3-Stage VTEC--COMPREHENSIVE INFO ON D15B/D15z7

[SYeNi69]

Hi ZTH members ... I'm keen on knowing the potential of a D-series engine ... unlike in the states ... most of the honda's there are still running with these engines .. either built N/a to turbochanged ... i own an EK3 which i brought back from HK when i was there ... It comes with a D15Z7 aka D15B engine ... unlike most of the 1.6L EK's in M'sia mine is a 1.5L ... i found some info on the net ... and reading from the D-series websites on the net .. they love this engine and are saying that it has alot of potential ... problem is ... i've yet to find a workshop that has done a D-series buildup ... apart from PnP/exhaust/CAI. All workshop malas layan when i say single cam ...

Yes i know that swapping a B engine is a good platform but i find no reason to change something that's still in very good cond.

I'm sure it would be rude to tell a pomen to read some post of how those guys in the US build the D-series ... So i won't even bother ...

Has anyone here ever tried to mod a D-series engine ?? results ?? satisfaction ??

p.s. i found this on the net.

FOR (stock) HPs
D15B (D15z7) D16z6
FOR MPGs
D15B (D15z7) D16y5

Alright, now that I got that out of the way, here's for the "intelligent talk"

There is such a massive amount of confusion surrounding this engine, mostly because of the confusion with the OBD1 D15B (Maybe the "engine naming guy" at Honda Japan wasn't there that day?), and because of the complexity of the entire system.

I would like to start referring to this engine as the D15z7 (its EDM designation)...i hope this catches on. "3-stage VTEC" or whatever is too cumbersome.

Due to this complexity, this engine is neglected by tuners, regarded as an "economy engine".

BEFORE you judge it, PLEASE become educated. I LOVE this engine, and I think with a little work, it could be a FANTASTIC DD engine. Sure, it ain't no GSR or B16, but this engine uses a LOT of fantastic technologies, and should at least be regarded as what it is.

So, basically, its a 130HP, single cam engine that uses BOTH VTEC and VTEC-E. Here are some basic Stats and background info:

D15B 1.5l SOHC VTEC

And another easy-to read site:

Cause For Alarm ver6.EG - 3 Stage VTEC JDM D15B

D15Z7
3-stage VTEC
Found in:
1996-1999 Honda Civic VTi EK3 and Ferio Vi
Displacement : 1,493 cc (91.1 cu in)
Bore and Stroke : 75 mm × 84.5 mm (3.0 in × 3.3 in)
Rod Length : 137 mm
Rod/Stroke : 1.62
Compression : 9.6:1
Power : 128 hp (95.4 kW, 130 ps) @ 7000 rpm
Torque : 102 ft·lbf (14.2 kg/m, 139 Nm) @ 5300 rpm
Valvetrain : SOHC VTEC (3-4 valves per cylinder, depending on rpm)
VTEC Switchover : 3k±200rpm (12-16v crossover) rpm 6000±200rpm (Aggressive cam)
Fuel Control : OBD-2 MPFI
ECU Code : P2J

Basically, its a D16y5 VTEC-E system combined with a D16y8 VTEC system. operating in the SAME engine.

THE TECHNOLOGY

Because we all know what regular VTEC does, i'm not going to go into that, but i'm going to give a quick lesson on VTEC-E.

SWIRL: its what's for breakfast.
Swirl is the pheonomenon that a jetstream of fresh air/fuel mixture circulating around the combustion chamber does not allow the atomized particles to "clump up", and therefore promotes a VERY homogeneous mixture inside the combustion chamber. Because of this fantastic mixing, the fuel is more completely and efficiently burned.

So because the fuel is used more efficiently, less of it is required for combustion. Therefore the A/F ratio can be as high as 20:1 with no decrease in performance or threat of detonation.

During the first phase of the valve operation, one intake valve opens (technically both open, but the second one is such a small lift we can pretty much disregard it in a theoretical discussion), and the intake air can SWIRL in and bask in its efficiency and awesomeness.

