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1.8L head on 2.0L block
I think this argument is for the 16V heads... it has been argued since the
beginning of time about the differences and benefits of the 1.8L 16V head
vs. the 2.0 16V head...
I don' t think you 8V'ers have this silly problem, lucky.
-Raffi
At 12:58 PM 6/28/2003 -0400, Marc Scirocco Qu?bec wrote:
>I have an 8V Audi 2.0 head. It is already ported a bit.
>
>Cheers.
>
>Marc
>'83 Scirocco
>'88 Scirocco Slegato
>
> > -----Message d'origine-----
> > De : scirocco-l-bounces@scirocco.org
> > [mailto:scirocco-l-bounces@scirocco.org]De la part de ATS - Patrick
> > Bureau
> > Envoy? : 28 juin, 2003 12:51
> > ? : Dave Ewing; scirocco-l@scirocco.org
> > Objet : RE: 1.8L head on 2.0L block
> >
> >
> > well I have a stock 1.8L on a 2L block , but its 8v, npw
> > anyone has a stock
> > 2L engine 8v on hand and we can compare..
> > I need to get a dyno run though.. :)
> >
> > ATS - Patrick Bureau - txrocco@sbcglobal.net
> > Http://www.longcoeur.com/scirocco/
> > ============================================
> > '85 2.0L Prowler Orange Kamei X1 Rocco
> > '85 1.8L Titian Red Rocco (daily driver)
> > '98 4.0L Jeep Cherokee
> > '91 7.3L F250 diesel Super cab,8 Ft box.
> >
> >
> >
> > =>-----Original Message-----
> > =>From: scirocco-l-bounces@scirocco.org
> > =>[mailto:scirocco-l-bounces@scirocco.org]On Behalf Of Dave Ewing
> > =>Sent: Saturday, June 28, 2003 11:47 AM
> > =>To: scirocco-l@scirocco.org
> > =>Subject: Re: 1.8L head on 2.0L block
> > =>
> > =>
> > =>But who in the world has a stock 1.8L head on a stock 2.0L block
> > =>and a stock
> > =>2.0L head on a stock 2.0L block?? Anyone??
> > =>
> > =>Dave
> > =>----- Original Message -----
> > =>From: "Dan Bubb" <jdbubb@ix.netcom.com>
> > =>To: <scirocco-l@scirocco.org>
> > =>Sent: Saturday, June 28, 2003 6:44 AM
> > =>Subject: Re: 1.8L head on 2.0L block
> > =>
> > =>
> > =>> I've been thinking about this alittle more. We all know
> > what that means!
> > =>> I was thinking about the conditions in the cylinder during the
> > =>intake and
> > =>> exhaust and how that is related to flow.
> > =>> The power an engine produces is largely related to how much air
> > =>it burns.
> > =>> >From that is subtracted the various inefficiencies.
> > Pumping losses,
> > =>> inefficient combustion, heat losses.....
> > =>> If your intake is restrictive then you get less air and
> > proportionally
> > =>less
> > =>> power. So, 7% less air pretty much starts you at 7% less
> > power. The
> > =>probable
> > =>> most important secondary effect on the intake side is intake
> > =>velocity. The
> > =>> same amount of air at a lower velocity will generally
> > produce less
> > =>> turbulence in the combustion chamber, slower burn and less power.
> > =>> Flow thru the exhaust is not a power producer. It's a
> > power loss. The
> > =>> exhaust valve starts to open well before the piston
> > reaches BDC on the
> > =>power
> > =>> stroke while the cylinder pressure is still very high.
> > So, alot of the
> > =>> exhaust gets a huge boost out the port due to the really
> > high pressures
> > =>> (compared to intake pressures or the average pressure level in
> > =>the exhaust
> > =>> system).
> > =>> Once this slug of exhaust is out the piston still has to do
> > =>work to force
> > =>> the rest of the exhaust into the pipe, but the general
> > exhaust system
> > =>> pressure isn't that high (on the order of a couple psi even for an
> > =>> inefficient system) so the power lost pushing the remaining
> > =>exhaust out is
> > =>> not huge. Now, obviously, the lower the exhaust port flow
> > the more power
> > =>is
> > =>> lost pushing the exhaust out and you also will get more
> > charge dilution
> > =>with
> > =>> high exhaust back pressures that will have an effect on
> > the amount of
> > =>power
> > =>> produced by the incoming charge.
