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      07-20-2019, 05:37 AM   #45
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Yea I'm about 30k deep on the engine build. Didn't stroke it because removing material from the cylinder walls isn't a good idea when adding boost to s65 block. We dropped compression to 10.5:1
Why would you need to bore the cylinders to stroke it? I'm assuming the alusil was prepped for new rings anyway with new pistons, no?
I'm not sure. How else can you stroke a motor without boring the cylinders? I didn't build it myself so not too familiar with the specifics.
One can stroke a motor with a different crank shaft. It would allow the pistons to travel farther. If I recall correctly one would get a 4.2 L motor with the S65 block.
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      07-20-2019, 07:59 AM   #46
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I'm not sure. How else can you stroke a motor without boring the cylinders? I didn't build it myself so not too familiar with the specifics.
Stroking and Boring a motor are 2 different ways to increase the displacement of an engine. Stroking works with the crank/rods to allow the piston to travel a further distance as the person above me stated. Boring makes the actual diameter of the cylinder larger to accommodate wider pistons.


For max block strength on a boosted application it's best to leave as much meat in the cylinder walls as possible. Drawback of stroking is the piston now moves much faster up and down and decreases rev limit.


Its best you stayed 4L if your end goal was high boost and 9K RPM
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      07-20-2019, 06:35 PM   #47
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Stroking and Boring a motor are 2 different ways to increase the displacement of an engine. Stroking works with the crank/rods to allow the piston to travel a further distance as the person above me stated. Boring makes the actual diameter of the cylinder larger to accommodate wider pistons.


For max block strength on a boosted application it's best to leave as much meat in the cylinder walls as possible. Drawback of stroking is the piston now moves much faster up and down and decreases rev limit.


Its best you stayed 4L if your end goal was high boost and 9K RPM
Dependent upon material choice, rod length choice and design, piston weight, etc, a stroker rotating assembly can easily be lighter than stock, especially the reciprocating mass if stock rod length isn't retained. This actually reduces the tensile stress on the rods at higher RPM.

Agreed on wall thickness though, not a fan of significantly increasing the bores on these motors since most of them get a lackluster tune after stroking anyway. That makes the additional .1 or .2L worthless.
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      07-20-2019, 07:12 PM   #48
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Dependent upon material choice, rod length choice and design, piston weight, etc, a stroker rotating assembly can easily be lighter than stock, especially the reciprocating mass if stock rod length isn't retained. This actually reduces the tensile stress on the rods at higher RPM.

Agreed on wall thickness though, not a fan of significantly increasing the bores on these motors since most of them get a lackluster tune after stroking anyway. That makes the additional .1 or .2L worthless.
I agree a stroker rotating assembly can easily be lighter than stock, but for sure a stock bore/stroke forged internal build would be even lighter than that. A little stroke would help spool the turbos faster but properly sized turbos on a 4L V8 should have little to no lag anyways.

This interesting gentleman is not even in the efficiency range of those turbos yet. Once he pushes past 20PSI is when this thing will really start making serious power.

OP: What turbos are you running again?
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      07-22-2019, 11:02 AM   #49
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Originally Posted by jcolley View Post
Dependent upon material choice, rod length choice and design, piston weight, etc, a stroker rotating assembly can easily be lighter than stock, especially the reciprocating mass if stock rod length isn't retained. This actually reduces the tensile stress on the rods at higher RPM.

Agreed on wall thickness though, not a fan of significantly increasing the bores on these motors since most of them get a lackluster tune after stroking anyway. That makes the additional .1 or .2L worthless.
When it comes to tuning I think Gintani does pretty good tuning these setups. Lucrecio84's setup speaks for itself. Mine runs fine. That's all we have to go by.
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      07-22-2019, 11:05 AM   #50
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When it comes to tuning I think Gintani does pretty good tuning these setups. Lucrecio84's setup speaks for itself. Mine runs fine. That's all we have to go by.
Wasn't aiming that at them, typically when the same company manages the engine build, accessories, installation, and tuning, you would assume they take the time to work through all the tuning tables properly and not just change the displacement values in the DME and call it a day.

I was referring to many who buy any non-stock displacement engine and install it and tuning is sort of an afterthought.

It's surprising how many "tuners" are out there who do little more than tweak a few lambda and full load timing maps and call it a day.
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      07-22-2019, 05:13 PM   #51
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Originally Posted by jcolley View Post
Dependent upon material choice, rod length choice and design, piston weight, etc, a stroker rotating assembly can easily be lighter than stock, especially the reciprocating mass if stock rod length isn't retained. This actually reduces the tensile stress on the rods at higher RPM.

Agreed on wall thickness though, not a fan of significantly increasing the bores on these motors since most of them get a lackluster tune after stroking anyway. That makes the additional .1 or .2L worthless.
I agree a stroker rotating assembly can easily be lighter than stock, but for sure a stock bore/stroke forged internal build would be even lighter than that. A little stroke would help spool the turbos faster but properly sized turbos on a 4L V8 should have little to no lag anyways.

This interesting gentleman is not even in the efficiency range of those turbos yet. Once he pushes past 20PSI is when this thing will really start making serious power.

OP: What turbos are you running again?
I am running twin 30r tial xona's
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GINTANI TWIN TURBO E92/F10 M5
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