Just trying to find out if you can swap out the head from a 88Si to a 91 hf? If you can, what else would you need to make it work? ECU?
Let me know guys, because I'm thinking about selling my head to this guy and want to make sure it will work.

 

well when i had to swap the head in my 91 standard hatch we just put the head right on there. from my knowledge you don't have to change the ecu or anything you just take the old head off and then put the new one on. i put an SI head on my motor

 

But aren't the fuel maps different and would require the Si ecu to run correctly? The HF is for fuel economy and I think would hurt the performance. What do you think about that??

 

well i had like the base model hatch , which was like the hf , and i didn't change anything. i even asked a honda mechanic and he said that i can just put the head on there. so tha tis what we did and we didn't notice any lack of horsepower, infact we felt a little increase and never had a problem with it until i blew a rod thru the block. the si ecu isn't sometihg he needs but it will make it run better. but it won't run like total butt without it

 

You're talking about the DX. I used to have a DX and it pulled a hell of a lot harder than my brothers HF. That's why I'm thinking that if we put the head on that we should also change the ECU to an Si. I doubt it would hurt anything.

 

no there was a model below the dx, it came with a 70 horse motor , 4 speed tranny, no tach in the guage cluster, and vinyl interior. that is what i had

 

Oh, are you talking about the civic hb? Also how did you blow a rod?

 

OK if you swap the head onto a DX, you need to swap over to Multi-point injection, which WILL require the Si ECU. The HF already has Multi-point, and the ECU is set up for that.......




[Modified by Phatwhippin_CRX, 10:25 AM 11/20/2001]

 

you do not need to change all that wiring, my car was a dual port and the SI head was multi and i didn't do that

 

yeah . i let it go low on oil too many times. and then one day it just said **** it and went flying out of my engine into my header, onto some part of the highway

 

So you want just the head? Nothing else? Will the intake manifold from your car bolt up to the Si head? If so, don't mind me, I'll shut up now

*edit* Yeah the Si head will work with Dual point, and you'll notice a slight performance increase from the head... BUT some of the difference between the DX and Si hp is the Multi-point fuel injection....... so it'd be worth it to wire it up for that.......*/edit*


[Modified by Phatwhippin_CRX, 10:34 AM 11/20/2001]

 

Well from what I've heard. The Si has a more aggresive cam, and also has a more performance oriented fuel curve. I'm just trying to make sure it will fit, and also if I would need to get the Si ecu. I'm pretty sure I know the answer to my question, but I just wanted to know if someone had a firts hand experience on this.
Note to self: Make sure I have enough oil in my car...

 

Need an Si cam? I got one if you need it.......

 

No. I have the whole Si motor. But it needs a head gasket and also a valve cover gasket. And that's what I can see so far. I'm probably going to sell the head to a friend that has an HF, but I wanted to make sure that it would work first. Has anyone ever done this swap??

 

I can see one potential problem. The Si is 16 valve and the HF is 8 valve. There may be some valve clearance issues with HF pistons. I will see if I can find out for sure.


[Modified by wronghand, 1:43 PM 11/20/2001]

 

Nope, contrary to what alot of people think there aren't valve clearance problems... I've seen an Si head on an HF block, and that little bastard was fast as hell.