Forged Pistons: 2618 vs 4032 alloy; who's using what
1 - 20 of 38 Posts
Joined
·
793 Posts
Just doing more research into engine building. Seems like the trade offs for each make it a tough decision between lengthy warmup & stronger vs quieter and longer lasting but weaker. Just wondering what the preferences were across the board for FI 2ZZ's
Joined
·
2,953 Posts
I've never heard anyone talk about quietness when developing a piston, and I meet with the developers from the well known piston suppliers like Mahle, KS etc. quiet frequently :shrug:
The material composition typically is part of their internal knowledge and so they will not share many details. What you should be interested in is things like metallurgical microstructure, piston ovality and skirt profile and things like that.
There is much more to it than just what alloy number to choose.
The material composition typically is part of their internal knowledge and so they will not share many details. What you should be interested in is things like metallurgical microstructure, piston ovality and skirt profile and things like that.
There is much more to it than just what alloy number to choose.
Joined
·
3,229 Posts
I think you will get more replies if you ask what pistons people are running...example; Cosworth, Mahle, etc.
BTW, I don't know what alloy each manufacturer uses...if you told us what alloy each manufacturer was using, you'd get some replies.
Compression ratio is very important and weather the engine is forced or not.
Have you looked into ceramic coating the crown of the pistons to improve thermodynamic efficiency? That would be worth some HP also...
BTW, I don't know what alloy each manufacturer uses...if you told us what alloy each manufacturer was using, you'd get some replies.
Compression ratio is very important and weather the engine is forced or not.
Have you looked into ceramic coating the crown of the pistons to improve thermodynamic efficiency? That would be worth some HP also...
Joined
·
793 Posts
Maybe I should have clarified; noise as in the piston slap upon startup. And correct me if I'm wrong, but "metallurgic microstructure" relates to the alloy.
There's definitely a good bid of discussion on other forums regarding the different alloys (Piston FAQ: Read if you are thinking about buying them! - NASIOC), just figured I'd see what the LT consensus was for the 2ZZ
This post was mainly regarding just the alloys. One thing at a time now
Pretty surprised there hasn't been any discussion here on the alloys of pistons. Considering the difference of the two main forged types, they should play a pretty big role in piston choice...
There's definitely a good bid of discussion on other forums regarding the different alloys (Piston FAQ: Read if you are thinking about buying them! - NASIOC), just figured I'd see what the LT consensus was for the 2ZZ
This post was mainly regarding just the alloys. One thing at a time now
Pretty surprised there hasn't been any discussion here on the alloys of pistons. Considering the difference of the two main forged types, they should play a pretty big role in piston choice...
Joined
·
793 Posts
Not to mention it won't let me change the poll now...
But generally what I've found;
Mahle: generally 4032, but 2618 offered
Wiseco: 2618
CP: 2618
Cosworth: *special alloy, similar to 4032 but stronger like 2618
Arias: 4032
Supertech: 4032
JE: 2618
**(Correct me if I'm wrong there)
But generally what I've found;
Mahle: generally 4032, but 2618 offered
Wiseco: 2618
CP: 2618
Cosworth: *special alloy, similar to 4032 but stronger like 2618
Arias: 4032
Supertech: 4032
JE: 2618
**(Correct me if I'm wrong there)
Joined
·
3,229 Posts
Alloy is only one small portion of microstructure. It has more to do with process; including casting/forging, heat treatment, shot peening, etc.
Joined
·
2,309 Posts
Opinions are like a$$holes, and pistons are more complicated than choosing an alloy. If there were piston design engineers on here then that single post would be more valuable than a poll on thousands of the ignorant. I am in the later group, but am resisting posting a non-factual opinion, because the question, as well as to whom it is directed, is flawed.
Joined
·
3,229 Posts
I'm an aerospace structural engineer. Aluminum alloys are very important to me also but, like holmz suggested, I don't think any one of us on here have designed pistons. But please share what you've learned or what you're thinking and why for selecting a piston design, manufacturer. From what I know about engines, the crown design is more important for HP output...
Joined
·
2,309 Posts
You've no doubt read some of the recent "Race Engineering" articles?
Joined
·
5,308 Posts
But generally what I've found;
Mahle: generally 4032, but 2618 offered
Wiseco: 2618
CP: 2618
Cosworth: *special alloy, similar to 4032 but stronger like 2618
Arias: 4032
Supertech: 4032
JE: 2618
Sorry but base material is just a small piece of the pie. Far more important with regards to the material final results is the forging process and heat treat process. And far more important than any of that is the design of the piston and reputation of the manufacturer.
