Engine Timing??

[beyond305]

So I was out hangin with a friend whos working on his eagle talon. I showed him my engine and hes like you here that clicking noise. Im like yea thats my valves right ? hes like yea but I can do something to make that go away and give u like 30 extra horsepower. He mentioned something about advancing the timing? Im not sure exactly what he meant but is this possible? Could you change the timing of the engine to produce more HP? Ive never messed with timing, just bolt on mods.

That ticking noise is the valves correct?

[Soulbane]

Uhh, advancing the timing without properly adjusting the A/F ratios is a bad bad bad bad bad bad bad bad bad bad bad bad bad bad bad bad bad bad idea.

The Eagle Talon is a different beast, it's essentially a Eclipse, a DSM family car, running on a 4G63.

Advancing the timing on a 4g63 is simple because with the aid of aA/F controller, like the Apexi S-AFC, you can get pretty decent tunes.

The 4g63 and 2AZ-Fe are two completely different animals. Just ignore that. lol

[beyond305]

oh i know all about the eagle talon beast my friend...Awd, turbo, dohc, 2.0... He was goin to do something to my car that would add HP not to his. Lets say he did advance the timing, what if I reset my ECU to change the A/F ratio? does reseting the ecu even change the a/f ratio? anddd what is the clicking noise i hear , my valves or do I have a problem in my engine?!

[Soulbane]

When you say you hear a clickin noise, I keep thinking valve tap, but seriously doubt you have valve tap. Try to be a little bit more specific with the diagnosis, what part of the engine bay does the sound come from, does it sound the worst at idle, slight rev, etc.

As for resetting the ECU, what that does is that it resets all your ECU's learned protocols and starts it from scratch. The various senors in your car will report data to your ECU, and your ECU will do its best to set things such as your A/F ratios, timing etc, to the most economical standards. You cannot directly alter the Timing and A/F settings by resetting the ECU, when you reset the ECU with new modifications, what the ECU essentially is doing is compensating for the new changes.

There is no "direct" way to advance or adjust timing or A/F ratios unless you have a stand alone unit or a piggy back unit. Unless you "reflash" your stock ECU to newer settings, you will not be able to directly affect the protols of your ECU.

[Ahriman]

the clicking is most likely the injectors.

and when your freind says hes going to advance your timing, hes talking about changing how soon your spark goes off before the piston reaches top dead center. it raises cylinder pressure and makes more power. its measured in degrees. for example, on pump gas i run 17 degrees of advance, meaning spark occurs 17 degrees before the piston reaches tdc. let me try and make this simple....

theres basically 3 ways to make more power... raising static compression, adding boost, and advancing the timing, and in that order. its a give in take kinda relationship though, if you raise compression or add boost you may have to back off on the timing. or you can use somthing to stabalize combustion like high-octane race fuel, or meth injection and still run decent timing. like i said before i run 17* on 93 octane without meth, but with the meth i run 24* of advance... and its a big difference.

im sure the stock tune is conservative, so you could probably get away with a little more timing, but if you run to much youll get knock.

[Soulbane]

He's not reflashed, or has any EM. I'm worried.

[navylife59]

He might be talking about advancing the cams. The tC already does that on the intake side with the VVT-i controller. This can be done manual, but the VVT-i system has to be removed also necessitating a standalone.

I concur. He was hearing the injectors. That is why the plastic engine cover has a thick foam pad on it; to absorb the injector noise, as well as, that of the valvetrain.

[Soulbane]

Main story to this lesson, get a some sort of engine management.

[beyond305]

well its just a slight clicking noise, im sure its what you guys said (injectors). Theres no knocking or pinging of any sort going on, Id let ya know if I thought there was something wrong with my engine. I havent let this guy do his "timing" trick yet but I was really curious as to what it could be.


so the VVTI only affects the intake cam and not the exhaust cam? I thought it affected both, thanks for the heads up tho. If I wanted to get the exhaust to act like the intake on VVTI, would it be hard and time consuming? I really would like to harness all this engine has to give me without going to boost or forced induction. Nothing against it, just dont have the money for that kinda stuff right now.

[navylife59]

You are correct in your assumption; the exhaust cam timing is set. You "could" degree in your exhaust, but not sure how that would work with the VVT-i on the intake side. I would imagine that it would be in conflict at times killing performance and drivability.

If your going be go the NA route, then wait a few weeks and see if Brian Crower makes good on the promise to deliver cams for the 2AZ-FE.

[floppe11]

yea that clicking sound is on all tcs.... my car does it at idle at first i thought maybe it was my valves going but its just the injectors....

[Soulbane]

Yeah, valve tap on a nearly new tC is a bad bad bad thing. lol

[floppe11]

Listen i have an 07 scion tc manual.. i am completely stock and i race other scions with intakes and exhaust and beat them everytime hands down.... i also just raced a civic bubble with a b16 motor in that did 14.1 at the track and i beat him to... is like the way i broke in my car in the beginng the reason for this..... is any1 else scion like a freak and just beat cars that u didnt think ud be able to beat....

[navylife59]

You are probably just driving their butts off. Breaking in a motor is more for longevity than just raw HP. I had my car for less than a week before I was smacking the fuel cut on the top end racing some Honda on an 18 mile causeway. I believe the manual states not to drive a constant high speed for the 1st 1,000 miles. Ooops!