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cgoldhill
Joined: 25 Sep 2004 Posts: 28
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Posted: Mon Sep 27, 2004 12:46 am Post subject: Copper head gasket again |
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I thought i had posted this but i can't seem to find it. Anyways, if i were to run 16 pounds of boost in a 924 turbo would i need to o-ring the block and use a copper head gasket or would it be safe to jsut use a copper head gasket? Also, if i plan on running this high of boost is it necessary for efi? |
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numbbers
Joined: 05 Nov 2002 Posts: 1910 Location: Highlands Ranch, Colorado
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Posted: Tue Sep 28, 2004 10:07 am Post subject: |
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Where are you located? What altitude? I run 17 PSI with no problems in the Denver area, using the factory head gasket. The headgasket won't be your problem, detonation will. _________________ 1980 924 Turbo |
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cgoldhill
Joined: 25 Sep 2004 Posts: 28
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Posted: Tue Sep 28, 2004 10:37 am Post subject: |
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i'm located in southern new jersey which i believe is close to sea level. Wow i'm didn't know the head gasket on these things were that strong. What do you need to do to these cars to prevent detonation at this high of boost levels? Is efi necessary or can i just use an adjustable fuel pressure regulator and higher flow injectors to prevent this detonation? |
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mick
Joined: 13 Jun 2003 Posts: 183 Location: ohio
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Posted: Tue Sep 28, 2004 12:19 pm Post subject: |
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i have that same question how can i stop detonation in my 80 931?? i think thats what blew my ring on #1 and #3. im at 1 bar with a top mount ic also i just put in a msd 6 complete kit. which i think was burning to much gas out cause of the 10 degree past spark _________________ 80 931 intercooled,1 bar, and kinda runs right |
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sandgroper
Joined: 07 Dec 2002 Posts: 108 Location: in limbo
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Posted: Tue Sep 28, 2004 2:58 pm Post subject: |
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Every 80 engine i have dismantled had broken rings,i have decided and scored at pickapart 3 87-89 pontiac sunbird turbo delco ecu,that car had boost control,anti knock etc,same ecu but different memcal gm used it in the typhoon and cyclone,a turbo v6 4x4,it also controls peak and hold injectors.the typhoon guys have got a program for that ecu thats a free download,in fact their is a couple of programs for that ecu.just need to spend half a day pulling a harness and probably a month to install neatly using new cheap as gm sensors,oh yeh its good for 2 bar map sensors as well.Should be a major improvement over cis. |
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jazz guy
Joined: 26 Nov 2002 Posts: 434 Location: Colorado
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Posted: Wed Sep 29, 2004 5:09 am Post subject: |
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In my experience, the stock headgasket has been quite reliable. I have a boost controller on my '82 931 and have run 12-14 lb. boost regularly for more than ten years with no (knock on wood) headgasket problems. As nummbers indicated, I think you will find detonation to be the big problem as you raise the boost level. Like numbbers, I live in Colorado (north of Denver), but I have never been able to run boost in 17psi range without some good octane booster and a cool day. I can say though, that things really do start to get fun when you get into the 16+ psi boost levels. |
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numbbers
Joined: 05 Nov 2002 Posts: 1910 Location: Highlands Ranch, Colorado
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Posted: Wed Sep 29, 2004 9:36 am Post subject: |
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My advice, just work your boost up slowly, until you start to get some detonation. Then back it off, at least 2 psi as a safety factor. Then go have fun if a fast old Porsche. _________________ 1980 924 Turbo |
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Kenodog
Joined: 25 Jun 2003 Posts: 2645 Location: Vancouver,B.C.
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Posted: Thu Sep 30, 2004 12:39 pm Post subject: |
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My advice is DONT run till you hear detonation.By the time your ear can hear it,and all of us hear different octaves differently,you will already be doing damage to your engine.To do it properly save some cash and buy yourself a good MSD set up.The one MSD suggests is a 6420 BTM iirc.These can be had on ebay for around $2-300.It comes with an in cockpit adjustable retard dial and you can hook an MSD knock sensor to it as well.Better idle,the benefit of more top end power and no engine damage,worth it to you? _________________ 1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140 |
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cgoldhill
Joined: 25 Sep 2004 Posts: 28
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Posted: Fri Oct 01, 2004 6:36 am Post subject: |
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What can do to eliminate detonation besides use an intercooler? Also, what intercooler is good for 17 psi? The top mounted intercooler or the 951 one? are either of these good enough? |
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Paul
Joined: 02 Nov 2002 Posts: 9491 Location: Southeast Wisconsin
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Posted: Fri Oct 01, 2004 8:33 am Post subject: |
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Higher octane gasoline will help. You can buy cans of octane boost at most auto parts stores and some tracks have high octane lead free. |
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Smoothie
Joined: 01 Jan 2003 Posts: 8032 Location: DE (the one near MD, PA, NJ)
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Posted: Fri Oct 01, 2004 9:35 am Post subject: |
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Some other tricks to postpone detonation are to retard the ignition and/or to richen the air:fuel, but your car should be doing both of those already to some extent. There's also water injection and/or using higher octane fuel as Paul mentioned.
Which series 931 do you have anyway? (ser.1 = '79-'80, ser.2 = '81-up) _________________ "..it's made in Germany. You know the Germans always make good stuff."
'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox |
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cgoldhill
Joined: 25 Sep 2004 Posts: 28
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Posted: Fri Oct 01, 2004 10:47 pm Post subject: |
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I will be purchasing an 81 or 82 as soon as i can find one in my area. If anyone knows of one being sold within 100 miles of Southern New Jersey, please pm with details. I notice that you live in jersey, where at?
Thanks guys for all the good info! |
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Smoothie
Joined: 01 Jan 2003 Posts: 8032 Location: DE (the one near MD, PA, NJ)
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Posted: Sat Oct 02, 2004 2:03 am Post subject: |
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Central NJ, next to New Brunswick. _________________ "..it's made in Germany. You know the Germans always make good stuff."
'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox |
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Raceboy
Joined: 01 Mar 2004 Posts: 2326 Location: Estonia, Europe
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Posted: Sat Oct 23, 2004 5:07 pm Post subject: |
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ok, to the topic , Question: does anyone have CAD file of the copper head gasket (in order to make one) ? And, does anyone, exept Racing, use CU head gasket at present time? _________________ '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.
http://www.facebook.com/vemsporsche |
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