]

I heard I could use my Si ecu, is this true?

[FourthGenHatch]

Get the ZC tranny because with the ZC tranny you can use an Intermediate Shaft which eliminates torque steer. And the Integra axles you use are 90-93 Integra Axles.

As for ZC tranny vs. Si I'm pretty damn sure the ZC has the lowest gearing of any D-series tranny. They say the Si one is better because it has a higher 5th gear. I know with my ZC tranny if I'm doing 80mph my tach is at 4k RPMs. Pretty high. With my DX one it was like 2k something. The ZC is awesome for around town but you might suffer gas mileage, but who cares.

88-91 Civic/CRX DX
3.25
1.894
1.259
0.937
0.771
3.88



88-91 Civic/CRX SI
3.25
1.894
1.259
0.937
0.771
4.25



??? JDM DOHC ZC
3.25
1.944
1.250
0.909
0.878
3.88

The actual gearing of the Si might be more but the final drive of the ZC is much lower so that is what is going to be the deciding factor.

The best tranny is actually the ZC housing and 1-4 with Si 5th and final drive.

[sastanley]

Originally Posted by Problem_Si

yes, i believe the bottom rad hose is from an 88-89 integra.

You dont need to get an ecu if your car is an Si, the pm6 Si ecu will do just fine with the zc. Your ecu options are as follows.

Pm6 - 88-91 Si (good)
Pg7 - 88-89 Integra (better)
Pm7 - Jdm Zc ecu (best)

Ive had all three, and the pg7 integra is a cheap and effective ugrade, but not absolutely necessary. Like I said, If you have an Si, your needed parts list should be very short.

Dude..how does the ZC run with Si ECU? I am still confused how the SOHC ECU makes a DOHC motor run OK...Do you wire the cam sensor on the ZC to the correct pins in the Si ECU so it can find it since it isn't inside the dizzy???

[FourthGenHatch]

Originally Posted by sastanley

Dude..how does the ZC run with Si ECU? I am still confused how the SOHC ECU makes a DOHC motor run OK...Do you wire the cam sensor on the ZC to the correct pins in the Si ECU so it can find it since it isn't inside the dizzy???

DOHC or SOHC means nothing to the ECU. All the ECU is doing is deciding how much fuel gets injected and when.

The only differences in ZC and Si wiring is that for the ZC the cylinder position sensor is on the exhaust cam and for the Si it is inside the distributor.

[Problem_Si]

Heres how it works....watch closely...

---------><---------- bam, done.

lol, just kidding....seriously, there are no changes needed other than to switch to the Us dizzy clip. Takes a steady hand, a small screwdriver, and about 2 minutes. All the wire colors are the same, so even a novice can handle this job.

Theres no real reason why sohc ecu's cant work on dohc motors, and vice versa. I mean, right now....my zc is in the shop, and im driving my Si with the stock a6 with a Zc pm7 ecu. Works just fine...

[sastanley]

Hmmm...OK cool...just out of curiosity, it would be interesting to see dyno #s between an Si, Teggy, & ZC ECU on the same motor...

Someone go waste some money on a dyno run to satisfy me!!!

[Problem_Si]

well ive had all 3 on my Si motor, currently running the Pm7 Zc ecu.

the pg7 is good, seems to have the most power in late 2nd gear all the way through 3rd.

the pm7 is a beast from 2nd all the way through 3rd, seems to have a wider powerband than the teg ecu. Thing that sux is, Zc limits out @ 115mph, so no highway racing.

With Intake clutchmasters clutch, and a bent ass thermal exhaust, my Si ran 16.3 with the Pm7 ecu (full interior/14's @20psi). I think its faster than 16 flat, but about 5 miles after i left the track that day, a case bearing grenaded in my trans. I wont know until I can afford a trans rebuild and lsd for my new trans... All I know is that both tires chirp going into 3rd gear.

[sastanley]

Hey..that's cool..I guess the butt dyno is as good as any.

I have the Zdyne ZC ECU so no speed limiter - now i just need to get off my lazy ass and get it all in!

[doug294]

20 psi?!?!?!?! No wonder, your lucky you didn't blow your motor running that much boost.

[FourthGenHatch]

Where can I get a ZC ECU (Zdyne one)?