Piston material
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From: Down Under
Piston material As most know, the majority of pistons are made from a cast or forged alluminum alloy. However, i am inquiring as to why other materials havnt been used, specifically Titantium alloy.
On paper the titanium properties are far superior to aluminum in the areas of:
Coefficient of thermal expansion (tight clearances can be run.. no knock, blowby, etc)
Thermal conductivity (good insulator.. no need for ceramic coating..)
Specific heat
melting point
Strenght @ high temperature (buring holes in pistons?.. no more..)
etc..
The titanium would make a much more thermally efficient engine.. even better for the turbo cars
However, titanium is more dense, but the weight penalties may be able to be accounted for in deisgn and geometry.
Maybe the benefits cant be seen with SI engines but what about CI engines with the high pressures of combustion that require thick aluminum pistons...
I will say COST is probably a large issue.. but you would think this would be seen on the high dollar racing teams and such.. I have looked yet cannot find anything about titanium pistons ever being tried or the CONS of them...
On paper the titanium properties are far superior to aluminum in the areas of:
Coefficient of thermal expansion (tight clearances can be run.. no knock, blowby, etc)
Thermal conductivity (good insulator.. no need for ceramic coating..)
Specific heat
melting point
Strenght @ high temperature (buring holes in pistons?.. no more..)
etc..
The titanium would make a much more thermally efficient engine.. even better for the turbo cars
However, titanium is more dense, but the weight penalties may be able to be accounted for in deisgn and geometry.
Maybe the benefits cant be seen with SI engines but what about CI engines with the high pressures of combustion that require thick aluminum pistons...
I will say COST is probably a large issue.. but you would think this would be seen on the high dollar racing teams and such.. I have looked yet cannot find anything about titanium pistons ever being tried or the CONS of them...
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From: Cleveland
alloy's you may want to take a look at the post I just made on the "turbo piston" in the ls2 forum.
I've had a titanium piston before...the problem is it's not production friendly. You can't really forge it. The one I had-had a electron-beam welded crown. It's also a "sticky" material...prone to galling everything it touches....DLC helps, but that's just the beginning to fixing the problems.
Magnesium has been done to, but it's got very *wierd* issues with growth..very hard to get the skirt to run nicely under all temperature conditions, but they are very light....the other issue with that is they need keronite treatment to stand up to decay.
4032 and 2618 are the standards used by all manufacturers....
The REALLY good futuristic stuff is lithium aluminum, Metal matrix Composite, or Berylium. The last was outlawed in because you didn't want a field of racecars spitting microscopic cancer particles as they went down the straight-away. You also didn't want to try and manufacture it anywhere but third world countries due to lawsuits.
Lithium aluminum and MMC are nice, but you're talking about very specialized forging capabilities and you're also talking about racing programs that have a barrels of money to spend.
I've had a titanium piston before...the problem is it's not production friendly. You can't really forge it. The one I had-had a electron-beam welded crown. It's also a "sticky" material...prone to galling everything it touches....DLC helps, but that's just the beginning to fixing the problems.
Magnesium has been done to, but it's got very *wierd* issues with growth..very hard to get the skirt to run nicely under all temperature conditions, but they are very light....the other issue with that is they need keronite treatment to stand up to decay.
4032 and 2618 are the standards used by all manufacturers....
The REALLY good futuristic stuff is lithium aluminum, Metal matrix Composite, or Berylium. The last was outlawed in because you didn't want a field of racecars spitting microscopic cancer particles as they went down the straight-away. You also didn't want to try and manufacture it anywhere but third world countries due to lawsuits.
Lithium aluminum and MMC are nice, but you're talking about very specialized forging capabilities and you're also talking about racing programs that have a barrels of money to spend.
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From: Down Under
Welll.. berrylium, lithium aluminum, etc.. has super HIGH thermal conductivity... not quite what you want in a piston... you better have tons of oil cooling on the botom of that piston..
And 4032 adn 2618 still have high CTE and thermal conductivity compared to titanium..
Titanium 6AL-4V = 6.6 W/m-k (yes.. the 4032 is 20 times greater..)
4032 = 138 W-m/k
Beryllium = 216 w-m/k !!!!!!!
Titanium 6AL-4V = 9.7 micrometer/m-k
4032 = 19.7 micrometer/m-k
For reference Cast iron is around 11-12 micrometer/m-k
I agree with it galling, but coating should be able to take care of that issue... its not like aluminum is free from that either..
It seems to me that all the heat is just being sucked into the piston with some of the "future" piston materials... Kinda backwards if you ask me.. I'd want to keep it as thermally efficient as possible.
And 4032 adn 2618 still have high CTE and thermal conductivity compared to titanium..
Titanium 6AL-4V = 6.6 W/m-k (yes.. the 4032 is 20 times greater..)
4032 = 138 W-m/k
Beryllium = 216 w-m/k !!!!!!!
Titanium 6AL-4V = 9.7 micrometer/m-k
4032 = 19.7 micrometer/m-k
For reference Cast iron is around 11-12 micrometer/m-k
I agree with it galling, but coating should be able to take care of that issue... its not like aluminum is free from that either..
It seems to me that all the heat is just being sucked into the piston with some of the "future" piston materials... Kinda backwards if you ask me.. I'd want to keep it as thermally efficient as possible.
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From: Cleveland
I can only tell you what's going on in F1, Cup, and the other biggest engine development programs. As you said, you did a search on Ti, didn't find anything. That means it's been looked at and people (very smart people with a lot of money) have been there, done that, and went elsewhere.
Originally Posted by H8 LUZN
Welll.. berrylium, lithium aluminum, etc.. has super HIGH thermal conductivity... not quite what you want in a piston...
