Clarification given on Forced Induction (S/C) 4GR FSE Engines
01-05-15, 08:59 PM
#1
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Clarification given on Forced Induction (S/C) 4GR FSE Engines
I've read in a few places on this forum about some of the concerns around boosting a 4GR or 2GR FSE.
There is a major clarification I wanted to make with regard to the pistons of the engine platform.
As many of you know, the block and body is aluminium, which is susceptible to thermal expansion, which increases the possibility of pre-ignition, or knocking, which is bad.
I've been digging around to find out what type of pistons are built into the 2/4GR FSE engines. What I have found will possibly bring relief to some of you who thinking about boosting your 2ISs, but worried about pre-ignition destroying the block and frying your pistons.
The pistons that are used are indeed cast; however, they are hypereutectic pistons. These pistons were introduced in the U.S. to conform to tighter smog regulation (reduce pre-ignition in the cylinders, which emits more smog), and has made boosting new gen imports a living hell. They are known to crack and deform during high performance; however, when 11% of the material grade is silicon, the heat generated by the engine is actually absorbed at ignition, and released upon exhaust. This is good news because it reduces thermal expansion on the aluminum block, which reduces knock/pre-ignition.
That being said, Toyota wrote a nice long PR piece for their parts department, giving us some tasty information about their setup. (see below)
https://parts.olathetoyota.com/eutec...r-pistons.html
It turns out, that Toyota over-engineers their components (surprise surprise), and these pistons will most definitely be able to handle boosted applications, possibly beyond 7PSI.
"The characteristics of pistons in each of these categories are very distinct. Hypereutectic alloys are stronger, resist scuffing and seizure, and reduce groove wear and cracking of the crown at extremely high temperatures. They're also very resistant to expansion, because the high percentage of silicon essentially "insulates" the piston from the effects of heat."
Straight from the horses mouth.
Lastly, hyperutectic pistons can be built to handle forced induction applications.
"The normal temperature of gasoline engine exhaust is approximately 650 °C (1,200 °F). This is also approximately the melting point of most aluminum alloys and it is only the constant influx of ambient air that prevents the piston from deforming and failing. Forced induction increases the operating temperatures while "under boost", and if the excess heat is added faster than the engine can shed it, the elevated cylinder temperatures will cause the air and fuel mix to auto-ignite on the compression stroke before the spark event. This is one type of engine knocking that causes a sudden shockwave and pressure spike, which can result in failure of the piston due to shock-induced surface fatigue, which eats away the surface of the piston.
The "4032" performance piston alloy has a silicon content of approximately 11%. This means that it expands less than a piston with no silicon, but since the silicon is fully alloyed on a molecular level (eutectic), the alloy is less brittle and more flexible than a stock hypereutectic "smog" piston. These pistons can survive mild detonation with less damage than stock pistons."
See wikipedia link for more info http://en.wikipedia.org/wiki/Hypereutectic_piston
It turns out that our stock pistons, are most likely 4032 performance pistons
Yes, these pistons are not forged, which is sad, but here is a final blurb I want to leave you all with.
"If there is a downsides to hypereutectic pistons, it's that they're brittle compared to forged pistons. Therefore, forged pistons are more forgiving of extreme conditions (like those found in a race car), and they give you a greater margin of error when dealing with timing problems, as detonation is less likely to destroy a forged piston than a hypereutectic cast piston.
Still, when it comes right down to it, the operational differences between forged pistons and quality hypereutectic cast pistons are smaller than ever. Unless you're running an engine in a race, or under extreme loads caused by high boost turbocharging, a hypereutectic cast piston is likely going to perform just fine for your specific use."
I don't think any of us want race cars, we just want a little bit of fun in our luxury sedans!
Cheers!
There is a major clarification I wanted to make with regard to the pistons of the engine platform.
As many of you know, the block and body is aluminium, which is susceptible to thermal expansion, which increases the possibility of pre-ignition, or knocking, which is bad.
I've been digging around to find out what type of pistons are built into the 2/4GR FSE engines. What I have found will possibly bring relief to some of you who thinking about boosting your 2ISs, but worried about pre-ignition destroying the block and frying your pistons.
The pistons that are used are indeed cast; however, they are hypereutectic pistons. These pistons were introduced in the U.S. to conform to tighter smog regulation (reduce pre-ignition in the cylinders, which emits more smog), and has made boosting new gen imports a living hell. They are known to crack and deform during high performance; however, when 11% of the material grade is silicon, the heat generated by the engine is actually absorbed at ignition, and released upon exhaust. This is good news because it reduces thermal expansion on the aluminum block, which reduces knock/pre-ignition.
That being said, Toyota wrote a nice long PR piece for their parts department, giving us some tasty information about their setup. (see below)
https://parts.olathetoyota.com/eutec...r-pistons.html
It turns out, that Toyota over-engineers their components (surprise surprise), and these pistons will most definitely be able to handle boosted applications, possibly beyond 7PSI.
"The characteristics of pistons in each of these categories are very distinct. Hypereutectic alloys are stronger, resist scuffing and seizure, and reduce groove wear and cracking of the crown at extremely high temperatures. They're also very resistant to expansion, because the high percentage of silicon essentially "insulates" the piston from the effects of heat."
Straight from the horses mouth.
Lastly, hyperutectic pistons can be built to handle forced induction applications.