> > =>> The main point is; power is directly related to intake flow, it is
> > =>> secondarily related to exhaust flow. i.e. the cylinder
> > =>pressures producing
> > =>> power (in the area of 1000 psi) are directly related to
> > intake flow and
> > =>the
> > =>> cylinder pressures loosing power (<10psi) are directly related
> > =>to exhaust
> > =>> flow.
> > =>> Having said all that it seems like intake flow is the most
> > =>important (and
> > =>as
> > =>> Dave points out, it's not just the port. it's the entire intake
> > =>tract) and
> > =>> exhaust flow of secondary, although not insignificant, importance.
> > =>> On the topic of intake velocity; I'm not sure the 2.0 head
> > =>necessarily has
> > =>> better velocity despite the lower flow. I haven't seen an
> > =>actual 2.0 head,
> > =>> only pictures, so I could be wrong, but it seems the
> > primary restriction
> > =>to
> > =>> flow is the center divider between ports is a big chunky
> > lump on the 2.0
> > =>and
> > =>> is more streamlined on the 1.8. So, it could be lower
> > flow without the
> > =>> benefit of higher velocity.
> > =>> Anyway, having now shot my mouth off again in favor of
> > the 1.8 head, I
> > =>still
> > =>> would like to see dynos comparing the two heads.
> > =>> Dan
> > =>>
> > =>> ----- Original Message -----
> > =>> From: L F <rocco16v@netzero.net>
> > =>> To: Dave Ewing <MK1Scirocco16v@attbi.com>;
> > <scirocco-l@scirocco.org>
> > =>> Sent: Saturday, June 28, 2003 7:34 AM
> > =>> Subject: Re: 1.8L head on 2.0L block
> > =>>
> > =>>
> > =>> Dave,
> > =>> You are right; the exhaust is positively expelled,
> > whereas the intake
> > =>only
> > =>> relies on vacuum to fill the cylinder (NA engines).
> > =>> However, the intake isn't more "restrictive" per se, it just
> > =>doesn't have
> > =>> the irresistable force in action that the exhaust has.
> > This is why the
> > =>> intake valve(s) is almost always larger than the exhaust
> > valve(s)....the
> > =>> intake needs all the help it can get.
> > =>> You stopped short on one sentence; the exhaust has to exit
> > =>the tailpipe
> > =>> into the atmosphere....not just into a pipe. (that's why
> > low restriction
> > =>> mufflers/cats, mandrel-bent large diameter tubing, etc.
> > are important)
> > =>> It's one reason to try to put the end of the tailpipe in
> > a low-pressure
> > =>area
> > =>> of the vehicle rather than a high-pressure area; helps scavenging.
> > =>> Good disscussion.
> > =>>
> > =>> Larry
> > =>> sandiego16v
> > =>>
> > =>> ----- Original Message -----
> > =>> From: Dave Ewing
> > =>> To: scirocco-l@scirocco.org
> > =>> Sent: Saturday, June 28, 2003 1:10 AM
> > =>> Subject: Re: 1.8L head on 2.0L block
> > =>>
> > =>>
> > =>> Along with Chris's statement, wouldn't you think that the
> > =>pressure that
> > =>> the
> > =>> piston creates when forcing the exhaust out of the
> > cylinder is greater
> > =>> than
> > =>> the vacuum that is created via the throttle body? As far as
> > =>exhaust is
> > =>> concerned (atleast the type of exhaust that most of us
> > are running,
> > =>fairly
> > =>> free flowing) I would have to say that the intake is
> > more restrictive
> > =>than
> > =>> exhaust. I realize you can increase intake flow by
> > adding a cam or
> > =>bigger
> > =>> TB or whatever but it is limited to some extent or another,
> > =>the exhaust
> > =>on
> > =>> the other hand only has to exit the head into a pipe.
> > It doesn't have
> > =>to
> > =>> pass through the air filter, intake boot, TB, intake, etc. I
> > =>don't know
> > =>> if
> > =>> this is relevant but something that makes sense to me.
> > =>>
> > =>> One other point to consider is that I would rather have the
> > =>exhaust flow
> > =>a
> > =>> little better than the intake (whether the intake ports
> > are hogged out
> > =>or
> > =>> not, either way) so that the heat is leaving the motor more
> > =>efficiently.