Maybe a piston needs to be able to get heat away from the crown quickly to avoid localized overheating and keep a more constant average temperature.
A coated piston (if the coating worked) would lower the amount of heat passing into the piston from the crown, but still conduct the heat away from this area very quickly as before.
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From: Blairsville, GA
Ever heard of zirconium oxide?
It's a ceramic material that I've seen used in tactical knives... reportedly 5 times harder than diamond. Being ceramic, it'd have excellent heat characteristics, being harder than Chinese calculus, it'd be stout enough to use as piston material... God help you if you have bad detonation issues, though.
Anyone know more about this stuff?
It's a ceramic material that I've seen used in tactical knives... reportedly 5 times harder than diamond. Being ceramic, it'd have excellent heat characteristics, being harder than Chinese calculus, it'd be stout enough to use as piston material... God help you if you have bad detonation issues, though.
Anyone know more about this stuff?
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Teching In
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Originally Posted by briannutter
I can only tell you what's going on in F1, Cup, and the other biggest engine development programs. As you said, you did a search on Ti, didn't find anything. That means it's been looked at and people (very smart people with a lot of money) have been there, done that, and went elsewhere.
Shaun from PRI dinner
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From: Cleveland
f1 Shaun, yep you're correct about the regulations stating Aluminum alloys. Lithal and MMC are both "aluminum alloys" so they are legal. Cost is one issue, but what I said about Berylium was the bigger factor. I commend them though....If everyone in the field is running the same basic technology, costs are reduced and winning comes down to the mind.
Cup and Pro stock used a minimum gram weight rule that's easily hit by present aluminum piston technology...so there isn't much of a point to going to anything else. A Cup or IRL piston easily costs about $270 a piston (in bulk) even in 2618 aluminum, so you could imagine what a MMC one costs. How many people here are in the market for a $8K set of pistons?
Cup and Pro stock used a minimum gram weight rule that's easily hit by present aluminum piston technology...so there isn't much of a point to going to anything else. A Cup or IRL piston easily costs about $270 a piston (in bulk) even in 2618 aluminum, so you could imagine what a MMC one costs. How many people here are in the market for a $8K set of pistons?
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I agree that the probability is that no one here would run pistons that expensive. Though, I'm sure many tech heads would enjoy seeing non-carcinogenic Ti or MMC pistons used in some open form of racing and reading up on finished piston properties and challenges or benefits in application.
Re: LithAl and MMC as aluminium alloys.. I'm pretty sure that the 40GPa/(g/cc) modulus of elasticity ceiling set by the FIA would preclude the use of these more exotic alloys ? In any case the 2006 and on rules are quite explicit in ruling them out..
Re: LithAl and MMC as aluminium alloys.. I'm pretty sure that the 40GPa/(g/cc) modulus of elasticity ceiling set by the FIA would preclude the use of these more exotic alloys ? In any case the 2006 and on rules are quite explicit in ruling them out..
5.13.1 Unless explicitly permitted for a specific engine component, the following materials may not be used anywhere on the engine:
a) Magnesium based alloys
b) Metal Matrix Composites (MMC's)
c) Intermetallic materials
d) Alloys containing more than 5% by weight of Beryllium, Iridium or Rhenium.
a) Magnesium based alloys
b) Metal Matrix Composites (MMC's)
c) Intermetallic materials
d) Alloys containing more than 5% by weight of Beryllium, Iridium or Rhenium.
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From: Texas
Originally Posted by Ric
Ever heard of zirconium oxide?
It's a ceramic material that I've seen used in tactical knives... reportedly 5 times harder than diamond. Being ceramic, it'd have excellent heat characteristics, being harder than Chinese calculus, it'd be stout enough to use as piston material... God help you if you have bad detonation issues, though.
Anyone know more about this stuff?
It's a ceramic material that I've seen used in tactical knives... reportedly 5 times harder than diamond. Being ceramic, it'd have excellent heat characteristics, being harder than Chinese calculus, it'd be stout enough to use as piston material... God help you if you have bad detonation issues, though.
Anyone know more about this stuff?
I heard a few topfuel teams using something like a ceramic composite. The piston has almost a dark greenish color.
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From: San Leandro(basically Oakland), CA
Originally Posted by Evo98z
I heard a few topfuel teams using something like a ceramic composite. The piston has almost a dark greenish color.
I mean correct me if I'm wrong but is there or will there ever be a market for this kind of thing? If I'm being an *** about this whole theoretical discussion I appologize, just wondering how this sort of thing would tie in to the real world practically.
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From: Blairsville, GA
Originally Posted by superGMman
That's definitly the new wave in piston technology, but I think one idea that is commonly overlooked is the practicality of the fact that who(besides racers with specific restrictions and rules) would pay a rediculous amount of money in R&D to make an unneccesarily high-tech piston?
I mean correct me if I'm wrong but is there or will there ever be a market for this kind of thing? If I'm being an *** about this whole theoretical discussion I appologize, just wondering how this sort of thing would tie in to the real world practically.
I mean correct me if I'm wrong but is there or will there ever be a market for this kind of thing? If I'm being an *** about this whole theoretical discussion I appologize, just wondering how this sort of thing would tie in to the real world practically.
Does anyone know any specific alloys that pistons are made of? 6061, 7075, 3003(hope not)???
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From: Cleveland
good info Shaun, good info about the MMC being banned. I wonder when they did that...Anyway, the green pistons in top fuel are still standard 2618 alloy, but they've got a teflon anodizing treatment.
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Originally Posted by briannutter
Shaun, good info about the MMC being banned. I wonder when they did that...