924Board.org

DD69 · Joined: 03 Jul 2003 Posts: 11

I've tried to simulate the 2.0 NA engine in Desktop Dyno but I can't get the figures right.
Does anyone have file with the flow in the head as well as the file for the cam?

flosho · Posted: Sun Jul 01, 2007 8:39 am Post subject:

Go to www.integralcams.com and use the stock 924 file cam.
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Peter_in_AU · Joined: 29 Jul 2001 Posts: 2745 Location: Sydney, Australia

For the stock head flow go to Applebit's site at http://come.to/924.org then click Engine and the Port & Polishing Head: Results. Jon has the stock flows and the results of a p&p.
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1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

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endwrench · Joined: 07 Dec 2002 Posts: 1631 Location: Victor, Montana

With the correct port flow numbers it is amazingly close to real world dyno numbers.

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
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flosho · Posted: Sun Jul 01, 2007 12:42 pm Post subject:

Where can I download a good desktop dyno program??
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DD69 · Joined: 03 Jul 2003 Posts: 11

I'm still about 20Hp too low even with the flow from his head.

I'm not sure if I got the camshaft right, the current values are:

cam specs@: 0.050
lifter: hyd.
lift: 12mm
lobe centre 110.3
valve overlap: 8
int. duration: 228
ext. duration: 229
IVO: 6
IVC: 42
EVO: 47
EVC: 2
Timing: -7

The engine is euro and the peak Hp is at 5500rpm and peak tork is at 4000rpm.

Lizard · Posted: Tue Jul 03, 2007 3:22 am Post subject:

the liftrs are solid,
and Euros ran at 10 deg BTDC
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DD69 · Joined: 03 Jul 2003 Posts: 11

112Hp at 5500rpm and
123 ft-lbs at 4000rpm.

Getting closer

Lizard · Posted: Tue Jul 03, 2007 5:10 am Post subject:

now the timing it is asking for is that max or at idle, as the spec I gave you was for timing at idle, I am not sure what max timing is on the euros though.
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Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

DD69 · Joined: 03 Jul 2003 Posts: 11

I misunderstood the timing I think, it's the timing of the cam so it probably should be 0.

I still don't get more than about 110Hp though. Since I got the flow values from the head and the cam profile there must be something else wrong.

Peter_in_AU · Joined: 29 Jul 2001 Posts: 2745 Location: Sydney, Australia

What compression ratio are you using?
_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

DD69 · Joined: 03 Jul 2003 Posts: 11

These are the current values I use:

Block: Porsche 2.0
Bore: 86.5
Stroke: 84.4

Intake Valve: 40mm
Exhaust Valve: 33mm

Compression: 9.3

Induction flow: 500.0 cfm @ 1.5inHg
Fuel: Gasoline
Manifold Type: Tuned-Port Injection

Exhaust: H.P Manifolds And Mufflers

Lifter: Solid
Cam Specs@: 0.050-lift
Int Lift: 12mm
Exh Lift: 12mm
Timing: 0.0
IVO: 6.0
IVC: 42.0
EVO: 47.0
EVC: 2.0

This gives me 114Hp @ 5000rpm and 133ft-lbs @ 3750rpm.

morghen · Joined: 21 Jan 2005 Posts: 9102 Location: Romania

well try @ 5800 RPM and see whats the power there. The 924 NA peaks a 125 HP at 5800 RPM.
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DD69 · Joined: 03 Jul 2003 Posts: 11

The peak is at 5000rpm, at 4500 I've got 109hp and at 5500 it's 113hp and 6000 is 107hp.