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3.8 Upgrade?

 
Old 01-30-2013, 03:39 PM
  #1  
TheBen
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Default 3.8 Upgrade?

Long story short - my motor may have to come out...and if it does, I was thinking if taking care of some 'while you're in there type stuff.' One thought that did pop into my mind was a 3.8L upgrade.

I found this kit on Ebay - http://www.ebay.com/itm/290697746144...84.m1423.l2649

It's all OEM Porsche stuff, but when I checked with Luke at Sunset Porsche, the Porsche 'kit' contained a lot more stuff like ECU, alternator, heads, valves, etc.

Can you do the 3.8L upgrade with just the stuff from this Ebayer's kit? I'm thinking he probably bought these parts and found it was way more involved.
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Old 01-30-2013, 04:12 PM
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The kit on ebay isn't a kit, and it's not advertised as a kit. It's advertised accurately as a set of 3.8 liter pistons and cylinders.

Do a search to learn more about the RS engine. Dozens of threads.

If I was going to spend money on a displacement increase, I'd buy the 9M 3.8 setup, which is 3.82 rather than the factory parts, which are 3.745 (if memory serves).
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Old 01-30-2013, 04:14 PM
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Bill Verburg
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Originally Posted by TheBen View Post
Long story short - my motor may have to come out...and if it does, I was thinking if taking care of some 'while you're in there type stuff.' One thought that did pop into my mind was a 3.8L upgrade.

I found this kit on Ebay - http://www.ebay.com/itm/290697746144...84.m1423.l2649

It's all OEM Porsche stuff, but when I checked with Luke at Sunset Porsche, the Porsche 'kit' contained a lot more stuff like ECU, alternator, heads, valves, etc.

Can you do the 3.8L upgrade with just the stuff from this Ebayer's kit? I'm thinking he probably bought these parts and found it was way more involved.
yes, you could rebuild w/ the e-bay 102s you would need a chip at minimum in addition to the other standard rebuild parts. But be aware that those are slip fit 102s and are more of a street p/c set than the 102s w/ larger 109mm bases. Regardless there are better choices out there, one issue w/ the factory Mahles is that there is only a single version, a flat 6 really wants a Left and a different right version w/ different pin o/s.

But anyway yes, you can use them w/ a chip, some common other accompanying changes are RS valves, RS cams, ARP or Raceware rod bolts(or even better Pauter/Carillo rods)

It's not going to be cheap but the extra torque through the whole rev range is really useful.
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Old 01-30-2013, 04:21 PM
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I'd prefer to do it the 'right way' and not just 'half-way'...
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Old 01-30-2013, 05:09 PM
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Originally Posted by TheBen View Post
I'd prefer to do it the 'right way' and not just 'half-way'...
Thats the right philosophy to have,...

JMHO,.....

The slip-fit 102mm P/C's aren't the best choice here since they do not stay round over time and we see this by observing less than optimal leakdown figures. The machine-in, thick-walled RSR version is FAR more durable and strongly recommended for much improved longevity.

One needs different rods since these RSR pistons have wider pin bosses, thus require a narrower wrist pin bore at the top of the rods. We use Pauters in these situations.

Depending on how the car is to be used and driven, there are some other modifications that should be done for improved reliability, too.

There are other P/C options here, however all of them use a 2618 alloy piston which doesn't last anywhere near as long as the Mahles. For race engines, thats not a concern since such things are disassembled and inspected every 100-200 hours, however that adds some significant costs over the long term for street usage.
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Old 01-30-2013, 05:35 PM
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Where else can one find advice like this?
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Old 01-30-2013, 06:06 PM
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Originally Posted by Steve Weiner-Rennsport Systems View Post
..... The machine-in, thick-walled RSR version is FAR more durable and strongly recommended for much improved longevity.

One needs different rods since these RSR pistons have wider pin bosses, thus require a narrower wrist pin bore at the top of the rods. We use Pauters in these situations.

