Honda D Series Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
99 Posts
Discussion Starter #1
Looking for bit of advice on whether to fit a y8 vtec head or buy aftermarket cam for my turbo d16zc(sohc non vtec, same as d16a6 I believe) I'm looking to try extend my power band, turbo is a TD04-15g. My main concern with fitting y8 head is that the compression ratio of my engine is going to be close to 10.5:1 and only available fuel in my area is 95 octane. Any help would be appreciated
 

·
Registered
Joined
·
841 Posts
Honestly just work with what you have now and just get a cam, a simple cheap one like a zex 59300 for a turbo street build.

Also do some porting to your head and intake manifold.

There's some guys on here that wish the stayed with a non vtec turbo setup and regret doing a mini me turbo setup, vtec isn't really shit in sohc, plus non vtec d series seem to love boost.

But all in the end its your ride so do what you want with it, good luck.
 

·
Classic Man
Joined
·
16,355 Posts
i would say the opposite as what you say.

the vtec heads flow way better and make way more power stock and can easily see 8000rpm stock if u need to with a bigger turbo.


but i guess there is an argument to be made for going really big with the pm3 heads if u reallllly wanted to.
 

·
Registered
Joined
·
841 Posts
I stated all that because it seems that he don't want big power as of now, like i said might as well throw a cam in it and do a little porting for that little extra flow.
 

·
Registered
Joined
·
841 Posts
why did some guys prefer to stay non-vtec rather than doing the mini-me? was hoping to go bisimoto for aftermarket cam but am now looking at exospeed

D16A6/D15B7 Stage 2- SR909 [SR909] - $195.00 : Exospeed Racing Products, Founded by Import Racers
Do what you gotta do and what you wanna do..

Like said before the vtec head will flow better but i'm saying work with what you got and go from there.

If you do plan on going with a vtec head then at least go with a z6 head, better flow and mate it with a y8 intake mani and do some porting. Best bet..

The z6 has a little less compression then the y8.

What ever you can get your hands on will still be fine.
 

·
insert user title here
Joined
·
3,014 Posts
The y8 has a couple advantages over the z6. The swirl port design helps for fuel economy. The quench pad helps for a tight fast burn in the center. The disadvantage of the y8 is that the swirl port design sucks for anything above 3,500 rpm's. The z6 has none of these swirl port designs therefore has a better flow rate than the y8. Both should make very similar power with modest power goals.
Personally Id go with the a6/zc head with a6 head-gasket to drop your cr down to more modest levels. Maybe use a zex or delta regrind for a cam.
You can go with a z6 head with a6 gasket, but then youre bumping your cr up to 9.7 range.
Another thing you might look into is getting a larger turbo, a 15g imo is a bit on the small side. Going with a larger turbo, maybe 16g, large t3, or small t3t4 will shift your powerband up a bit.
 

·
Classic Man
Joined
·
16,355 Posts
Do what you gotta do and what you wanna do..

Like said before the vtec head will flow better but i'm saying work with what you got and go from there.

If you do plan on going with a vtec head then at least go with a z6 head, better flow and mate it with a y8 intake mani and do some porting. Best bet..

The z6 has a little less compression then the y8.

What ever you can get your hands on will still be fine.


im gonna have to disagree again

darin made 479whp on a stock y8 head with stock cam. no porting. i think thats more than most anyone will ever want!! and that was on a t3/t4 50 trim!! not even a billet or anything

the z6 head will flow AWESOME 100% stock.

dont port anything if u run a VTEC head. they work GREAT out of the box.

and dont waste money on a shitty aftermarket "billet" cam that will just destroy your motor. stick with OEM proven reliability. and why bother fixing something that aint broke?
 

·
()*#$(*$
Joined
·
11,404 Posts
I dislike VTEC and prefer non-VTEC heads in general. I would get an Exospeed or Colt Cam and get the engine tuned.

Non-VTEC heads need a little more work but, IMO, are better in terms of valve placement, especially the DOHC D.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #11
y8 or aftermarket cam

thanks guys for replys..to be honest its a nightmare building a turbo d over here because is so limited but i do have a great tuner tha can work with the advice given.

i spent most of today trying to get an engineering company to port and polish my zc head (a6) and they wont touch it saying my standard engine will blow up, basically telling me i was stupid to even turbo an engine like that. the height of ignorance and unability to even see that we are trying and so far succeeding in something new is depressing.

if i stick a y8 head on over here its gonna cost €1500, yes Ireland is very expensive and thats still with stock block.

