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1.8L head on 2.0L block
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
> =>> > >
> =>> > >
> =>> > >
> =>> > >_______________________________________________
> =>> > >Scirocco-l mailing list
> =>> > >Scirocco-l@scirocco.org
> =>> > >http://neubayern.net/mailman/listinfo/scirocco-l
> =>> >
> =>> >
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