The Project Pad

JE pistons are nice, but they are way to expensive in my opinion. You might look into some other options. Wiseco, CP, etc.

I don't know if this is a good way of looking at it, but I think it's better to use a head gasket to do CR than to have too high a CR if those are your only choices.

I, too, don't care for large bores. With the limitations imposed by cylinder spacing, w just can't gain that much displacement from boring. My pistons will be a nice safe 82mm.

Honestly I don't think you need to drop the CR. I'm running the same to more boost on less octane and no meth with no issues. If you want to run Diamond pistons I can get them to make duplicates of my 82mm units in a couple days supposedly now that mine are on file. They were ~$1200 for ceramic tops, friction coating on the skirts, Total Seal rings, spiral locks, and lighter wrist pins.

123quattro wrote:Honestly I don't think you need to drop the CR. I'm running the same to more boost on less octane and no meth with no issues. If you want to run Diamond pistons I can get them to make duplicates of my 82mm units in a couple day supposedly now that mine are on file. They were ~$1200 for ceramic tops, friction coating on the skirts, Total Seal rings, spiral locks, and lighter wrist pins.

Agreed - I run 9.3:1 and love it.

123quattro wrote:Honestly I don't think you need to drop the CR. I'm running the same to more boost on less octane and no meth with no issues. If you want to run Diamond pistons I can get them to make duplicates of my 82mm units in a couple days supposedly now that mine are on file. They were ~$1200 for ceramic tops, friction coating on the skirts, Total Seal rings, spiral locks, and lighter wrist pins.

Didn't you just say on the last page that you're running 8.5:1? Or do you mean not any lower than 8.5:1. The reason we want to lower CR is to allow the turbo to be in its sweet spot, which is likely above 30psi (I say likely because we don't have a map for it). With the ignition advance of the lower CR the CR drop isn't as significant a factor in driveability, as per PRJ and our own experience with this car.

Anyway, dad's shop neighbour (engine builder) is a Weisco dealer. He can get us a very nice deal on a set of coated pistons with rings etc. I think we're going to go that route with the same block with a new copper head gasket.

EDIGREG wrote:Agreed - I run 9.3:1 and love it.

PSHAW, you don't count Mr. E85

Weisco seems to be pretty decent. I think Diamonds are pretty good too, but no first hand experience.

Matt, I'm running 8.5:1. I meant I wouldn't go lower than that. What kind of timing numbers are you running? At 28 psi 5000 rpm is 21* and 7500 is 28* on mine.

Diamond makes really nice stuff, but generally they just do domestic V8 applications. I only went with them because they were local to me and came highly recommended by my machine shop.

This is (cough.. WAS) our spark map

123quattro wrote:Matt, I'm running 8.5:1. I meant I wouldn't go lower than that. What kind of timing numbers are you running? At 28 psi 5000 rpm is 21* and 7500 is 28* on mine.

Diamond makes really nice stuff, but generally they just do domestic V8 applications. I only went with them because they were local to me and came highly recommended by my machine shop.

what do you run for fuel? octane? how many miles on this map and boost level?

chaloux wrote:Anyway, dad's shop neighbour (engine builder) is a Weisco dealer. He can get us a very nice deal on a set of coated pistons with rings etc. I think we're going to go that route with the same block with a new copper head gasket.

Exactly what we spoke about 5 days ago, nice!... which rods are you slapping in there?

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Mushasho! wrote:Exactly what we spoke about 5 days ago, nice!... which rods are you slapping in there?

The Pauters. I think. We'll see which weigh less

How much those o rings stick out above the deck??? I did run copper hg twice both times it did got lifted, last time around I did put stock ml gasket bored to 83mm in with grate success ARP told me to TQ head studs to 75ft with they lube, and they told me to check tq after every 1k miles like 3 times and every time I got little more turn out of nuts.

fasterthenrs2 wrote:How much those o rings stick out above the deck??? I did run copper hg twice both times it did got lifted, last time around I did put stock ml gasket bored to 83mm in with grate success ARP told me to TQ head studs to 75ft with they lube, and they told me to check tq after every 1k miles like 3 times and every time I got little more turn out of nuts.

Did you use The same block? What about their cutouts for the O rings? I think they stick out around .010

chaloux wrote:

fasterthenrs2 wrote:How much those o rings stick out above the deck??? I did run copper hg twice both times it did got lifted, last time around I did put stock ml gasket bored to 83mm in with grate success ARP told me to TQ head studs to 75ft with they lube, and they told me to check tq after every 1k miles like 3 times and every time I got little more turn out of nuts.

Did you use The same block? What about their cutouts for the O rings? I think they stick out around .010

same block, what you mean by cutouts for o rings??? i did set up mine 5 thousands above the deck

You used the orings with the mls gasket as well then?

chaloux wrote:You used the orings with the mls gasket as well then?

yes

pkw wrote:what do you run for fuel? octane? how many miles on this map and boost level?

pump gas, 93 octane, 15,000 miles at 28 psi. The difference might be that I pull timing aggressively as IAT goes up. Probably too aggressively, but it's lived so far.

OP, what was the CR in the first place on the stroker?

Jonathan wrote:OP, what was the CR in the first place on the stroker?

8.5:1

should have allowed us some headroom for boost

So it turns out JE are pretty interested in the pistons with the 5 thou difference thing. They'll be receiving them shortly and we'll be getting an RMA #

chaloux wrote:So it turns out JE are pretty interested in the pistons with the 5 thou difference thing. They'll be receiving them shortly and we'll be getting an RMA #

Nice! Maybe they'll send you a free set

did they overheat and shrink???

We're still in touch with JE. So far their assessment was: det = not our problem. Two interesting quotes from their assessment:

Boost pressure is not relevant to a tune being detonation inducing or not.

The compression ratio is not relevant to boost pressure, as the pressure is a measurement of restriction.

Once the pistons get figured out, the approach to the rebuild will be as follows:

Definitely
- 81.5mm pistons, 92.8 crank (2.4l)
- re-do turbo water/oil lines with proper AN fittings
- finishing details - fuel filter heat shield etc.

Maybe
- hank manifold and downpipe, possible white lightning coating
- Tial MVR 44mm wastegate

Who wants a Wagner SQ replica manifold? $800
Perhaps a CT3-6465 billet/ceramic ball bearing turbo? Was $1850 new. $1300? Absolutely perfect in every way, but needs a smaller hotside housing (comes with 1.0AR divided)

"Boost pressure is not relevant to a tune being detonation inducing or not." HUH? Of course it is, amongst many other variables.

You should move everything in the "maybe" category to the "definitely" category. Seriously, you will be soo happy with the setup.

What is the plan for a turbo?