After spending the last two weeks reading up on this engine...I feel that
I am more lost than ever. So I'm asking for help from those in the know.
What buildup possibilities are there? Here's my senario:

- '89 CRX HF (mpfi already okay that hurdle passed )
- '89 D15b2 and tranny ( thanks Icon150 )
- a few si computers
- '89 si tranny ( condition is questionable)
- a few misc parts I snagged from a parts rex ( inj box,pm6 vaccumn thingy from
under a black cover on firewall,etc)
Now I know that I need a D16 intake mani,an A6 cam,adj cam wheel,I/H/E wont
hurt. What would be the proper course of action to build this up? My reasons:
- The rising cost of fuel
- I don't want a Mini-Me or boost (at least not yet...last resorts)
- Don't have as much "disposible income" as before,so swaps are a NO!!
- I wanna buck the trend ( ie: crx with LS/Vtec,B16,K20's)
Any and all info is welcome...Just trying to squeak at least 108-112 hp .
(Compared to the 52 hp the stock HF motor..this should be a world of differemce)

Thanks
-

 

I have no clue what I'm doing with d-series but it should be similar to the b-series engine. So basically what I'd say if you're going to go NA you should raise the compression, port the head, cam it, good intake, good headers, nice flowing exhaust, and tune it using uberdata or some free tuning software. That might get you around your hp goal but you'd probably be spending more than you need to.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by michaelOlson &raquo;</TD></TR><TR><TD CLASS="quote">tune it using uberdata or some free tuning software.</TD></TR></TABLE>

Uberdata = obd1; Turboedit = obd0

1. This is the first thing I would recommend doing. Getting an Si transmission put on the d15b2. With the '89 Si transmission you have now, open it and see if its in good working order. If not, buy one that is in good condition (they can be had for 150 bux). Also, try to get a '90-'91 flywheel and clutch combo (they are bigger than the '89). The '90-'91 f/w and clutch WILL work on a '89 Si transmission, thats the setup I am running now.

2. The A6 head is one of the best flowing D-series heads. I would definately get one of those. Put a nice cam in it, and if you got the cash, port and polish the head. Since you will be changing out the head, put on a y8 headgasket (someone verify if the y8 headgasket fits on the d15b2), which will raise the compression ratio. Its not a mini-me cuz there is no vtec.
2a. If you elect to keep the B2 head, yes, get a good A6 cam and cam gear, Port and polish, if money allows.

3. If you can chip ecus, try and get a chippable pm6 so you can tune it with turboedit. If not, get a pg7 ecu. It has a 7500 rpm redline and it runs richer. Which will be better for the modifications you have.

4. Definately get a y8 intake manifold and LS throttle body. And some more bolt-ons.

Pretty sure you will hit atleast 110 hp with this setup.

 

you could use the newer rods ( i think thyre cx or vx) and a pm7 or p29 piston. swap to a d16a6 head or you could use a sohc zc head (ive got one shoot me an offer if interested) cause they have a little taller lift. gasket match everything, then port match it all, get a b series or h22 throttle body, I/H/E, chipped pm6, up the redline, and tune it with turbo edit.

p.s. definitely get a y8 manifold too. you could get a bigger cam and for 250 or so have a new set of springs and retainers.

 

okay I have a real newbie question...I read that both the a6 and b2 heads
were the same...is this true or was the a6 worked for better flow? Also I
remember something about the b2 being the "ideal" bore and stroke for an
engine. can someone explain this. One last item...what would a decent level
of compression be so that I would not require 104 octane or higher.

thanks

 

Ive heard that the b2 and a6 heads are nearly identical minus the camshaft. Which the A6 cam is has a more aggressive profile. I had a b2 with an a6 cam, and SI tranny, and raced a stock SI crx and beat him by about 1/2 car. Could have been drivers, could have been because I weigh less.....dunno.

 

Head casting is identical.
Cams are different.
Some say the valve springs are weaker on the D15 version.

Fro a chippable PM6 make sure it's from a 90/91. The 88/89 are the messy ones that don't chip normally.

Look into getting a tranny gear set from a ZC tranny.
Throw that in the Si trans with the Si final drive and you get some SHORT gearing

A decent aftermarket cam along with the Y8 manifold (as suggested in other posts) and a port and polish (also as suggested - if you have the $) will set it all off for putting down some decent power.

One thing - not sure if the Y8 gasket fits (as suggested), BUT Honda did some changes. They used to make a thin gasket for the Y8 and a slightly thicker for the Z6. Now they are the same gasket when you go buy one. I'm not sure which they decided to use, thinner or the thicker, but it's some info either way.

 

okay heads are the same..sweet so need to work on cam and valve springs.
Per the prior owner it burned oil...maybe a quart every month. Based on this
I'm planning to freshen up the motor...start with 0 miles. So a teardown is in
order. Since I have decided to do this...what would you suggest in the way of:
- pistons
- rods
- bore
- cam choices
I found that I have a '90 pm6 box in my set..so tuning is okay .
I plan on starting teardown on the motor this weekend ( weather permitting)
Just need to find a local machine shop.

 

do you want after market parts or do you want to use stoch honda parts?

 

you neeed to check your information. "D15 Tech:

When putting other pistons in a D15 you can use a set of VX rods (the calculator assumes you will be using them) effectively increasing the compression height of any D series piston by 3mm. The D15 rods have a 45mm crank end.( D16 = 48mm )"

info taken from http://www.knology.net/~jediklc/D.htm

but if your gonna be boosting the rods will not hold past 250. (maybe less) and if your all motor your not gonna be making more than that.

