[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Question for all those with a 16v 2.0 block and 16v 1.8head
Dave,
I have the article on the TT head as well. You're stating that=20
the 2.0 head flows better because its exhaust flows 15cfm more while its=20
intake is 10cfm, leaving it with a net 5cfm advantage. I'm not so sure=20
that it's so simple.
My first guess as to the reason people think that the 1.8 head=20
flows better is that of the redline of the 2 motors. The 1.8 redlines at=20
7200; with Motronic, the 2.0 redlines at 6800. There's no sense getting=20
into a discussion of whether that has any bearing on how well the head=20
breathes (or whether the redline is in a reasonable place anyway), but that=
=20
certainly would give the impression that the head flows better.
Secondly, if you look at the intake ports themselves, the=20
difference is *enormous*. It certainly looks like there would be more than=
=20
a 10cfm flow difference, and that's probably convincing people as=20
well. The exhaust difference is not as noticeable.
Thirdly, the fact of the matter is that the 1.8 head does make=20
better power at high rpms. I've yet (unfortunately) to see a back-to-back=
=20
same-car 1.8 head vs. 2.0 head dyno run. But I did do a stock 1.8 engine=20
run and a stock 2.0 engine run on my car -- with the same exhaust, fuel=20
injection system, everything. All I did was take the manifolds off, rip=20
the 1.8 out and put the 2.0 in. Same tranny, same driveline, same=20
everything. Therefore, the only difference on the dyno is the motor.
What you see in the dyno runs is that the 2.0 has an enormous=20
torque advantage over the 1.8 over most of the engine's range. In fact,=20
the 2.0 made more torque at idle than my 1.8 did at its peak. However (and=
=20
this is the reason that the stock 2.0 cars didn't knock any significant=20
time off the 0-60 numbers vs. the 1.8) at high revs, this advantage begins=
=20
to dwindle, and by 7200rpm, the 2.0 head isn't making much (if any) more=20
than the 1.8 did. Exhaust restriction comes into mind as a factor... but=20
other than that, the only thing to explain that drop in advantage is that=20
the 1.8 head is flowing better.
Furthermore, 87 octane is not the best gas for the 16V. If=20
someone made more power using 87 on the dyno than 93, their engine is not=20
tuned properly. With stock ignition advance and compression ratio, the 16V=
=20
will ping non-stop on 87. The knock sensor will retard the iginition to=20
stop this, but in the process you'll lose power...
It is true that the energy contained in 87 octane gas is=20
(fractionally) higher than 93... but not nearly enough to make up for the=20
difference in power lost by the knock sensor. If your car doesn't enter=20
ignition retard mode on 87, something's up...
Jason
At 05:53 PM 1/10/2003, Rabbit16v wrote:
>The 2.0L head flows better than the 1.8L head in it's stock form. You got
>that backwards. I don't know how many times the link to the TT flow test
>site has been put up here on the list but it shows without a shadow of a
>doubt that the 2.0L head flows better than the 1.8L head. And, with the
>2.0L head being just plain newer than the 1.8L head, the 2.0L head is a
>better choice you don't have to worry as much about the tensioner stud
>pulling out or the cam bearings being worn so much, etc. And this is
>without even mentioning the fact that the 2.0L head has more material for
>porting than the 1.8L head. See, even though the 2.0L head has smaller
>intake ports it depends on how it is ported not necessarily how big but it
>does have larger exhaust ports so overall the 2.0L head flows better. So=
if
>you find a 2.0L 16v tallblock somewhere, just slam the whole thing into=
your
>car and swap the manifolds.
>
>I wonder how this whole 1.8 is better than 2.0 thing got started? Maybe
>someone who ain't into 16v. Hmmmmmmmm, MEZE?????
>
>HTH!!
>
>Dave
>----- Original Message -----
>From: "Allyn" <amalventano@sc.rr.com>
>To: "Joe Doty" <Joe.Doty@lcnetwork.com>; "Nathan Frechette"
><desertwind16v@attbi.com>; <scirocco-l@scirocco.org>
>Sent: Friday, January 10, 2003 10:36 AM
>Subject: Re: Question for all those with a 16v 2.0 block and 16v 1.8 head
>
>
>i've been wondering about this myself lately. the head chamber volumes of
>1.8 and 2.0 heads are both 45cc. so the head doesnt change c/r.
>the advantage of a 1.8 head on a 2.0 block is that the 1.8 flows better=
than
>the 2.0 in their respective stock forms. this could effectively make a
>person think the engine has a higher c/r since it would get slightly higher
>max pressure readings during a compression check.
>Al
>
>
>----- Original Message -----
>From: "Joe Doty" <Joe.Doty@lcnetwork.com>
>To: "Nathan Frechette" <desertwind16v@attbi.com>; <scirocco-l@scirocco.org>
>Sent: Friday, January 10, 2003 3:06 AM
>Subject: RE: Question for all those with a 16v 2.0 block and 16v 1.8 head
>
>
> > Nathan,
> >
> > The combustion chambers on the 1.8 16v and 2.0 16v heads are identical,=
so
>the head doesn't change the compression. The Bentley says the 2.0 comp.
>ratio is 10.8:1.
> >
> > Joe
> >
> > -----Original Message-----
> > From: Nathan Frechette [mailto:desertwind16v@attbi.com]
> > Sent: Fri 1/10/2003 12:03 AM
> > To: scirocco-l@scirocco.org
> > Cc:
> > Subject: Question for all those with a 16v 2.0 block and 16v 1.8 head
> >
> >
> > What does the compression ratio come out to be. I have been searching=
on
>the tex and haven't been able to find good answers. Thanks
> >
> > Nate
> >
> > IIi zz j)fj=7F b=CB=9D? (
>
>
>_______________________________________________
>Scirocco-l mailing list
>Scirocco-l@scirocco.org
>http://neubayern.net/mailman/listinfo/scirocco-l
>
>
>_______________________________________________
>Scirocco-l mailing list
>Scirocco-l@scirocco.org
>http://neubayern.net/mailman/listinfo/scirocco-l