89 dx head on std civic block

[mikes89civicstd]

I currently own a red 89 civic std which i have already replaced an exhaust valve on it so i am familiar with removing the head and such things. However, I am also buying a white 89 civic with the same problem, (hopefully) that my red civic had. However, I was wondering since I already wil have the stock head off to replace the valve, if I put on a dx head instead of the stock one, will I expierce power gains at all?

I know that the STD block runs with higher compression, by the 70hp rating leave ALOT to be desired, esp with the 4 spd. However, I know that both the dx and the std both run with dual port fuel injection, and both are 1.5 l motors, so im guessing that most of the difference is in the camshaft profiles and the head porting and such. The difference between the two in power numbers is 22 horsepower, from 70 to 92, and still maintaining excellent fuel economy. Will the head swap be a simple plug and play swap? Will the oil passages line up? If anyone has any info about this please let me know.


thanks alot.

 

[mikes89civicstd]

i'm not gonna swap the motor. i'm just trying to find out if the head is a direct bolt on the STD block and if so, what power gains does it have. Also, are any 5th gen series motors DPFI besides the CX that will bolt on also? I don't want to do the wiring for the MPFI swap or buy the different intake manifold. I only have a budget of about 50-70 bucks and just had the idea.

 

[jlicrx]

the STD D15B1 and DX D15B2 as well as the Si D16A6 all use the same cylinder head and the B1 and B2 also use the same pistons:

Head Part No. 12100-PM6-J01

The only thing different on the head is the camshafts - the biggest difference between the STD and DX is the throttle body - put a DX throttle body and camshaft in it and you have a DX - also use the PM5 ECU

 

[mikes89civicstd]

are you positive the throttle body is different? and if i swap the camshafts, is the dx ecu essential? to me, the throttle body looks the same as the STD but i dont know for sure.

Has anyone done this swap, if so, what gains did you get from it?

If anyone has a dx head or camshafts, ecu, or throttle body for a cheap price or even free email me at the_ataris017@yahoo.com

 

[jlicrx]

Quoted post[/post]]
are you positive the throttle body is different? and if i swap the camshafts, is the dx ecu essential? to me, the throttle body looks the same as the STD but i dont know for sure.

the throttle bodies are different - the throttle plate in the STD only opens a little over half as far as the DX and has a restrictor plate between throttle body and manifold - the PM9 ECU does not supply enough fuel - it will run with it, just will run better with the PM5 - another difference in the two engines is the exhaust system - the STD has a close coupled cat (like a CRX HF) and smaller diameter piping

 

[mikes89civicstd]

thanks for the support bub. do you know if i could modify the std throttle body at all so that it is similar to the dx? also, wouldn't i just be able to remove the restrictor plate instead of buying a new throttle body?
Also, what would be easier/more cost efficent, swapping the whole head or just the camshaft?


also, this is slightly off topic, but i found a metal plate right after the intake enters the top of the throttle body. It was held on by one screw, so I took it out. Any ideas what this was put in for? My guess was to make sure the motor doesnt backfire back into the air intake.

thanks for your guys input.

 

[mikes89civicstd]

yeah im not even trying to get alot if power at all. if i was id do a swap for sure. im just exploring my options to try to get a little more juice outta my d15 with minimal cost to make my voyage up hills a little bit quicker and with a little less downshifting. i thought about the si cam, but i didnt think it would work well because it was designed for the mpfi system. and doing the mpfi swap brought the gas economy down quite a bit for what ive heard, and i get about 38-39 now which is dandy. also, im trying to stay under 100 bucks for sure, cause college is expensive now in days.

thanks for the info though

 

[mikes89civicstd]

do you still have the d16 laying around?

 

[mikes89civicstd]

Awesome man. yeah, id love if you could hook me up with some leftover parts. i'm really starting to get into engines and im thinking about building one up bit by bit with parts. Of course, id love an intake manifold and throttle body of course. but yeah man, anything you wouldnt use. good luck on the z6 man. thanks for the info too, i wish i knew that much.

 

[mikes89civicstd]

sweet, thanks alot man. by the way, is the Z6 motor the sohc vtec out of the 5th/6th gen ex models?

 

[mikes89civicstd]

wow i bet thats gonna be a fun peppy little car when your finished with it. how hard is the swap compared to the B16 swap? and the price difference? i was thinking about that lately but it probally wouldnt happen until i find a really good deal on all the parts i need.

 

[mikes89civicstd]

Does the z6 and the d16 out of the 4th gen use the same bottom end? Could I, then, put the z6 head on the d16 block and save some $$$ or are the oil passages different because of the higher oil demands VTEC has?

You got me thinking more in the ways of a d-series swap than just the camshaft stuff i was talking about earlier..

 

[mikes89civicstd]

So, in other words, I would need a 5th gen z6 ex/si head, si throttle body and intake manifold, and the d16 cam gear? Or would I also need to swap the ecu? Do you know what kind of power numbers this would push out? I'm guess a bit over 100 hp and 95 tq... which would be quite nice for me . If you have any of these parts from your destroyed d16 i'd be quite grateful..

Thanks for all the input so far man.

 

[phunky.buddha]

Quoted post[/post]]
Does the z6 and the d16 out of the 4th gen use the same bottom end? Could I, then, put the z6 head on the d16 block and save some $$$ or are the oil passages different because of the higher oil demands VTEC has?

You got me thinking more in the ways of a d-series swap than just the camshaft stuff i was talking about earlier..

The 4th gen D16 (The D16A6) actually has a slightly stronger bottom end than the Z6 and Y8.

Quoted post[/post]]
So, in other words, I would need a 5th gen z6 ex/si head, si throttle body and intake manifold, and the d16 cam gear? Or would I also need to swap the ecu? Do you know what kind of power numbers this would push out? I'm guess a bit over 100 hp and 95 tq... which would be quite nice for me . If you have any of these parts from your destroyed d16 i'd be quite grateful..

Thanks for all the input so far man.

Yup, you need the ECU too. Most people see a compression gain when doing the mini-me, so if done correctly- you should actually see the same power if not more than the Z6 and Y8. You'll probably hit something like 130hp. It's a very economical way to pick up 20-30 horsepower.

 

[mikes89civicstd]

Just read your z6 writeup. That block looked fantastically clean, I'm amazed. Also, I was surprised of how much stuff you had done to your motor and car. I am quite impressed with everything and how it looked.

Makes me wanna buy a si hatch and do the same.. too bad im only 17 and make five and a quarter an hour...

I guess I gotta stick with Std's and suffer from the 70hp sickness for now...

 

[phunky.buddha]

Quoted post[/post]]
Thanks Cal. I thought I remembered the A6 bottom end being better but I couldn't remember for sure.

Nah. It's not anything to write home about.