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The V is getting more grunt

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Howard said:
Right.

I would think that forged pistons would most likely add to, not reduce, piston slap since forged pistons tend to be used in hotter (more powerful) applications, which necessitates more gap for the piston's expansion.
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That's what hes saying. Go forged, or if you don't like piston slap, really good hypers made for forced induction (thicker ring lands, etc).

Forged pistons require more clearance due to being more dense and having a higher coefficient of expansion at the same temperature, regardless of application.
 
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exdeath said:
That's what hes saying. Go forged, or if you don't like piston slap, really good hypers made for forced induction (thicker ring lands, etc).
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Reading it again, yes, that does seem like what he meant. But for the same power rating, it seems as though you would need the same amount of gap.
Forged pistons require more clearance due to being more dense and having a higher coefficient of expansion at the same temperature, regardless of application.
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I don't think it's the density that matters.

http://www.ergaerospace.com/Aluminum-properties.htm
http://www.matweb.com/search/DataSheet.aspx?MatGUID=4303c5b908ff4cbd91a02fed7d4e8202

Exactly the same, though one is 8% the density of the other
 
There is a big difference with a forged piston and a cast one as far as how it sounds cold. There are things you can do sometimes to minimize that noise.

It's unappealing to many, much like putting a race exhaust on a luxury car.
 
Howard said:
Reading it again, yes, that does seem like what he meant. But for the same power rating, it seems as though you would need the same amount of gap.
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The clearance is the same once the engine is warmed up, that is the whole point of allowing more cold clearance with forged parts.
 
exdeath said:
The clearance is the same once the engine is warmed up, that is the whole point of allowing more cold clearance with forged parts.
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I concede. I recently became aware of the fact that hypereutectic Al alloys have significantly lower thermal expansion coefficients (thanks wikipedia), which corroborates what you and alkemyst said.
 
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Howard said:
Reading it again, yes, that does seem like what he meant. But for the same power rating, it seems as though you would need the same amount of gap.

I don't think it's the density that matters.

http://www.ergaerospace.com/Aluminum-properties.htm
http://www.matweb.com/search/DataSheet.aspx?MatGUID=4303c5b908ff4cbd91a02fed7d4e8202

Exactly the same, though one is 8% the density of the other
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I think you're right. It's the alloy that matters, aluminum casting alloys are different from normal forging alloys. A354, a common casting alloy, has a CTE around 10% lower than 6061, a common forging alloy. I don't know what exact alloys are used in pistons though, this is just an example from my knowledge of common automotive alloys.

FWIW forgings typically have higher densities than castings, so the CTE and densities are correlated, but there is not causation.
 
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ExarKun333 said:
Why would you buy a CTS-V, spend money to upgrade it, and include a K&N filter that lets in an absurb amount of dust into your engine?
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I'm guessing because with forced induction, intakes make a noticable difference in power and most owners would do normal oil changes anyway, negating any possible ill effect from the negligable increase in dust ingested by an on-road driven car.

Though I could be wrong. Perhaps the plan is to drive the car offroad and never do oil changes.
 
vshah said:
so you're saying OP needed to worry about 1000HP from day one? :awe:
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Nope, Im saying that anyone who doesn't even have close to 500 HP should worry about getting to 500 HP themselves before telling someone else "1000 HP or GTFO" 😀
 
exdeath said:
Nope, Im saying that anyone who doesn't even have close to 500 HP should worry about getting to 500 HP themselves before telling someone else "1000 HP or GTFO" 😀
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It's tough to hook that kind of power up anyways with a car like this. I read the review of a nice 700hp upgrade for the CTS-V and it was the same 0-60 but a little faster in the 1/4mile and 0-100 (as expected). It's fun to mess with the car for sure, but at some point these cars have issues getting it to the ground.

That said, I would be pretty happy with 500hp myself. 🙂
 
ExarKun333 said:
It's tough to hook that kind of power up anyways with a car like this. I read the review of a nice 700hp upgrade for the CTS-V and it was the same 0-60 but a little faster in the 1/4mile and 0-100 (as expected). It's fun to mess with the car for sure, but at some point these cars have issues getting it to the ground.

That said, I would be pretty happy with 500hp myself. 🙂
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Even stock, the car has enough power to spin the tires in 1st gear when the rpms top 4k from an easy launch. As it nears red line, I can feel them starting to spin.
 
KentState said:
Even stock, the car has enough power to spin the tires in 1st gear when the rpms top 4k from an easy launch. As it nears red line, I can feel them starting to spin.
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What is your current tire size? Curious how large the CTS-V can comfortably accomodate.
 
haha, just saw a guy taking off in his gen2 CTS-V while coming back from the bank and some MAF calibration logging. Sounded so gooooood - he def didn't have a stock exhaust.
 
AdamK47 said:
It's an SUV manufactured by General Motors. It seats 20 and gets 6.3MPG with a 9L V8. Fat republicans from mostly poor backgrounds with little financial sense purchase them. They drive them while eating giant greasy hambugers. They have blue collar jobs. The vehicle cannot be operated while wearing penny loafers.
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LOL Sounds like the car for me.
 
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