Let's say I want to keep the dpfi on a d15b2 but increase compression to about 10:1. What piston do I use and what is the limit for the dpfi system to handle?

If this has been answered elsewhere I apologize. I searched but couldn't find an answer. Thanks for your help.

 

The limit to the DPFI system is the factory non-sense. DPFI is dumb. do yourself a huge favor and MPFI swap it, it will give you just as much if not more power than the pistons, especially if it stays DPFI.

to answer your question I would imagine that wiseco makes something that will fit your application.

 

its pointless to tell you the truth think about it 2 injectors for 4 cyl's come on. but man does the b2 wake up with a mpfi swap and a6 cam and y7/y8 cam gear.

 

That would be cool but I already have a g20 with sr20ve motor. Don't really need a d15b2 to wake up. I'm aiming for better combustion of fuel to help with fuel economy. I may just go for the thinnest headgasket I can get in there. I like the idea of a cam and cam sprocket.

Does anybody make an economy cam for these motors?

 

I could be wrong, but i believe the pm7 pistons drop right in, i was pretty sure it said ALL d-series, might just be d16, can't remember, but anyways, if it fits, it will for sure raise comp. I've been looking at a set from Nippon racing, like 120 a set + rings/pins. I believe they make the pistons for oem honda, so reliability isn't an issue. They have a set that'll supposedly raise c/r to 10-12.1 depending on motor.

 

Excellent, I'll look into it. Thank you.

 

Anytime, look on ebay, that's where i was gonna source em from, but they are Nippon, and i've read several reviews from civic owners using these without any problems. For the money you can't beat em, just don't boost! lol..naturally

 

Honda makes the stock OEM economy cam for the motor.
These cars are econo-boxes... not sports cars.

The cam profile isn't crazy on these engines and stock compression is about 9.2:1 (if I remember right) with the design intent to run 87 octane.
With your proposed 10:1 compression you are more than likely going to have to run higher octane fuel or retard your timing (will end up dumping fuel amongst other problems that will surface over time - fouled spark plugs, fouled O2, clogged cat, etc.

So I don't understand your angle of 'economy' where you are spending money on parts, time, labor, and more expensive fuel.

If you really want to go economy, change out your transmission for an HF unit... or even better do the whole HF swap. It will probably cost about the same as getting the aftermarket pistons.

 

HF transmission or 4 speed transmission to save fuel.

 

Well, you don't get better economy by leaving everything the way it is...

Again with everyone on the hf trans, it may be effective, but 1. it is more expensive and harder to change the trans than switch the pistons, don't have to drop everything for that, and they cost about 120, i can't get a trans from pick n pull for that price, besides the fact, the hf trans is dull, there's no fun to be had when you want to, it's better to make an effecient engine and keep the trans.

 

All good points. Thanks. It makes me think before I act. I may just switch to obd1 for tuning ability.

 

[QUOTE=BigD4207;45420433]
1. it is more expensive and harder to change the trans than switch the pistons, don't have to drop everything for that, [quote]
Oh really? A clutch job costs about $300~400 labor and basically requires the trans to be dropped. Just tell the mechanic to put in the HF trans and you are done.
Honda pistons come out of the bottom of the engine and you have to remove the crank to get them out. So, you have to take your timing belt off, drop the oil pan and crank. Right there is $$$$$. But wait - there's more! No respectable mechanic will do all this work and not check your cylinder walls. So expect to pull the head off the engine too and hone the block. Then you get to reassemble the block along with all the refreshed bearings and bolts.
My *** it's cheaper to do pistons than a trans.

Please link me a set of aftermarket 10:1 compression pistons for $120.
Your pick-n-pull is a rip off. Private sellers that sell their engine for a swap would be a better place to shop anyway.