"The normal temperature of gasoline engine exhaust is approximately 650 °C (1,200 °F). This is also approximately the melting point of most aluminum alloys and it is only the constant influx of ambient air that prevents the piston from deforming and failing. Forced induction increases the operating temperatures while "under boost", and if the excess heat is added faster than the engine can shed it, the elevated cylinder temperatures will cause the air and fuel mix to auto-ignite on the compression stroke before the spark event. This is one type of engine knocking that causes a sudden shockwave and pressure spike, which can result in failure of the piston due to shock-induced surface fatigue, which eats away the surface of the piston.
The "4032" performance piston alloy has a silicon content of approximately 11%. This means that it expands less than a piston with no silicon, but since the silicon is fully alloyed on a molecular level (eutectic), the alloy is less brittle and more flexible than a stock hypereutectic "smog" piston. These pistons can survive mild detonation with less damage than stock pistons."
See wikipedia link for more info http://en.wikipedia.org/wiki/Hypereutectic_piston
It turns out that our stock pistons, are most likely 4032 performance pistons
Yes, these pistons are not forged, which is sad, but here is a final blurb I want to leave you all with.
"If there is a downsides to hypereutectic pistons, it's that they're brittle compared to forged pistons. Therefore, forged pistons are more forgiving of extreme conditions (like those found in a race car), and they give you a greater margin of error when dealing with timing problems, as detonation is less likely to destroy a forged piston than a hypereutectic cast piston.
Still, when it comes right down to it, the operational differences between forged pistons and quality hypereutectic cast pistons are smaller than ever. Unless you're running an engine in a race, or under extreme loads caused by high boost turbocharging, a hypereutectic cast piston is likely going to perform just fine for your specific use."
I don't think any of us want race cars, we just want a little bit of fun in our luxury sedans!
Cheers!
01-08-15, 07:00 AM
#2
Regardless of the engine internals strength, no one has been able to reliably boost over 8.5psi reliably due to our fueling limitations. Guys in australia have proven the transmission of the is350 is capable of around 500hp, but i havent seen anyone run stand alone tuning (and fueling) on the 2IS; it's just not easy (the electronics and multiple controlling ecu's on the car make anyone serious about power not attempt it).
I was very close to a single snail 2jz-gte swap last year, because in the end that investment is much easier and cheaper than trying to get the 350 (or 250) engine to reliably put down big numbers. After discussing with the major tuning companies of past IS builds, I decided it wasnt quite worth it for me at this time to have the car down for a long period of time (again) and to lose so many comforts of the car.
01-09-15, 03:26 PM
#4
Pole Position
Thread Starter
Engineers will always put safety factors on their designs; the last thing we want is a failure to occur and the finger (and lawsuit) pointed at us.
Regardless of the engine internals strength, no one has been able to reliably boost over 8.5psi reliably due to our fueling limitations. Guys in australia have proven the transmission of the is350 is capable of around 500hp, but i havent seen anyone run stand alone tuning (and fueling) on the 2IS; it's just not easy (the electronics and multiple controlling ecu's on the car make anyone serious about power not attempt it).
Regardless of the engine internals strength, no one has been able to reliably boost over 8.5psi reliably due to our fueling limitations. Guys in australia have proven the transmission of the is350 is capable of around 500hp, but i havent seen anyone run stand alone tuning (and fueling) on the 2IS; it's just not easy (the electronics and multiple controlling ecu's on the car make anyone serious about power not attempt it).
I was just at Serious HP (don't know if you have been there or not, they're by Jersey City, but you should check them out if you get a chance, they do a lot of custom work on blower kits, one of the techs has an IS300 and is trying to get 1000WHP out of the thing)
We talked extensively about boosting the 2IS, and one of the topics we've come up with was transmission.
Does the 2IS and 3IS share the same transmission?
They think they can build a stand alone fuel management system for the car, don't know how much that would cost or how feasible it is, but it is something we talked about.
In your beast, do you have a standalone fuel management system, or a piggy back?
01-09-15, 06:08 PM
#5
Thanks for the clarification. I am shooting for 7 to 7.5 without losing driveability and reliability, but we'll see. This is still very pie in the sky for me.
I was just at Serious HP (don't know if you have been there or not, they're by Jersey City, but you should check them out if you get a chance, they do a lot of custom work on blower kits, one of the techs has an IS300 and is trying to get 1000WHP out of the thing)
We talked extensively about boosting the 2IS, and one of the topics we've come up with was transmission.
Does the 2IS and 3IS share the same transmission?
They think they can build a stand alone fuel management system for the car, don't know how much that would cost or how feasible it is, but it is something we talked about.
In your beast, do you have a standalone fuel management system, or a piggy back?
I was just at Serious HP (don't know if you have been there or not, they're by Jersey City, but you should check them out if you get a chance, they do a lot of custom work on blower kits, one of the techs has an IS300 and is trying to get 1000WHP out of the thing)
We talked extensively about boosting the 2IS, and one of the topics we've come up with was transmission.
Does the 2IS and 3IS share the same transmission?
They think they can build a stand alone fuel management system for the car, don't know how much that would cost or how feasible it is, but it is something we talked about.
In your beast, do you have a standalone fuel management system, or a piggy back?
They talked to me about the same years ago... They don't understand the complexities of the new lexus ECU's to be honest, it's not their fault... They pull 1000whp cars (2jz power plants like supras, is300's, and of course all the domestics) all the time there.
7-7.5psi is what I run, it's not unsafe and no piggy back is needed. All stock ecu. Over 2 years and 20k miles on my setup.
01-12-15, 12:18 PM
#6
The piston material is irrelevant until someone comes up with a good solution to run more boost through ECU tuning/changes. Even if someone comes up with a good electronic solution I'm betting the limitations of the piston will be the high compression (and DI) design rather than the material itself.
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