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Pistons
- Thread starter jwehrheim
- Start date
do you want to uses stock cast pistons or are you looking to forge your motor. 9:1 compression forged pistons and forged rods would be the best bet for a good mild build. You can't put as much psi on it but it would be very DD friendly, compared to 8.5 or 8.0 compression pistons.
I have forged rods. Is there a preference to the 9.0 CR Pistons, such as Weisco vs Arias vs. CP etc. I remember hearing one of the problems with the aftermarket pistons is the piston slap during engine warm up. Is this due to the material or clearance issues?
Last edited:
Outlawstar98
Member
- :
- 2003 MazdaSpeed Protege / 2013 BRZ
how about 8.8 weiscos and k1 long rods for a dd?
I have those. And they work good. But I am fully built DD lol
I have forged rods. Is there a preference to the 9.0 CR Pistons, such as Weisco vs Arias vs. CP etc. I remember hearing one of the problems with the aftermarket pistons is the piston slap during engine warm up. Is this due to the material or clearance issues?
Piston slap is usually more prominent in pistons that are higher in silicon(not silicone), like SRP pistons which I don't think are even offered for the FS. All the pistons you have listed are pretty good so just choose what you think would be the best. Some people talk of Arias having issues of chipping apart, but I have not had issues with Arias on my 4g63 that had them with about 25+psi on gt30r. I have a set that will be going into my FS so we will see what the deal is.
pistons slap is the skirt of the piston hitting the wall of the cylinder. The higher silicon content in the metal, the longer it takes to expand and quit slapping. Silicon is a cheap material used to augment and lighten forged pistons because it can handle alot of heat, so piston manufacturers use it to keep cost down.
The downside is that it expands slower than other metals so it takes slightly longer to fully warm up
no, theyre not. arias pistons crack. ask maxx mazda, he went through 4 sets.
cp or wiseco -- only. i cant recommend arias.
Did Arias or anybody find out why?
thecrash91
Member
- :
- 2003.5 Mazdaspeed Protege
ive never had any problems with my arias, the original owner had this car at 16 psi with greddy emanage, and he was pushin 280whp or something like that with no problems. you have to take timing into consideration when your that high HP so a knocklight would be a great investment, its next on my list after SSFTC
black daliha
Member
- :
- 2003 mazdaspeed protege
go with any major brand piston might as well go forged if your gonna tear it down. Make sure the top is smooth, you dont want a dome piston due to uneven pressure on the flame front and as far as oversised pistons they are designed only for boring the motor over in case of wear so you dont have to throw away the block in case of damage. There is no power to be found there so as long as your block is good your fine.
the way theyre designed causes them to get hot spots, so theyre unevenly heated... then when you get any kind of pinging, they shatter. its well documented and he wasnt the only one with issues.
they work ok for a mild build with a good timing map, but when you can get wiseco and cp for cheaper, why take the chance?
they work ok for a mild build with a good timing map, but when you can get wiseco and cp for cheaper, why take the chance?
as far as oversised pistons they are designed only for boring the motor over in case of wear so you dont have to throw away the block in case of damage. There is no power to be found there so as long as your block is good your fine.
As long as it's been brought up, my local machine shop quoted me $150 to do a .020" over bore on the block. I figure as long as everything is coming out that it's cheap insurance to make sure tolerances were pretty much back to original on a block with 120k miles. At least that's my logic
Wow, there's so much misinformation in this thread, i don't know where to begin.
In terms of compression ratio, running a forged motor for turbo use with a stock compression ratio is more or less a waste of time. The first motor I built for my personal car (about 8 years ago) used stock compression pistons. Once I started making decent power, I would start running into issues with knock due to the CR. A year later, I rebuilt the motor with 8.5:1 pistons and ultimately made much more power with no knock.
If you're going to spend the coin to build your motor, why restrict yourself to low boost by having a high CR? It's simply counterintuitive. Learn from my mistake 8 years ago.
Moreover, there are no real drawbacks to running a slightly lower CR. You won't be able to feel a difference in off boost power, and you'll make more power under boost since you'll be able to run more boost an hotter timing. What's not to love?
As for 4032 vs 2618 Aluminum pistons (low silicon vs high silicon), the high silicon pistons actually have a lower rate of thermal expansion by about 15%. So to the poster that said that the high silicon pistons expand more, that's the opposite of the truth. The advantage of of high silicon 4032 is that you can run tighter piston to wall clearances and have less piston slap. The disadvantage is that the pistons aren't quite as strong as 2618. That said, CP, Arias, and Wiseco all use 2618 low silicon pistons.