Mahle: generally 4032, but 2618 offered
Wiseco: 2618
CP: 2618
Cosworth: *special alloy, similar to 4032 but stronger like 2618
Arias: 4032
Supertech: 4032
JE: 2618
Sorry but base material is just a small piece of the pie. Far more important with regards to the material final results is the forging process and heat treat process. And far more important than any of that is the design of the piston and reputation of the manufacturer.
Joined
·
6,306 Posts
JE, CP, Arias, Ross, etc (and probably US Cosworth) use the same foundry anymore. Their base forgings are all similar. Wiseco does their own forging,but not sure that it matters.
CNC machines along with foundry consolidation have removed a good bit the "art" of making pistons and have leveled the playing field when it comes to QC...
Nowadays, it's more about the features and design of the pistons such as valve reliefs, oiling, cam, coatings, porting, rings, quench area, pin placement, skirt design (cushion, X, rigid, etc), and dome design...
Most of the aftermarket pistons are 2618, but at our power levels a forged 4032 piston is probably fine. The arias pistons we spec are 2618.
Not much to do on the 2ZZ with dome design. We use a "mini dome" on our 9:1 pistons and I saw Cosworth did the same when they came out with theirs. Mahle and wiseco just use a dish. Doubt either do much impact on flame propagation. The dome is so minimal on the 10-12:1 pistons that it probably doesn't matter...
Most of the other items do matter a good bit though...
For instance:
Valve reliefs... We found that the wiseco pistons had the valve reliefs miscut early on. through a lot of fighting with them, we got them to acknowledge their mishap and they changed their design accordingly. Terrible experience that cost us a lot of money, time, and gray hair. I won't deal with them again unless I have to
Another thing that matters is pin location and cam. I tore down a motor from a competitor that uses JE pistons in their sleeved motors. They were farming out their engine building to Nogrady, but I believe he's no longer doing their builds. Regardless, each JE pistons skirt had significant scuffing on one side of the skirts. I checked the pin location. It was not correct. I didn't check the cam, but the pin mis-location could have easily caused the issue... incorrect cam could have contributed, but the pins were absolutely in the wrong position for a 2ZZ. JE is a fine piston maker but whoever was calling the shots on those pistons was missing the boat. Those pistons had no coatings either, FWIW.
Features such as gas porting, the type of gas porting, skirt design, ceramic tops, skirt coating, add'l pin oiling, ring dimensions, etc all play into addition design criteria that can make one piston better than the other. I'd not forget the importance of dealing with a piston company that has good customer service (recalling the Wiseco BS from years back).
The alloy used is one factor, but far and away not the only or even the primary factor... I don't think it's a crime to look at a single factor and I'm sure others don't either. Forums tend to find a subject and blow it out of proportion. If you tell the piston maker the intended use, level of boost, and fuel you're running, they'll recommend the alloy. It's that simple. The other stuff I mentioned are features that cost money or specifications that are derived through experience and good measurement. Recall the JE and Wiseco pistons built to improper spec...
-Phil
CNC machines along with foundry consolidation have removed a good bit the "art" of making pistons and have leveled the playing field when it comes to QC...
Nowadays, it's more about the features and design of the pistons such as valve reliefs, oiling, cam, coatings, porting, rings, quench area, pin placement, skirt design (cushion, X, rigid, etc), and dome design...
Most of the aftermarket pistons are 2618, but at our power levels a forged 4032 piston is probably fine. The arias pistons we spec are 2618.
Not much to do on the 2ZZ with dome design. We use a "mini dome" on our 9:1 pistons and I saw Cosworth did the same when they came out with theirs. Mahle and wiseco just use a dish. Doubt either do much impact on flame propagation. The dome is so minimal on the 10-12:1 pistons that it probably doesn't matter...
Most of the other items do matter a good bit though...
For instance:
Valve reliefs... We found that the wiseco pistons had the valve reliefs miscut early on. through a lot of fighting with them, we got them to acknowledge their mishap and they changed their design accordingly. Terrible experience that cost us a lot of money, time, and gray hair. I won't deal with them again unless I have to
Another thing that matters is pin location and cam. I tore down a motor from a competitor that uses JE pistons in their sleeved motors. They were farming out their engine building to Nogrady, but I believe he's no longer doing their builds. Regardless, each JE pistons skirt had significant scuffing on one side of the skirts. I checked the pin location. It was not correct. I didn't check the cam, but the pin mis-location could have easily caused the issue... incorrect cam could have contributed, but the pins were absolutely in the wrong position for a 2ZZ. JE is a fine piston maker but whoever was calling the shots on those pistons was missing the boat. Those pistons had no coatings either, FWIW.
