Is it more complicated than just swapping in the new head and ECU?

Is the MPFI system and wiring harness on the HF the same as the Si (other than the ECU)?

TIA.

 

well the bottom isnt as strong so it wont be able to handle the high revving.

 

pistons only have valve reliefs for two valves. you'll have to change pistons.

 

its possible but most of them seem to be rediculously slow....

 

What about the wiring harnesses?

Can you drop an Si motor in an HF chassis and just plug it in along with the PM6 ECU?
I would assume so, since they are both MPFI.

 

as long as you use the hf engine harness on the si it will work.

 

i've heard many different stories about the valve reliefs. you might as well build up a cheap high comp d-series if you're thinking about swapping heads, it's really not that much more work to pull the engine and build her up. but maybe it is...to some.

goodluck with the dirty d

 

So here's what it looks like I'll be trying to do. PLEASE let me know if you guys think this will work.

Civic HF Chassis and harness.
D15B2 Bottom End.
Si Head with cam.
Si Distributor
Si MPFI
Si ECU

Will this work?

Basically, I have most of this stuff lying around and have a line on a really nice, cheap HF tub. Trying to see if it will all work together and make a fairly light and quick car.
My main worry is making all the wiring work. I see guides all over the place for swapping DPFI for MPFI, but I can't find anything on dropping Si parts into an HF. I'd *think* it would work since they are both MPFI, but I honestly don't know.

 

sounds good. b2 bottem wont rev very high tho.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kyle h. &raquo;</TD></TR><TR><TD CLASS="quote">sounds good. b2 bottem wont rev very high tho.</TD></TR></TABLE>

the 1.5L honda engines have a shorter stroke than the D series 1.6L engines. this means the 1.5L engines can actually handle higher revs *better* than D16s.

Its true that D15 rods are smaller than D16 rods, but the shorter stroke and better engine geometry makes up for this fact. just dont go revving it to 8500.

remember that most ofthe time, its the valvetrain that cant handle the revs, not the block.

 

Yeah.
And there's a D15 block laying in the corner of my garage. Which makes the D15 the absolute best choice for this project.

Any other thoughts on the HF to Si wiring harness issues?

 

i tired this swap and about 2 hours into it i had the local shop i work at on the phone ordering me a DOHC zc....good luck though