Ignition advance, AFR and tuning
Discussion
Hi guys,
From what I've read ignition advance should create a 'valley' (start and end higher and gradually transition down and then up throughout the rev range).
My question is what are ideal target ignition advance and AFR values and what range is 'safe'.
From what I've read ignition advance should create a 'valley' (start and end higher and gradually transition down and then up throughout the rev range).
My question is what are ideal target ignition advance and AFR values and what range is 'safe'.
Edited by Rtig on Tuesday 24th December 12:18
Rtig said:
One gains knowledge by asking questions and learning.
Either of you have any actual answers to the question to have a proper discussion, or, just your own opinions as per the usual on PH?
You've already been given the answer.Either of you have any actual answers to the question to have a proper discussion, or, just your own opinions as per the usual on PH?
Get yourself onto a dyno and see what your engine wants. Not what some random person on the internet thinks it might want.
No sense huffing if it isn't the answer you want.
Rtig said:
One gains knowledge by asking questions and learning.
However one needs at least a certain amount of starting knowledge to know which questions to ask. That starting knowledge comes from listening, reading and learning before you even know enough to ask further questions. If you can ask about ignition advance curves without even saying what type of engine it is shows that you don't yet know enough about the subject to even start asking sensible questions. Do you actually think a 2 valve road engine running on pump unleaded would want anything remotely similar in terms of ignition advance to a 4 valve race engine running on 100 octane fuel? What about forced induction or doesn't that matter?Next weekend I fancy doing a bit of amateur brain surgery on my cat to cure him of his habit of biting me. Can anyone give me an idea of where to drill into his head and how deep would be a safe amount? I should add I know nothing about medicine or feline brains but I've got a Black and Decker and a reasonable selection of drill bits. Oh, oh, oh - and what size drill bit please?
DeadCatWalking said:
Rtig said:
One gains knowledge by asking questions and learning.
However one needs at least a certain amount of starting knowledge to know which questions to ask. That starting knowledge comes from listening, reading and learning before you even know enough to ask further questions. If you can ask about ignition advance curves without even saying what type of engine it is shows that you don't yet know enough about the subject to even start asking sensible questions. Do you actually think a 2 valve road engine running on pump unleaded would want anything remotely similar in terms of ignition advance to a 4 valve race engine running on 100 octane fuel? What about forced induction or doesn't that matter?Next weekend I fancy doing a bit of amateur brain surgery on my cat to cure him of his habit of biting me. Can anyone give me an idea of where to drill into his head and how deep would be a safe amount? I should add I know nothing about medicine or feline brains but I've got a Black and Decker and a reasonable selection of drill bits. Oh, oh, oh - and what size drill bit please?
What an arrogant post!
You do not appear to even possess enough basic knowledge or humility to realise when people are trying to point you in the right direction.
Just because the reply given is not the one you want it to be doesn't mean that your toys have to exit the pram.
If you read the replies given you will start to acquire the basics you so obviously lack .
A dyno ,as stated, is the only way to thoroughly map an engine .
You do not appear to even possess enough basic knowledge or humility to realise when people are trying to point you in the right direction.
Just because the reply given is not the one you want it to be doesn't mean that your toys have to exit the pram.
If you read the replies given you will start to acquire the basics you so obviously lack .
A dyno ,as stated, is the only way to thoroughly map an engine .
Boosted LS1 said:
The 3 people who replied all have 'knowledge' and could be quite helpful.
Why don't you start again and inform us of the engine you have, it's state of build and the application it's for?
The engine is a 2.0 tsi (EA888) running breathing mods and currently an extra 6psi of boost at peak over stock on a preset map. Currently the map tapers off boost after 5k where the peak power is, on a standard engine, at 6k.Why don't you start again and inform us of the engine you have, it's state of build and the application it's for?
I would like to know what the typical safe range of ignition advance and AFR is to check against the data logs to see where, if at all, it is possible to add in more boost above 5k.
There are plenty of cars running the same engine, with the JB4, that have only ever seen a rolling road for power runs.
What I'm asking for is information so I can learn and look at it and understand what is going on.
If I can across wrong earlier, sorry, its just any time you ask anything on PH you can guarantee the first answers are "why would you want to do that" type rather than helping people out.
Rtig said:
My original post had the engine etc in it but I changed it to a more general question to try and avoid the standard PH responses and actually find someone with knowledge. Guess that also failed
I don't see any other post from you on this so I guess you are expecting to find people who are not only engine experts but also psychic. Good luck with that. If any of us were psychic we would have claimed the $1 million James Randi Foundation prize and not be bothering to waste our time on stoopid questions in here.Boost is probably tapering off, because the turbo is already flat out and pointless trying to push it further. This would be very apparent if you already looked at logs to see what boost control etc is doing.
But again it all comes back to the same thing. That you need to dyno your car/setup to see what will work best for it, and whatever you are trying to achieve with the parts you have.
