How will a Steeda Timing Adjuster effect the 4.6 engine
08-31-2005, 12:16 AM
#1
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How will a Steeda Timing Adjuster effect the 4.6 engine
There has been some discussion on another thread about how timing adjusters will effect the 4.6 engine.I think the adjusters only change spark timing,others say that it will change fuel delivery.I don't know everything so I would like to learn.Anyone that can educate an old graybeard will be listened to.
08-31-2005, 01:44 AM
#2
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RE: How will a Steeda Timing Adjuster effect the 4.6 engine
1. Crank sensor on MOD motor is 50 degreese before missing tooth, which is lined up with TDC. Steeda adjuster varies this position of 50 degrees up and down.
2. Crank position is used by ECM to determine RPM, and position of the crank shaft, and thus position of cylinders in relationship to TDC of 1st cylinder. This information is critical to deliver precise ignition and injection events.
3. This timing adjuster works by falsifying this information, it tells ECM this cylinder is at 10 BTDC while in reality this cylinder is at 20 BTDC, thus if there is event in ignition map at that rpm and throttle and 10 BTDC, ignition will fire, computer thinks it's firing at 10 BTDC, but in reality it is 20 BTDC. That's how ignition timing is adjusted. An ignition map itself has highs and lows. What this adjuster is doing is rasing or lowering the entire map by one single number. Generally, with a stock map you could advance very little at idle, but you could advance (and thus make more power) a lot as rpm increases. Since you adjusting the entire map with one number, you are limited to that very little increase before you get knock at idle.
4. Injection will be screwed up in a similar way. If event is set to fire injector at 20 BTDC, and sensor falsly tells the cylinder is at 20 BTDC but in actuallity it is at 10 BTDC, this will result in decreased efficiency and power. Why I don't feel power loss? You can only adjust so much before you get knock at idle!
Nobody but steeda supplies these. Saleen don't do it, SHM don't do it, most smart tuners don't do it. So think.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++
Proper way to adjust timing on EFI is to modify the actual map. That's it, no other way. If you're getting chip chances are the tuner adjusted the entire map with one single value either up or down, just like with steeda's timing adjuster, but since adjustment was made to the actual map there is no adverse effect on injection. A proper performance tune will involve modifying each and every values in the map, 100+ at least.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++
Correct timing is a critical step in 4 stroke engine. Fire too early and you have more time to build up pressure, fire too late and you have less time to build up pressure. Think of advancing timing as increasing CR naturally. In this process next event is dependant on the previous event. And so next event will be powerful only if the previous event was delivered at the right time.
Timing could be increases as engine accelerates faster. If engine accelerates faster than 1000 - 1500 rpm/s, then detonation becomes not important, since mixture don't have time to detonate. That's one power trick racers use. Timing also could be increases as engine rpm goes up, and it could be increases as engine load goes down, and vise versa. In performance applications every advance value in the map works with advance values on all sides of it, so this way maximum engine acceleration could be achieved and timing could be adjusted even further.
In street applications, your stock ECM, every value in the map is designed to reduce emissions. So varying the entire table up or down has little effect on the power, every little. (How much rwhp difference in a chip tuned for 87 octane vs 93 octane?)
++++++++++++++++++++++++++++++++++++++++++++++++++ +++
Modern ECM is hard to tune, complicated. Many people wish they had a carb and rotor so that they could tune easily, but that is neither efficient nor very powerful. This desire to be able to turn a rotor to adjust timing is where this timing adjuster comes from.
Sad thing is, a good ignition controller cost less than this timing adjuster, and it does more.
2. Crank position is used by ECM to determine RPM, and position of the crank shaft, and thus position of cylinders in relationship to TDC of 1st cylinder. This information is critical to deliver precise ignition and injection events.
3. This timing adjuster works by falsifying this information, it tells ECM this cylinder is at 10 BTDC while in reality this cylinder is at 20 BTDC, thus if there is event in ignition map at that rpm and throttle and 10 BTDC, ignition will fire, computer thinks it's firing at 10 BTDC, but in reality it is 20 BTDC. That's how ignition timing is adjusted. An ignition map itself has highs and lows. What this adjuster is doing is rasing or lowering the entire map by one single number. Generally, with a stock map you could advance very little at idle, but you could advance (and thus make more power) a lot as rpm increases. Since you adjusting the entire map with one number, you are limited to that very little increase before you get knock at idle.
