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The Wife and the Car
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Discussion Starter #1
Ok here is the catch. We can not change the engine block.
Everything else inside can be changed.

If we where to consider the optimum borexstroke as well as the rod to stroke ratio.

What combination of parts would give the best results on a D15B engine
As you know we allready have the Y8 head and the D15 Block.

I feel compared to the Suuki 1.6 this engine serioully lacks grunt.
Would it be possible to bolt on a crank from one of the other engines.
While still retaining the stock engine block ?

Something like building a stroker kit for your banshee.
 

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JDM d15b Crank

d16 rods, and pistons of choice
 

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92 cx
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If you can find a stroker kit for a d15 let the whole world know. To me it's called get a D16, or if you got a D16 put D17 internals in it.

I think you'd need a custom crankshaft to stroke it though.
As far as rod to stroke ratio, D series isn't your engine, look into the K series or B series. You can't swap those so you might as well get strong lightweight rods and just build for boost and skip your n/a idea.

If you build for n/a, then build for boost later you will have to rebuild it all from scratch again. Unless you have an overabundance of $ then it doesn't matter. But when you build for boost you'll need diff. pistons/rods compared to your n/a build. If you wanna do n/a right the way i think you do.
 

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88 ED6
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You can probably bore out the main journals to fit a D16 crankshaft but I'm not sure how much material you have to work with.

+1 on the JDM D15B crankshaft. The stock D15B rod-stroke ratio is already about 1.62(1.59 with the regular non-VTEC rods). Run the JDM crankshaft with D16 rods, and just overbore the motor(possibly resleeve if it's allowed and run a large piston like a 78mm piston).
 

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2005 Legacy GT
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The only problem I see with the JDM crank and d16 rods advice is that with the lower deck height of the d15 most pistons other than the JDM d15B or the USDM d15z1 will be sticking out of the hole ... which is no good.

So as far as OEM options you are kind of screwed. But you can nab yourself some crower stock length rods and I think there are a couple of shelf forged pistons (arias and SRP IIRC). However most aftermarket d series stuff is aimed at boost.
 

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why dont you fist tell us if this is a n/a, boost, nitrous, ect... build

and fj dist. does make a custom length i-beam for the jdm d15b
 

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88 ED6
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The only problem I see with the JDM crank and d16 rods advice is that with the lower deck height of the d15 most pistons other than the JDM d15B or the USDM d15z1 will be sticking out of the hole ... which is no good.

So as far as OEM options you are kind of screwed. But you can nab yourself some crower stock length rods and I think there are a couple of shelf forged pistons (arias and SRP IIRC). However most aftermarket d series stuff is aimed at boost.
You can use modified B16 rods(in the same manner as LS rods) on a JDM D15B VTEC crankshaft to run "normal height" pistons. Though, D16 rods would work fine if you're getting custom pistons anyways(custom pistons are usually cheaper than custom rods).
 

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92 cx
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On zealworks it said that with b7 block, jdm d15b rods, crankshaft, and pistons (i used d16 on zealworks cuz that's technically what it is) w/y8 head he has is sticking out the hole 0.094in....Using a shorter custom rod could help, but then your rod:stroke ratio does down...

Hope Bone chimes in. He probably tell you your wasting $, just go boost already.
 

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JDM D15B rods=D16 rods; hence why it was suggested to use modded B16 rods if you want to stick with D16 pistons. If you're going custom pistons, then it wouldn't matter.

Only OE pistons that readily work with the D15 long-rod setup is D17 pistons, VX pistons, and the stock JDM D15B VTEC pistons.
 

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Brokedick Millionaire
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40,237 Posts
see my D15Baby8.

D15 block, any.

D15B crank, D16 Rods w/ARP's, OEM P29's, A6/B7 head, Z6 intake, Crane cam or similar

13.7:1 compression or lower depending on headgasket choice. The head chamber will need to be opened up to 75.5mm when ported.
 

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Honda City
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We have a JDM D15B block guys. There was some confusion regarding the block but rdc measured a rod and piston and it was the same as the one from a D15B.

Rod specs:
137 mm length
19 mm wrist pin diameter
48.006 mm be bore diameter

We will probably be the first ones with a forged rod + vitara setup in the country, so it'll be a learning experience. Going with stock D16 rods would be pretty pointless for a maybe 20 whp higher safety margin.

I've also read that some guys have managed to make B16/LS rods fit in these engines. That will probably be our next goal after reading and finding out what machining has to be done. Nothing like cheap B16 rods raping some tuner's unlimited-budget crap build :)

For the rest of the bottom end, please keep the suggestions coming in :)
 

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The Wife and the Car
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Discussion Starter #13
Thanks for the input guys.
Our piston CR height is 27.4

On the bikes. You can plug in a +4,6,8,10mm stroke crank and you get custom pistons and spacer plates that allow you to put it all together. Was wondering if they have something similar for the cars.

My first build will be NA. Since we already know the stock internals can handle 220 BHP. We plan to push the limits on NA. When that is done. We will boost. Wit a small/Med size turbo. After that go for forged internals and an all out turbo build.

THe trick with NA builds in this country is knowing how to port and tune for high CR.
Without deto. Cause the gas we get here is CRAP. You cant even buy high octane gas if you wanted to. you can try octane boosters. But even those only give you 2-3 points at best. And is not an option on a daily drive.

If I could somehow get the engine stroked to 90mm it would go a long way in helping pick up on that missing low end Trq.

Mr. Bone what was the reading on a compression gauge for your high comp setup.
 

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95 CX Hatch
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I would do a very stealthy hidden nitrous setup. something that couldnt be detected to the untrained eye. Build the bottom end using the stock crank, fjt custom length d15b rods with vitara pistons. Juice the hell out of it!
 

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The Wife and the Car
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Discussion Starter #17
Nitor / turbo / Cams / Ecus / ITBs is all pretty common stuff.
A nice stroker would be something different and would sure help the wimpy bottom end.
I like grunt in my motors. Not the ones where you have to spin the tits of it to make power.
 

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Brokedick Millionaire
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Nitor / turbo / Cams / Ecus / ITBs is all pretty common stuff.
A nice stroker would be something different and would sure help the wimpy bottom end.
I like grunt in my motors. Not the ones where you have to spin the tits of it to make power.
Then forget the D15 and honestly SOHC D's Honda's in general. You're not gonna get V8 style curves out of a I4...

Now a H23 or a F/H frankenstein could be a torque monster.
 

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The Wife and the Car
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Discussion Starter #19
We have a slight negative deck height.
Cynide has an engine open he can confirm the exact number.

Mr. Bone. Its all very relative. I just want the most power possible under 6000 RPM.
We never got any of those model's your referring too. And even if we could get an engine down. With some bribes it would not be a street legal car.

Ill figure out a new way to get that grunt and when I do. Will share it with you.
Have a few ideas on sim. Need to bring them to a boil.
 

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Honda?
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Really it looks like your trying to do something that just isn't really pheasible.

Is the 220 bhp goal running it naturally aspirated or boosted/nitrous? I know you're talking about bottom end stuff, but what about individual throttle bodies if you're going naturally aspirated?

I'm not very learned yet in engine building, but wouldn't your head choice make a difference on what pistons/rods you can run?
 
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