In higher RPMs (above 3k), the single valve cannot flow the intake A/F mixture into the combustion chamber fast enough, so 16V operation takes over (pretty much "normal" operation for a standard VTEC motor)

Then, in even HIGHER rpms, VTEC happens and that's where we get the highest hp numbers.

So now that the technolgy is covered, Let's talk about the engine itself

The trickiest thing about this engine is the tuning. Because of the multitude of valve operations, the ECU programming is complex. The P2J ecu is OBD2, so you can only run that with a stock-ish engine.

A standalone system is the only thing that could possibly do this engine justice, but an IMMENSE amount of tuning and dyno time is necessary to squeeze the full potential from the engine.

I know there are quite a few people out there who have gotten this engine to work. Mostly on their own. If we can unite all the knowledge under one thread, i'm sure we can crack down on unlocking the awesome potential of this engine.

There's much more to come with this, but for now, That's all i got time for.

I am by no means a D15z7 expert. there are a LOT of people out there who can illuminate much more about this engine. I hope you guys can add whatever CONSTRUCTIVE info about this engine.

 

[SYeNi69]

Anybody ??? Takkan all main DOHC ... where are the SOHC Vtec ???

 

[dcloo]

not to says D -series was not good
1st- How the performance if compare to 4G15/4G91 or cam pro/neo?
2nd- malaysia was very hard/rare to get performance parts for D-series
3rd- if going to boost how reliable its can hold for your engine life spent
4th same amount money you spent on D-series which you made modification on B-series/K series(example cam shaft,con rod, bearing,close ratio) so the total out i think you can figure it out by yourself

just my 2 cent no heart feeling VTEC

 

[SYeNi69]

Hi dcloo

I'll answer ur questions ... correct me if im wrong ... i'm pretty noob at this ...

1st - So far as far as the once u mentioned ... i have no probs with thoose ... i've done a couple of benchmark with my car including with stock Putra and Gti ... not to say i won or anything ... but my car was ahead and my engine is a 1.5L

2nd - i would have to agree with u on that ... but then finding to me is not a problem ... but to find a person who's willing to RND the engine ... '0' ... and to find a workshop who knows what their doing ... thats the hard part ... and i dont wanna be the 1st person to try or a.k.a. LAB RAT

3rd - about BOT on a d-series ... i have read alot about this ... and the weak link on a d-series engine would be the conrods ... so freaking thin ... eagle has made custom rods ... price is not too expensive and can be bought online or ordered through authorised dealers in M'sia ... sources - Turbo D16 website ... other stuff like piston all can kacuk ...

4th - but then to start of with a D engine and dump the RM7-8k money for b-series in it ... i'm pretty sure it can easily makan a stock B16A (as the US people claim and i find true) ... cam shaft/LSD/gear ratios can be made by Charlie matspeed ...cams weither regrind or billet ... cost also about the same as some would buy HKS/BC/Skunk2 ... bear in mind that product liability for Matspeed cams is 1M ...

What im trying to say is ... everytime i go to workshop i will see these D-engines lying around everywhere left to root or sold to besi buruk ... its sad cause the people in the states prefer this to a B-series engine why not us ??? ... if proton and mitsu engine 1.3 and 1.5 also people mod kawkaw here ... why leave the D-series 1.5 and 1.6 ???

p.s. - the truth is i wish can afford buy B18C5 or K20 straight ... but to mahal ... so wanna experiment 1st with my factory given engine ... and try to do what those poeple in US doing ...

 

[aalto]

If you pump in 7K-8K on a d-series, you'll probably smoke a stock B16a...but not by that much..

So how long do you think you'll be happy smoking stock B16a's? not long I would guess...

how bout modded B series then? you'd have to pump in more cash for your d-series...

Theres also more options for performance parts on a b-series.

Then there the reliability issue....the more you mod the lower the reliability....