It's true that Maxx Mazda melted some arias pistons. But it was not the fault of the piston...any piston would have melted in his case. He will be the first to tell you that he had his standalone set up wrong, the ignition timing was way off, and it caused the piston to melt. I don't care if your pistons are made by the hand of God, if they are aluminum, they will melt if your tuning setup is wrong.
Secondly, of the three brands mentioned, Wiseco has the most issues when it comes to structural integrity and production tolerances, piston noise, etc.
In the FS motor, I have experience with JE/SRP, CP, Wiseco, and ARIAS pistons. The only brands I would even bother with would be ARIAS and CP, as they are both great pistons.
Personally I prefer the ARIAS pistons since we actually have our own custom design for the pistons, and have perfected the piston over the years. One look at any of the work that I've done will show you what an anal bastard I am, and I've tweaked the hell out of the design of these pistons over the years. From the valve reliefs, to the ring package, to the wire locks, to the custom length wrist pins, as well as the largest oil squirter clearance available in any piston for the FS.
You'd be hard pressed to find anyone who has built more forged FS motors than myself, and we have a virtually flawless track record with our engines. I have been building FS engines since 2003 with outstanding results. We use the best quality stuff we can get our hands on. If ARIAS pistons (and Pauter rods) weren't outstanding, I wouldn't dare use them in my engines - I would simply start using the better product if one existed.
In terms of compression ratio, running a forged motor for turbo use with a stock compression ratio is more or less a waste of time. The first motor I built for my personal car (about 8 years ago) used stock compression pistons. Once I started making decent power, I would start running into issues with knock due to the CR. A year later, I rebuilt the motor with 8.5:1 pistons and ultimately made much more power with no knock.
If you're going to spend the coin to build your motor, why restrict yourself to low boost by having a high CR? It's simply counterintuitive. Learn from my mistake 8 years ago.
Moreover, there are no real drawbacks to running a slightly lower CR. You won't be able to feel a difference in off boost power, and you'll make more power under boost since you'll be able to run more boost an hotter timing. What's not to love?
As for 4032 vs 2618 Aluminum pistons (low silicon vs high silicon), the high silicon pistons actually have a lower rate of thermal expansion by about 15%. So to the poster that said that the high silicon pistons expand more, that's the opposite of the truth. The advantage of of high silicon 4032 is that you can run tighter piston to wall clearances and have less piston slap. The disadvantage is that the pistons aren't quite as strong as 2618. That said, CP, Arias, and Wiseco all use 2618 low silicon pistons.
It's true that Maxx Mazda melted some arias pistons. But it was not the fault of the piston...any piston would have melted in his case. He will be the first to tell you that he had his standalone set up wrong, the ignition timing was way off, and it caused the piston to melt. I don't care if your pistons are made by the hand of God, if they are aluminum, they will melt if your tuning setup is wrong.
Secondly, of the three brands mentioned, Wiseco has the most issues when it comes to structural integrity and production tolerances, piston noise, etc.
In the FS motor, I have experience with JE/SRP, CP, Wiseco, and ARIAS pistons. The only brands I would even bother with would be ARIAS and CP, as they are both great pistons.
Personally I prefer the ARIAS pistons since we actually have our own custom design for the pistons, and have perfected the piston over the years. One look at any of the work that I've done will show you what an anal bastard I am, and I've tweaked the hell out of the design of these pistons over the years. From the valve reliefs, to the ring package, to the wire locks, to the custom length wrist pins, as well as the largest oil squirter clearance available in any piston for the FS.
You'd be hard pressed to find anyone who has built more forged FS motors than myself, and we have a virtually flawless track record with our engines. I have been building FS engines since 2003 with outstanding results. We use the best quality stuff we can get our hands on. If ARIAS pistons (and Pauter rods) weren't outstanding, I wouldn't dare use them in my engines - I would simply start using the better product if one existed.
the way theyre designed causes them to get hot spots, so theyre unevenly heated... then when you get any kind of pinging, they shatter. its well documented and he wasnt the only one with issues.
This is completely false. They are a simple dished piston with valve reliefs. There are no notable hot spots in arias pistons. They do not "just shatter". Your tune has to be off by a mile to damage a forged piston, and an ARIAS piston is a very beefy piston.
I've only heard ONE person - maxx mazda have issues with severely damaging the piston, and he flat out accepted responsibility for it. If there are others who had issues, I would have heard about it since SpeedCircuit has sold all of the ARIAS pistons for the FS motor. Moreover, I would love to see where these "well documented" claims are, since, as the guy who has personally spec'd these pistons, I haven't even heard of this. Please stop spreading misinformation.
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