HSV Dyno day Oct SRR
Discussion
monkfish1 said:
ringram said:
9 degrees is a lot. FI on stock NA compression isnt a good recipe, its a compromise which more people are realising. This illustrates nicely the concept of being knock limited.
All FI setups on stock engines are knock limited. Even with no knock registered power gains are limited by the fact that timing is reduced to avoid knock.
Therefore timing moves further and further away from Mean Best Timing (MBT)
Very misleading Richard. Its got knock because it has a problem, not because its supercharged. Fix the problem and it will be OK. All FI setups on stock engines are knock limited. Even with no knock registered power gains are limited by the fact that timing is reduced to avoid knock.
Therefore timing moves further and further away from Mean Best Timing (MBT)
ringram said:
I have reread the comment you quoted squire Keys and the entire piece is talking about FI on stock engines being knock limited.
That is the statement you said was misleading. However it is not.
The knock retard is a symptom of the problem. Lower octane fuel is only exacerbating the issue. With high octane fuel the issue is still there. Timing is set well away from MBT to avoid knock. That has a follow on effect of reducing power from the theoretical level.
Intake temp also further aggravates the issue. I refer you to page 2 of the article. It states the factors all of which were present in the car on the day which lead to knock retard.
But Im talking about being knock limited in general. Not the knock retard on the day. That was the statement you quoted and has nothing misleading in it at all. Can you point out the specific statement or error please as I would genuinely like to know.
Mr ARAF for your elucidation the answer is in black and white above. I have typed what the issue is and linked to a detailed article explaining not only MBT and Knock Limited theory. But also factors that affect knock and mitigations etc. The fixes and answers are all there.
Still incorrect. The very first statement was the 9 degrees was a lot of retard (true). The knock retard of 9 degrees has nothing to do with any of the above, and everything to do with the fact the car has a problem. The issue with this car is NOT what you have stated.That is the statement you said was misleading. However it is not.
The knock retard is a symptom of the problem. Lower octane fuel is only exacerbating the issue. With high octane fuel the issue is still there. Timing is set well away from MBT to avoid knock. That has a follow on effect of reducing power from the theoretical level.
Intake temp also further aggravates the issue. I refer you to page 2 of the article. It states the factors all of which were present in the car on the day which lead to knock retard.
But Im talking about being knock limited in general. Not the knock retard on the day. That was the statement you quoted and has nothing misleading in it at all. Can you point out the specific statement or error please as I would genuinely like to know.
Mr ARAF for your elucidation the answer is in black and white above. I have typed what the issue is and linked to a detailed article explaining not only MBT and Knock Limited theory. But also factors that affect knock and mitigations etc. The fixes and answers are all there.
My point was and still is, that the knock limited theory has nothing to do with the gentlemans car. The commanded timing on this car should allow it to run with NO knock retard. Even at high AIT's. Sadly it suffered knock retard of significant proportions.
If you were correct, all the other cars with similar setups would have suffered in the same way. They did not. I know this because I logged many of them, as indeed i logged this particular car.
Once this car is fixed, it will quite happily run with the commanded timing and make the power one would expect from this combo.
ringram said:
Mr ARAF for your elucidation the answer is in black and white above. I have typed what the issue is and linked to a detailed article explaining not only MBT and Knock Limited theory. But also factors that affect knock and mitigations etc. The fixes and answers are all there.
I've got a lot of time for both you and Roger, Richard. However, I can't see that the problem on this car is merely poor fuel and the heat pulling the timing, - so IMHO, you and Roger working together to solve the riddle would be more constructive than the last few posts.
just putting this out there, if it was built by either WP or Wortec originally I doubt the tune will be the problem. Could it just be down to a f
ked knock sensor or something triggering it? When Tuna Bee fked my Long tubes up originally they vibrated trigging KR and dropping to base timing.
Howver if it was hammered together by the smelly prawn fingers.... who did the build?
Garry, it isn't going to grenade itself - if you need a runaround the beemers there but you'll cry when you hhand it back
ked knock sensor or something triggering it? When Tuna Bee fked my Long tubes up originally they vibrated trigging KR and dropping to base timing.Howver if it was hammered together by the smelly prawn fingers.... who did the build?
Garry, it isn't going to grenade itself - if you need a runaround the beemers there but you'll cry when you hhand it back
Wyld Stallyn said:
Meanwhile on a more sensible note:
If I got 377..2 RWHP
How do I Work out the Fly BHP?
You guess! If I got 377..2 RWHP
How do I Work out the Fly BHP?
