I am considering buying the d15b vtec motor from hmotors,

first of all, how does this motor stand up to the d16z6 in mod'ability and reliabilty in tubo applications?

and which tranny should i run, i currently have a sohc si tranny but it needs rebuilt. is the trany that hmotors will sell you with the d15b the same ratio as the si?

thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by confusion &raquo;</TD></TR><TR><TD CLASS="quote">I am considering buying the d15b vtec motor from hmotors,

first of all, how does this motor stand up to the d16z6 in mod'ability and reliabilty in tubo applications?

and which tranny should i run, i currently have a sohc si tranny but it needs rebuilt. is the trany that hmotors will sell you with the d15b the same ratio as the si?

thanks</TD></TR></TABLE>

For all intents and purposes it's exactly the same as the Z6. The reliability in turbo will be the same, modability will be exactly the same, as for the transmission run the '92-'95 Si trans or the '92-'95 EX trans (the one u have now). I don't know if the ratio on the JDM D15B is different, so I'm not sure on that one.

For all intents and purposes the motor is the JDM version of the Z6 - the only difference is the JDM D15B doesn't just have regular 2 stage VTEC (that's what the Z6 has), while the JDM D15B has that, it also has VTEC-E, giving it the term "3 Stage VTEC." In case you don't know how VTEC-E works, it's what was used on the D16Y5 ('96-'00 HX) and the D15Z1 ('92-'95 VX). It works by only using 8 of the 16 valves before some low number (like 2500 RPM) where it switches to all 16 valves. So it's pretty economic (about the same as a D15B8 (civic CX) if you keep the RPM low, but even in regular 16 valve mode, it still has the same gas mileage as a Z6, so yea.

3 stages, stage 1, 0-~2500 RPM (I forgot the exact number) - 8 valves, stage 2, ~2500 RPM to ~4800 RPM (depending on throttle pos.) - Stage 3, 16 valves, 4800RPM to the redline, VTEC engages - 16 valves plus locks the more aggressive lobes. -- 3 Stage VTEC.

In synopsis: This will give you about the exact same gas mileage, power from mods, reliability, etc. as a Z6.

 

Well people state they are the same.But other peopl say it has a more aggressive cam.My friends like my D15B better than there Z6 engines.If your interested ina D15B I can get you one from a shop where I got mine.I got mine for 350 complete w/no tranny though.Your socal so I can get you hooked up.They come with a 6 month/unlimited miles warranty.Pm me if you are interested.

 

thanks for the help guys, i really appreciate it

 

.1 liter smaller, has a more aggressive cam to make up for this, horsepower and torque output is also increased by a little. I'm running mine with a ex/si transmission and have beaten every sohc car I've raced (z6,y8). Getting all the parts together is also easy now considering theres a thread dedicated to this motor on d-series.org. D15b

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ejoner &raquo;</TD></TR><TR><TD CLASS="quote">.1 liter smaller, has a more aggressive cam to make up for this, horsepower and torque output is also increased by a little. I'm running mine with a ex/si transmission and have beaten every sohc car I've raced (z6,y8). Getting all the parts together is also easy now considering theres a thread dedicated to this motor on d-series.org. D15b </TD></TR></TABLE>

D15B &gt; D16Z6-Y8 all day any day...

an THANK GOD for that D15B thread on dseries...

 

Which d15b do you have? I can think of three versions...

EDIT: I can't read...

 

D15b and a z6 have the exact same heads, intake manifold, sans camshaft. imagine a VX block with a z6 head and viola(still diff rods). i have heard all day people say the d15b cam is more aggressive and don't belive it.

they have no solid numbers thus yet(or that i've seen). i have had both motors in my CRX and both feel very similar.

i do feel the d15b likes the higher RPMs though, and this could be since it has a shorter stroke. my current d15b loves boost just as much as my z6 did.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ddd4114 &raquo;</TD></TR><TR><TD CLASS="quote">Which d15b do you have? I can think of five versions...</TD></TR></TABLE> i wasn't aware of 5 d15b vtecs??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NastyHabitzCRX &raquo;</TD></TR><TR><TD CLASS="quote"> i wasn't aware of 5 d15b vtecs?? </TD></TR></TABLE>
Oops! I missed the "vtec" part of his description.

