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Location: Sydney
Registered: July 2002
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Tuning day
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Sun, 25 May 2003 02:22
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Did a tuning day on friday! Was freaking awesome.
Power went from 112 to 157 - 40% increase! Didn't even change the ignition, just got the mixtures right!
I'm not going to say what unit of measurement those power figures are from because its not comparable between dynos. 40% increase is the number to look at!
Nearly had an accident last night as I tried to get around a truck, but put my foot down early and the car leapt to life! nearly ran into the back of the truck as I wasn't ready for the power. Did a quick whip around and it took off like a rocket!
Oh also, the redline is around the 7,200 mark now. Engine EASILY goes up and over 7k! Sounds like a racecar too!
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Sun, 25 May 2003 04:14

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That's awesome Pete, what air fuel ratios where you running at the begining of the tune and what where they at the end?
I take it it was massively too rich?
Wait till you start throwing in some ignition timing, BIG improvement then!!! 5deg netted me 30rwhp on the top end
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Sun, 25 May 2003 04:54

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Paul, I don't know what we were running at the start of the day. At the end of the day it was pretty constant 12.5-12.6 (What I can gather from watching) on load, and 14.7 on cruise and up to 70% MAP.
We added some timing down low as I could feel it was too sluggish even though it was the right mixtures. I think there still needs to be 1 or 2 more degrees around the 3,000->4,500 mark.
We had already put a fair bit of timing in last time, so this time we were just making the mixtures for that change right.
Will have an extra tuning day to add some more timing and get another maybe 10-20% increase. I don't think there is much more possible with this engine as standard.
What mixtures you usually aim for? I know running a turbo you've gotta run it more rich.
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Sun, 25 May 2003 05:37

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12.4 to 12.6 is what I aim for too. With NA's you can head towards 13.1 without an issue but it depends on how much timing your running and if it's prone to detonation which the 1UZ should be.
By running big ignition timing at 13:1 af, which puts it close to detonation you can then bring the af ratio down further to say 12.5:1 and stave off the detonation with the extra fuel which removes heat from the intake charge.
That's maybe what your tuner is doing. It's best to do timing to the point of detonation first and then add fuel to give you the safety margin and drop back the timing 1 or 2 degrees then you'll be running at optimum with a safety.
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Sun, 25 May 2003 08:34

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The way we've been doing it - we because I do the driving and he does the logging on the laptop and changes the maps etc. is that we increase the timing, then get the fuel right (stop pinging etc.) then increase it more, then get the fuel right, then more timing. Big repetetive process.
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Sun, 25 May 2003 09:36

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You should only have to set the fuel once though Pete. Have a target AF ratio and tune to it. Advance your timing to detonation point, bring it back a safety margin and add a few more points of AF ratio and your done
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Sun, 25 May 2003 10:58

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Yeah but getting it to that point to set it once you need to know how far you can go.
Increasing the timing to detonation without using the right AF it will detonate too early. You need to take it all the way so that when you've got the right AF and it still detonates, that is where you bring it back a bit. And also setup the knock sensor so it does its job properly.
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Sun, 25 May 2003 11:33

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Yep, i see what you mean.
Knock sensors are only used in open loop or cruise conditions only though. So you have to setup the full load tuneing correctly as the ECU looks to these maps for ign timing regardless.
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Sun, 25 May 2003 11:41

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I'm not an expert, but I thought that when looking at the logs of a tuning run when we were testing full load (MAP 100%) I'm sure we could see if it was knocking during this power run. When it does detect a knock it retards the timing depending on the size of the knock (can set the range, I think we set the max retard is about 8 degrees).
How would you know if the full load timing was at its limit if you couldn't detect it knocking?
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Tue, 27 May 2003 09:53

