What exactly is Hypereutectic?
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: What exactly is Hypereutectic? (A)
I think they are pretty crappy. I don't know that they are any better than cast, certainly nowhere near as good as forged. I've been meaning to ask this myself, maybe we'll get a good response.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: What exactly is Hypereutectic? (A)
http://www.harcourt.com/dictionary/d...1/5031900.html
this link may not help, but it does imply one thing, the alloy is densor.
this link may not help, but it does imply one thing, the alloy is densor.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: What exactly is Hypereutectic? (A)
There are a lot of high performance cars out there running Hypereutectic Pistons and they perform just fine.
The advantages are compared to cast are:
1. Stronger than standard cast aluminum.
2. Similar heat expansion as cast pistons.
3. Cheaper than forged pistons.
With Hypereutectic pistons, you can install them with about the same bore clearance as cast pistons, thus they have less tendency to slap or leak when cold. Forged pistons expand quite a bit as they get hot, so you have to install them with a bigger piston to cylinder wall clearance and less blow by when cold.
Hypereutectic are stronger than cast due to higher silicone content but not as strong as forged. But are only a little more expensive than standard cast pistons.
The real advantage to using Hypereutectic pistons is if your engine is not subject to a high boost from turbo charger, blower, or extremely high RPM, or big nitrous shot, you can save some cash by using Hypereutectic pistons rather than more the expensive forged pistons. The LT4 and other high performance engines come standard with Hypereutectic pistons.
[Modified by Mez, 5:52 PM 2/25/2002]
The advantages are compared to cast are:
1. Stronger than standard cast aluminum.
2. Similar heat expansion as cast pistons.
3. Cheaper than forged pistons.
With Hypereutectic pistons, you can install them with about the same bore clearance as cast pistons, thus they have less tendency to slap or leak when cold. Forged pistons expand quite a bit as they get hot, so you have to install them with a bigger piston to cylinder wall clearance and less blow by when cold.
Hypereutectic are stronger than cast due to higher silicone content but not as strong as forged. But are only a little more expensive than standard cast pistons.
The real advantage to using Hypereutectic pistons is if your engine is not subject to a high boost from turbo charger, blower, or extremely high RPM, or big nitrous shot, you can save some cash by using Hypereutectic pistons rather than more the expensive forged pistons. The LT4 and other high performance engines come standard with Hypereutectic pistons.
[Modified by Mez, 5:52 PM 2/25/2002]
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: What exactly is Hypereutectic? (A)
Hypereutectic discribes the aluminum alloy. It refers to the silicon content in the alloy and the degree of saturation. When the aluminum alloy is saturated with silicon, at about 12 %, it is refered to as "eutectic". Less than 12 %, the alloy is called hypoeutectic. A mixture with more than 12 % silicon has particles floating in it, like iced tea with too much sugar. That is called hypereutectic. As a rule they don't have all the strength of a forged piston, but they definitly do have some advantages. One is that they can be run at closer tolerances, reducing noise and increasing piston ring seal. Do some research. Don't be too quick to dismiss them. That is what I am doing now. They have some interesting heat dissapation properties.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: What exactly is Hypereutectic? (CFI-EFI)
Don't be too quick to dismiss them. That is what I am doing now. They have some interesting heat dissapation properties.
Team Owner
Joined: Aug 2000
Posts: 24,125
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St. Jude Donor '14
Re: What exactly is Hypereutectic? (CFI-EFI)
I've used Hypereutectic pistons many times, they did have some advantages due to their higher silicon content, one being the piston can fit tighter in the cylinder due to less expansion and take advantage of a better combustion( Quench area), but you have to also be careful as how you set the gap on the top rings as the hypereutectic piston will reflect more heat into the combustion, causing the top ring to run much hotter. They are really not bad pistons, but as mentioned before for extreme performance being supercharged, turbo's or lots of nitrous, you can't beat a good set of high quality forged pistons.
Thread Starter
Melting Slicks
Joined: Sep 2000
Posts: 2,683
Likes: 0
Re: What exactly is Hypereutectic? (8388)
How big is the price difference?
If the cost were not a factor but also N20 and turbo/supercharger were not to be used, then would forged still be a better choice over hyper?
Does one have a longetivity advantage over the other (forged vs hyper)?
If the cost were not a factor but also N20 and turbo/supercharger were not to be used, then would forged still be a better choice over hyper?
Does one have a longetivity advantage over the other (forged vs hyper)?
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Team Owner
Joined: Aug 2000
Posts: 24,125
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St. Jude Donor '14
Re: What exactly is Hypereutectic? (A)
Keith Black, or KB signature pistions are a good choice if your on a budget and do not plan on running nitrous, superchargers or turbos. I have run them in engines that would rev to 7000 rpm without any problems over a long period of time. But a special note must be taken by your engine builder to set up the cylinder properly, along with the proper gap on the top ring as I mentioned before. You can pick up a set hypereutectic pistons for about
$ 280.00, and just to give an example of another extreme, my last set of high quality Forged piston set me back over $ 800.00.
$ 280.00, and just to give an example of another extreme, my last set of high quality Forged piston set me back over $ 800.00.
Burning Brakes
Joined: Dec 2000
Posts: 1,023
Likes: 0
From: Marietta, South Carolina, USA
Re: What exactly is Hypereutectic? (A)
Hypereutactic pistons are good pistons but they are not much stronger then a cast piston but for a daily driver they are just great for the price, KB are about the same as them good for the price but not much better then stock.
Jay
Jay
Burning Brakes
Joined: Feb 2002
Posts: 871
Likes: 1
From: Union KY
Re: What exactly is Hypereutectic? (A)
I've had zero experience with these pistons, but I can add a tad to your now growing metalurlurgical knowledge. The term "eutectic" in alloys referrs to the property of synergy (best described as 1+1= >than 2).
The simplest examply I can give is the alloy solder. It's normally 50% lead and 50% tin. The melting point of the combination alloy is lower that either lead or tin. In the case of these pistons, the silicone must impart some synergistic (eutectic) property. That's two cents worth. Cire96 :seeya
The simplest examply I can give is the alloy solder. It's normally 50% lead and 50% tin. The melting point of the combination alloy is lower that either lead or tin. In the case of these pistons, the silicone must impart some synergistic (eutectic) property. That's two cents worth. Cire96 :seeya
Le Mans Master
Joined: Nov 1999
Posts: 8,512
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From: Memphis, Tn
Re: What exactly is Hypereutectic? (cire96)
I ran Keith Black hypereutectics in my Solo II/Solo I race car. I reguarly ran the engine up to 7500 rpm. No problems. As noted above, stronger than cast, similar expansion characteristics as cast, and cheaper than forged.
