Okai i asked this before but no one really answered so ill ask again.

What are the disadvantages of running advanced tuning, say around 17 degrees?
Im running only high octance and gas, but if i lower the tuning a bit will i get a smoother idle or anything like that?

Or does advancing the tuning ONLY give advantages as long as the right fuel is used?

Thanks.

you will lose power and do dammage your throwing a spark in the clyinder too early it will ping and do dammage as well as use more fuel

Magnus, you'll find, if done properly he'll actually gain power. It's just a matter of getting it right and doing it slowly.

What sort of magna do you have?

I advanced the timing on my old SOHC 12v 6G72 and only ran 98 octane petrol. It made a considerable difference. Definitely more low end power, and mid/top end didnt suffer from it.

However, I would advance only a couple of degrees, go for a drive (take your tools with you) and as SOON as you hear ANYTHING that isn't normal, pull over, and retard that timing!

I'm not sure if the 4G54's (looking at your profile) have knock sensors, but if they do then that'll save you. If not, then you have to keep a close ear on the motor when messing with timing.

Mine was advanced quite a bit and no pinging. I also advanced the timing on the DOHC 24v with very similar results.

Advancing the timing means making your sparkplug FIRE LATER.

As your piston moves up (compression stroke), there is an optimum point
where the sparkplug should fire for the most efficient burning of the fuel mixture.

Low octane fuels' mistures cannot be compressed as much before they self-ignite.
That is called "pinging". If your plug fires too late, your engine will knock/ping - very bad!!

If you over-advance to cause pinging you will lose power.

How much you can advance will also depend on the ambient temperature, fuel etc.

The best engines have knock sensors... engine will automatically advance the timing
until the engine knocks, then it retards it one step.

Yes i understand the concept and higher octane fuel can compress more etc etc

Did you know octane is an 8 carbon, 18 hydrogen hydrocarbon, and something that was 98 octane would mean it had 98% octane. But now its become more as a standered as LPG has no octane in it what so ever and it would be impossible to have a mixture of 105% octane.
Anyways thats the chem student coming out in me.

But thats why i run only 98 octane and lpg, and lpg octane rating is something like 105.


Anyways ive got a 2nd Gen 4 cyl EFI.
But what i want to know is... lets just say i have found the optimum advanced timing, so an extra 5 or 10 degrees with no pinging what so ever, will their be any disadvantages from this???
Thank you.

Advancing the timing definately causes the spark to fire earlier, before the piston reaches top dead centre. A small amount of advance from normal can be of advantage, but pinging and piston damage is a reality if advanced too much.
Has anyone worked out how to advance the timing on a 3rd gen. The base timing signal comes from the crank angle sensor. Is it adjustable?
Cheers

Did you know octane is an 8 carbon, 18 hydrogen hydrocarbon, and something that was 98 octane would mean it had 98% octane. But now its become more as a standered as LPG has no octane in it what so ever and it would be impossible to have a mixture of 105% octane.

CH2CH2....OH

Join the geek club. :P


Anyways ive got a 2nd Gen 4 cyl EFI.
But what i want to know is... lets just say i have found the optimum advanced timing, so an extra 5 or 10 degrees with no pinging what so ever, will their be any disadvantages from this???
My AstronII came back from smack repairers with too-advanced timing.
Ping'd like crazy on 92RON, but ran fine on PULP 96RON.
(different brand fuels had different results too)

When the dealer "corrected" the timing at next service... damned, less power.


If you're willing to pay for 98RON, there's no harm going advanced if it doesn't knock.


But as your car gets older and you get carbon buildup in the cylinders/pistons,
the knock point will gradually reduce. You'll have to re-time if 98RON can't cure knocking.

Running LPG might be cleaner than petrol, cause less carbon buildup.
LPG could also burn hotter than petrol so it burns more completely.

Did you know octane is an 8 carbon, 18 hydrogen hydrocarbon, and something that was 98 octane would mean it had 98% octane. But now its become more as a standered as LPG has no octane in it what so ever and it would be impossible to have a mixture of 105% octane.
Anyways thats the chem student coming out in me.