...
there are at least 2 different versions of the 109mm base x102mm bore Mahle p/c sets, the 964 version does require the 930/964/GT3 sized rods, the 993 version works correctly w/ the stock or w/ aftermarket versions of the 993 rods.
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Old 01-30-2013, 06:28 PM
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Originally Posted by solomonschris View Post
Where else can one find advice like this?
Agreed.

Two idiots, one thought. (its a Germanisim)
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Old 01-30-2013, 11:19 PM
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Love the ad, that the slip-ins will "save you many thousands of dollars". Uh huh. Can't add to what's posted above.
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Old 01-31-2013, 05:31 PM
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Originally Posted by M. Schneider View Post
Agreed.

Two idiots, one thought. (its a Germanisim)
This thread, why this forum / site is a daily read +3.8
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Old 01-31-2013, 06:10 PM
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Originally Posted by solomonschris View Post
Where else can one find advice like this?
The new Rennsport Systems tech web site! LOL!........
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Old 01-31-2013, 07:25 PM
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Default 993 Mahle 3.8 pistons

Originally Posted by Steve Weiner-Rennsport Systems View Post
Thats the right philosophy to have,...

JMHO,.....

The slip-fit 102mm P/C's aren't the best choice here since they do not stay round over time and we see this by observing less than optimal leakdown figures. The machine-in, thick-walled RSR version is FAR more durable and strongly recommended for much improved longevity.

One needs different rods since these RSR pistons have wider pin bosses, thus require a narrower wrist pin bore at the top of the rods. We use Pauters in these situations.

Depending on how the car is to be used and driven, there are some other modifications that should be done for improved reliability, too.

There are other P/C options here, however all of them use a 2618 alloy piston which doesn't last anywhere near as long as the Mahles. For race engines, thats not a concern since such things are disassembled and inspected every 100-200 hours, however that adds some significant costs over the long term for street usage.

Steve while your on the subject. I have a 3.8 RSR build that I did not do the original assembly on. I was not 100% happy with the performance which was based on a set of JE pistons /Mahle 3.8 RSR cylinders. I was lucky to come up with a set of lightly used factory RSR pistons with the titanium wrist pins. I am having the cylinders/pistons checked and machined to match as a set. Rods are Carillo. Do you see an issue with the Carillos over the Pauters? I thought the issue with the Carillos was all the case machining that ends up being needed ? (but better geometry). Are you seeing some other problems?
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Old 01-31-2013, 08:54 PM
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Hi Bob,

Those Carrillo rods will be just fine as long as the bolts are still within stretch spec, otherwise new ones are in order. You may need to clearance the oil pump, depending which one you have.

There is zero difference in geometry between Pauter's and Carrillo's unless someone specified a longer, custom rod (we do this all the time). Just check the Mahle RSR pistons for the correct pin height to help confirm this.

Go for it,
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Old 01-31-2013, 09:29 PM
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Mike J
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Does someone want to estimate what doing it correctly will cost, given its not just pistons and jugs? $10,000+? That would stop 99% of the people from doing this. "TheBen", make sure you understand all the components to do this, as well as the labor to assemble and tune. You will need pistons, jugs, con rods, upgraded valves, head work, tuning work, etc. Do a search, this has been discussed many times before.

I think for most street use, the 3.8 upgrade is a very expensive way to gain some power and torque. By the time the dust settled, the cost per hp is, well, astounding. Same goes for 9M heads, great idea but very expensive. While it does not really add power, a re-gear or switch of transmissions can give you a more fun ride, although these days doing that is getting very expensive as well.

If the engine is apart anyways, its alway tempting to upgrade - go for it if that's your decision, but make sure you have your eyes wide open. I looked at it, and when I did my rebuild, I went 100% stock - no regrets.

Mind you, I am not sure what part of Porsche ownership I expected to be cheap...

Cheers,

Mike
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Old 01-31-2013, 10:13 PM
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TheBen
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Thanks Mike. I talked to Steve Weiner about this more in depth today, and am just going to stay 3.6...but I will be sending my ECU to Steve for a software upgrade and immobilizer removal.
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