[tCXGreek]

Did it to my Taurus and saw slight improvements (shut up, first car) is it possible or even worth it to do it to the Scion? Crank it a few degrees and run Premium, how much power will it give?

 

[zeromotorsports]

you would have to use a piggy back computer of some sort to do that with the tC as it has no distributor.

 

[tCXGreek]

Even if we could somehow do that, would the tC see any increase in power?

 

[zeromotorsports]

i dont know, you wouldhave to strap it down to a dyno if you were going to see any real gain

 

[lo bux racer]

Maybe, but your risking the entire engine by advancing the timing. For instance, I set an engine I was tuning to 28 degrees full advance and it ran great, but economy seemed low. I added two degrees and promptly detonated the thing to death on the next WOT run. It crushed the ring lands and cracked the head between the intake and exhaust seats in one cylinder. Expensive lesson.

Timing isn't usually where you look for performance increases, and advancing timing is just the opposite of what you want to do anyway. The more you advance timing, the sooner you reach peak cylinder pressure. There is a "sweet spot" for when that should happen. If it happens too soon, you are just working the engine against itself and putting a very large stress on the crank bearings.

A truly powerful and efficient combustion chamber needs very little advance to work well. Yes, you want to advance to get the pressure peak at the right time, but, you want to modify the piston and combustion chamber to allow the smallest amount of advance to get there.

 

[QuadinScionTC]

Use the string cheese plugs and wires, they work wonders

 

[silverrsxjezus]

Originally posted by ZEROmotorsports@Feb 24 2005, 09:15 AM
you would have to use a piggy back computer of some sort to do that with the tC as it has no distributor.

ah, i see. so what does it use as a substitute as a distributor?

 

[lo bux racer]

Four ignition coils. One on each plug. The ECM does all the figuring when to charge and discharge them. Just like the injectors, they're (thankfully) sequential too, not batch fire like so many cheaper systems.

 

[FrostbytetC]

Originally posted by lo bux racer@Feb 24 2005, 06:09 PM
Maybe, but your risking the entire engine by advancing the timing. For instance, I set an engine I was tuning to 28 degrees full advance and it ran great, but economy seemed low. I added two degrees and promptly detonated the thing to death on the next WOT run. It crushed the ring lands and cracked the head between the intake and exhaust seats in one cylinder. Expensive lesson.

Timing isn't usually where you look for performance increases, and advancing timing is just the opposite of what you want to do anyway. The more you advance timing, the sooner you reach peak cylinder pressure. There is a "sweet spot" for when that should happen. If it happens too soon, you are just working the engine against itself and putting a very large stress on the crank bearings.

A truly powerful and efficient combustion chamber needs very little advance to work well. Yes, you want to advance to get the pressure peak at the right time, but, you want to modify the piston and combustion chamber to allow the smallest amount of advance to get there.

Well said Lo Bux! Very good post. Yes, the tC uses a coil pack instead of a distributer. Alot of cars are Distributer-less now, at least most imports from my experience. Better way of doing things as far as I'm concerned. But yes, don't mess with timing. Too risky. I'm sure Toyota tested and tuned this motor for the tC and used the best timing to give it the best power. Could you theoretically squeek an extra 3 or 4 ponies out of the car if it had a distributer? Probably, but with gas prices on the rise, why force a car that is perfectly tuned to 87 octane to use more expensive gas for the same amount of power the TRD air filter would give you?

 

[redamnavit]

There's no distributor but there has to be some form of crank angle sensor (CAS). The car has to know where on the combustion stroke a given piston is so it knows when to fire. Turn your car off, remove the battery, reset the ECU, hook the batter back up and the car still knows when to fire. I'll look under the hood after work and see where they mount the thing on this engine.

Most CASs I've seen are attached in a way that allows you to adjust them across a few degrees so they can be aligned. Its possible you could get a timing gun and play with that to adjust your timing a bit. As Lo bux said, incredibly bad things can happen and a lot depends on the engine design. The GA16s in the old 200sx's benefitted from a timing increase with no reliability issues that I'm aware of. A few degrees increase on the CA18 in my 240sx will crack the ring lands. YMMV. Ask some Corolla guys; this engine has been around awhile and they'd know if anyone would.


P.S.: lo bux racer, 28 degrees advance?? What engine was that?

 

[lo bux racer]

Yamaha FJ1200 with 11.25:1 compression (measured) and 1mm squish. A bit modified from stock.

 

[SupraTC]

Originally posted by lo bux racer@Feb 24 2005, 06:09 PM
Maybe, but your risking the entire engine by advancing the timing. For instance, I set an engine I was tuning to 28 degrees full advance and it ran great, but economy seemed low. I added two degrees and promptly detonated the thing to death on the next WOT run. It crushed the ring lands and cracked the head between the intake and exhaust seats in one cylinder. Expensive lesson.

