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Compression question
I dont think you calculate piston compression and
compression reatio that way..
My 8v 1.8: stck ran 160 PSI on all four pistons
(bentley tells 145-174 average for new engine) but it
still only 8.5:1 compression ratio. (ie: 8.5 times the
weight of earth's atmostphere (which is the base
xx:1).
VW engines which came stock in a Scirocco, or are a
popular replacement
Typical Name & Code Bore (mm) Stroke (mm) Year / Model
available HP@RPM / TQ@RPM CR
1.8L JH 8v 81 86.4 83-89 90@5500 / 100@3000 8.5:1
1.8L GX 8v 81 86.4 Fox 85@5250 / 96@3000 8.5:1
1.8L PL 16v 81 86.4 86.5-92 Scirocco (88 USA, 89
Canada, 92 Europe) 123@5800 / 120@4250 10:1
2.0L 9A 16v 82.5 92.8 90 - 92 Passats / Golfs / Jettas
134@5800 / 133@4400 10.8:1
2.0L ABA 8v 82.5 92.8 93-98 Golf / Jetta / Cabrio
115@5250 / 122@3250 10.5:1
Note that all the engines up to the first 1.8L have
136mm rods, while the later motors have 144mm rods
look it up on the net.. my numbers are pretty close to
what it is all about.
--- worldcyclist <worldcyclist@earthlink.net> wrote:
> I've got some firsthand experience that might be
> helpful.
> My 1.8 16V with stock cam timing gave 150psi doing a
> compression test.
> With the cam advanced 8* it was 175psi. Otherwise
> it's 10-1 in terms of
> ratios.
> The JH engine I had was 135psi or 8.5-1.
> The Alfa with 9.5-1 gives me 173 psi with stock cams
> and timing.
>
> An interesting site is www.smokemup.com
> they have GUI programs to play with stuff like this,
> plus more.
>
> Gary
> 87 16V Scirocco (FS $975)
> 80 Callaway Stage 3 Rocco
> 91 Alfa Romeo 3.0 V6 5spd, lowered
>
> Message: 57
> From: "Scourge" <scourge@cogeco.ca>
> To: "Rocco list" <scirocco-l@scirocco.org>
> Subject:
> Date: Mon, 5 May 2003 18:33:42 -0400
>
> This is a multi-part message in MIME format.
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>
> Hey
>
> Just curious, what the stock compression on 16v's?
> 2.0 and 18
> And what about a stock jh?
>
> I think it's in the high 8's or low 9's for the jh.
> Does a 1.8 16v head
> =
> on a 2.0 16v actually increase compression?
>
>
> thanx
>
> -The George
>
>
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