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Who the Hell has dynos of 1.8 vs 2.0 stock heads! was Re:1.8L headon 2.0L block
I have several dyno runs of my 2.0 when it was stock (2.0 block, 2.0 head,
CIS-E).
Does someone have a run for a stock 2.0/1.8 in good running order?
Jason
At 02:54 PM 6/28/2003, Dave Ewing wrote:
>I'm thinking that the difference between the two heads would be tough to
>tell with the butt dyno. Reg. dyno would have to be done!
>
>Dave
>----- Original Message -----
>From: "Dan Bubb" <jdbubb@ix.netcom.com>
>To: <scirocco-l@scirocco.org>
>Sent: Saturday, June 28, 2003 10:57 AM
>Subject: Who the Hell has dynos of 1.8 vs 2.0 stock heads! was Re: 1.8L
>headon 2.0L block
>
>
> > Or better yet, who has a stock 2.0 head on a 1.8! I'm hearing some voices
> > saying the 2.0 is the hot head. Why not on a 1.8?
> > Seriously, I would imagine most people have stock heads. Just because a
>2.0
> > short block is installed doesn't mean the money to pay somebody or the
> > talent to do it yourself is available to port the head.
> > But, the original question was which head (presumeably stock) is better (I
> > believe from a performance point of view1!). I'm still holding out for
>some
> > dyno graphs.
> > A word about butt dynos!(from one of Allyn's posts) First, they are
> > impossible to calibrate! ;^) Second they respond to change rate of change
> > of acceleration, not acceleration. Didn't I already relate the story about
> > the Audi R8 driver's (Professionals!) thinking the direct injection engine
> > was slower despite it producing gobs more torque!
> > Dan
> >
> > ----- Original Message -----
> > From: Dave Ewing <MK1Scirocco16v@attbi.com>
> > To: <scirocco-l@scirocco.org>
> > Sent: Saturday, June 28, 2003 12:47 PM
> > 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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