What steps can be taken to safely raise the redline with the stock bottom end?

 

Why would you want to do this? Unless you are going FI theres really no point there is so much power/torque drop off after 6.5K that it feels to me as if it were trying to start rolling in 3rd gear.

 

Please forgive me for being a newb, but what does FI stand for? The reason I'm looking to rev higher is because I'd like to try and offset the hugely short final drive with more revs. Also, more revs = more power if you have enough air and fuel right?

 

FI = forced induction

the reason torque drops off is due to how HP and lbs/ft are calculated (notice that at 5250 hp and torque are equal. that happens to all motors...)

 

plus the gearing isn't made for higher revs...

 

you can change the gearing...

 

Want a better gearing? Find an Echo Transmission, Switch out the Final Gear(or all of em )
Also more revs does not equal more power. More Air and More fuel equal more power(Oversimplified statment there).
I'll tell you now that if you do you will lose some acceleration and not gain any top end(unless you remove the speed restrictions).
I owned an Echo and I can tell you stock the xA accelerates faster, and both top out around 118 when the restrictor cuts on.

 

How would changing the gears change the redline? I thought your gearing affected your acceleration.

 

all motor cars like foruma 1 cars and NHRA import all motor cars run better at high RPMs because the engine benefits from the higher revs. if you notice when driving the car around 5800 will fall flat on its face.

more revs dont really equal more power unless the parts in a car can work with such a mixture

 

what restrictor? my xB doesn't have one. the hp and torque starts to curve down, but I think that there would be more at 7000 than 3500(where he would shift too)

 

the reason the redline is there is to prevent the Engine from tearing itself apart, Toyota's are overengineered however I am a firm believer of "It was put there for a reason". Even if you were to change the redline to 8K you still wont get anything out of it without changing Internals, or doing other stuff. the redline has absolutly nothing to do with HP. Have you seen the Power Curve on a 1NZFE?

 

Boombox, the computer controlled top speed, is the restrictor I am talking about

 

I don't have any restrictor on mine, there is nothing that bumps me back down like my moms camry(125)

 

No I never have seen the power curve. Where does the engine make it's peak torque/hp? Do you have a link for a 1nzfe dyno chart?

 

http://www.overboost.com/picture.asp...Scion%20xb.jpg
If you look at the second one just past 65K youy can see the dropoff I was talking about.

 

Wow! 65K RPM!

The limiting factor in RPM is the fatigue life of the reciprocating parts, primarily the rods. As the RPM goes up, the stresses also go up. As the stresses go up, the parts will not last for as many reciprocating cycles.

The stock rods will have infinite fatigue life at 2000RPM. Raise that to 4000RPM and the life becomes finite, but is still longer than the life of other engine parts. Go to 6000RPM continuously and the life is shortened to a number of hours. At 8000RPM, fatigue life is reduced to minutes.

How to raise the red line? Well, it can't be done on a stock lower end! You can raise it if you replace the crank, rods, and pistons with items designed for a longer fatigue life. Be prepared to spend $$$, though!

George

 

xb's do not have a speed limiter , but do have rev limiter. , (just clearing things up in case people didnt understand)

 

I could swear there was a . in there, should read 6.5K

 

exactly, what car doesn't?

 

there are plenty of cars that do not limit the speed....they just gear the car to top out at that speed in sted of making the ECU do it...