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Discussion Starter #1
Had a couple of questions on the ISF motor
1. Why is the engine capped 6800rpm?
2. Can this engine be modified to generate more torque at higher rpm?

Cheers,
Jay
 

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Had a couple of questions on the ISF motor
1. Why is the engine capped 6800rpm?
2. Can this engine be modified to generate more torque at higher rpm?

Cheers,
Jay
1. The engine is capped at 6800 rpm because that is how Toyota decided to build and tune the engine. My guess is that it could probably handle a higher redline, but it probably wouldn't meet Toyota's ridiculous longevity standards. They could have build a more expensive motor designed for higher rpms, but I imagine that the current setup met their cost goals, while allowing them to position the ISF's power rating comfortably between the M3 and the C63 AMG. Everything in the auto industry ultimately comes down to money. (Also, by building it the way they did, the ISF gets significantly better gas mileage than either the Bimmer or the Benz)

2. You can build/tune a motor in a variety of ways, so nothing is impossible...BUT...typically your horsepower is the only thing that keeps climbing with a higher redline. Your torque tends to taper off well before redline. Also, chances are that if you increased your high-end torque, you would sacrifice some low-end.
 

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Discussion Starter #3
Thanks G for your response.
I do agree, there is a lot to smile in the current motor. It's not just the sport button, but last time i was driving on the highway, i noticed my avg mpg for that tank was 28.6 mpg...it was amazing..only Lex\Toyota can build such a good balance.

At times i do wonder about what it would be like to have a higher torque cutoff. I was watching the video of the LF-A the other day and that engine seems to be a beauty as it loves to rev high up.

Wonder if anybody will tune the ISF engine to deliver higher. Will a lot of the internal components from camshafts to valves, have to be strengthened?
 

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that reminds of an article I read in motor trend today, I think it was the sept issue. They did a write up on the "F" and drove it for 13 months. They said that the sport button to them felt zero effect. and that there were too many gears, they said when trying to pass someone that you had to go down 4 gears, then shift back up through them. they mentioned nothing about how the MPG was blowing out the bmw, C63, CTS-V. typical Lexus basher article, with little knowledge about the car, I doubt they actually daily driven it for those 13 months. To not notice the difference between the power button is ridiculous. They prob. drove it on the first day they got it and the last day the article was do. How sad.
 
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