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There hasn't been an engine yet that I know of that has been released that used closed loop knock detection on whilst on "load".
That's because knock sensors are merely ultrasonic piezo shock sensors on the block. They pick up noises accross a certain bandwidth and the ECU then retards the timing the preset amount but only in "cruise" conditions.
This is perfect for the manufacturers. Eg you are cruising aloung the freeway at 110km/h, light throttle. The ECU goes into cruise mode, lean's off the fuel by monitoring the O2 sensor and simultaneously advances the timing to the point of detonation and then retards it by a few degrees. It then does this over 50 times a second. More timing = more power as you know so effectively you'll get the most power possible from a comparatively small amount of fuel.
This can't be done on "load" or above a certain RPM as the engine makes too much mechanical noise from things like the valves, pistons etc that is within the sensors bandwidth.
That's why the ignition maps are there, otherwise it would never need them. You could simply let the closed loop go on the knock sensors and it would always run to the most advance you could have with that fuel, that intake air, etc.
The ignition and fuel lookup tables are their cause they are safe and tested values programmed by the engineers at the factory. They are also conservative, which is where many of us can tinker and get some decent gains
Holden Commodores disregard knock sensor input above 3500rpm because there is too much mechanical noise.
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Location: Central Coast, NSW
Registered: May 2002
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Re: Tuning day
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Tue, 27 May 2003 22:46

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and thats why i don't own a commodore!
Dan
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I supported Toymods
Location: Perth
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 01:09

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Okay, I understand where you're coming from (particularily with the Commodore ), but explain this.
BMW's 330Ci makes 170kW, using 98RON petrol. According to them it will run fine on 92RON petrol, but it will not be making max power.
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Wed, 28 May 2003 02:21

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Paul,
I've got my tuning logs on my computer now, and I can definately say that it can detect knocking while on load. Its not in closed loop on load as it won't learn more ignition.
But it definately does show knock on load. From this we can tell if it can handle more ignition or not.
If you want you can drop in and I'll show you the program. Problem is I'm not sure on the copyright of it so I don't think I should send it to you.
Problem is it changes screen modes when displaying, so I can't take a bloody screenshot! Grrr.
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 04:56

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Frankie, that's because the fuel is more dense. Ie in 1ml of higher octane fuel there is more energy stored. If you get 40L of Optimax and weigh it against 40L of normal fuel the Opti will weigh more cause its more dense, which = more power. That's without advancing the timing. The higher octane fuel can also be advanced more and you can get more out of it.
Pete,
I know what you mean Pete but what i'm saying is it's not wise to set yours up to use the knock sensor on closed loop because it will be false triggering from engine noise instead of knock.
If you want to do it that way, delete all the ignition maps and run it off the knock sensor.
That's why no factory car in the world does it. All the engineers in the world must know something if they're all doing it.
Tune it with the knock sensor's and lock those ignition values in but don't drive around "on load" in closed loop. You wont be making as much power as you potentially could.
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I supported Toymods
Location: Perth
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 05:02

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I get that too. Running higher octane fuel without increasing the timing to account for it actually costs power. On the other hand, leaving the timing high would just cause the engine to ping, and thats different to a reduction in power. Then you say with the higher octane you can advance to make more power, but how does it know it has higher octane and can advance it?
What you're saying is valid, but it still doesn't answer my question.
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 06:08

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I hope I don't sound condescending in my explanations guys, just trying to explain without giving every finite detail.
There's two main aspects of fuel. Octane and density.
Think of them both separatly.
Density- If you have an engine with a fixed full load timing of say 20deg adv on normal unleaded. You then put Optimax in, it will produce more power because it is more dense. If its more dense it therefore contains more power per ml, pushing the piston down harder.
That's why you will get a gain in power without adjusting the timing.(It's only small though)
Octane- Its basically its resistance to ignition, whether it be from detonation or from the spark plug. You put in normal fuel again and on full load(say 10psi) your ECU will look up it's pre-determined ignition values that were determined at the factory by the engineers. They tune deliberatly on basically lowest common grade fuel you can get at the pump so the engine performs well and doesn't detonate on full load otherwise they'd have engine's being destroyed all over the place.
(This is where aftermarket ECU's rock cause you set all these values) Like Draven's 1jz pulling 183Rwkw on stock boost.
Now, in closed loop(light throttle, <3500rpm, highway conditions) the knock sensors are used and the ignition is continually advanced to detonation point and dropped back again. In closed loop therefore you will get more power.
Hope this answers it Frankie,
[Updated on: Wed, 28 May 2003 06:11]
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I supported Toymods
Location: Perth
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 06:17

