I agree, best bet would be a non-sleeved 3.8L stroker, cost effective, and awesome response.

-George
GT Motorsports

 

With some aggressive cams and head work, that would be a very unique setup. If you're looking to set yourself apart from the crowd, that'd be one way to do it.

 

Thanks for the pictures.

It looks like the sleeved block has more water jacket passages at the deck of the cylinder block. Is that what you mean by open and closed deck? I don't see how that could be a side effect of putting in sleeves, unless extreme decking of the block is required to shave down the sleeves.

That was my original plan.

It seems like the additional displacement added by the 100mm bore would be really attractive on an NA motor. I didn't realize there were so many negatives.

 

I'm not sure I'd call it negatives, but is a definite increased cost/benefit trade-off as you make more and more elaborate modifications to the car.

 

the sleeves don't really have more water passages

the stock one is totally open around the cylinders while the sleeves fill in all that space and then have those little holes going down the sleeves instead of having the whole area available for coolant

 

The open deck is closed of at the top by the cylinder head & head gasket with just a few small holes & slots to let the water flow through.
With the Dartron sleeves there is a groove machined in the top that mimics
the open deck & the holes you see drilled in the top line up with the holes in the head gasket & head.
The water flow & capacity is the same OE, the only difference being the flange at the top of the sleeve that makes it a closed deck.

 

I understand the technology, I'm just having trouble with the terminology. So the picture below is a stock, OEM, open deck.



And the picture below is of Darton sleeves that are closed deck.



Seems like the sleeves would keep the cylinder wall straighter and rounder with the extra metal near the top of the cylinder.

Thanks for the help.

 

Correct.
Most people, but not all fit the Dartron sleeves so they can bore them out to increase the capacity of the motor. Others feel that the open deck is weakness on an all out FI motor.
The open deck has a thin steel sleeve fitted on the inside of the bore which will only allow about a 20 thou overbore.

 

So the dyno graph of the 3.8L APS twin's was non-sleeved correct?

 

Of course keep in mind for the sleeves to keep the bores straighter and rounder you need to have a problem with them being distorted in the first place. I think it has been proven that there is no need for sleeving the block for less than 600whp.

JET

 

Has anyone thought through the dampening dynamics of a stroked engine? Even if it's balanced/ blueprinted, it's still going to need dampening for longevity sake.

https://my350z.com/forum/showpost.ph...9&postcount=26

https://my350z.com/forum/forced-induction/337947-mrc-first-cracked-crankshaft.html