Add 120 ish is about as good as it gets.Using the basis that on Charlies dyno a stock LS2 monaro will turn in about 285-290 bhp at the wheels for a 400 flywheel engine. Obviously, drivetrain loss is a percentage, so apply similiar to your numbers. VXR8's seem to fair a little better.
Tattooboy said:
Wyld Stallyn said:
Meanwhile on a more sensible note:
If I got 377..2 RWHP
How do I Work out the Fly BHP?
I wouldn't bother, only people who want bigger numbers work out a fictional number !If I got 377..2 RWHP
How do I Work out the Fly BHP?
stigmundfreud said:
just putting this out there, if it was built by either WP or Wortec originally I doubt the tune will be the problem. Could it just be down to a fked knock sensor or something triggering it? When Tuna Bee fked my Long tubes up originally they vibrated trigging KR and dropping to base timing.
Howver if it was hammered together by the smelly prawn fingers.... who did the build?
Garry, it isn't going to grenade itself - if you need a runaround the beemers there but you'll cry when you hhand it back
We built it i believe stig. Saw EXACTLY this on an LS1 where the knock sensor wire was trapped against the valley plate. Was fine until you went full load. Then it went knock crazy. Numbers that simply cant be. And these numbers simply cant be real. These are the things that need looking at on this car. As i discussed with the owner when trying to give helpful advice.ked knock sensor or something triggering it? When Tuna Bee fked my Long tubes up originally they vibrated trigging KR and dropping to base timing.Howver if it was hammered together by the smelly prawn fingers.... who did the build?
Garry, it isn't going to grenade itself - if you need a runaround the beemers there but you'll cry when you hhand it back
monkfish1 said:
Still incorrect. The very first statement was the 9 degrees was a lot of retard (true). The knock retard of 9 degrees has nothing to do with any of the above, and everything to do with the fact the car has a problem. The issue with this car is NOT what you have stated.
My point was and still is, that the knock limited theory has nothing to do with the gentlemans car. The commanded timing on this car should allow it to run with NO knock retard. Even at high AIT's. Sadly it suffered knock retard of significant proportions.
If you were correct, all the other cars with similar setups would have suffered in the same way. They did not. I know this because I logged many of them, as indeed i logged this particular car.
Once this car is fixed, it will quite happily run with the commanded timing and make the power one would expect from this combo.
Ok I think I see the discrepancy. I stated FI is knock limited on the stock engine. Sounds like you are not challenging that. Lets keep that statement separate. As the debate seems to be between 2 things. Though I believe they are related as Ill try and explain.My point was and still is, that the knock limited theory has nothing to do with the gentlemans car. The commanded timing on this car should allow it to run with NO knock retard. Even at high AIT's. Sadly it suffered knock retard of significant proportions.
If you were correct, all the other cars with similar setups would have suffered in the same way. They did not. I know this because I logged many of them, as indeed i logged this particular car.
Once this car is fixed, it will quite happily run with the commanded timing and make the power one would expect from this combo.
The challenge was that Gary's specific issue is not to do with that fact. I would agree totally that if he had run the right fuel he may well have not experienced the issue noted. Timing would have been close or at commanded as you say (except iAT) and power would have gone up. This I agree with and of course its not debatable as you point out many others had no such issue.
My statement was that being knock limited FI is going to have issues with the relevant factors in a far more sensitive manner than stock. Even FI commanded timing is not MBT timing. MBT sits further into the area of knock. But you cant go there for obvious reasons, hence tuning results in lower than stock timing values in order to avoid knock and get the best power possible.
Being knock limited means knock occurs before power falls with advancing timing. FI is very sensitive to these factors because it is knock limited. That is the point Im making. Yes you can alleviate some of the factors, but you cant change the fact that due to pressures, temperatures etc the engine is knock limited in power development.
If Gary had alleviated the problem by running the right fuel he may have avoided the knock on the dyno and got the same numbers as everyone else. Im not arguing that point. I accept it totally.
So yes there are 2 separate points. 1. The cause of Gary's knock (likely fuel) and 2. The theory of knock limited engines. (Which fuel octane helps address)
monkfish1 said:
You guess! Add 120 ish is about as good as it gets.
Using the basis that on Charlies dyno a stock LS2 monaro will turn in about 285-290 bhp at the wheels for a 400 flywheel engine. Obviously, drivetrain loss is a percentage, so apply similiar to your numbers. VXR8's seem to fair a little better.