Actually, the number has nothing to do with the percentage octane in the fuel. It is 98 RON not 98% octane. It is a fuel quality rating system not a gurantee of ingredients.

See here:

http://www.motorcycle.com/mo/mcnuts/fuelron.html

http://en.wikipedia.org/wiki/Octane_rating

Has anyone worked out how to advance the timing on a 3rd gen. The base timing signal comes from the crank angle sensor. Is it adjustable?
With a piggy back ECU, yes. You splice the crank angle sensor wire before the ECU and the interceptor changes the output timing by however many degrees you require.

It's a case of definition. Sure moving the distributor in the direction of rotation will cause the spark to fire later, I agree. But this is how you retard the timing - ask any motor mechanic. Advancing the spark timing involves moving the distributor back in reverse of the direction of rotation so that the spark is triggered earlier. It depends on whether you mean advancing/ retarding the dizzy or advancing/ retarding the spark timing. They give opposite effects. I believe my definition is correct.
Any mechanics out there? Help.........!!!!

It's a case of definition. Sure moving the distributor in the direction of rotation will cause the spark to fire later, I agree. But this is how you retard the timing - ask any motor mechanic. Advancing the spark timing involves moving the distributor back in reverse of the direction of rotation so that the spark is triggered earlier. It depends on whether you mean advancing/ retarding the dizzy or advancing/ retarding the spark timing. They give opposite effects. I believe my definition is correct.
Any mechanics out there? Help.........!!!!
Ok hope this helps, I'm hopless with diagrams, imagine the whole outer circle is the engine, the small inner circle is the dissy, if you move the dissy counter clockwise you will be sparking earlier than top dead centre hence 5 degrees BTDC is 5 degrees advance, and if you rotate clockwise and have it spark after top dead centre you are actually retarding timing,
Try use the centreline between the two circles as a reference point kind of thing and that the engine spins clockwise (unless its a honda lol )

if your timing is ment to be at 10 deg and you wind it to 15 the spark is fired in the plug earlier ....the spark if fired btdc before top dead center if you advance it to far the compressed air fuel mixture explodes too early trying to force piston backwards but the flywheels foward momention makes it go foward a ping is when the piston is trying to compress an explosion .... this is what causes dammage

CH2CH2 would be ethane, ("eth" meaning two and "ane" meaning singly bonded carbons) and if you put an OH

on the end it becomes ethanol, good old alcohol.

The wikipedia says
"So an 87-octane gasoline has the same knock resistance as a mixture of 87% iso-octane and 13% n-heptane."

Okai i said "and something that was 98 octane would mean it had 98% octane" so i messed up and said

octane instead of iso-octane, which is really the same thing cept the way the carbons are connected, no biggie really.

But 98 RON fuel isnt the same as having a 98 octane rating (i'm pretty sure, but i think i came across in my other post saying it is the same)


Can someone PLEASE answer this question.

If i advance my car to a SAFE degeree, eg NO pinging. Is their any disadvantages?

As I understand it, a RON of 98 means the fuel has the equivalent resistance to knock as fuel with 98% isooctane content.. but it's still possible to have a RON greater than 100 because isooctane isn't the most knock resistance substance out there.

Also, I don't believe there are any drawbacks to advancing ignition. The only reason it is retarted in the first place is as a precaution against knock.

Note that from articles I have read there is an ignition advance angle called the Minimum advance for Best Torque (MBT) which gives you the sweet spot for tuning for best torque (and therefore power) production, but depending on compression ratio and fuel octane rating, it might be impossible to attain that level of advance before knock occurs. However if you advance beyond that point you'll go backwards in power.

if your timing is ment to be at 10 deg and you wind it to 15 the spark is fired in the plug earlier ....the spark if fired btdc before top dead center if you advance it to far the compressed air fuel mixture explodes too early trying to force piston backwards but the flywheels foward momention makes it go foward a ping is when the piston is trying to compress an explosion .... this is what causes dammage
what he said

Ans: no providing it is not pinging

Thank you guys, thats what i wanted to know.