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serz
Joined: 22 Aug 2007
Posts: 77
Location: Lithuania
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 Posted: Fri Jul 06, 2012 5:48 pm Post subject: s1 turbo boost rpm |
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is there any table of engine rpm - boost levels? How much vacuum should be on idle, 2000. 3000 rpm? Mine reaches 0 only ~3000rpm, isn;t it little bit high? When there should be full boost then?
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Fri Jul 06, 2012 6:13 pm Post subject: |
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At 3000 rpm you should get boost for sure. But of course only when driving the car not revving it in neutral.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
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'82 924S/931 "Gulf", sold 
'84 924, turbocharged, sold.
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serz
Joined: 22 Aug 2007
Posts: 77
Location: Lithuania
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| Posted: Fri Jul 06, 2012 6:29 pm Post subject: |
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and what (why?) is the difference between driving and reving?
what influence can have boost leaks? I'm not sure about my IC piping, and boost gauge itself is simply plugged onto hose, without cramp brace
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Raceboy
Joined: 01 Mar 2004
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Location: Estonia, Europe
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| Posted: Fri Jul 06, 2012 7:27 pm Post subject: |
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Difference between revving and driving is everything because turbo works on exhaust energy and engine does not produce energy when revving standstill.
I suggest you to read Corky Bell's "Maximum Boost" book, very good reading and easy to understand.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
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banana944
Joined: 30 Sep 2009
Posts: 4
Location: Upton, MA
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| Posted: Sat Jul 14, 2012 12:51 am Post subject: |
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An engine needs load to build boost, when in neutral the engine experiences no load.
You can pressure test your intake to search for leaks.
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1986 951
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Rasta Monsta
Joined: 12 Jul 2006
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Location: PacNW
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| Posted: Sat Jul 14, 2012 1:35 am Post subject: |
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My car makes 50% boost under 2500 RPM, and is at 100% by 3000.
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ideola
Joined: 01 Oct 2004
Posts: 15550
Location: Spring Lake MI
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| Posted: Sat Jul 14, 2012 2:21 am Post subject: |
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| Rasta Monsta wrote: | | My car makes 50% boost under 2500 RPM, and is at 100% by 3000. |
I presume you mean at WOT. Boost will be highly variable depending on throttle position...
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Rasta Monsta
Joined: 12 Jul 2006
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Location: PacNW
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| Posted: Sat Jul 14, 2012 3:18 am Post subject: |
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| ideola wrote: | | I presume you mean at WOT. |
One of only two positions utilized with regularity.
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Toofah King Bad
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jazz guy
Joined: 26 Nov 2002
Posts: 434
Location: Colorado
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| Posted: Sat Jul 14, 2012 7:37 am Post subject: |
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| ideola wrote: | | I presume you mean at WOT. |
| Rasta wrote: | | One of only two positions utilized with regularity. |
You sir, are AWESOME!
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serz
Joined: 22 Aug 2007
Posts: 77
Location: Lithuania
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| Posted: Sun Jul 15, 2012 6:21 am Post subject: |
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getting back to my question - what ten should I see on boost gauge while idle rpm, revving the engine 2000, 3000 rpm?
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ex Porsche 924 1982
Now Porsche 924 turbo
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Sun Jul 15, 2012 7:28 am Post subject: |
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| serz wrote: | | getting back to my question - what ten should I see on boost gauge while idle rpm, revving the engine 2000, 3000 rpm? |
If you have just a boost gauge (i.e. no vacuum reading), then zero, nothing. If you have vacuum/boost reading, then maximum of 100 kPa/1 bar of absolute pressure, i.e. atmospheric pressure.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
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serz
Joined: 22 Aug 2007
Posts: 77
Location: Lithuania
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| Posted: Sun Jul 15, 2012 5:46 pm Post subject: |
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as mentioned before, have vacuum and boost gauge, From -1 to 1 bar. As I haven't yet driven my car, I only start it up from while to while, doing modifications and putting it all together.
so now I see -1bar vacuum while idling ~900 rpm, then 2000rpm is -0,5bar, and 3000 rpm shows 0. Would be nice to compare with "running" cars, prior going on street and waiting for boost to kick in or engine to fly out 
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ex Porsche 924 1982
Now Porsche 924 turbo
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924 FAQ (Technical)