> > =>> 16v motors run hotter due to their increased compression and
> > =>the higher
> > =>> rpms
> > =>> needed to make useable torque.
> > =>>
> > =>> I understand the importance of velocity, speed, etc.
> > but when you
> > =>consider
> > =>> that you could make a smaller port flow better than a
> > larger port then
> > =>> this
> > =>> would be an argument against the 1.8 head considering that
> > =>the 2.0 heads
> > =>> are
> > =>> newer and more technology has gone into the port
> > design. I don't know
> > =>the
> > =>> specifics but wouldn't you agree that VW wants to
> > consistantly improve
> > =>> their
> > =>> motors especially with tighter emmissions standards?
> > =>>
> > =>> Actually, all of this is rather irrelevant as most power
> > =>hungry listers
> > =>> have
> > =>> already ported and polished their 1.8 or 2.0 heads so
> > stock standards
> > =>> don't
> > =>> really apply but I, again, would much rather have a newer
> > =>head on my car
> > =>> that hasn't seen as many miles or as many kids beating
> > it to death.
> > =>Since
> > =>> the 1.8 heads came on the scirocco/jetta/golf and the
> > 2.0 heads only
> > =>came
> > =>> on
> > =>> the jetta/golf/passat, I'd think that the 1.8 heads on
> > the sciroccos
> > =>have
> > =>> taken the most beating.
> > =>>
> > =>> Dave
> > =>> ----- Original Message -----
> > =>> From: "Chris DeLong" <green536@hotmail.com>
> > =>> To: <amalventano@sc.rr.com>; <jdbubb@ix.netcom.com>;
> > =>> <scirocco-l@scirocco.org>
> > =>> Sent: Friday, June 27, 2003 3:52 PM
> > =>> Subject: Re: 1.8L head on 2.0L block
> > =>>
> > =>>
> > =>> > Ok so then you are saying that increased air velocity due
> > =>to port size
> > =>> and
> > =>> > shape DOES NOT flow more air? Hmm, I would think that
> > INCREASED air
> > =>> velocity
> > =>> > would yeild more flow due to the forced induction
> > =>characteristics that
> > =>> you
> > =>> > mentioned below.
> > =>> >
> > =>> >
> > =>> >
> > =>> > Chris DeLong
> > =>> > Fine Tuning
> > =>> > 206.367.5503
> > =>> > www.finetuningperformance.com
> > =>> > Seattle, WA USA
> > =>> >
> > =>> >
> > =>> >
> > =>> >
> > =>> >
> > =>> > >From: "Allyn" <amalventano@sc.rr.com>
> > =>> > >To: "Chris DeLong" <green536@hotmail.com>,
> > =>> > ><jdbubb@ix.netcom.com>,<scirocco-l@scirocco.org>
> > =>> > >Subject: Re: 1.8L head on 2.0L block
> > =>> > >Date: Fri, 27 Jun 2003 14:05:54 -0400
> > =>> > >
> > =>> > > > More airflow=better efficiency=more power.
> > =>> > >
> > =>> > >umm
> > =>> > >depends on runner diameter/taper / rpm
> > =>> > >rpm change = different intake air pulse size/speed,
> > therefore some
> > =>> > >configurations make more power at low rpm, where
> > some others make
> > =>more
> > =>> > >power
> > =>> > >at higher rpm.
> > =>> > >just boring the crap out of intake doesnt give you
> > more airflow in
> > =>all
> > =>> > >situations. narrower intake passages cause faster air
> > =>velocity while
> > =>> > >filling
> > =>> > >the cylinder, and that very momentum can actually
> > cause a forced
> > =>> induction
> > =>> > >effect, as it squeezes that much more air in the cylinder
> > =>just before
> > =>
> > =>> the
> > =>> > >intake valve closes. this is how some engines can
> > have a volumetric
> > =>> > >efficiency approaching (and possibly exceeding) a
> > value of 1. the
> > =>> narrower
> > =>> > >intake is not perfect though, as it begins to
> > restrict airflow at
> > =>> higher
> > =>> > >rpm.
> > =>> > >
> > =>> > >so... from an intake perspective, a stock 1.8 head
> > is meant to flow
> > =>> most
> > =>> > >efficiently at a higher rpm than a stock 2.0 head is
> > meant to.
> > =>> > >Al
> > =>> > >
> > =>> > >
> > =>> > >
> > =>> > >_______________________________________________
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> > =>> >
> > =>> >
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