elevatethis

Looking to increase my compression as I build my all motor d-series. Not trying to win any NIRA circuts, but just trying to build a quicker SOHC.

Anyone have any suggestions as to what pistons I should use?

Upon increasing compression, are there any other modifications I need to make to the motor as a result (ignition, timing, air flow, etc)???

Bottom line is, any opinions on whether this is worth the cost, or should I look elsewhere since I am just starting out?

The GreenD16

There ya go.

https://honda-tech.com/zerothread?id=335078

BauleyCivic

P29's...they'll up your compression to about 12.5...heh have a ball

Spade

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BauleyCivic &raquo;</TD></TR><TR><TD CLASS="quote">P29's...they'll up your compression to about 12.5...heh have a ball</TD></TR></TABLE>

Not recommended for 91 octane users.

If you cannot get higher than 91 octane suggest looking into the PM3's
11.1:1 Compression.

AgentJam

How much power does raising your compression actually give you? Given that the rest of your engine is stock and all you replace are pistons, rings, and rod bearings. Say a Y8 is brought from stock (9.6:1?) to 11.1:1 how much power would that yeild? I'm looking to do the same thing.

Thanks,
VINCE

BauleyCivic

Rule of thumb...1 compression point roughly equals roughly 10 HP

westcoaststyle

There's a guy on http://www.turbod16.com selling a set of SRP pistons at 0.020 overbore with Eagle rods for a D16Y8.

hih

v4lu3s

going by one compression point is worth 10hp, that would mean that going from 9.6:1 to 11.1:1 would yeild gains of 150hp
that doeesnt sound right to me....

AgentJam

I dont want to yank my motor (d16y8) but i want to bump the compression to somewhere between 11-12:1 From what i'm looking at with an otherwise stock engine the PM3 (USDM D15B7) Pistons will give me around 11.3:1 ratio.

To my next question...Can i do the piston/rod swap myself if i have never done any bottom end work before? I'm a quick learner and am determined however i don't have any special tools available to me besides a craftsman set . Given that my sleeve's aren't scratched, what else do i need to replace...

1. Rod Bearings?
2. Piston Rings?
3. ???

Thanks in advance,

VINCE

westcoaststyle

Since you're taking them out, I would replace the rod bearings. Get OEM "colored" ones. I put some green and some brown in there. Honda should know what you need if you call them and give them info on your block.

New pistons will come with rings. You will need to file them or have them filed to fit the cylinders correctly.

You will also need to get a piston ring compressor to put them into your block. A rubber mallet and wooden dowel is also a couple good things to have.

hih

AgentJam

Thanks a lot by the way...one more quick question. Would this setup be reliable with the rest of the engine being stock? I plan on a cam some time down the line but i want this engine to last a few more years.

Thanks,
VINCE

SOHC_MShue

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v4lu3s &raquo;</TD></TR><TR><TD CLASS="quote">going by one compression point is worth 10hp, that would mean that going from 9.6:1 to 11.1:1 would yeild gains of 150hp
that doeesnt sound right to me....
</TD></TR></TABLE>

15whp every 1 point = about 10whp not every .1 points.

kommon_sense

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by v4lu3s &raquo;</TD></TR><TR><TD CLASS="quote">going by one compression point is worth 10hp, that would mean that going from 9.6:1 to 11.1:1 would yeild gains of 150hp
that doeesnt sound right to me....
</TD></TR></TABLE>

going from 9.6 to 11.1 is only 1.5 points, not 15...

AgentJam

I get it...i'll be getting anywhere from 15-20 whp depending on my outcoming compression. Will rasing compression to this ratio be dangerous at all to the reliability of anything else in the engine/head? or will i need anything more than a FPR?

Thanks,
VINCE

AgentJam

anybody? i know this is probably a simply/stupid question but....

MrTodd

At the very least you'll need an adjustable FPR... Have you converted to OBD-1 on your CRX? What exactly are your current mods as far as electronics/tuning-options goes? (my mods are in my profile)

I'll soon be tossing in PM3 pistons in my Z6 block. Combined with my Y8 head, y8 headgasket, it should be giving me between a 11.5-12:1 CR, depending on the piston-to-deck height (you really can't tell this until the pistons are installed).

I already have a V-AFC, FPR, and a good (not cheap autometer)A/F guage - so I have enough tools to tune it somewhat (it will be on a dyno someday).

Good Luck with the setup! If you finish yours before mine (which you probably will), let me know how it turns out!!!

AgentJam

I've got a FPR ready to go it but my existing mods are DC headers, Intake, Exhaust and OBD1 conversion with P28 ecu. I've got a D16Y8 engine with Z6 IM so injectors are matched to ecu. Do you think i should be alright? I know i need a A/F gauge soon as well. A few more Q's...

1. When tuning with A/F gauge do you always want it in Stoich? I've heard people making it run lean but from what i know it's bad.

2. Do you know any good resources on how to change out pistons/rod bearings?

Thanks and good luck with your build. I wont start till probably after winter just because right now i need my car everyday.

Thanks,
VINCE

BMac86

Im thinking of doing the same thing, with the D16a1 pistons I believe. Whered do you guys get your parts and what does it run you? Anywhere besides the good 'ol H dealer, theyre such a rip-off IMO. Supply and Demand dammit.

AgentJam

I thought honda was the way to go...that's where i plan to go i don't have my parts yet.

SOHC_MShue

yea man the d16a1 pistons are the way to go. Super high compression though. Make sure you get it tuned well though. I've heard you gotta run 93 octane and tune well to run those pistons. I'm thinkin about d16a6's. They will give about a point lower than the a1's and be a little safer.

AgentJam

Hmmm i'm showing a 14:1 ratio for d16a1 pistons which IMO is way to hight. I don't know too much about this stuff but so far what i've researched it's hard to run on an everyday driver. Mine will be an everyday driver so with a stock D16Y8 i'm using PM3's (D15B7).

BMac86

Which ones should I do? The a6's or the b7's? Thanks!

BauleyCivic

You all are ******* retards...B7 PM3 pistons wont fit in a D16...

AgentJam

they wont? not to question you but i've heard it done in other threads...can anyone confirm this?

AgentJam

https://honda-tech.com/zerothread?id=588692

Then what does the last post mean? Thanks for the help and encouragement anyway...