Only a crazy person would start throwing timing numbers out to some random person who wishes to just randomly add more timing/boost etc to their own car, with no actual means of testing etc etc or without full in depth knowledge of tuning either their ecu and car.
You are asking for trouble, when you can just go to dozens of tuners who will hopefully already have done all this testing with experienced people and facilities....and you just buy the results from them and load them to your car.
But if you want a number.....42
But again it all comes back to the same thing. That you need to dyno your car/setup to see what will work best for it, and whatever you are trying to achieve with the parts you have.
Only a crazy person would start throwing timing numbers out to some random person who wishes to just randomly add more timing/boost etc to their own car, with no actual means of testing etc etc or without full in depth knowledge of tuning either their ecu and car.
You are asking for trouble, when you can just go to dozens of tuners who will hopefully already have done all this testing with experienced people and facilities....and you just buy the results from them and load them to your car.
But if you want a number.....42
for a well designed naturally aspirated engine on pump fuel like 98RON 12.5:1 should be safe at maximum hp rpm at WOT pretty much universally
the timing is highly engine dependant i dont agree with the OP comment about a valley. the target is MBT, ideally the engine isnt knock limited but often this is not the case so you just look to avoid knock with a safety margin. how long is a piece of string? some engines will want upto max 38-42 or more degrees at WOT others as low at 20-24* depending on the combustion chamber shape and size and how much mixture motion and about half a dozen or more other variables.
the timing is highly engine dependant i dont agree with the OP comment about a valley. the target is MBT, ideally the engine isnt knock limited but often this is not the case so you just look to avoid knock with a safety margin. how long is a piece of string? some engines will want upto max 38-42 or more degrees at WOT others as low at 20-24* depending on the combustion chamber shape and size and how much mixture motion and about half a dozen or more other variables.
Edited by Inline__engine on Tuesday 24th December 23:32
Inline__engine said:
for a well designed naturally aspirated engine on pump fuel like 98RON 12.5:1 should be safe at maximum hp rpm at WOT pretty much universally
the timing is highly engine dependant i dont agree with the OP comment about a valley. the target is MBT, ideally the engine isnt knock limited but often this is not the case so you just look to avoid knock with a safety margin. how long is a piece of string? some engines will want upto max 38-42 or more degrees at WOT others as low at 20-24* depending on the combustion chamber shape and size and how much mixture motion and about half a dozen or more other variables.
But he's asking about a boosted engine...where getting numbers wrong by only a few degrees, will result in him wishing he never attempted anything, as his engine will be dead lol.the timing is highly engine dependant i dont agree with the OP comment about a valley. the target is MBT, ideally the engine isnt knock limited but often this is not the case so you just look to avoid knock with a safety margin. how long is a piece of string? some engines will want upto max 38-42 or more degrees at WOT others as low at 20-24* depending on the combustion chamber shape and size and how much mixture motion and about half a dozen or more other variables.
Edited by Inline__engine on Tuesday 24th December 23:32
When it's a market/engine/platform already catered for aplenty......it's hard to imagine how he feels he will improve upon what is already offered as tried, tested and safe options
didnt get that far.
a shop experienced in that particular engine will be the best people to ask, there are of course people who armed with a laptop and the right software suddenly think they are tuners so need to be mindful of asking the right people
a shop experienced in that particular engine will be the best people to ask, there are of course people who armed with a laptop and the right software suddenly think they are tuners so need to be mindful of asking the right people
Edited by Inline__engine on Wednesday 25th December 00:06
Like all things "tuning" it's far better to try to understand the underlying physical principals rather than ask generic questions.
So, let me ask a question "why do we even need to change the point at which the fuel / air mass is lit"??
Have a think about that, and you're halfway (or more) to your answer!
So, let me ask a question "why do we even need to change the point at which the fuel / air mass is lit"??
Have a think about that, and you're halfway (or more) to your answer!
Max_Torque said:
Like all things "tuning" it's far better to try to understand the underlying physical principals rather than ask generic questions.
So, let me ask a question "why do we even need to change the point at which the fuel / air mass is lit"??
Have a think about that, and you're halfway (or more) to your answer!
Because for maximum effect from the combustion it would need to be completed shortly after tdc to provide maximum downward "push" on the piston. So, in theory the higher the engine speed the earlier the spark needs to be as the whole process will be happening quicker? So, let me ask a question "why do we even need to change the point at which the fuel / air mass is lit"??
Have a think about that, and you're halfway (or more) to your answer!
With a higher boost and therefore fuel in the mid range would the mixture burn quicker therefore needing less advance than what is needed at the higher RPM range?
Thinking about it a little bit further, if the mixture is too lean (caused by too much of an increase in boost and the ECU cant provide enough fuel) the mixture would burn faster and complete its combustion too early? If I'm thinking this correctly that would show in logging as the ignition advance decreasing rapidly as it had detected knock?
Thanks Max_torque for your response and question
Thanks Max_torque for your response and question
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