"F" Marks The Lexus Spot!!! EXCLUSIVE VIDEO & PHOTOS
01-23-07, 12:39 PM
#31
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Just keep in mind that despite the beautiful geometry of the 2GR-FSE, in the end it's still an "F" motor. Not that there is anything bad about that, but simply that the heads are designed with fuel economy in mind. G heads are designed with performance in mind.
Historically, G heads on Toyota engines have meant fuel thirsty engines with higher emissions.
Historically, G heads on Toyota engines have meant fuel thirsty engines with higher emissions.
I've stuck porting tools in a number of G heads, and they're all second tier compared to motorcycle engines. The reason the G heads are historically the way they are is to reduce the angle of the port in relation to the valve stem and improve ultimate flow. So they have to splay the valves wider to get the intake and exhaust packaging right, and completely compromise the combustion chamber with too much surface area and not enough squish. The F heads are much more like bike engines - narrow valve angles, compact combustion chambers with lots of squish, and exceptional combustion efficiency - but unfortunately large angles between the port and valve stem for packaging reasons.
I'm hoping these new G heads will have the narrow included angle AND a small angle between the port centerline and the valve centerline. It's a lot easier to do with a V engine, and you can see they've done this with the 2GR-FSE. I'm also hoping the G heads have plenty of squish area either for better efficiency on poor quality fuel, or for exceptionally high compression and detonation resistance. Yamaha has LOTS of experience doing this with their bike engines, I'm just hoping it finally makes it into this new engine. It would make an ideal platform for boost if they do ('cause 432 hp still isn't enough...)
01-23-07, 08:01 PM
#32
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01-23-07, 10:12 PM
#33
Has anyone heard what rear gear the IS-F will use? I hope they leave the 4.0gear in there. On the RX 330 when they went to the 350 they went to a higher rear gear. I hope they don't ruin a good low gear when they add the extra HP V8. Anyone know?
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01-25-07, 04:48 PM
#37
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That's mostly marketing speak. Fuel thirsty just means it's a fundamentally poor combustion chamber design with compromises not supporting good efficiency and good power.
I've stuck porting tools in a number of G heads, and they're all second tier compared to motorcycle engines. The reason the G heads are historically the way they are is to reduce the angle of the port in relation to the valve stem and improve ultimate flow. So they have to splay the valves wider to get the intake and exhaust packaging right, and completely compromise the combustion chamber with too much surface area and not enough squish. The F heads are much more like bike engines - narrow valve angles, compact combustion chambers with lots of squish, and exceptional combustion efficiency - but unfortunately large angles between the port and valve stem for packaging reasons.
I'm hoping these new G heads will have the narrow included angle AND a small angle between the port centerline and the valve centerline. It's a lot easier to do with a V engine, and you can see they've done this with the 2GR-FSE. I'm also hoping the G heads have plenty of squish area either for better efficiency on poor quality fuel, or for exceptionally high compression and detonation resistance. Yamaha has LOTS of experience doing this with their bike engines, I'm just hoping it finally makes it into this new engine. It would make an ideal platform for boost if they do ('cause 432 hp still isn't enough...)
I've stuck porting tools in a number of G heads, and they're all second tier compared to motorcycle engines. The reason the G heads are historically the way they are is to reduce the angle of the port in relation to the valve stem and improve ultimate flow. So they have to splay the valves wider to get the intake and exhaust packaging right, and completely compromise the combustion chamber with too much surface area and not enough squish. The F heads are much more like bike engines - narrow valve angles, compact combustion chambers with lots of squish, and exceptional combustion efficiency - but unfortunately large angles between the port and valve stem for packaging reasons.
I'm hoping these new G heads will have the narrow included angle AND a small angle between the port centerline and the valve centerline. It's a lot easier to do with a V engine, and you can see they've done this with the 2GR-FSE. I'm also hoping the G heads have plenty of squish area either for better efficiency on poor quality fuel, or for exceptionally high compression and detonation resistance. Yamaha has LOTS of experience doing this with their bike engines, I'm just hoping it finally makes it into this new engine. It would make an ideal platform for boost if they do ('cause 432 hp still isn't enough...)
But who knows what the 2UR-GSE will have in reality. First ever application of G heads in a Toyota V engine. Also, all previous G heads were in older engine designs. None of the new Toyota engine designs have had G heads, and the 2UR will be the first. It may be an all new design for the G heads.
01-25-07, 09:04 PM
#38
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01-26-07, 07:16 AM
#39
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01-26-07, 07:49 AM
#40
EV ftw!!!
01-26-07, 10:20 AM
#41
Beauty is in the eyes of the beholder. Since you are on the waiting list of the new M3, obviously the IS-F is not for you.
The IS-F fit all my needs, so it is beautiful to me. Since the M3 is not for me, it doesn't attract me one bit. In case you think I want the IS-F because it is cheaper then the M3, my budget is high enough for a new M6.
The IS-F fit all my needs, so it is beautiful to me. Since the M3 is not for me, it doesn't attract me one bit. In case you think I want the IS-F because it is cheaper then the M3, my budget is high enough for a new M6.
01-26-07, 10:27 AM
#42
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Hey, I just remembered something. The G head designs were the ones on which VVT and VVT-i were introduced to toyota engines. The last G series engine (2ZZ) introduced VVTL-i.... Variable valve timing and lift... maybe we will have this on the IS-F? VVTL-iE ?? hmmmmmm
more and more i'm thinking that the '400hp+' is closer to 450hp
more and more i'm thinking that the '400hp+' is closer to 450hp
01-26-07, 10:33 AM
#43
Hey, I just remembered something. The G head designs were the ones on which VVT and VVT-i were introduced to toyota engines. The last G series engine (2ZZ) introduced VVTL-i.... Variable valve timing and lift... maybe we will have this on the IS-F? VVTL-iE ?? hmmmmmm
more and more i'm thinking that the '400hp+' is closer to 450hp
more and more i'm thinking that the '400hp+' is closer to 450hp
01-26-07, 12:06 PM
#45
Tech Info Resource
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If it had VVTLi they would have surely mentioned it at the show, or it would have been in the press kit. Without better details on how this engine is built, we're all guessing anyway. It would be nice to have some dimensions, but we'll just have to wait until closer to release for these.