Building a powerful street NA d16y8/z6

[builthatch]

I am throwing this post together to make is easier for people to get info about getting the most out of a D16 VTEC, NA, while keeping it completely streetable. I am approached every day by people who ask me about my setup, etc, and this will make things easier for sure!

The advantages of going NA with the D16 VTEC are that it is easy to work on, the majority of the OE parts can be had for less than their DOHC counterparts (since alot of these parts are laying around due to DOHC swaps) and it will get you moderate power for moderate price.

This chart is one that i compiled previously to compare swapping vs. building an NA D16 VTEC. The one thing you need to keep in mind is- if you need more than 160whp, either consider boosting or swapping, because even tho the D is a value, it has a low NA power ceiling vs. the DOHC.

stock b18c5 - 161-165 whp, 109-113 wtq, cost 5K
stock b18c1 - 140-144 whp, 103-107 wtq, cost 4K
stock b16a2 - 132-135 whp, 94 - 98 wtq, cost 3K
stock b18bX - 121-125 whp, 108-112 wtq, cost 2K
stock d16vtec - 105-110 whp, 97- 101 wtq, cost <1K
built d16vtec - 150-160 whp, 114-120 wtq, cost 3K (90% OEM parts)

You obviously need alot of compression, tuning and a severely modified intake and exhaust configuration. I will go over the combinations that i like.

bottom end

If you live in an area where 93/94 octane gas is not available, your best bet is to try to keep your compression below 12:1, in fact between to 11.5-11:1 would be ideal. The piston i prefer for all setups is the p29 from 88-89 Integra d16a1. This piston is also found under the pm7 designation in the Japanese DOHC ZC. The reason i like it is because i know it works for all setups; there are no valve relief issues re: big cams, head configuration, etc. The catch with this piston is it has a lot of dome, so you will need to tailor your compression ratio by using assorted headgasket thicknesses. This selection depends on some things-

1. Fuel quality/availability

2. Head; the z6 head combustion chamber is larger than the y8 head, enough that, all else equal, the y8 head can raise the compression ratio approximately 1/2 point vs. a z6 head.

These suggestions are assuming you have close to a stock surface level head…meaning unmilled or no more than .010 milled. If you have more than that milled, you need to adjust the headgasket choice accordingly using one of the reliable d-series compression calculators available. The headgaskets I suggest are OE Honda metal 3-layer, A’pexi 1.1mm (.043”) PN 814-h101, A’pexi 1.5mm (.059”) PN 814-h102, or Greddy 2mm (.079”)

Some baseline configurations…(ratios are approximate static compression, assuming stock bore and unmilled head)

- y8 head w/ 91 octane – 2mm HG – 11.2:1 CR
- y8 head w/ 93-94 oct – 1.5mm HG – 11:8 CR
- z6 head w/ 91 octane – 1.5mm HG – 11.3:1 CR
- z6 head w/ 93-94 oct - .037 OE HG – 12:1 CR

Please note: some of the 93/94 setups have more room for compression, so another .010 off of the head through milling would be ideal. Typically, a .5 overbore will add approx. 1/10 a point of compression. My ideal bottom end for this setup is composed of all stock components. The stock rods are capable and rather lightweight pieces which should be at minimum shot-peened, a process that is cheap and adds strength. I would even feel safe at 200whp if these rods were shot-peened and cryogenically treated, which is a deep-freezing process that even strengthens them further. A popular upgrade is installing ARP rod bolts. This stems from the fact that a high-compression D with a big cam needs some more revs than stock, and with a 90mm stroke, the stresses on the rod bolts are incredible. I recommend all new bearings, Honda OE pieces, color/ number matched to the crank and at minimum plastigauged. Cylinder treatment is up to you- I personally like to over-bore to 75.5mm…any added displacement helps a 1.6L. Nippon Manufacturing offers 76mm cast p29 pistons, however, I do not agree with going that big overbore. I believe there is a reason Honda offers a max .5mm overbore, and that is with a stock engine! At any rate, over-bore is not necessary: 75mm is more readily available used and boring cost additional dollars. Honda recommends that if there are no score marks and cross-hatch is visible, do not hone, however, I recommend to at the least check cylinders for ovalling and hone per Honda’s bore/hone specs. Honda OE rings are wonderful. Stock wrist pins are fine, but I suggest using new ones. Make sure that the piston tops are smooth: the better the polished surface, the less chance for detonation. Balance the entire bottom end to 10,000 rpm. I feel compelled to mention that there has been talk about the y8 oil pumps being inferior re: oil supply vs. z6. I have used y8 oil pump with not one issue of such starvation, however, if you prefer, manufacturer TOGA offers a higher volume oil pump for this application.