So i am trying to think of ways for myself to enable me to hold the powerband all the way and for the turbo not to be backing off circa 5000. I thought maybe this evening scrap the idea of port and polish, scrap the cam and why not buy a more capable turbo even such as t28 so i can just hold my powerband all the way to redline.

I do not care if i only make 200bhp I just want the powerband with no dropoffs.

Apologies for the very long post.

heres my dyno graph

[/IMG]
 

·
()*#$(*$
Joined
·
11,404 Posts
That's not a long post, and you shouldn't apologize for intelligently and succinctly explaining your situation.

Given the expense of going with a VTEC head, a cam and a T28 will absolutely get you to your goal with a stock block, without even pulling the head. You will need a few other parts, the foremost of which is a better intake manifold. The A6-style intake manifold is utter crap for anything at over 4.5-5K. Add to that a decent flowing exhaust manifold and you will have a flat torque curve that will make you smilethe first time you take it all the way to redline.
 

·
Classic Man
Joined
·
16,355 Posts
shit i dont really think the head or cam is your problem right now.

i have a feeling your turbo is pushing hotter air than it needs to, and it might be from a few things...

intercooler big enough if its not getting the amount of air flow it needs? thats a big one right there.
how many psi are you pushing?
could you have a boost leak?
could you have a pre-turbo intake restriction?
could your exhaust be leaking pre-turbo bleeding off manifold pressure?
could your exhaust be suffering from cylinder cross contamination?
is the tune off(i know you trust him, but id like to see the maps with a boost and afr overlay if i may).....

i could go on and on....

if you are stuck with the A6 head, and you just cant find anything else, i would recommend a colt tri-flow stage 2 and ditch the small turbo and upgrade to something a bit bigger and better.
 

·
Registered
Joined
·
99 Posts
Discussion Starter #15
y8 or aftermarket cam

That's not a long post, and you shouldn't apologize for intelligently and succinctly explaining your situation.

Given the expense of going with a VTEC head, a cam and a T28 will absolutely get you to your goal with a stock block, without even pulling the head. You will need a few other parts, the foremost of which is a better intake manifold. The A6-style intake manifold is utter crap for anything at over 4.5-5K. Add to that a decent flowing exhaust manifold and you will have a flat torque curve that will make you smilethe first time you take it all the way to redline.
thanks man you have been a big big help since i started posting here as have all members that replied.

i have a y8 intake manifold port matched to a b16 throttle body ( my bad i didnt mention that)

so you actually recommend its not necessary for me to port the a6 head as no one hear wants to touch it for me anyway.

it would be a great relief if i could just stick in a exospeed sr909 and possibly bigger turbo or else that little 15g scream for its life


@ danz

i am 100% sure i suffer from none of the problems listed and i just done a double check to make sure..intercooler is the stock intercooler that comes with greddy kit so is sufficient im sure but than you for stating possible problems:8:

i am going to look into a colt tri flow stage 2 as i m definetly stuck with the a6 head, as mentioned earlier it will cost approx €1500/2000 us dollars to simply fit a y8 head properly
 

·
Registered
Joined
·
92 Posts
what seems strange in your dyno graph is that boost builds up too late and too "lazy". try searching for leaks.

and as for further upgrades I would suggest better intake manifold and adj camgear. it`s cheap enough and will allow you to "move" torque across the rpm range
 

·
()*#$(*$
Joined
·
11,404 Posts
You're welcome.

I would do two things to the head on your own:
1. Gasket match the intake port inlets to match the Y8 intake manifold gasket.
2. Clean up the rest of the ports by knocking down any gnarly stuff left over from casting.

A good valve job and that pretty much takes care of the head. That will certainly help you achieve your goals and can be done safely and inexpensively on your own.

There are SOME competent shops in Ireland, or at least competent people, since I've helped out a few guys tune their cars on those greeeeeeeeeeeeeeen shores. (Anyone who hasn't visited or at least flown over Ireland has no idea how )(#$(*)#$*( green everything is! LOL)

I happen to love most T28s, especially the OEM Nissan units. I would recommend finding one in good nick and using that over the 15g, which is OK, but I don't think that yours is really working all that well, unless there is something else that we don't know about holding everything up.

How do you have the engine tuned?

I like the SR909 cam, but think the Colt Tri-flow cam is technically superior and likely better for turbo use, in this case.
 
1 - 18 of 18 Posts
Top