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Anyone know these Pistons?

I'm told these are for a turbo; however, most turbo pistons I have seen are flat on top. If they are, what kind of compression ratio would these be, and is that a good ratio to have on a turbo?


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John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle

Last edited by AngM018; 02-20-2007 at 04:18 PM..
Old 02-20-2007, 04:14 PM
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Here are some more pics



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John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-20-2007, 04:17 PM
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Stock turbo pistons are not completely flat. There is a slight dome.
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Old 02-20-2007, 05:02 PM
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Thanks for the correction. any idea of the compression on these ones?
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John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-20-2007, 05:08 PM
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If I were to venture a guess, I'd have to say maybe 7.0:1 and no more than 7.5.

Here is an 8.0:1 98mm JE:

http://www.lnengineering.com/930turboloaded.JPG

BTW, what manufacturer are those? They have some wierd looking skirts.
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Old 02-20-2007, 06:25 PM
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Thanks Charles, I'm told they are Mahle. The seller doesn't know what he has so thats why I'm trying to find out.
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John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-20-2007, 06:30 PM
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Rings most definately don't look like they are what mahle typically includes - looks like a hastings ring to me with chrome rails, but maybe I need to have a drink and watch some tv (and get away from the computer) :-)
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Old 02-20-2007, 06:37 PM
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You think these would be worth taking a risk on?
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John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-20-2007, 06:42 PM
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Tough call. I would have to say no since more than likely you are going to have to have a set of cylinders plated and honed to match, and if you are going that far, you might as well use a set of pistons that is exactly what you need. I don't imagine they would just drop in to a set of cylinders without some work.
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'99 Boxster powered by Flat 6 Innovations; '10 Cayman S (DFI testbed)
Old 02-20-2007, 06:47 PM
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yeah I've got to do that anyways (3.4 Mahle cylinders will be their new home). But your right, I'm going to hold out at least till I know exactly what these are. Those skirts dont look like mahle.
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John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-20-2007, 06:57 PM
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I don't think I'd role the dice on these unless an experienced Porsche engine builder and/or machinist could look them over (and possibly identify them) for you. Just my $.02....and that's pretty much worthless these days.
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Old 02-21-2007, 05:31 AM
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If you need a lead on some great priced turbo P&C's, PM me.
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Old 02-21-2007, 02:32 PM
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