Head

People bicker about which head is supreme and for good reason. The z6 head has ideal ports for better flow and the y8 head has a better and smaller combustion chamber, which resists detonation. I used to suggest using the head that is easiest to adapt to your chassis, but i no longer feel that way. This originated in the fact that the engine harness plugs for an obd1 z6 distributor will not work with the y8 distributor, and vice versa...and, you can't use the z6 dizzy on the y8 head because the arms will not line up. I feel that the best bet is to use the z6 head. If your are putting this in an obd2 car, then take the insides out of the y7/y8 distributor and put them in a z6 distributor so the arms can line up to the head. I feel it's worth it. A z6 head has straight ports called tumble ports and a y8 head has off-set ports called swirl ports. Without getting too crazy describing them, the tumble ports can promote the best top end and the swirl port can offer somewhat better low rpm torque and better mixture and MPG with the right tune. But the bottom line is the ports are offset with the y8 head and that will limit your top end power making capability. It's not to say that you can't make power with a y8 head, you can, but it's just not going to be able to go where the z6 head can as far as high-end power, flow and rpm. Granted, the y8 chamber offers better resistance to detonation due to it having more quench area; part of the reason they made the CC smaller was to fit these areas. Make sure that all edges of the CC are smooth to prevent hot spots. Another performance difference is the ports.A requirement for high-horsepower NA is porting. You NEED to have a properly ported head to eclipse 150 whp. Even a mild-port job will suffice, however, the more extravagant the porting, the more power potential. The cam to use is the Crower Stage 3 cam, hands down. Regrinds are limited (amongst other things) and other fresh billet cams are just not optimized the way the Crower profile is. It has the most advanced profile for these engines and offers the broadest power band. Again, this cam requires porting to be effective, and also you must install valve springs and Ti retainers, Crower. I use new stock keepers, however, you may feel inclined to use performance branded ones. Their Ti compound is very resistant to wear, it's called Ti-17 and is supposedly tougher than the stuff everyone else uses, 6AL4V. An adjustable cam gear might be necessary for tuning, though I find that Crower Cams do not need incredible adjustment. I ended up keeping mine at "0". Please note: there is a difference between z6 and y8 cam gears. The only cam gear I recommend is AEM. They have the difference between the keyways of the z6 and y8 nailed. Many manufacturers DO NOT! New OE timing belt is fine. OE valves are fine. A 3 angle valve job will assure consistent seat seal. I use OE Honda head bolts, however, they can only be used once so if you want to, ARP head studs are ideal for those of you who like to take the head on and off. Make sure to contact ARP for their recommendations on which combination or kit to get…block and head configurations cover a vast array of different ARP sets. I recommend using HYLOMAR spray gasket coating available through VALCO Cinicinnati. Torque the head as per stock specs or ARP specs, however, if you are using an extension, remember to compensate by adding 5 ft/lbs or so on the wrench!

con't V

[builthatch]

bolt-ons

I recommend a smooth-tract tube cold-air intake of 3” diameter. It provides a nice torque hump at low rpm and also offers access to more dense air. An upgraded throttle body is optimum, 62-65mm are popular options. The intake manifold is very important. My favorite is the Skunk2 offering. It is cheap and works well and has a 62mm ID TB bore. There have been issues with quality control with the entire Skunk2 line, however, several Skunk2 intake manifolds (h22, b20, sohc) were manufactured in factories with good QC so the risks are low. I have had no issues with mine nor has AgentJam. Fitment is poor in an EG, and really tight in an EF (but doable). EK fitment is fine, however, some adjustment will have to be done to a few brackets on the firewall. If you have an EG, I might suggest the Edelbrock unit. It is expensive, but is superior to any OE manifold. I do not know about adapting a tube cold air to it, since that manifold has a unique angle for the throttle body. Port-matching is ideal for this manifold to your head, however, I did not see a need for it with my particular setup. Inspect yours to see if the path of runner-gasket-port is smooth.

