Pull boost or pull timing.

[method]

Car is knocking ever so slightly. Its a 4age bluetop with a ht18/t3 hybred turbo with factory ECU.

Running around 13psi, just a touch under boost cut.

When i accelarate the car pulls timing at 5300rpm, no matter what gear im in. Even in 5th gear, its like a switch as soon as it hits 5300rpm.

Base timing is only around 9* advanced, was running 12* and had the same problem.

I was wondering whats better to pull, boost or timing and how if effects performance?

Im guessing pulling timing = loss of power down lower rpm slightly slower spool up of turbo
pulling boost = loss of mid and top end

I like having power between 2k and 4k rpm ( well "power" in terms of a light car and 4age)

[Crampy]

Pull a bit ot boost out of it.
Have you checked the AF ratio at that boost level as well? It might also be getting a bit lean at 13psi.

Pulling boost will help in two ways then.

[MAGN1T]

Fit water injection.

Steve

[fivebob]

Im guessing pulling timing = loss of power down lower rpm slightly slower spool up of turbo

You will lose power, but spool up should improve because more energy is driving the turbo through the hotter and possibly still burning exhaust gasses. However, depending on where you maximum boost is reached, this may create a problem as it will move your boost curve lower to a point where the engine may be more sensitive and therefore result in knocking at a lower rpm level.

Probably best to drop the boost and maybe retard the timing 1-2° as well until you can replace the ECU with something more suited to the task.

[method]

Cheers, thanks for the good advice guys.

Yeah, if i ever buy a decent engine ill go for a water injection system. There are some nice ones avalable. A friend was making 330kw on a standard evo7 engine with standard computer running the show.

My turbo 4age is just supposed to be a cheap upgrade, ie keep as much of it oem as possible while getting good results. Dont think a 1.6ltr is worth putting too much money into.

[Adydas]

Im glad this has been asked, im very curious whats the norm on timing.

Im currently running 19 degrees timing @ 1.3 bar.

I guess im curious what this means, car ran appaulingly when it was on 15 degrees, so i guess more timing = more power. Somthing ive never understood..

Whats the normal safe range of timing that can be ran? is it allways relative to the ecu or what?

[method]

I understand it that its when the spark is fired in relation to the piston being at point X of its stroke (top of compression stroke i think). The later after its reached the top of its stroke the less power it makes.

If its advanced too far it will knock. Most engines add timing with RPM but also pull timing with more boost. Not sure how much they add or remove though.

Feel free to correct me.

[mjrstar]

are you sure it's knock, not just normal engine vibration? which is being picked up by the knock sensor.
if not, i'd say fit a bigger intercooler and try a colder spark plug with a smaller gap..as 13 psi does not seem excessive unless the turbo is making massive heat.
I run my n/a toyota motor at 20 psi and it loves it.

[method]

Yeah, it always hits at the same RPM, 5300. No matter what gear its in.

Might try repositioning the knock sensor.

My engine is just a bluetop, turbo isnt too hot. Intercooler piping is always cold to the touch.

What 4age engine is yours, and any mods done to it? What timing you running?

[fivebob]

Im glad this has been asked, im very curious whats the norm on timing.

Im currently running 19 degrees timing @ 1.3 bar.

Depending on the rpm it sounds a bit high for a 3S-GTE at 1.3bar. Have you checked that your base timing is correct?

[Crampy]

What size injectors have you got?
4AGZE 365cc injectors would be getting dangerously close to maxing out at 12psi and over with that size turbo with a stock 4AGZE computer. From memory Barry and Brendon were using extra injector setups at boost levels over that, before they went to full stand alone ECUs.

Feel free to correct me on this though guys.

[ChaosAD]

Are you running a 4agze ecu? as they are known to cause a sudden drop in power somewhere around those revs.

[barryogen]

Not sure how much they add or remove though.

My altezza(non-turbo) has anywhere from +5 to +49 depending on where it is in the rev range.

It's not exact(there are a few areas that differ), but on my map higher revs = higher advance

[MAGN1T]

Might try repositioning the knock sensor.

?

That's got to be the dumbest idea imaginable.


What CR are you running.?

Generally a high CR (N/A) requires a small ammount of base timing, a lower CR requires more although the overall timing is about the same.

On a car with a distributor, there's base timing (static), maybe between 5 and 10 deg depending on motor.
Then there's centrifugal advance that might start at 1000rpm and be "all in " by 3000.(in the order of 25 deg max depending on motor)
Then there's vacuum advance which is dependant on load. Maybe 10 deg max.

So at full load, full rpms you'd have static + centrifugal, probably never any more than 30 deg.
Low rpm, low load you'd have static + vacuum, 15 to 20 deg.
Low RPM, high load, just static advance.


Anybody who says that they've got X degrees advance at XX rpm is wrong unless they've measured it with a timing light. Computers tell lies.

Steve

[Crampy]

Not sure how much they add or remove though.

My altezza(non-turbo) has anywhere from +5 to +49 depending on where it is in the rev range.

It's not exact(there are a few areas that differ), but on my map higher revs = higher advance

High revs does mean more advance, but more load means less advance.

[Adydas]

Im glad this has been asked, im very curious whats the norm on timing.

Im currently running 19 degrees timing @ 1.3 bar.

Depending on the rpm it sounds a bit high for a 3S-GTE at 1.3bar. Have you checked that your base timing is correct?

Abit high as in overly aggressive or high as in waterd down?

After the BHG repairs i took it to the shop yesterday and had it all re checked and tweaked against the ECU, Dizzy to match up to 19.5 Degrees.

Just somthing about cars id never paid attention to any detail on, so to now have to go have my car re aligned to match its all intresting to me what the ecus doing, WHY its 19 degrees, what does that mean? as far as tuning goes is that an agressive tune..

When the car was @ 15 degrees it ran slow as piss ( still fast, but slow as piss )..

[YeMs]

running on 98? throw sum octane boost or sum toly in it lol.

[fivebob]

Anybody who says that they've got X degrees advance at XX rpm is wrong unless they've measured it with a timing light. Computers tell lies.

Timing lights tell lies, good aftermarket computers that have been properly set up don't !!!

[sergei]

Anybody who says that they've got X degrees advance at XX rpm is wrong unless they've measured it with a timing light. Computers tell lies.

Timing lights tell lies, good aftermarket computers that have been properly set up don't !!!

strobe is hopeless at high frequency (RPM).

[fivebob]

Abit high as in overly aggressive or high as in waterd down?

High as in too agressive. Even the agressive stock Apexi PFC map is only 16° at those boost levels, and that's only above 7200rpm, from 3500-6500 it's only 13-14°.

After the BHG repairs i took it to the shop yesterday and had it all re checked and tweaked against the ECU, Dizzy to match up to 19.5 Degrees.

How did they adjust it? On a Motec they should have set it to test mode, which fixes the timing, then altered the Crank Index Position (CrIP) in the software so that the timing matched what the ECU is set to.

You should also be aware that 3S engines, especially Gen IIIs, crank timing marks can be way out, so they should have checked that the TDC mark is infact at 0° before starting the whole procedure. Mine was 5° out!!!

WHY its 19 degrees, what does that mean? as far as tuning goes is that an agressive tune..

When the car was @ 15 degrees it ran slow as piss ( still fast, but slow as piss )..

Without seeing the whole ignition map it's a bit difficult to comment on the agresssiveness or otherwise of the tune, just saying it's 19° doesn't mean much unless yout know at what RPM and boost levels it's set to that and what the advance curve is like. Also what the compensation tables are set to also alters the timing in the base table depeneding on things like engine temp, air temp etc.