Advancing Timing

[RBwhatever]

Hi. I have heard of some tinkering with the crank angle sensor and advancing their timing to get a a bit more power.

I've never had the privilege of doing this myself and just wanted to know what the affects would be on doing so with the stocko computer, power, torque, economy, running quality etc.

Thanks

[RBwhatever]

bumpity bump

[mad082]

i've done it. advanced it about 5/6 degrees. went much better. i just took it to the point of pinging, then came back a touch. helps build revs faster. you just have to make sure you run the best fuel you can, and always run that fuel.

[MANWHORE]

do it on a dyno so you can listen out for knock. If you've got a stock ecu, and run 100 octane shell, you should be able to wind a fair amount of timing into it.

The effect is more power, better fuel economy, more torque and faster spool time

[BAMR33]

Retarding the ex timing after mods ie. turbo, hi-flowing exhaust etc can give noticeable gains in all the categories mentioned by you. Advancing ex timing will make less power, torque, response etc. but also make the motor less prone to detonation. If your car is stock it's not worth touching full stop, if your car is modified an adjustable cam gear and tune is a far better idea than DIY CAS adjustment and hope for the best.

[mad082]

most of the people out there that say that 200rwkw from a stock ecu/turbo rb25 are probably running stock timing. there are also other things you can do to get more power, but i can't tell you, otherwise i'd have to kill you.

[mad082]

Retarding the ex timing after mods ie. turbo, hi-flowing exhaust etc can give noticeable gains in all the categories mentioned by you. Advancing ex timing will make less power, torque, response etc. but also make the motor less prone to detonation.

that's weird cause in the missus pulsar i advanced the timing from 15 degrees to 19 degrees and it went much better. the problem with retarding the timing is that by the time the fuel has finished burning it may be past TDC. as the fuel burnst it expands, so by advancing the timing you have more fuel burnt by TDC. this however means that the pressure inside the chamber is higher, so the temp is higher (as well as a higher temp from more fuel being burnt). then when it next puts fuel in the chamber temp is higher, so it is closer to pre ignition.

if you retard the timing less fuel gets burnt under high pressure, so there is less heat. while the fuel is unburnt it keeps the chamber cool.

[RBwhatever]

i've done it. advanced it about 5/6 degrees. went much better. i just took it to the point of pinging, then came back a touch. helps build revs faster. you just have to make sure you run the best fuel you can, and always run that fuel.

How can you tell how many degrees your dialing in?

Retarding the ex timing after mods ie. turbo, hi-flowing exhaust etc can give noticeable gains in all the categories mentioned by you. Advancing ex timing will make less power, torque, response etc. but also make the motor less prone to detonation. If your car is stock it's not worth touching full stop, if your car is modified an adjustable cam gear and tune is a far better idea than DIY CAS adjustment and hope for the best.

Don't you mean more power and more prone to detonation etc etc?

most of the people out there that say that 200rwkw from a stock ecu/turbo rb25 are probably running stock timing. there are also other things you can do to get more power, but i can't tell you, otherwise i'd have to kill you.

hahaha is that so? You can't kill the unkillable cos i'm invincible.....I think.

[RBwhatever]

that's weird cause in the missus pulsar i advanced the timing from 15 degrees to 19 degrees and it went much better. the problem with retarding the timing is that by the time the fuel has finished burning it may be past TDC. as the fuel burnst it expands, so by advancing the timing you have more fuel burnt by TDC. this however means that the pressure inside the chamber is higher, so the temp is higher (as well as a higher temp from more fuel being burnt). then when it next puts fuel in the chamber temp is higher, so it is closer to pre ignition.

if you retard the timing less fuel gets burnt under high pressure, so there is less heat. while the fuel is unburnt it keeps the chamber cool.

Whats TDC?

Shouldn't it be that when its running leaner it runs hotter?

[MANWHORE]

hang on hang on, you guys are talking about 2 different things. Mad is talking about advancin timing via the cas.

Bam is talking about the exhaust cam timing.

[MANWHORE]

how could he tell how many degrees? timing light?

[BAMR33]

Don't you mean more power and more prone to detonation etc etc?

Nope, you guys got it the wrong way around.

Have a read of previous threads on retarding exhaust cam. Plenty of information about it and you don't even have to start a new thread.

http://www.skylinesaustralia.com/forums/in...stable+cam+gear

[RBwhatever]

whoa, that just spun me out for a second. I don't have an adjustable exhaust cam gear.

I'm talking about advancing the timing (base timing?) via the CAS (crank angle sensor) and any benefits....

[RBwhatever]

has anyone else done this to their car?

[Marco-R34GTT]

Retarding the ex timing after mods ie. turbo, hi-flowing exhaust etc can give noticeable gains in all the categories mentioned by you. Advancing ex timing will make less power, torque, response etc. but also make the motor less prone to detonation. If your car is stock it's not worth touching full stop, if your car is modified an adjustable cam gear and tune is a far better idea than DIY CAS adjustment and hope for the best.

Wouldn't advancing the cam give you more torque and quicker spool time? As advancing the cam allows the valves to stay open longer, hence more fuel and air can get into the combustion chamber, and also, it allows exhaust gases more time to escape from the cylinder, leading to better breathing abilities, hence more power and less heat generation?

Edited April 3, 2007 by Marco-R34GTT

[jake33]

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id also be inerested to know about this advance timing. 4 degrees 3 degrees,, ect..what do you have to actually do to adjust it.??? anyone recommend it? worth it?

[BAMR33]

Advancing the the ex cam makes the valves open earlier, not stay open longer because the duration the valves are open is dependent on the profile of the cam and that does not change.

A quote from somewhere:

'Where the turbo engine will gain most from cam gears is by retarding the exhaust cam shaft. Normally manafactures like to advance the cam more than optimum for peak power because their highly restictive exhaust manifolds and systems can force hot gases back into the cylinder, promoting detonation.

Start retarding the exhaust cam a couple degrees at a time and watch the power climb, particularly if the engine has a larger exhaust housing on the turbo or an extremely low-restriction exhaust system.'

[Marco-R34GTT]

Funny, in the VL, retarding the cam one tooth and 8 degrees made a massive difference for power when included with even minor mods. About 92kw stock at the wheels, with K&N air filter, twin hyclones, performance extractors, 2.5 exhaust/hi flow cat and an ecu remap, power jumped to an unbelievable 128kw at the wheels. Nothing amazing for Skylines but it made a world of difference for the VL, completely different car to drive... It looks here as if the opposite is true...

[Cubes]

Adjusting cam timing = off topic.

Adjusting Ignition timing = ON topic.

[RBwhatever]

Adjusting cam timing = off topic.

Adjusting Ignition timing = ON topic.

Thanks cubes

Ok so just to clarify if I'm correct, Looking the engine from the front and turning the CAS:

Advance =anticlockwise

Retard =clockwise

And only adjust the timing while the car is running?

After adjustment put it under load in 5th and check it doesn't ping?

If I'm correct only advance it about 4-5 degrees. Should that be a safe amount running BP Ultimate fuel?