Header choice is limited to one- SMSP. Contact member SMSP for price info, however, this header is not cheap. It comes in mild-steel, so coating will make it even more expensive. The thing is, it makes the most power of any header available that works with A/C and/or P/S. In fact, I would pit it against the crazy headers that due to their bends don’t allow for these creature comforts. The exhaust is up to you, I just would make sure there are no sudden restrictions or dips in inside diameter. I prefer a 2.25 ID. Not having a cat is ideal, however, SMSP offers some high performance functioning catalysts if you can get away with that in your area. An ignition is not necessary, however, i feel it helps. A multiple spark unit with external coil assures complete combustion and spark survival in the storm of high-compression cylinder conditions. I prefer either NGK wires or Nology Hotwires (if you have the money). Both work fine, however, I have found various small improvements in a few areas with the Hotwires. Dyno sheets with these will be coming soon vs. NGK. Stock rotor is fine with an MSD Cap. MSD now offers performance rotors, this might be something to consider.

tuning

To assure your build doesn’t die from a dying fuel pump, I recommend an upgrade to a 255lph fuel pump from Walbro. Yeah, it’s overkill, but it cost the same as the 190lph and is not any less reliable, so just get it. A new fuel pump is a wonderful thing. Stock injectors are perfect for this build, provided they are not dirty. Most of the smaller displacement 1.6-.8 Honda injectors are 240cc. The lone exception is d16y7 injectors are 190cc, so do not use these. Your best bet is to send the 240’s you choose to RC Engineering to get them balanced and flowed. Fuel pressure regulator upgrade is recommended, even though you will have a tuneable ecu. The reason is optimum atomization occurs @ 55psi with these Honda injectors, which is a significant amount over stock spec. I got this information from SOHC VTEC legend Nathan Tasukon who did extensive testing with his company Motec. I like the on-rail AEM unit as it is perfect. It’s got a reliable diaphragm, and adjustable return orifices, meaning you won’t have issues with the big fuel pump like you would if you used a modified stock FPR (like the Vortech, B&M, Hayame, etc). The spark plugs to use are NGK bkr6e-11 or 7e-11. The heat range depends on a few things. If you are running the lower tier compression levels (<11.5:1), then a 6 should be fine year-round. If you are in the higher compression bracket, then you might want to run a 6 in cold weather and a 7 in hotter weather; that is what I do. To get the target NA power levels, obd1 conversion is necessary due to its extensive tuning capabilities, unless you are using an obd2 adaptable engine management like A’pexi Power FC or AEM EMS. The Power FC is what I use and I feel it is an incredible value for what it offers. On-board parameter monitoring, knock monitor, etc & light adjustments via the in-cabin commander, with deep tuning capability via PC. It also features a very powerful idle stability feature which keeps the wild Crower 3 cam stable in all idle conditions. Some viable tuning options are Neptune, Hondata, Uberdata, etc. It has come to pass that RPM switches, VAFC, E-Manage, Z-Dyne, etc are not practical options for this type of setup. Full tuning range is required, both timing, fuel, and various other parameters where stock settings will not suffice. A capable tuner on a eddy-current type dyno is ideal for max power tuning, while still being able to tune other than full-throttle throttle positions/ vacuum levels. I recommend a Mustang eddy dyno or Dynapack for tuning and a Dynojet for internet comparisons.


4/25/07: EDITED HEAD CHOICE OPINION

[Blanco]

Great info. Just one question, where do you guys find ARP rod and/or main bolts for D's?

[Import Al]

That answered a lot of questions I had before.

I have one question though; do I have to bump up compression to like 11.5+ to run a wild cam like Crower Stage 3?

I want to build a JDM D15B N/A but would like to run regular gas.

If a fully-built high compression sohc got about the same gas mileage on premium (91 octane), it would be fine.

The D15B vtec has a nice cam anyways if I left it stock.

[Honda4VW]

Originally Posted by Blanco

Great info. Just one question, where do you guys find ARP rod and/or main bolts for D's?

They do not make main bolts, however you can get them vustom made with an ARP supplied measurement form

One thing to add is that if you are trying to work with headgaskets....stay away from anything over .070" thick. There tends to be great diffuculty in keeping these sealed

[builthatch]

Originally Posted by Import Al

I have one question though; do I have to bump up compression to like 11.5+ to run a wild cam like Crower Stage 3?