4. Injection will be screwed up in a similar way. If event is set to fire injector at 20 BTDC, and sensor falsly tells the cylinder is at 20 BTDC but in actuallity it is at 10 BTDC, this will result in decreased efficiency and power. Why I don't feel power loss? You can only adjust so much before you get knock at idle!
Nobody but steeda supplies these. Saleen don't do it, SHM don't do it, most smart tuners don't do it. So think.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++
Proper way to adjust timing on EFI is to modify the actual map. That's it, no other way. If you're getting chip chances are the tuner adjusted the entire map with one single value either up or down, just like with steeda's timing adjuster, but since adjustment was made to the actual map there is no adverse effect on injection. A proper performance tune will involve modifying each and every values in the map, 100+ at least.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++
Correct timing is a critical step in 4 stroke engine. Fire too early and you have more time to build up pressure, fire too late and you have less time to build up pressure. Think of advancing timing as increasing CR naturally. In this process next event is dependant on the previous event. And so next event will be powerful only if the previous event was delivered at the right time.
Timing could be increases as engine accelerates faster. If engine accelerates faster than 1000 - 1500 rpm/s, then detonation becomes not important, since mixture don't have time to detonate. That's one power trick racers use. Timing also could be increases as engine rpm goes up, and it could be increases as engine load goes down, and vise versa. In performance applications every advance value in the map works with advance values on all sides of it, so this way maximum engine acceleration could be achieved and timing could be adjusted even further.
In street applications, your stock ECM, every value in the map is designed to reduce emissions. So varying the entire table up or down has little effect on the power, every little. (How much rwhp difference in a chip tuned for 87 octane vs 93 octane?)
++++++++++++++++++++++++++++++++++++++++++++++++++ +++
Modern ECM is hard to tune, complicated. Many people wish they had a carb and rotor so that they could tune easily, but that is neither efficient nor very powerful. This desire to be able to turn a rotor to adjust timing is where this timing adjuster comes from.
Sad thing is, a good ignition controller cost less than this timing adjuster, and it does more.
08-31-2005, 05:27 PM
#3
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RE: How will a Steeda Timing Adjuster effect the 4.6 engine
Still,the fuel injectors are controlled by the cam position sensor not the crank position sensor.And if there's so little to gain then how did my efficiency go up a little over two MPG's.Before you say that it's just my imagination,I drive the same road at the same speed and fill up at the same pump every time.The results were taken over a months time and so there is little room for error.
08-31-2005, 09:53 PM
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RE: How will a Steeda Timing Adjuster effect the 4.6 engine
I went from 220 miles per 15 gallons, to 300 miles per 15 gallons of city driving in 4000 lb vehicle. I also went from 16.4 quarter mile to 15.8. I was spinning wheels in 2-3 upshift. What's 2 MPG in comparison? I bet it's not even two though, I bet you had it less, between 1 and 2. When done right this is performance at expense of emissions, realiability, and longivity. When done wrong it can lead to broken pistions, exhaust leaks, and possible engine mealt down.
Fuel injectors are controller by ECM. Amount of fuel delivered is dependant on MAF, air temerature, amount of oxigen in exhaust, amount of egr flow. ECM knows when to fire injectors based on crank position and cam position. There is no way to deliver fuel based on just cam position, cam position is only good for knowing where the valves are (provided that you know the cam profile). Cylinder position is very important in delivering fuel and spark.
That's it buddy. You either get it, or you don't get it. I don't have dyno nor resources to prove steeda wrong. Base your usage on other facts, such as who in the reputable racing world is using this.
Fuel injectors are controller by ECM. Amount of fuel delivered is dependant on MAF, air temerature, amount of oxigen in exhaust, amount of egr flow. ECM knows when to fire injectors based on crank position and cam position. There is no way to deliver fuel based on just cam position, cam position is only good for knowing where the valves are (provided that you know the cam profile). Cylinder position is very important in delivering fuel and spark.
That's it buddy. You either get it, or you don't get it. I don't have dyno nor resources to prove steeda wrong. Base your usage on other facts, such as who in the reputable racing world is using this.
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