I can now only think of 3, and one is VTEC-E.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NastyHabitzCRX &raquo;</TD></TR><TR><TD CLASS="quote">D15b and a z6 have the exact same heads, intake manifold, sans camshaft. imagine a VX block with a z6 head and viola(still diff rods). i have heard all day people say the d15b cam is more aggressive and don't belive it.
</TD></TR></TABLE>

shocking comin from someone with a d15b... u cant tell just from driving both motors..?? my d15b ***** on my old z6, n my z6 had a fresh rebuild at the time when it ran best, an the used d15b still **** on it... an the numbers prove the cam is more aggressive so its about time to be a believer homey...

 

It is subjective to say "my d15b feels so much faster than my z6". Can you really feel the minuscule difference in horsepower?

Once somebody specs out both cams and posts up the results, I'll be convinced. Until then, it is just hearsay.

 

[QUOTE=ddd4114]It is subjective to say "my d15b feels so much faster than my z6". Can you really feel the minuscule difference in horsepower?

Once somebody specs out both cams and posts up the results, I'll be convinced. Until then, it is just hearsay. [/QUOTE

very subjective... do u feel a difference in a d15b7 and d15b..?? d16z6 and d16y8..?? i've owned all of them an can say yes, i've felt noticeable differences in all the motors... but maybe i just pay more attention than most people... minuscule changes stand out when ur hooked into ur laptop an actually messing with the #'s...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">

shocking comin from someone with a d15b... u cant tell just from driving both motors..?? my d15b ***** on my old z6, n my z6 had a fresh rebuild at the time when it ran best, an the used d15b still **** on it... an the numbers prove the cam is more aggressive so its about time to be a believer homey...</TD></TR></TABLE>
d15b &gt; z6

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">

D15B &gt; D16Z6-Y8 all day any day...

an THANK GOD for that D15B thread on dseries... </TD></TR></TABLE>

Hell yeah!! Can i get a AMEN to that

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">
an the numbers prove the cam is more aggressive so its about time to be a believer homey...</TD></TR></TABLE>
and what numbers are you putting up from your butt dyno?? cause i see you giving me no specs, or dyno validation.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">
very subjective... do u feel a difference in a d15b7 and d15b..?? d16z6 and d16y8..?? i've owned all of them an can say yes, i've felt noticeable differences in all the motors... but maybe i just pay more attention than most people... minuscule changes stand out when ur hooked into ur laptop an actually messing with the #'s... </TD></TR></TABLE> mmmkay comparing a d15b7 to a d15b vtec is like comparing a d16z6 to a b16...., now compare a b16a1 to a b16a2 and tell me the diiference. not a whole hell of alot.

to the OP: buy a d15b cause they are dirt cheap and still be satified there is still lots of support for these motors out there. and if you're lucky get your hands on the stock LSD

 

I had a d15b in my old Crx. It had to be the best feeling D series motor I have ever driven or been in. I loved it!

 

When I hear **** like "I just gained 15hp from my Bomz Racing SRI", I become less inclined to believe biased comparisons. Claiming to clearly tell the difference between two very similar engines is subjective and proves nothing.

The obd1 JDM d15b vtec's peak horsepower rating is (very) slightly more than that of the z6. It has a shorter stroke and 0.1L less displacement. Its rod ratio is slightly higher (which won't affect 97% of this board). Those are the only notable differences between the two engines. I suggest simply getting whichever one is in better shape and/or is cheaper unless you're planning a very serious build.

I'm not saying that the d15b's cam is not more aggressive than the z6's cam, but I have never seen any proof. If you can show me some, then you can say "I told you so".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Syndacate &raquo;</TD></TR><TR><TD CLASS="quote">

For all intents and purposes it's exactly the same as the Z6. The reliability in turbo will be the same, modability will be exactly the same, as for the transmission run the '92-'95 Si trans or the '92-'95 EX trans (the one u have now). I don't know if the ratio on the JDM D15B is different, so I'm not sure on that one.