 

well they are talking about the d15z1 (vtec-e) which is an economy motor. the d15b is a vtec performance set up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by audioroach &raquo;</TD></TR><TR><TD CLASS="quote">...what would you suggest in the way of:
- pistons
- rods
- bore
- cam choices
</TD></TR></TABLE>

I would suggest stock rods since you aren't going to putting anywhere near 200 hp with this setup and you are also keeping it in streetable compression. The rods aren't going to need any changing.

Might as well get a set of OEM pistons too!

Might as well bore and hone to .025" oversized to get rid of the "burning oil" problem. You can go with a bigger bore (.050"), but that's up to you. If you ever plan to rebuild the motor in the future you won't be using OEM pistons.

CAM - I would personally go with one from EXOSPEED. They are proven to do good things and they don't cost a rediculous ammount of $. They also sponser Honda-tech so that's another plus! =P

 

are you sure they didnt mean different size crank snouts? and im 99% sure that the d15b2 and b7 are the same bottom end. meaning that the vx rods would work in either.

 

i would say if you want to use the a6 head its not worth porting. i have heard around that not much can be done for it in that way. i would think about using a y7 head with the b2 or a6. the compression should be in the mid 10s or around there. i have heard good things about exospeed like everyone else here so i'd go with that. the stage 2 sounds nice. the y8 im and ls tb is a good set up. chip the a6 ecu and there you go.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by audioroach &raquo;</TD></TR><TR><TD CLASS="quote">- The rising cost of fuel
</TD></TR></TABLE>

If this is truly of concern to you, you might want to consider swapping back to DPFI. More HP = more fuel used, unless you're running terribly inefficient at a lower HP level.

I'm trying to gather info and resources on converting one of my D15B2's to alternative fuel [probably LPG] to combat the rising cost of fuel.

 

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

If this is truly of concern to you, you might want to consider swapping back to DPFI. More HP = more fuel used, unless you're running terribly inefficient at a lower HP level.

I'm trying to gather info and resources on converting one of my D15B2's to alternative fuel [probably LPG] to combat the rising cost of fuel.</TD></TR></TABLE>

MPFI is actually more fuel efficent than the DPFI...thats why it was used in the HF.

I am currently peicing together a setup for my B2 motor. However, I am going to just keep the stock bottom end, and throw my Y8 head on with a ZEX cam. The CR is about 11.5:1 with the 2 layer metal headgasket, and it shouldn't be too much power to break the bottom end.

All I want is a little more power, and great gas mileage.

 

Well my DPFI still nets me about 400 miles per tank, so I'm not changing a good thing!

 

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

If this is truly of concern to you, you might want to consider swapping back to DPFI. More HP = more fuel used, unless you're running terribly inefficient at a lower HP level.

I'm trying to gather info and resources on converting one of my D15B2's to alternative fuel [probably LPG] to combat the rising cost of fuel.</TD></TR></TABLE>

make sure you have a good write-up ready for me when you figure the alternative fuel issue out. i want to be first in line

 

yea i can confirm that a y8 headgasket would fit a d15b2... i got one for sale... but if no one buys it imma keep it up until i blow a headgasket... then imma get to use it... but this is a nice informative thread....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaX &raquo;</TD></TR><TR><TD CLASS="quote">Well my DPFI still nets me about 400 miles per tank, so I'm not changing a good thing! </TD></TR></TABLE>
MPFI will net you more mpg.

 

I'm in the same boat you are, trying to get as much out of the b2 as I can.... Sadly, it would be cheaper to get a dohc zc or an a6 then it would be to do new rods/pistons etc...

But the B2 is a challenge so I am gonna keep working on it. Two things you might want to consider. Instead of using the a6 intake. Try and get a y8 (manual) intake and tb. It flows more air than the a6. And for cams, the SOHC ZC has the same pm3 head as the a6 and b2. If you can get a cam off of one of those then I would go that route and get new valve springs.

My plan is to do the y8 intake, a6 cam and get a cheap header. If I'm not happy with that then its a coin toss for the mini-me or dohc zc. I have a zc/si hybrid tranny that I just love so I have no plans on going over to the b-series.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by liquidoblivion &raquo;</TD></TR><TR><TD CLASS="quote">
MPFI will net you more mpg.</TD></TR></TABLE>

None of my MPFI setups have gotten mileage like this, with the exception of my VX. I'm putting an L3 transmission in my DPFI as soon as I can gather up some motor mounts, so I hope to achieve even better mileage.

 

Sat morn bump for those weekenders.

To all those who responded I humbly thank you. This has been a wealth of info.
Plus I feel that there are many others out there with similar ideas. So please
keep them coming. My goal is to have spirited performance with some respectable
gas mileage...which I think is possible. This will be my 1st engine build and it will
be a fun summer. I want to do this right...if it cost me a few bucks..i'll just have
to save my pennies . Let the flow of information continue.

thank you

 

the d16y7 has smaller combustion chambers then the a6 head. its a non vtec head from the 96-2000 dx. it would need to be ported though because it doesnt flow as well but it would bump the compression well.

 

There's a guy on here who did a crazy built-up of a D16a. Crazy head porting, manifold port matching on the intake, bored out TB, bored out exhaust manifold, complete engine rebuild, maybe a new cam, etc. He works at a shop, so the labor was free, but the engine was impressive. I believe it dyno at 130 to 140 whp.


That built-up was probably 3 G's in labor alone.