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Every test I've seen where a "higher-octane" fuel is put in place of a lower one a big swag of power has been lost, not gained, the density had a much lesser impact. Problem with what you are saying is that maximum power is not made under closed loop, so that argument doesn't make sense. I was under the assumption they were aiming for stoichiometric AF ratios and highly advanced ignition under closed loop, but thats as outlined above, different to maximum power.
I understand the closed loop explanation perfectly, and that of engine noise, but you basically re-wrote what you said in the first place. If the engineers put it in the ignition tables accounting for the lowest common denominator, then why would they bother to claim their max power is only produced at a higher octane level? In that case their max power would only be the same as that on the lower octane.
I think what you're getting is that they're not using knock sensors to determine the octane rating, but in that case what is going on? You still haven't explained the question, you just wrote in more words what you originally said.
I'm not having a go dude, its just I'm no clearer as to how they're doing it than I was in the first palce
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Wed, 28 May 2003 06:46

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Paul,
Using closed loop on load and letting the computer add in more timing (I don't know if computers actually add in more timing, or just get the fuel to be closer to a set ratio) is silly.
But not using a knock sensor to find out if an engine is pinging while on load, how do you tune?? How do you know if you can increase the timing more?
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Location: North Sydney
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 08:08

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Quote: | Every test I've seen where a "higher-octane" fuel is put in place of a lower one a big swag of power has been lost, not gained, the density had a much lesser impact.
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Frankie,
I've haven't seen any graph's where you loose power with higher octane fuel so I can't comment but I don't see why you would loose lots of power, its strange.
Quote: | Problem with what you are saying is that maximum power is not made under closed loop, so that argument doesn't make sense. I was under the assumption they were aiming for stoichiometric AF ratios and highly advanced ignition under closed loop, but thats as outlined above, different to maximum power.
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That's right max power isn't made on close loop, it's too dangerous, particularly when sensors can fail. Yes they do go for stoich and max timing in closed loop.
Quote: | If the engineers put it in the ignition tables accounting for the lowest common denominator, then why would they bother to claim their max power is only produced at a higher octane level?
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I don't know why they say 7MGTE Supra 173Kw on high octance fuel. I've never really seen them state a power rate that can only be acheived on a high octane fuel. Perhaps they are urging drivers to use higher octane fuels as much as possible, they are always cleaner and better for the longevity of the engine anyway.
Higher octane fuels usually have more density as they are a more refined fuel, that could be the reason, the more density gives the extra power (would be slight, but still a gain)
Quote: | I think what you're getting is that they're not using knock sensors to determine the octane rating, but in that case what is going on?
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They don't use knock sensors to determine octane rating. They are used to sense detonation occuring only at light throttle conditions and retard the timing. Octane rating is only one of a few reasons for detonation like intake air temp, which you can't control as you can with what fuel you put in your tank.
Pete,
using closed loop whilst on load is silly, as you just said but you were saying earlier
Quote: | when we were testing full load (MAP 100%) I'm sure we could see if it was knocking during this power run. When it does detect a knock it retards the timing depending on the size of the knock (can set the range, I think we set the max retard is about 8 degrees).
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I thought you were saying that you've set it up to retard the timing when it detects knock on full load above. I think you mean, in closed loop it can retard the timing up to 8 degrees if it detects knock.
Damn thats alot of text! Sore arms now, hehehe
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I supported Toymods
Location: Perth
Registered: May 2002
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Re: Tuning day
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Wed, 28 May 2003 08:14

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T'sall good dude.
I'll have to look into it more once these assignments are over.
The most recently I saw it was in a Zoom article. They were testing high-octane fuels, only I had seen it before.
The car was a BMW 330Ci, when they first released their 170kW 3l six. Its in a MOTOR mag somewhere, but alas, as my magazine collection gets bigger and bigger, things become harder and harder to find. I really need a new room just to store my magazines in Its like an addiction, least it'll only send me broke instead of killing me
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Location: Sydney
Registered: July 2002
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Re: Tuning day
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Wed, 28 May 2003 12:55
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SUPRAGTE wrote on Wed, 28 May 2003 18:08 | Pete,
using closed loop whilst on load is silly, as you just said but you were saying earlier
Quote: | when we were testing full load (MAP 100%) I'm sure we could see if it was knocking during this power run. When it does detect a knock it retards the timing depending on the size of the knock (can set the range, I think we set the max retard is about 8 degrees).
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I thought you were saying that you've set it up to retard the timing when it detects knock on full load above. I think you mean, in closed loop it can retard the timing up to 8 degrees if it detects knock.
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The point I was making was that you CAN detect knocking on full load. The computer automatically retards the ignition to stop the knocking - ON FULL LOAD, not just in closed loop!
When it does knock on full load and correct AF ratios THAT is where the maximum ignition advance is.
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