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brealytrent
Joined: 28 Dec 2008 Posts: 414 Location: Goldsboro, NC
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Posted: Sun Sep 29, 2013 9:10 pm Post subject: Curious Question: How to make a rev monster? |
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This is more of a ponder than serious question, but what would need to be done to make an early car ('77) with '81 head on it be able to safely rev to something like 7500-8000 rpm and still be streetable? Would it even be possible? _________________ 1977 Porsche 924 - sold
1980 Porsche 931 - sold
1984 Porsche 928 'S2' Euro - sold
2016 Ford Fiesta ST - sold
2009 Porsche Cayman |
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Rasta Monsta
Joined: 12 Jul 2006 Posts: 11724 Location: PacNW
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Posted: Mon Sep 30, 2013 12:56 am Post subject: |
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It would need to be precisely balanced, obviously, and need a serious upgrade to the fuel delivery system! Lightening the valve train would probably be beneficial as well. _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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fiat22turbo
Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR
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Posted: Mon Sep 30, 2013 1:25 am Post subject: |
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Lightened or aluminum flywheel.
Lighter rods and pistons. Possibly even a lightened and/or knife edged crankshaft.
Ported head and higher compression to flow enough air at that RPM
Higher lift cam possibly
Lightweight lifters, which may or may not require stronger valve springs.
Better intake and exhaust (header, side draft carbs or a larger plenum/throttle body)
The lifters are a problem on the street since they require dissasembly of the camshaft to adjust for wear.
Since you'll be pushing the engine pretty hard, a reversed cooling system isn't a bad idea either. _________________ Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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Fifty50Plus
Joined: 28 Feb 2008 Posts: 1361 Location: Washington DC area
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Posted: Mon Sep 30, 2013 2:23 am Post subject: |
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The stock cam runs out of snuff at around 6000 RPM. It will rev higher but why bother. You will need a better cam profile to have fun in the upper ranges. _________________ 1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Sat Nov 23, 2013 1:48 pm Post subject: |
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This combination ought to get you close: _________________ erstwhile owner of just about every 924 variant ever made |
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daniel
Joined: 18 Jun 2009 Posts: 670 Location: Sydney, Australia
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Posted: Tue Nov 26, 2013 7:58 am Post subject: |
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How would the standard bottom end go above 7000rpm? _________________ Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Tue Nov 26, 2013 8:27 am Post subject: |
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I don't think the bottom end is the problem, although lighter rods, pistons, and flywheel would help with freer revving, obviously. _________________ erstwhile owner of just about every 924 variant ever made |
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daniel
Joined: 18 Jun 2009 Posts: 670 Location: Sydney, Australia
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Posted: Wed Nov 27, 2013 8:01 am Post subject: |
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So what compression ratio is recommended with the stage 3 cam? _________________ Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet |
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