I was just looking over my setup and the stock head keeps bugging me. I was going to build the head later on but as of right now I kinda want to get boosted again and take a break from the car (and the spending associated with it). here's the motor setup and the turbo setup going on...

77mm D16Z6 Golden Eagle Sleeved Block
JE 77mm 9:1 Pistons
Eagle H-Beam Rods
Cometic 77mm Standard Headgasket
ARP D16Z6 Headstuds
Skunk2 Intake Manifold
H22A Throttlebody
Golden Eagle Fuel Rail
Precision 880cc Injectors
3" Catback Exhaust w/ Magnaflow muffler
ACT XTR6 (Six Puck Clutch)
ACT XACT Streetlite 12.5lb Flywheel
Hurst Short Shifter
Precision SC60 Turbo (.63 a/r turbine)
SFP Tubular Turbo Manifold
2.5" downpipe
TiAL 50mm Blow Off Valve
Tial 38mm Wastegate
Precision AS 1025 Intercooler
Hondata Stage 2 with Boost option
MSD 3Bar Map Sensor
Greddy Profec E-01

I was wondering what kinda limitations would the stock head create. obviously it would limit the power i can make at the same boost levels, and i wouldn't be able to rev it as high. My goal is 350-400whp for now. Would the stock head limit the power the motor itself would handle? What i mean by this is that is there like an hp level i wouldn't want to go over on the stock head? Or is 400whp attainable on a stock head? I know this is DOHC city in here but I'm asking a simple question. Zex Man, ladysman, turbodcx, gitwidit... any of you d-series turbo ninjas have any input?

Thanks in advance
Marc

 

There are no problems with using a bone stock head and making big power numbers. I have been making upper 400's for the past two years on a stock , unported head with stock valves and have had no problems. To make 400whp on boost alone, you will need around 32 PSI of boost on a stock head to do it. I have never seen a compressor map of an SC60, so I don't know if it will work at those boost and flow ranges. You will need a compressor that flows around 47 lbs. of air at a pressure ratio of 3.18. I would call the guys at Precision and see if they will let you know if your compressor will work in that range. Good luck on your project!

Later,

ZEX Man

 

ok not bad not bad. the SC60 is pretty much a T3/T04E 60 trim so I'm guessing the precision unit should flow similarly. The SC60 is what I plan to get. I actually ordered it through a friend of mine but he says when he gets his shipment of turbos in I can probably get the SC61 if I decide on it. I may get it anyway, try it out and see if it's too laggy... oh well sucks for me. I'll sell it and buy a normal garrett unit. thanks for the input Zex Man. hopefully gitwidit gets his sc61 on and running before I get mine in so he can tell me how it is.

 

ZEX Man's right. Head flow on a boosted engine means absolutely nothing in most cases, as you just make your power figure at a higher pressure differential. A look at the Dodge 2.2 turbo is a good example of this... 11's off of a stock head that is lucky to flow 4 cfm in NA form (slight exaggeration, I think 6 cfm is the actual stock flow wink wink nudge nudge) is commonplace, some are hitting 10's.

As far as 3:1 pressure differentials... look into some diesel applications and see if you can't match up a compressor map. Holset HX35 with 14 cm^2 turbine should do you fairly well if I just hazarded a guess - it's 70% efficiency plateau contains a complete T04B compressor map, it's about equivalent to the GT level compressors Precision uses.

 

well i've already got the manifold so i'm stuck with soemthing T3 flanged. I was considering the sc61. main reason I was iffy about it was the stage 5 wheel. how much different do you guys think spoolup would be when comparing a T31 wheel vs a T350 wheel?

 

oh and about that 32psi deal to make 400whp. ar fabrications posted up a dyno of their sohc. stock bore with rods, pistons and like slight headwork nothing major. i think it might have just been springs and retainers. they were making 395whp on a 50 trim t3/t04e @ 30 or 32psi. with that said and compared to my setup seeing as how i have a slightly bigger bore as well (almost 1.7L). how more efficient do you think the 60 trim or even the sc61 would be? not asking for exact guesses because as we know there are a lot of variables. but i was under the impression that if the same setup he had was on the 60 trim it would probably have broken 400whp at a slightly lower boost level... say 28psi for arguments sake

 

HX35 is T3 flanged, stunna.

 

hahaha. i'm stuntastic. well i know nothing really about the holset turbos. i just ASSumed it was flanged differently. is there any site i can find info abuot their turbos? it's kinda poitnless to find out since i've already paid for the SC turbo but i'd stil like to know.

 

Precision SC's rock, don't get me wrong, I just like to bring flavor to the scene, as competition brings diversity and encourages advancement and all that happy horseshit.

http://www.holset.com has product specs on their website, poke around some.

 

Marc,

I think that with the stock head and the SC60 you will be able to hit your goals.

It is just like you said, with out valvetrain you wont be able to rev as high,but with out a cam it will be hard to make power outside of the engines stock revlimit anyhow. I wouldnt worry about it oo much.

Good luck bro

Brian

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">Precision SC's rock, don't get me wrong, I just like to bring flavor to the scene, as competition brings diversity and encourages advancement and all that happy horseshit.

http://www.holset.com has product specs on their website, poke around some.