But in the end....it's whatever makes you happy i guess......even if its just to be different then go ahead....

 

[deacon]

This particular D series engine has tonnes of potential, but you need to do research on what parts are needed to perform an upgrade in power.

I would suggest getting a custom regrind cam perhaps from matspeed (but only if you know what durations you want). Preferably something that can accommodate the 3 stage vtec system.

Then were it me, i would attempt to swap the bottom end for a D16 if it all bolts up nicely.

With a SOHC you get less rotational losses but then again having to operate two sets of valves and springs with one cam shaft could produce some unwanted stress.

Perhaps you should hit up forum from which you got this info, look for a setup that's relatively easy to perform and copy it wholesale. Start with the build threads they usually put their specs down with pics included.

 

[LuKa]

its the same in the states as well bro... Vtec Dohc B-Series aint cheap there as well... not all honda modders uses a B series motor for their civics...

the D Series are more popular there since it is much cheaper.. n most of them can do a head swap for their existing D15 or D16 engine for the Single Vtec head convertion.. which is in malaysia equivalent to Eg8 1.5 single V.tec and Ek99 Spec Local Model (EJ) with 1.6 v.tec single cam... also.. in the states their modification job or transplant is rated by hours of work which is expensive n not like in malaysia which is total package of installation... thats y the american like to DIY almost everything they can... tools and equipments for DIY are a norm to see in their garage or houses due to this reasons.. and americans dont like the idea spending n having loans on cheap japs cars to refurbished or do transplant...the max is credit card usage for parts n that it.. the rest is DIY.. coz maintaining cars is expensive enough in their country.. they rather spend it on morgage n stuff...

While

in malaysia the D Series is less popular.. since Malaysians find that the head swap does not make much different hp and response for the Head swap for the normal Honda 1.5/1.6 Efi engines.. plus the gear box ratio isnt as good as the Vtec 4.2 n 4.4... also plug n play parts are not easily found in aftermarket shops for further upgrades.. u need to modify or fabricate to fit the D series engine... however the D Series is a good engine for a stock non racing type user.. easy to maintain n a bundance of used parts u can salvage... Malaysian like to follow the latest trend... now most modified civic are equip with JDM parts inside n out... n malaysian would go to extend to get personal loans to own a B-series honda or to get an engine transplant..

 

[civic EdGe]

D-Series engines are not so popular here...... I have to agree that quite many workshops do not layan D-Series engines.... the ones i came across that layan the D-Series are not that knowledgeable in Honda engines, at least from what i have observed.... Kesian those D-engines lying around, rotting into besi buruk...

For the RnD part, i think most of it will have to depends on your own research....
You can try honda-tech.com, d-series.org and zealautowerks.com to get ur info n play around wif the compression ratio, CC and etc of your future build.... (maybe u already know this since you have searched the potential of the D15B through mat salleh sites)

I have been crazy bout the d-engines before as well.... read up quite a lot on it... in case you have done so, u will notice a few "usual" builds, such as using JDM ZC pistons to bump up the compression ratio, combining better flowing heads with high revving block (D15), swapping for better flowing IM from other D-engine and etc... usually D15 blocks are preferred due to shorter stroke n higher R/S ratio, therefore more suitable for higher rev limit compared to D16......

And to sum it up, I am personally still using D16 non-vtec.......sigh...
Would love to convert to B-Series, but...... no money la...
So, cant help u on the recommendation of workshops to pioneer your D-series build...
Anyway, Good luck in your project!

* btw, anyone knows the market price for D15B halfcuts or other SOHC Vtec halfcuts?

 

[LuKa]

dont need to buy halfcut... theres plenty of engine lantai at chopshops.. u can mix n match if u already hv a D series block in yr honda

 

[webeck948]

I also own an EK3 D15B with multimatic transmission, sad how very little can be done( or sourced here) to it, I would too go for a B series transplant if I could afford it haha!

Please share more of what we can do with what we have!

