Boosting a SOHC: Difference between A6, Y7, Y8 and ZC?

[DarkCreep]

Hey all..

1990 Honda Civic Si
D16A6 w/ 190,xxx miles.

My brother wants to keep his SOHC and boost it. Yeah I know a lot of people say that but, this is a realistic goal for him. He put almost a grand into his EF without having a job. This guy knows how to manage and save his money.
Well onto the question. His EF has the stock A6 motor. We DO NOT know how well it was taken care of, but we know its far from perfect. Do all these SOHC motors have the same block? He said he wants to boost a ZC. My Y7 is in PERFECT condition. Can he use it for parts? Or should he swap a Y8+boost? Or ZC+boost? We may end up tossing the A6 and start with a cleaner platform, but we need some input first.

He wont be running high boost, just enough to pump out HP and still be daily driven.


Sorry for all the questions and thanks in advance for your courteous replies.

 

[rickles8099]

each block is slightly different. like the a6 does not have a threaded hole for a knock sensor, the dipsticks are located in different places, etc. but you can put a y7,y8, zc, d15 engine into another d car without any problems.

if you have an extra y7, i would say to boost it or to just boost the a6 and if it blows, swap in the y7 then. several of us in st louis are running turboed singles into the mid 13's on stock engines. the engines we are using are y7's, d15b7's, and y8's.

 

[AlexM]

They started making SOHC ZC's?

 

[rickles8099]

They started making SOHC ZC's?

started? if i remember correctly, they do not make d series engines anymore, so the correct answer is no.

they did make them:

ZC(similar to D15Z4, D16Z6, D16A1, D16A3, D16A6, D16A8, D16A9 and D16Z5 engines)
A few D-series variants are labelled "ZC" (usually JDM), but they are not truly a different series.

There are both SOHC and DOHC ZC engines.

The non-VTEC SOHC ZC is similar to the D15Z4 and D16A6 engine, but with more aggressive cam timing.

The VTEC SOHC ZC is identical to the D16Z6, and the DOHC ZC is similar to the D16A1, D16A3, D16A8, D16A9 and D16Z5 engines.

Euro Mk1 (85-87) 1.6 CRX's are fitted with an engine designated "ZC1" which is a higher spec 130 bhp version of the D16a1.

The JDM Browntop ZC from the 84-87 Civic CR-X and Integra made 135hp from the factory.

 

[toneekay]

i think the usdm crx si came with the sohc zc, my cousin had pea green one lololol

 

[rickles8099]

i think the usdm crx si came with the sohc zc, my cousin had pea green one lololol

the usdm crx si came with the d16a6. stats are as follows:

D16A6
Also known as D16Z2.

Found in:
1988-1991 Honda Civic Si, CRX Si, Civic Wagon RT4WD
1990-1991 Honda Civic EX Sedan
1988-1995 Honda Civic Shuttle RT4WD (UK/Europe/Asia/AU/NZ)
1989-1996 Rover 216/416 GSi (UK/Europe)
Displacement : 1590 cm³
Bore and Stroke : 75 mm X 90 mm
Compression : 9.1:1
Power : 115 hp (86 kW) @ 5600 rpm & 100 ft·lbf @ 3,800 rpm, redline 7200 rpm (USA)
Note: 1988 engines were 105 hp (78 kW), MY89-91 hp was increased to 108
Valvetrain : SOHC
Fuel Control : OBD-0 four-point PGM-FI
Head Code : PM3
Piston Code : PM6

 

[DarkCreep]

the usdm crx si came with the d16a6. stats are as follows:

Thanks for the info. You seem to know your stuff.


Is it the A6 or the Si tranny in the EF Si's that make them feel so quick?? I LOVE driving my brothers car, it feels liek a go cart and is rev happy.

 

[4drcivicmaster]

stick with the a6 for now. they are said to be one of the best blocks out there for d-series and the a6 head is the best non vtec flowing head d-series has.

 

[rickles8099]

Thanks for the info. You seem to know your stuff.


Is it the A6 or the Si tranny in the EF Si's that make them feel so quick?? I LOVE driving my brothers car, it feels liek a go cart and is rev happy.

the combination of more hp and the final drive in the ex/si tranny is what makes them faster. the first through fifth gears gearing are teh same in the dx vs the si. its the final drive that makes the difference. the dx has a 3.88 final drive as opposed to the si's 4.25 final drive.