I want to build a JDM D15B N/A but would like to run regular gas.

If a fully-built high compression sohc got about the same gas mileage on premium (91 octane), it would be fine.

i would not recommend this...the dynamic compression would just be too low...it's just one of those things....

you can get pretty good gas mileage on a high compression d, it simply depends on the tune and driving style. Agent Jam claims 30 something....

however, having an engine like this can nudge you to get on it very often, so i would look for approx 25mpg or so average.

[builthatch]

Originally Posted by civic4ges

They do not make main bolts, however you can get them vustom made with an ARP supplied measurement form

One thing to add is that if you are trying to work with headgaskets....stay away from anything over .070" thick. There tends to be great diffuculty in keeping these sealed

stock mains should be MORE than enough man!

i've done a bit of research with the 2mm HG and it seems the people who use these are often boosting, hence the increased potential of issues.

in speaking with a few builders, many feel, like AEBS, that with straight mating surfaces, proper torque process including well-lubed bolts, and hylomar that there should be no issues with such a gasket...

great info answered a few of my questions too.

[AgentJam]

Originally Posted by builthatch

you can get pretty good gas mileage on a high compression d, it simply depends on the tune and driving style. Agent Jam claims 30 something....

I beat the crap out of my car, and when i say that i'm not kidding. In my 88 crx dx i have gotten no less than 29mpg even balance city/highway. When just highway I easily get over 40mpg (i calculate my gas mileage each and everytime i fill up).

It's about as good on gas as the stock y8 was a few years back with only an obd1 conversion.

I was soooo surprised how good my mileage was with this build...i love it!!!

Vince

[f00ker]

good thread, might I add...dont use the p29's at all, if you dont have tuning! Stock brains = blown motor

[modsHXcivi]

good info built ....you the man

[berettagtz117]

Good shit man!

[builthatch]

Originally Posted by berettagtz117

Good shit man!

guys thanks for the responses!

[domnic]

good shit... saved me a lot of searching... awesome writeup!!

that was good to know,cause im building an engine as we speek,i used the p29 pistons,skunk intake manifold,megan headers,3 angle valve job, zcvtec aggressive cam exc. i hope to get good power over stock...but good write up in deed..

[orangePEEL]

Best Write Up Thread Evar!!!!!! Good Job!!

[elgs]

Good info!!!!!

Have some questions.

With a y8 head(not milled) on a y8 block(not milled), with a 3 layer oem headgasket, you get a 260psi of cilinder compresion.

With the same setup, but with the head milled 0.040", what would be the new cilinder compresion? maybe 300psi-310psi?

[builthatch]

Originally Posted by elgs

Good info!!!!!

Have some questions.

With a y8 head(not milled) on a y8 block(not milled), with a 3 layer oem headgasket, you get a 260psi of cilinder compresion.

With the same setup, but with the head milled 0.040", what would be the new cilinder compresion? maybe 300psi-310psi?

it depends on the header, intake, cam, comp. tester, crank number and battery charge...but the first number (260) sounds incredibly high for a stock y8 block....are you talking about a y8 block with p29's?

[elgs]

it depends on the header, intake, cam, comp. tester, crank number and battery charge...but the first number (260) sounds incredibly high for a stock y8 block....are you talking about a y8 block with p29's?

Ok, for example, the engine has a dc sports 4-2-1 header, stock cam, new battery, full build head, mi engine drop that numbers, but the head is not milled, and yes is a y8 block with p29s, the crank number i dont have, but is a y8 crank.

If i mill my head 0.040" with that same setup, what could be the new compresion?310psi?320psi? what about the new cr?

Thanks...

[builthatch]

Originally Posted by elgs

Ok, for example, the engine has a dc sports 4-2-1 header, stock cam, new battery, full build head, mi engine drop that numbers, but the head is not milled, and yes is a y8 block with p29s, the crank number i dont have, but is a y8 crank.

If i mill my head 0.040" with that same setup, what could be the new compresion?310psi?320psi? what about the new cr?

Thanks...

by crank number, i meant how many times the engine is cranked during the compression test. sure, 260 sounds normal in that case...

with the .040 milled, i would assume it would increase substantially since the static CR would jump up to almost 14.5:1 (14.4:1)