Features such as gas porting, the type of gas porting, skirt design, ceramic tops, skirt coating, add'l pin oiling, ring dimensions, etc all play into addition design criteria that can make one piston better than the other. I'd not forget the importance of dealing with a piston company that has good customer service (recalling the Wiseco BS from years back).
The alloy used is one factor, but far and away not the only or even the primary factor... I don't think it's a crime to look at a single factor and I'm sure others don't either. Forums tend to find a subject and blow it out of proportion. If you tell the piston maker the intended use, level of boost, and fuel you're running, they'll recommend the alloy. It's that simple. The other stuff I mentioned are features that cost money or specifications that are derived through experience and good measurement. Recall the JE and Wiseco pistons built to improper spec...
-Phil
Joined
·
2,309 Posts
^I found Phills post to be pleasent reading.^
1) As the 2618 expands and contracts more, the engine can rattle when cold; so it is worse from a thermal expansion perspective.
2) It also wears faster, so it worse from a wear perspective.
3) It is stronger, so it is better from that perspective.
#1 might be mitigated with more piston oiling and getting the engine to temp more quickly (maybe a laminova would help???)
#2 might be mitigated with some DLC or other coating on the skirts???
#3 is the main (only) reason why someone would run them. They are worse in every way except for the most important (strength), but that is assuming one is breaking pistons or needs the strength... Which might be hard to know.
Often the RPM in a forced induction engine is lower, so the 2600 alloy is not required from forces due to RPM. Whether they are required from a boost perspective might have more to do with detonation than simple pressure force calculations.
Since the understanding of the dome shape as well as modern coatings affect detonation, it is not easily clear as to whether the alloy makes as much of a difference as it makes in the olden days with naturally aspirated engines.
And since many of the components like pistons, chambers, port design and cam timing, compression ratio... all interact... It can be much more compliacted to understand the impacts that changing one can compenent can make... Which often has a trickle through effect to other engine considerations.
If it is not a piston design expert that needs to comment, then it is an engine builder... and Phil chirped up in the previous post.
Maybe issue 61, but I though there was a more reecent article.
https://www.highpowermedia.com/c/31/race-engine-technology?pagenumber=2
This is also worth having:
https://www.highpowermedia.com/p/1085/race_engine_technology_-_issue_007
Again it is complicated.
1) As the 2618 expands and contracts more, the engine can rattle when cold; so it is worse from a thermal expansion perspective.
2) It also wears faster, so it worse from a wear perspective.
3) It is stronger, so it is better from that perspective.
#1 might be mitigated with more piston oiling and getting the engine to temp more quickly (maybe a laminova would help???)
#2 might be mitigated with some DLC or other coating on the skirts???
#3 is the main (only) reason why someone would run them. They are worse in every way except for the most important (strength), but that is assuming one is breaking pistons or needs the strength... Which might be hard to know.
Often the RPM in a forced induction engine is lower, so the 2600 alloy is not required from forces due to RPM. Whether they are required from a boost perspective might have more to do with detonation than simple pressure force calculations.
Since the understanding of the dome shape as well as modern coatings affect detonation, it is not easily clear as to whether the alloy makes as much of a difference as it makes in the olden days with naturally aspirated engines.
And since many of the components like pistons, chambers, port design and cam timing, compression ratio... all interact... It can be much more compliacted to understand the impacts that changing one can compenent can make... Which often has a trickle through effect to other engine considerations.
If it is not a piston design expert that needs to comment, then it is an engine builder... and Phil chirped up in the previous post.
Maybe issue 61, but I though there was a more reecent article.
https://www.highpowermedia.com/c/31/race-engine-technology?pagenumber=2
This is also worth having:
https://www.highpowermedia.com/p/1085/race_engine_technology_-_issue_007
Joined
·
3,229 Posts
Surprising to hear that about Wiseco... :huh: I thought they had a very good reputation... But they did learn from their mistake... Too bad it cost you too...Valve reliefs... We found that the wiseco pistons had the valve reliefs miscut early on. through a lot of fighting with them, we got them to acknowledge their mishap and they changed their design accordingly. Terrible experience that cost us a lot of money, time, and gray hair. I won't deal with them again unless I have to
Joined
·
2,953 Posts
Not true
Responsible for the design of the entire engine at one of the big ones, and that includes pistons, crank shafts, con rods and all that....
Hence why I talk to the guys at Mahle and such.
1 - 20 of 38 Posts
Join the discussion
Join now to ask and comment!