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prometey1982
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« Reply #2445 on: December 24, 2023, 12:07:22 AM »
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got an interesting read today.
later 2004 2.5t with fps / pem running the 50QKHJ never seen that on a non 04R
USA facelift 2.5T always has PEM. Funny than you didn't know it. |
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s60rawr
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« Reply #2446 on: December 24, 2023, 01:35:50 AM »
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USA facelift 2.5T always has PEM. Funny than you didn't know it.
no, this is not facelift software. MY05+ is facelift QKHJ is software 250can similar to what u prolly know as qhhj naming conventions from EU / US are a bit different. the 2007 date in the bin is a 2007 update for the 04 only QKHJ software |
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« Last Edit: December 24, 2023, 01:53:03 AM by s60rawr »
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s60rawr
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« Reply #2447 on: December 24, 2023, 01:43:11 AM »
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USA facelift 2.5T always has PEM. Funny than you didn't know it.
most the 2004 2.5t i ripped were a 40LNHJ / 40LRHJ without pem and fuel pressure sensor 04 is a first year 2.5t 250 can 05+ in the states are "Facelift" and 500can |
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« Last Edit: December 24, 2023, 02:06:07 AM by s60rawr »
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dikidera
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« Reply #2448 on: December 28, 2023, 02:51:12 AM »
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Here is my intake VVT map tuned on dyno. I've got 440 bhp. But it looks like dyno stand lowered the result because I've got only 220 bhp on 1 bar of boost (spring pressure boost with 0 ldtvm).
Are those negative numbers indicating the VVT retarding by that many degrees? |
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keichi
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« Reply #2449 on: December 28, 2023, 05:27:49 AM »
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Are those negative numbers indicating the VVT retarding by that many degrees?
It's rather the other way (other way then ignition for example). Negative valves open earlier, positive later. To achieve the best torque you open intake valves sooner on low rpm and later on high. |
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dikidera
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« Reply #2450 on: December 28, 2023, 05:55:58 AM »
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I was asking because from what I see on the non turbo versions, there are no negative values, it's either no advance(0 degrees at very high RPM) or maximum advance of 40 degrees in low rpm as you said for better torque.
But the values I have are all positive, never negative so I was just surprised. But hey, different ecus and different reference points.
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« Last Edit: December 28, 2023, 06:11:34 AM by dikidera »
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prj
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« Reply #2451 on: December 28, 2023, 06:12:53 AM »
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On NA you don't have any significant backpressure that you need to deal with.
The reason that on turbo you have to retard the intake cam a lot on high rpm is that if you have overlap then EMP makes cylinder filling drop off a cliff, as during the overlap phase it pushes exhaust backwards into the intake, and then back into the cylinder.
When pushing high EMP at high RPM even the exhaust cam tuning can make quite a lot of difference as it further allows you to reduce the overlap.
You really need to understand the combustion process and the function of the engine. Looking at the ECU like an excel spreadsheet makes very little sense when the fundamentals are not there.
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dikidera
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« Reply #2452 on: December 28, 2023, 06:39:13 AM »
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You are right, but I am not looking at it as an excel spreadsheet, more like from a programmer's point of view. Probably makes little difference though, but little by little I am learning stuff. https://imgur.com/fqHwy6qI am sure in the future I will learn plenty more. |
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« Last Edit: December 28, 2023, 06:48:29 AM by dikidera »
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prj
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« Reply #2453 on: December 28, 2023, 08:16:59 AM »
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You are right, but I am not looking at it as an excel spreadsheet, more like from a programmer's point of view. The engine is not a computer. I'd put down IDA and get some engine fundamentals in. Once you understand why things are the way they are then everything starts to make much more sense and becomes much easier to find order in the chaos. |
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prometey1982
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« Reply #2454 on: December 28, 2023, 08:49:48 AM »
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There are VVT intake tuned on dyno (by me) and VVT exhaust from other man who tuned it on dyno.
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prometey1982
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« Reply #2455 on: December 28, 2023, 08:59:43 AM »
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I was asking because from what I see on the non turbo versions, there are no negative values, it's either no advance(0 degrees at very high RPM) or maximum advance of 40 degrees in low rpm as you said for better torque.
But the values I have are all positive, never negative so I was just surprised. But hey, different ecus and different reference points.
Denso can has different centerpoint. For Bosch ECM with 2 VVT is 25 degrees. So -25 means 0 shift from startpoint. Looks like for Denso 0 means zero shift i.e. maximum advance. And if your want to choose the best VVT positions then you should run on dyno with 0, 10, 20, 30, 40, 50 VVT positions and then choose best values for the RPM range. |
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prj
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« Reply #2456 on: December 28, 2023, 09:05:23 AM »
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Unless the engine is highly modified it is a waste of time because stock map is already going to be tuned for best power at high rpm. If the engine is not DI, low RPM won't be tuned for best power, but tuning it for best power will result in absolutely insane fuel consumption and cat fouling because you'll be dumping straight fuel into the exhaust. An extreme example is the MIVEC in the later Mitsubishi Evo's where the range is large and advancing the camshaft at low RPM results in having to add 25-30% fuel, because a bunch of it just goes right into the exhaust. The fuel consumption is also more similar to a V8 than a R4 after that  |
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prometey1982
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« Reply #2457 on: December 28, 2023, 09:37:53 AM »
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Unless the engine is highly modified it is a waste of time because stock map is already going to be tuned for best power at high rpm.
If the engine is not DI, low RPM won't be tuned for best power, but tuning it for best power will result in absolutely insane fuel consumption and cat fouling because you'll be dumping straight fuel into the exhaust.
In case of Volvo's turbo engines they are tuned not propertly from the factory. I ran on dyno with different VVT positions and stock intake VVT positions isn't optimal. They move from -25 to 0 too early. And in high RPM range they move camshaft also not optimal. Need more retard. Exhaust VVT maps which I posted also helps to add torque in low RPM range. Это чувствуется пятой точкой) |
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prj
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« Reply #2458 on: December 28, 2023, 09:44:04 AM »
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The reason is tradeoff between efficiency and power.
The more overlap you add on low RPM on non-DI engine the more fuel goes in the exhaust.
Also in your case as I understand engine is not stock - turbo is not stock.
The bigger the turbo is, the more benefit you have keeping advance for longer.
If you log EMP by adding a sensor and then empirically find the optimal advance, you will find that EMP and advance have a very strong correlation.
Larger turbo -> less EMP -> can advance longer.
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« Last Edit: December 28, 2023, 09:45:41 AM by prj »
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prometey1982
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« Reply #2459 on: December 28, 2023, 12:34:07 PM »
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Also in your case as I understand engine is not stock - turbo is not stock.
The bigger the turbo is, the more benefit you have keeping advance for longer.
If you log EMP by adding a sensor and then empirically find the optimal advance, you will find that EMP and advance have a very strong correlation.
Larger turbo -> less EMP -> can advance longer.
Engine is stock excepts intake manifold. Turbo isn't stock but I got similar results on stock turbo and stock engines on other cars. What does EMP means? |
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