Timing isn't usually where you look for performance increases, and advancing timing is just the opposite of what you want to do anyway. The more you advance timing, the sooner you reach peak cylinder pressure. There is a "sweet spot" for when that should happen. If it happens too soon, you are just working the engine against itself and putting a very large stress on the crank bearings.

A truly powerful and efficient combustion chamber needs very little advance to work well. Yes, you want to advance to get the pressure peak at the right time, but, you want to modify the piston and combustion chamber to allow the smallest amount of advance to get there.

That is what can happen to a forced Induction motor but it is very unlikely that an NA motor will be damaged from too much timing advance within reason.

The Scion will advance timing as much as possible on its own until the knock sensor starts hearing knock and it will then settle timing just below that #.

If you put higher octane fuel in your car and want better performance be sure to reset your ecu so that it will advance timing up until the knock threshold again.

Moving the CAS is NOT recomended as this sensor measures engine position for not only ignition timing but also injector timing.

Plus if the CAS doesn't coincide perfectly with the cam angle sensor you will get a check engine light immediately.

 

[lo bux racer]

2JZ's won't even start if the crank and cam signals are out of phase.

 

[SupraTC]

Originally posted by lo bux racer@Aug 9 2005, 12:04 AM
2JZ's won't even start if the crank and cam signals are out of phase.

They absolutely will.

They will throw a check engine light and the ECU will revert to the cam sensor for timing input.

Ever hear of people breaking the little spot weld on the crank timing gear that holds the pickup in place?

Its pretty common, its happened to me and several others.

The car runs just badly.

 

[lo bux racer]

It won't run if the cam signal happens before TDC. Ask Guilly, Michael Gaari, or a small host of others who ran Unorthodox pullies and had their crank triggers float, then rotate out of position. No start condition.

 

[lo bux racer]

Originally posted by SupraTC@Aug 8 2005, 05:02 PM
That is what can happen to a forced Induction motor but it is very unlikely that an NA motor will be damaged from too much timing advance within reason.

This is funny. The engine I described is a Yamaha FJ1100 NA engine running 30 degrees full advance in a 76mm bore. It blew up. I've seen lots of other NA engines do the same. FI just makes it easier with boost overshoot, but the fact remains, any engine will blow up from too much advance.

 

[OliverThomas]

Originally posted by SupraTC+Aug 11 2005, 03:30 PM-->QUOTE (SupraTC @ Aug 11 2005, 03:30 PM)

<!--QuoteBegin-lo bux racer

@Aug 9 2005, 12:04 AM
2JZ's won't even start if the crank and cam signals are out of phase.

They absolutely will.

They will throw a check engine light and the ECU will revert to the cam sensor for timing input.

Ever hear of people breaking the little spot weld on the crank timing gear that holds the pickup in place?

Its pretty common, its happened to me and several others.

The car runs just badly. [/b]

I'd put my money on Lance. He know's more than god. (about engines at least).

Played with the timing on my Z-28 years ago, only ever succeeded in messing things up.

 

[tCXGreek]

Originally posted by SupraTC+Aug 8 2005, 05:02 PM-->QUOTE (SupraTC @ Aug 8 2005, 05:02 PM)

<!--QuoteBegin-lo bux racer

@Feb 24 2005, 06:09 PM
Maybe, but your risking the entire engine by advancing the timing.  For instance, I set an engine I was tuning to 28 degrees full advance and it ran great, but economy seemed low.  I added two degrees and promptly detonated the thing to death on the next WOT run.  It crushed the ring lands and cracked the head between the intake and exhaust seats in one cylinder.  Expensive lesson.

Timing isn't usually where you look for performance increases, and advancing timing is just the opposite of what you want to do anyway.  The more you advance timing, the sooner you reach peak cylinder pressure.  There is a "sweet spot" for when that should happen.  If it happens too soon, you are just working the engine against itself and putting a very large stress on the crank bearings.

A truly powerful and efficient combustion chamber needs very little advance to work well.  Yes, you want to advance to get the pressure peak at the right time, but, you want to modify the piston and combustion chamber to allow the smallest amount of advance to get there.

That is what can happen to a forced Induction motor but it is very unlikely that an NA motor will be damaged from too much timing advance within reason.

The Scion will advance timing as much as possible on its own until the knock sensor starts hearing knock and it will then settle timing just below that #.

If you put higher octane fuel in your car and want better performance be sure to reset your ecu so that it will advance timing up until the knock threshold again.

Moving the CAS is NOT recomended as this sensor measures engine position for not only ignition timing but also injector timing.

Plus if the CAS doesn't coincide perfectly with the cam angle sensor you will get a check engine light immediately. [/b]

So theoretically if I wanted to spend the $5/gallon on Permium resetting the ECU (remove negative on battery?) will cause the vehicle to relearn its timing to 93 fuel? That sounds way too easy... and will it even increase HP?

 

[lo bux racer]

No. Premium fuel only helps if you have a detonation problem. The stock configuration does not need premium fuel. You would need to increase compression either statically with a mechanical change or dynamically with forced induction to get an advantage from running premium fuel.