 

[SYeNi69]

hehehehe ... i have searched alot though thoose american forums .. and from my investigation hehehe ... there is one malaysian by the nick BIG[V] in these forums that seems to know alot about d-series engine ... wonder if he is here in ZTH hehehe ... please reveal yourself we need ur help

I also own an EK3 D15B with multimatic transmission, sad how very little can be done( or sourced here) to it, I would too go for a B series transplant if I could afford it haha!

Please share more of what we can do with what we have!

You and me both bro ... btw .. bro ur gb same like mine ... wonder if u use the S mode often ... hehehe ...

come on where are all the SOHC honda owners !!!

p.s. just got my ass handed to me by a stock neo cps ... haiyaaaa ... not good ...
campro also gettin fast nowadays ...
need to start modding ...

Thx for posting guys/sifu's ... will put the dohc vtec under consideration ...

 

[webeck948]

hehehehe ... i have searched alot though thoose american forums .. and from my investigation hehehe ... there is one malaysian by the nick BIG[V] in these forums that seems to know alot about d-series engine ... wonder if he is here in ZTH hehehe ... please reveal yourself we need ur help



You and me both bro ... btw .. bro ur gb same like mine ... wonder if u use the S mode often ... hehehe ...

come on where are all the SOHC honda owners !!!

p.s. just got my ass handed to me by a stock neo cps ... haiyaaaa ... not good ...
campro also gettin fast nowadays ...
need to start modding ...

Thx for posting guys/sifu's ... will put the dohc vtec under consideration ...

Yes I do use the S-Mode quite often(esp when I'm late for work!haha)but my gb feels a bit sluggish and jerks sometimes, looks like it's time to do another CVTF flushing soon, sigh!

Looking to plunk in a manual gb if I can find one.

 

[LuKa]

Neo is already running DOHC engine...n it performs good on High rev..
you can opt for a manual transmission from vtec Single cam with LSD... but it wont be cheap... for those using normal Efi head.. u can swap to V.Tec single cam head for abit of power.. aftermarket extractor would help too... however.. the D series piston n conrod is not as strong for high revving.. some opt for Bot with low boost..

If you r looking for serious power n high revving... B series is the way to go.. n for long run.. theres a lot of performance parts sold new or chopshop for options.. buying and installing a halfcut engine to your existing ride can easily go beyond rm10k for eg n ek... in malaysia.. ppl pLay honda with JDM parts... some cant afford just play interior n exterior only... but if u socialize with honda modders with Bseries... most probably you will get the urge to get the Bseries engine even if it cost an arm n a leg...

 

[SAO 6418]

Ex 3-stage Vtec D15B user (sold oledi),
Previously install in 2nd gen civic, performance quite good (if FD ratio more higher let say 4.4) i guess can makan stock b16a oledi.

If wanna play, 1st thing is to get the manual g/box (can rev till 7.3k rpm), cvt only can get 6.2k rpm even in S mode for my case - g/box old oledi). Sohc vtec fd is 4.25 only unless u rojak from ZC, if not mistaken 4.37

Better spend the amount of money u spend on D-series and put to B-series. Btw, the most important thing is the vtec sound (prraaang....) D-series very soft even u put 4-1 kah, 4-2-1 kah....

Besides, if wanna play D-series better play D15B vtec from EG (get the manual version to unleash the true potential) coz 3-stage vtec very kacau especially the 2 stage vtec kick-in (hard to tune) and ecu (manual ek3 ecu if damn hard to source unless u go for standalone).

Finally, wish u happy modding...... vtec...:wavey:

 

[Andres]

I m new for D series engine.. i own a D17A2 engine.. I also wan to know more about this engine... saw the previous forums, found out that this engine can't do more and let other to throw in here and there... ....

Sifu.. pls advice what need to do from start to end for this engine to make this engine more powerful.. i really feel that the VTEC sound "praggg" very soft.. even we can't know that the VTEC is open or not also sometimes....

Pls advice..