Power happy at 4500
05-20-15, 01:35 PM
#1
Power happy at 4500
I pushed her a little harder for the first time last night, and at about 4500 it was like a light switch turned on and she went like hell!! 2j non turbo. I'm just curious if there is anyone else experiencing this smile fest, it's a first for me.
05-20-15, 02:41 PM
#2
what you are likely experiencing is the ACIS valve doing its job, our stock 2jz na intakes have dual length intake runners.
a long runner for max torque in lower rpm's (only activates above a certain tps % and below a certain rpm so you only get max torque when punching the gas and not in cruise), and majority of the time its a short runner to achieve max hp in the upper rpm's (like a GTE).
http://en.wikipedia.org/wiki/Acousti...duction_System
the default for the system is open or short runnner. this is good for HP up top but looses some torque down low.
so if you are not gunning it ever, the system just stays in short runner. its only when you gun it under 4k rpm's do you get long runner, and then the switch back to short runner, which gives you like a double power boost feeling.
so when you are full throttle from an early rpm, the engine goes to long runner to generate max torque, then around 4k rpm's where HP is taking a hit from long runners, it switches to short runner and you get an instant HP boost that carries to redline allowing you to achieve max HP (you dont notice the small loss of torque when the engine is in this rev range).
in a normal intake design engine you would have to choose 1 intake length to optimize max torque or max hp, as one goes up the other goes down, you cannot have both with 1 intake length.
The toyota design allows you to hit max Tq and max HP in the same pull, pretty neat if you think about it.
if you had a turbo on there, that long runner would spool up your turbo faster as well.
alot of toyota n/a motors came with it to make it feel like a larger displacement motor down low.
on the turbo motors they just use short runner all the time as the idea is the turbo's generate extra torque down low so no one is going to miss it, and they were right about that.
changing the intake length to gain power is similar also to what turbo users call the "quick spool valve". it basically changes the exhaust a/r on the fly allowing you to change the VE of the engine, so with 2 VE's you can increase down low spool in a similar technique but on completely different parts of the motor.
a long runner for max torque in lower rpm's (only activates above a certain tps % and below a certain rpm so you only get max torque when punching the gas and not in cruise), and majority of the time its a short runner to achieve max hp in the upper rpm's (like a GTE).
http://en.wikipedia.org/wiki/Acousti...duction_System
the default for the system is open or short runnner. this is good for HP up top but looses some torque down low.
so if you are not gunning it ever, the system just stays in short runner. its only when you gun it under 4k rpm's do you get long runner, and then the switch back to short runner, which gives you like a double power boost feeling.
so when you are full throttle from an early rpm, the engine goes to long runner to generate max torque, then around 4k rpm's where HP is taking a hit from long runners, it switches to short runner and you get an instant HP boost that carries to redline allowing you to achieve max HP (you dont notice the small loss of torque when the engine is in this rev range).
in a normal intake design engine you would have to choose 1 intake length to optimize max torque or max hp, as one goes up the other goes down, you cannot have both with 1 intake length.
The toyota design allows you to hit max Tq and max HP in the same pull, pretty neat if you think about it.
if you had a turbo on there, that long runner would spool up your turbo faster as well.
alot of toyota n/a motors came with it to make it feel like a larger displacement motor down low.
on the turbo motors they just use short runner all the time as the idea is the turbo's generate extra torque down low so no one is going to miss it, and they were right about that.
changing the intake length to gain power is similar also to what turbo users call the "quick spool valve". it basically changes the exhaust a/r on the fly allowing you to change the VE of the engine, so with 2 VE's you can increase down low spool in a similar technique but on completely different parts of the motor.
Last edited by Ali SC3; 05-20-15 at 02:53 PM.
.
Trending Topics
05-21-15, 09:59 AM
#9
the reason toyota never put it on the 1uz was because the 1uz made enough torque already off the line, all it needed was hp up top, so short runner is pretty much what you want on that kind of v8.
probably by the time the vvti came out they were like, lets see how much stuff we can slap on here to make it as complicated as possible and less reliable.
the early sc400 motors were everything you needed and nothing you didn't, with the exception of that hydraulic cooling fan, thats some seriously complicated stuff for replacing a clutch fan like found on the ls400.
It would probably be one of my first mods to just rip all that stuff out and put a ls400 clutch fan on it. nothing like your fan being connected to your engine the old fashioned way.
probably by the time the vvti came out they were like, lets see how much stuff we can slap on here to make it as complicated as possible and less reliable.
the early sc400 motors were everything you needed and nothing you didn't, with the exception of that hydraulic cooling fan, thats some seriously complicated stuff for replacing a clutch fan like found on the ls400.
It would probably be one of my first mods to just rip all that stuff out and put a ls400 clutch fan on it. nothing like your fan being connected to your engine the old fashioned way.
Thread
Thread Starter
Forum
Replies
Last Post
ItzFilyO
GS - 4th Gen (2013-2020)
45
02-07-15 02:42 PM