120hp is nearky 90kW Add 120 ish is about as good as it gets.Using the basis that on Charlies dyno a stock LS2 monaro will turn in about 285-290 bhp at the wheels for a 400 flywheel engine. Obviously, drivetrain loss is a percentage, so apply similiar to your numbers. VXR8's seem to fair a little better.
yep it does seem to be the case as no way would a base spark be that retarded, fingers crossed its a simple fix
in other good news I found out my brake pressure sensor is fcked hence the inability to disable active handling. In bad news I got a call during the service asking for 168 for an air filter, ONE HUNDRED AND SIXTY EIGHT, I laughed and said I can get a CAI for less, 168
you need to start offering corvette servicing!
in other good news I found out my brake pressure sensor is fcked hence the inability to disable active handling. In bad news I got a call during the service asking for 168 for an air filter, ONE HUNDRED AND SIXTY EIGHT, I laughed and said I can get a CAI for less, 168
you need to start offering corvette servicing!
ringram said:
I stated FI is knock limited on the stock engine.
I don't understand how that can be true when it depends on so many factors: fuel, IATs, compression ratio/boost? Low boost is fine on a stock, supercharged engine and you get less heat and excellent drivability.I've seen low rpm/WOT knock in my own car in summer and all it turned out to be was crap fuel. On Optimax, I never see any knock retard.
Edited by anonymous-user on Monday 20th October 21:16
MyM8V8 said:
Gary H 2008 said:
Maybe raise the rev limit just for one run?
And raise the limiter? Yes, but only if you have the balls to match (mines up to 7K now).
ringram said:
Ok I think I see the discrepancy. I stated FI is knock limited on the stock engine. Sounds like you are not challenging that. Lets keep that statement separate. As the debate seems to be between 2 things. Though I believe they are related as Ill try and explain.
The challenge was that Gary's specific issue is not to do with that fact. I would agree totally that if he had run the right fuel he may well have not experienced the issue noted. Timing would have been close or at commanded as you say (except iAT) and power would have gone up. This I agree with and of course its not debatable as you point out many others had no such issue.
My statement was that being knock limited FI is going to have issues with the relevant factors in a far more sensitive manner than stock. Even FI commanded timing is not MBT timing. MBT sits further into the area of knock. But you cant go there for obvious reasons, hence tuning results in lower than stock timing values in order to avoid knock and get the best power possible.
Being knock limited means knock occurs before power falls with advancing timing. FI is very sensitive to these factors because it is knock limited. That is the point Im making. Yes you can alleviate some of the factors, but you cant change the fact that due to pressures, temperatures etc the engine is knock limited in power development.
If Gary had alleviated the problem by running the right fuel he may have avoided the knock on the dyno and got the same numbers as everyone else. Im not arguing that point. I accept it totally.
So yes there are 2 separate points. 1. The cause of Gary's knock (likely fuel) and 2. The theory of knock limited engines. (Which fuel octane helps address)
Which is what i said. Im glad you now see the "discrepancy".The challenge was that Gary's specific issue is not to do with that fact. I would agree totally that if he had run the right fuel he may well have not experienced the issue noted. Timing would have been close or at commanded as you say (except iAT) and power would have gone up. This I agree with and of course its not debatable as you point out many others had no such issue.
My statement was that being knock limited FI is going to have issues with the relevant factors in a far more sensitive manner than stock. Even FI commanded timing is not MBT timing. MBT sits further into the area of knock. But you cant go there for obvious reasons, hence tuning results in lower than stock timing values in order to avoid knock and get the best power possible.
Being knock limited means knock occurs before power falls with advancing timing. FI is very sensitive to these factors because it is knock limited. That is the point Im making. Yes you can alleviate some of the factors, but you cant change the fact that due to pressures, temperatures etc the engine is knock limited in power development.
If Gary had alleviated the problem by running the right fuel he may have avoided the knock on the dyno and got the same numbers as everyone else. Im not arguing that point. I accept it totally.
So yes there are 2 separate points. 1. The cause of Gary's knock (likely fuel) and 2. The theory of knock limited engines. (Which fuel octane helps address)
I disagree that 95 octane fuel would give this result, though if it was exceptionally poor i guess its possible. But unlikely. I have done one or two FI engines in my time on which to base my advice.............
ARAF said:
stigmundfreud said:
in other good news I found out my brake pressure sensor is fcked hence the inability to disable active handling.
I hope you're not having it fixed on the premise that pressing the button before parking means you can use the spaces reserved for blue badge holders. )Gassing Station | HSV & Monaro | Top of Page | What's New | My Stuff