Stardust

Hey guys, I bought the tC to be a go-around-town daily driver, but the damn b/f is rubbing off and getting me to mod lol.

He has a question...

Whats the deal with the engine choking up and loosing its gusto in the higher RPMs??

He thinks it isn't a VE problem (intake, exhaust fixable) but it feels like Scion has the timing way too conservative at the higher RPMs, limiting power. The car picks up off the line amazingly, but after 3K RPM it begins to just fall on its face.

Has anyone put a timing light on the car during a dyno session or has a log of the OE timing curve? If it really is timing, an Emanage Ultimate could net some good gains all by itself.

trojan105

for the tc...all the torque is at the low end of the RPM

draxcaliber

are you kidding me?

1. peak torque is at 4000 rpms, and peak hp is at 6000 rpms.

2. it makes most of its torque between 3-4 thousand rpms.

3. if your tc is falling apart in the higher rpms, then there is something wrong with it because its horsepower rises pretty linearly straight to 6000 rpms, and the torque curve is pretty flat too.

so it sounds like there is something wrong with your tc if it is just falling apart after 3000 rpms.

the car is tuned to just about peak n/a performance from the factory, tuning can only get you a reasonable gain if you have intake/header and exhaust upgrades.

nominal_asu

I think this is just yet another person complaining that the tC is slow, which it isnt, for what it is.

captainlaziness

The transmission's crap too...

chrisNOF

Stick or auto?

captainlaziness

Stick. I was being sarcastic.

Mid_Life_tC-risis

3K is about when the stock muffler valve is supposed to open up.

Best fix is replace with a good aftermarket straight-though muffler, if this is the problem ...

draxcaliber

or maybe she has some kind of ultra rare scion tc with a diesel engine...

Stardust

I guess something is wrong then, the power is impressive off the line, but feels kinda weak after that. Freeway passing power is hardly there.

Its not a slow car IMO, its low end pep is very nice, easy to break traction. But it doesn't have the climbing power band I'm used to until it gets close to redline. Maybe its the flat torque curve giving me this impression.

btw its an auto. Didn't know about the exhaust valve, something to look into. Is it pressure or electronically operated?

Gotta go to one of these SoCal meets or the stealership to drive another to see if its the car, or me.

Stardust

I talked with him and he looked at this thread (this whole thing stemming from me complaining the car is TOO perky from a stop). We did some spirited driving and his conclusion (made excuse about his timing idea was the fault of him tuning a megasquirt lately and he had timing on his mind lol) that its the DBW.

He said when heavy on the throttle, its a very peppy car throughout the powerband. But in partial throttle conditions sometimes it seems to be underpowered (not due to the engine itself, but the DBW settings), kind of like how his IS feels when the traction control kicks in, or driving in "snow" mode.

He mentioned Toyota has a recall, maybe more than one, to re-flash Camry ECU's DBW program for certain year models that had a lot of complaints about power band.

Maybe this is it. Sorry guys.

CuRiOuSfIsH

This is going to sound dumb but if the driver is not close to flooring it, they are not exploring the powerband. Aside from DBW, there is the motor design and the Toyota tuning. The motor was built for good torque and decent gas mileage, not high RPM fun.

Mightygnu

See my signature, buy my turbo kit, and you'll feel power throughout the powerband guarentee'd!

Stardust

Hello its Stardust's b/f.

I'm not young, nor is this my first car. I just got done getting a custom MSII to run the IS 300, there was no DIY, its a first and only so far.

Please don't take the above as a rant, but just trying to set up a foundation to my opinion. This car does not drive in a typical sense, the DBW in my opinion could use some more ironing out, programming wise. I have driven cars without DBW, and other cars with.

I'm not calling this car out as slow, or messed up. I really like this car, and I'm a die-hard Toyota enthusiast. Toyota having a TSB to reflash camrys brought in with a power delay complaint (NHTSA Item Number: 10022143 I believe) makes me feel that its not craziness, but it is possible they have dropped the ball a little bit on their DBW tuning.

Call me out cause you feel I'm attacking your car, but this is an opinion from an avid Toyota enthusiast and autox/road course driver.

draxcaliber

wow, i very very rarily use full throttle in my tc and it moves just fine.

makaveli510

sorry bro but your g/f bought a auto thats your first problem second i have a bit of mods and my tc has plenty and i mean plenty of passing power but i also was smart and bought a manual, why would you waste money on modding an auto?? doesnt make sense to me, your never gonna get the same fell from an auto as you do a manual, also the auto is a lot heavier then the manual..just my $.02

Stardust

makeveli510, I share the same feeling. My IS is manual.

But its her car, what can I say. Maybe its the auto, maybe its in both of our heads, maybe its DBW, maybe its that I'm used to a higher compression I6 and my DD is a TRD s/c'ed Tacoma (its an auto, but it moves), not an I4.

I think the car has plenty of pep, but the throttle is un-natural.

CuRiOuSfIsH, my first indication if this was on the freeway and in a slow linear fashion increasing throttle to speed up, but the acceleration was hardly there. Today I tried to duplicate that and somewhat get it. But if I press down quickly (but not anyfurther throttle pedal % wise), the power is there, so I'm still convinced its the DBW algorithm.

I thiknk I should get my own scionlife screen name lol.

deathbyc4

have the dealer check the transmission, could be bad? Manual is usually the way to go but like you said, its her car. Girls drive fast enough as it is and we're the ones that have higher insurance

nominal_asu

Its definitely the auto, my manual has great power thoughout the rpm range, regardless of easing onto the throttle or simply flooring it.

chrisNOF

Wow! Sounds like you have a Honda engine under that hood. You shouldnt have to almost redline to get power out of a Toyota. To me that sounds like a Honda. Take it to the dealer and find whats really going onn