I'm trying to figure out the motor differences between the Civic Std, DX, and Si. If I've got something wrong please let me know.

1.The block is the same on all three motors, but the 1500's use a different crank (and rods?) to reduce displacement. The bore is the same on all three motors.

2. The Std. has an 8 valve head, while the DX and Si have a 16 valve head.

3. The Si makes more power due to MPFI, cam timing, and compression.

Are the DX and Si heads the same externally? I'm guessing not due to the MPFI but I just wanted to check.

Thanks for the info!

 

DX and Si heads are the same aside from cam and valve springs (or so the story goes).

I think the STD has the same engine as the DX, and the HF is the only 8 valver out there. Not sure on this one though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by STS_Underdog &raquo;</TD></TR><TR><TD CLASS="quote">I'm trying to figure out the motor differences between the Civic Std, DX, and Si. If I've got something wrong please let me know.

1.The block is the same on all three motors, but the 1500's use a different crank (and rods?) to reduce displacement. The bore is the same on all three motors.

2. The Std. has an 8 valve head, while the DX and Si have a 16 valve head.

3. The Si makes more power due to MPFI, cam timing, and compression.

Are the DX and Si heads the same externally? I'm guessing not due to the MPFI but I just wanted to check.

Thanks for the info!</TD></TR></TABLE>

All three have the same heads, only difference is the cams. Also the D15 engine has higher compression than the d16.

 

I'm thinking about building a motor for a race class that bases your car weight off of displacement. Cams, valves, and valvesprings are unrestricted so basically I should be able to build a 1500cc Si motor by using a DX engine and just swapping over cams and valvesprings, right? Thanks again!

 

Actually, the D15B1 (STD) has a 16 valve head.

The D15B6 (CRX HF) has an 8 valve head.

The D15B1 makes less power than the D15B2 (DX) because of tuning. Both are DPFI.

The D16A6 (Si) head has a longer duration and higher lift cam.

The D16A6 deck hight is about 5mm higher (for obvious reasons) than the B1, B2 and B6.

The rod and main journals on the B6 are a lot smaller than the rest but the B1 and B2 rod and main journals are smaller than the A6.

The A6, B1 and B2 heads are the same externally, they just have different markings on them.

Hope that helps.

 

OOPs. I guess It took me too long to write that.

 

This is good stuff. Basically I can take a D15B1 (which I already have) and use an Si intake and cam and not be giving up too much power since I get a compression bump to offset the displacement decrease? Sweet! This is sounding better and better!

 

Don't forget to use a d16y8 head gasket for even higher compression,

 

isnt the y8 head gasket 3 layer? and it lowers compression???

 

I think you're right, Exsinnovation. It's the Y8 head that bumps compression up a lot, not the head gasket.

 

The Z6 head raises it even more right?

 

no the y8 has smaller combustion chambers hence, the increased compression

 

std dx and si all have 16valve. Si has a more agressive cam and is a 1.6 litre engine. dx and std are 1.5litre

 

what about the Vtak?

 

there is no vtec on std dx or si. i bought my si head under the impression i was gettin vtec...i was disappointed to learn there is none on the Si. and to get vtec is a pain in the ***. im just sayin expletive it, unless your car is ready for vtec its expensive to install the wiring n ****, unless you can DIY..i cant though. if you want vtec, my suggestion(unless you got alot of money) is to test compression, etest, and all that **** on your stock motor. if its running like new, get it tuned, and put on an Si head from an eg

 

oh. i like to use search

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dseries_ef &raquo;</TD></TR><TR><TD CLASS="quote"> ...all that **** on your stock motor. if its running like new, get it tuned, and put on an Si head from an eg</TD></TR></TABLE>

what is needed for this? my DD's headgasget blew and i got a vtec head. i need the LOWWEST compresson head gasget out there( i dont wana but premum gas. cant affored it)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mikerbike &raquo;</TD></TR><TR><TD CLASS="quote">

The D15B1 makes less power than the D15B2 (DX) because of tuning. </TD></TR></TABLE>

So can a DX ECU Will bump the power up a little bit in an STD without causing problems?

 

That's what I would think. The B1 might have a crappier cam too. All I know is what I've found out from the internet and from taking apart engines for research. How do you do that quote thing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mikerbike &raquo;</TD></TR><TR><TD CLASS="quote">That's what I would think. The B1 might have a crappier cam too. All I know is what I've found out from the internet and from taking apart engines for research. How do you do that quote thing?</TD></TR></TABLE>

Click reply, and in the reply box hit quote.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by deanh8 &raquo;</TD></TR><TR><TD CLASS="quote">

Click reply, and in the reply box hit quote.</TD></TR></TABLE>


Ohhhhh... Okay, Thanks. I'm such a dork. I put a DX computer on an STD once. I didn't drive it before the computer, so it's hard to tell if it was better or not. The guy that owned the car was too clueless to know if it was different or not.