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

yah i understand lol. just only a few people have actually brought up holset turbos on this board so i have no clue on like the sizing, etc and which on to choose

 

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

I think that with the stock head and the SC60 you will be able to hit your goals.

It is just like you said, with out valvetrain you wont be able to rev as high,but with out a cam it will be hard to make power outside of the engines stock revlimit anyhow. I wouldnt worry about it oo much.

Good luck bro

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

yah i was thinking so too just wanted a few other opinions. so you think i should stay sc60 right... don't worry about the sc61?

 

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

I think that with the stock head and the SC60 you will be able to hit your goals.

It is just like you said, with out valvetrain you wont be able to rev as high,but with out a cam it will be hard to make power outside of the engines stock revlimit anyhow. I wouldnt worry about it oo much.

Good luck bro

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

I agree to a point.

The stock head is fine. The valvetrain is needed IMO along with a bigger cam.

I do feel though the head needs to have the chambers opened up for the bigger bore. This is very important IMO on a bigger displacement motor. As you know mine is 78mm and the combustion chambers are opened up to match.

My $.02.

 

to bring this thread back to life... i have my old y8 head sitting here. i was going to sell it... you guys think i should keep it and get smoe work done to it later... or if i do anything just go with a z6 head (the built motor is a z6 motor in my car now)

 

Is there anyone of the D-series guy running/going to run a stage 5 wheel?

And I think CivicRyda2K will make your 400whp no problem with a stock head.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicRyda2k &raquo;</TD></TR><TR><TD CLASS="quote">to bring this thread back to life... i have my old y8 head sitting here. i was going to sell it... you guys think i should keep it and get smoe work done to it later... or if i do anything just go with a z6 head (the built motor is a z6 motor in my car now)</TD></TR></TABLE>

You want the Z6 head!!!!

 

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

You want the Z6 head!!!!</TD></TR></TABLE>

hehehe yah i've been told that. just wondering since i had this head sitting here... it's been in the classifieds since yesterday anyway hehe

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicRyda2k &raquo;</TD></TR><TR><TD CLASS="quote">

hehehe yah i've been told that. just wondering since i had this head sitting here... it's been in the classifieds since yesterday anyway hehe</TD></TR></TABLE>

A Y8 head is killer for a street motor. It will make much more power below 5000rpm than the Z6 head. The Z6 head is THE head for high hp, high rpm applications. I have run both on my race engine and speak from experience.

Later,

ZEX Man

 

yah i remembered you saying something like that on another D-series board. Well I have a couple questions since you refreshed my memory. First I'll tell you the goals again that I'm looking for and the other factors. considering both heads are stock...

1. 12.xx in the 1/4 and low 100's (100-120mph) trap speed
2. 280-320whp on pump gas (i'm guessing @ 18spi or so) and 350-400whp on race gas and whatever boost level. all on a T3/T04E 60 trim with .63 a/r turbine, 1.7L d16z6, 9:1 compression.
3. it is a daily driven car so low end responsiveness will be a little more comfortable i assume.
4. if i keep the y8 head. i'd probably have mild work done i guess since it's off the motor as it is. nothing major though. maybe springs, retainers, open the combustion chambers and then later on a cam. if i keep the z6... it will stay jsut as stock as it is now.

my goals maybe a bit incohesive. for example i'm not sure what is the highest boost/hp level i could run on pump gas so i just threw a number out there. just wondering... i always want to explore my options before i make a decision. thanks


Modified by CivicRyda2k at 10:06 AM 1/30/2004

 

updog

 

So part failure doesn't come into play above say 300whp on a stock sohc head? Like retainers or springs? Or would those only fail because of revs and not power level?

 

that was part of my question... well i didn't say it but i was kinda expecting someone to tell me about that hehe

 

I may be talking out of my ***, but from what ive read the z6 valvetrain is pretty lightweight. With the addition of some Ti retainers the rev limit can be raised significantly. Not that the stock cam will make power with the higher revs though. A cam such as the zex cam would definately be a benefit. This is what i plan to do myself along with a mild gasket matching port job. Hope that helps some.

Toby

Edit: Btw it sounds like a real nice setup you have there. I would be looking for more in the 11's with that setup. I am shooting for mid 12's with were i sit right now.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CivicRyda2k &raquo;</TD></TR><TR><TD CLASS="quote"> hopefully gitwidit gets his sc61 on and running before I get mine in so he can tell me how it is.</TD></TR></TABLE>

I'm looking at late Feb early March Marc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 5thgencivic &raquo;</TD></TR><TR><TD CLASS="quote">So part failure doesn't come into play above say 300whp on a stock sohc head? Like retainers or springs? Or would those only fail because of revs and not power level?</TD></TR></TABLE>

Shouldn't fail if you stay close to your factory rev limit.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by norcalcrx &raquo;</TD></TR><TR><TD CLASS="quote">I may be talking out of my ***, but from what ive read the z6 valvetrain is pretty lightweight. </TD></TR></TABLE>

With a stock head we hit valve float around 7.8 on my old setup. Others may have had different results in the past.