For all intents and purposes the motor is the JDM version of the Z6 - the only difference is the JDM D15B doesn't just have regular 2 stage VTEC (that's what the Z6 has), while the JDM D15B has that, it also has VTEC-E, giving it the term "3 Stage VTEC." In case you don't know how VTEC-E works, it's what was used on the D16Y5 ('96-'00 HX) and the D15Z1 ('92-'95 VX). It works by only using 8 of the 16 valves before some low number (like 2500 RPM) where it switches to all 16 valves. So it's pretty economic (about the same as a D15B8 (civic CX) if you keep the RPM low, but even in regular 16 valve mode, it still has the same gas mileage as a Z6, so yea.

3 stages, stage 1, 0-~2500 RPM (I forgot the exact number) - 8 valves, stage 2, ~2500 RPM to ~4800 RPM (depending on throttle pos.) - Stage 3, 16 valves, 4800RPM to the redline, VTEC engages - 16 valves plus locks the more aggressive lobes. -- 3 Stage VTEC.

In synopsis: This will give you about the exact same gas mileage, power from mods, reliability, etc. as a Z6.

</TD></TR></TABLE>

thats the 96-00 version with the 3 stage vtec. the eg version has the same head as a z6 with slightly different cam. if you look at a z6 mani it actually says p08 on it and not p28. and it would be like a vx motor which goes from 12v-16v...the cx has 8v

 

well also take into consideration the R/S Ratio on D15B's being almost identical to the B17A... I'm sure besides the cam ordeal, a couple extra HP are thrown in because of that ratio...

The Primary, Mid, an Secondary lobes on the D15B cam are like .05" in difference to the Z6 all the way down... That's where the #'s play the role with Cam differences, and make the D15B come off as the stronger and better motor, also adding in the R/S Ratio facts, i still say D15B &gt; Z6....

 

If you do end up boosting, it would not matter which cam is more agressive, or not..as we can help you by designing one for your application.

I like the D15B units as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">well also take into consideration the R/S Ratio on D15B's being almost identical to the B17A... I'm sure besides the cam ordeal, a couple extra HP are thrown in because of that ratio...

The Primary, Mid, an Secondary lobes on the D15B cam are like .05" in difference to the Z6 all the way down... That's where the #'s play the role with Cam differences, and make the D15B come off as the stronger and better motor, also adding in the R/S Ratio facts, i still say D15B &gt; Z6.... </TD></TR></TABLE>
You've measured both cams?

For the majority of this board, the rod ratio is just a number. The piston dynamics are barely affected. If you're going to do a very serious build, then it might become a factor.

I see Bisi posted in this thread, and I'm sure he has a much better idea than any of us: if you were an average consumer, and you were offered a z6 for $500 or a d15b vtec for $550 (both are in great condition), which one would you choose and why?

 

thanks for all the input, keep it coming. do any of you have rock solid info on the tranny that comes with these motors? because i would rather just buy a motor and tranny then have to buy a motor and rebuild my other tranny if the gears are just about the same.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">
That's where the #'s play the role with Cam differences, and make the D15B come off as the stronger and better motor, also adding in the R/S Ratio facts, i still say D15B &gt; Z6.... </TD></TR></TABLE>
no, it isn't. what are the durations for each? that matters a whole lot, i can see the d15b having more lift with less duration(again shorter stroke means less time to get air in). while conversly the z6 have more duration than lift. till i see some cam wheel measurements i still don't think all this cam hype is true.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by confusion &raquo;</TD></TR><TR><TD CLASS="quote">thanks for all the input, keep it coming. do any of you have rock solid info on the tranny that comes with these motors? because i would rather just buy a motor and tranny then have to buy a motor and rebuild my other tranny if the gears are just about the same. </TD></TR></TABLE>

anyone????