OP was talking economy so this should have been left out of your post

 

[QUOTE=4drEF;45423766][QUOTE=BigD4207;45420433]
1. it is more expensive and harder to change the trans than switch the pistons, don't have to drop everything for that, I can get the bore honed here for like $50, pistons 120, labor for me...free. So yes it is cheaper, of course i do it all myself. And in that sense, it's easier for me with what i have to change the pistons than the trans. And actually...there's tools to hone your own block, though i don't recommend most do this at home, and you can do that in the car if you're careful and have an air compressor or power sprayer for cleaning. So yes, regardless of what you might think, it CAN be cheaper to do the pistons, just depends on circumstances and location, and naturally, what you are comfortable and able to do. Oh, and you said, just labor is 3-400, that doesn't include parts dude. New clutch and trans, something i wouldn't pay for to get less out of the car anyways hf trans is weaksauce, but regardless, 3-400 isn't gonna be the final price of that one. I'd do all this for under 250, just price of parts, not that i'd necessarily do it for that price for someone else. Pick n pull isn't really a rip off either, you wanna spend 10x as much for new oem? BE MY GUEST lol....haven't seen many private sellers sell an entire engine for under $200, never in fact. And here are your $120, well 135 now that i look at the buy it now price, but still 10.1 c/r pistons.. http://cgi.ebay.com/ebaymotors/JDM-N...Q5fAccessories

 

For fuel economy, maybe just get a better flowing air filter with 13 inch steelies with low rolling resistance tires filled with like nitrogen.

 

Actually they don't. The way the engine is cast/machined prevents them from dropping out of the bottom (upper main journal seats are blocking the cylinder partially at the bottom). This does however reinforce the need to remove the head.

Just pointing that out in case someone tries to do this and finds out the hard way...like I did a few years ago

 

That's something i wasn't really sure about, thanks for clearing that up. Still, much rather take the head off and re time than drop a tranny, at least it'd keep me from throwing my back out lol.

 

Hahaha, gotta love them nitro tires lol. But that does bring a good point of wheel size, any time you lower a cars rotational force, you gain mpg cause it takes less to actually make the wheels move, lightweight wheels and low pro tires would make a good improvement, just depends on how you go about it as to how it affects ride quality, not really sure, don't see many people purposely put smaller rims on. Good thinking though. However, i would try to find some good light alums instead of steel, if strength isn't a concern weight is the only factor.

 

Actually, one of the best things about car work, that I really enjoy....laying on the ground, under the car, on cardboard. It's great for the back. Actual work is not, but laying there...very relaxing.

 

Yup, economy is the goal. I also meant to keep the dpfi system, just add a little more compression.
I'm starting to think that it's just better to convert to obd1 for tuning. That likely means I'll swap in either the d15z1 or the d15b8.

 

You are 100 correct. I was typing too fast with a different point in mind. I have built engines so I have no idea why I had a brain fart like that.
I was meaning to explain that the crank has to come out as well as the head.
This isn't a cut-dry process and replacement part cost and labor involved adds up quickly.

Looking at what "BigD4207" had to reply with, I'm sure he could do this 10:1 build for cheap.
But personally, I have and never will use eBay cheapo parts.
I don't know what you have in mind, but I like my engines to run reliably and have peace of mind for the quality of the parts in it so I don't suggest to anyone to do something that I feel would compromise any of this.

Honda OEM stock pistons from the dealership are about $160 for a set +rings. Right there you would be spending $40 more than those "performance" pistons in the link. However, when you buy a known brand name performance racing piston you will see the price soar far and above in ranges like $400 ~$700.
And don't forget about gasket sets, bolts and bearings.
Just the Honda cylinder head gasket alone is $45 - but then again there is eBay (search and see what people are saying about the quality of different headgaskets.)

 

^I had a feeling you just had a brainfart

 

Hahaha, i agree it is very relaxing, but the working part kills my back, i've had bad back problems for years, so it's easier for me to work on top, trying to hold stuff underneath does me in.

 

Actually...from what i understand, Nippon is the company that makes honda's factory oem pistons....so reliability and quality aren't an issue. And futhermore, i have heard from plenty of honda fanatics, many even on here and the zcr, have used these with zero problems with the quality. Nippon isn't just some off the shelf toss in ebay pistons, they just happen to sell their stuff on ebay. And, unlike most, made in japan for japanese motors. Who can improve on their own stuff better than the japanese. Also, i was posting with the assumption the op would be doing this himself, labor would rack up pretty high in either case, and depending on who you know or where you go, could be cheaper in either case. It was all just a viable option for a good and fairly cheap high comp setup.