Help me understand timing

Jason1320 · 03-08-2004, 07:05 AM

I know this has probably been posted a million times, but I can't seem to find the answers I'm looking for. Can some one please tell me where I can learn about timing? How does bumping the timing up help or hurt you? Retarding it? What is the difference between bumping the timing manually with a Steeda T/A kit and the spark advance I get from a chip?

Thanks,

jaxter1 · 03-09-2004, 11:28 AM

Suprised nobody replied.....yep, the stock 4.6 is retarded, set to run 87 octane, there's a good 5 HP gain if it's set to accept high 90's, I bet, at least with a better intake. Your next thread is interesting, about lo-end torque.....If you swap gears, and plan on running an advance, get the Diablo or Steeda setup. I plan on this soon. You will need to reprog for timing and gears, why not do both at once? A stock vs bumped timing and gears would be an interesting poll.......seems the smartest mod to me, any thoughts out there?

xxxBlakexxx · 03-10-2004, 12:59 AM

Higher octane fuels burn slower than lower octane fuels. If you put 93 Octane in a stock GT, there is no performance gain, in fact, you can loose power if too high of an octane is used for the motor. If you put 87 Octane in a car designed to run on 91/93, the fuel will/can actually ignite early. This is called "knock", "ping", or "pre-mature ignition". When this ocurrs, the car looses power and damage can/will be done to the engine. In a bad case, it can sound like marbles rattling under your hood.

Think of "octane" as meaning "resistance to knock".

Most modern cars are equipped with knock sensors. My Ford servive manager told me that this is the case with my Mustang ('00) as well. These devices use a special pressure device that can sense knock before it ocurrs and adjusts the timing (advance, I think).

Most cars can experience conditions that would cause some knock or ping from time to time. These conditions can ocurr because of other factors such as load on the motor and outside temperatures or fuel that is not quite what it is rated. So as you can see, modern cars are constantly "thinking" and making adjustments.

In theory, a chip will allow you to advance your spark to take advantage of higher octane fuels. But if you use a chip you MUST always use high octane fuel. In my case, with my Diablo chip, it has a switch so I can turn it off and stay with 87 for those moments when gas hits $2.50 a gallon.

I agree, though, if you are going to add gears, wait for the chip. It will save you some bucks and a lot of time pulling the chip out again. Chips will also give you a little more top-end in your power as they generally raise your rev limiter a little and I believe most of the spark advance happens at higher rpms too. I suppose this would not do much for the low-end power issue that you complained about in a previous post and may even make it feel more pronounced.

I can say that my car pulls much better from about 4,000 rpms + that it did when stock. Although I have other mods that impact this.

Despite all the hoopla about mods, my favorite two mods so far on my Steedia Shifter and my rims. Both do crap for performance. Kind of funny huh? When I add my exhaust, I am sure that I will love that more than my "power adding" mods too. The more I learn, the more I wish I just stuck with wheels, exhaust, shifter, and gears. Throw in some nitrous and you have a quick machine.

MiracleMax · 03-10-2004, 09:05 PM

Ignition timing encompasses two things total advance and intial timing which can be retarded or advance.

Initial timing is set via its relationship to the position of the piston and top dead center (TDC). This is affected by a great many things; quality of fuel, combustion chamber design, engine operation tempeture, fuel homoginezation, ect. and in the case of Ford the assumed operating parameters of the engine. Ford apparently uses a conservative ingnition seting to avoid possible damage to the engine (I assume due to the quality of available fuels and the tinker factor).

Anywhosit that aside, intial timing is usually set so that the ignition fires sometime before top dead center giving the charge time to burn across the cylinder creating maximum pressure on the piston as it crosses over from top dead center to after top dead center (IIRC its like 4 to 6 degrees after TDC you want maximum pressure on the piston). Again the amount of intial advance depends on fuel type and engine design. Typically a more efficent design combined with fast burning fuels requires less initial advance.

total ignition timing is the range of advance that the ignition system can move through so that precise timing can be adjusted based on speed and load (basically). As engine speed increases it requires more ignition advance to precisely fire the plug so that maximum pressure can be placed on the piston. The chief reason is that the psiton is moving much faster and the charge doesnt have as much time to complete its burn as the piston approaches TDC and then begins to move away.

I once had a shop teacher that swore up and down (and probably to his grave) that no engine could rev past 6000 rpm. his reasoning was based on the notion that gasoline burned at a constant rate (wrong) and that it took a defined amount of time for a air/fuel charge to burn no matter what type of engine if it was using gasoline.

I'm no guru and he might have been right about a single droplet of regular gas but he was completely wrong about the the time it takes to burn across the cylinder.

Physical size of the cylinder has alot to do with this, so does the the combustion chamber shape and the piston shape. As well as the quality of the air/fuel mixture (small droplets burn faster and big droplets burn slower or not at all). Take a look at an F1 engine, very small bores with extremely compact combustion chambers.

Want the best sort of combustion chamber, make it a small bore/long stroke hemi with a centrally located spark plug and a flattop piston.

Jason1320 · 03-10-2004, 09:14 PM

Thanks, that was very informative. There is still one question left unanswered. How does this affect performance from a tinker's point of view. For instance, on a basicly stock GT with my few mods, could I see a gain from advancing the timing and running better gas? Would it be in best intrest to lose the Jet Chip (cuz it sucks anyway) and go with a Steeda T/A kit? Or would a programable chip and dyno tune be the way to go?

Thanks,
Jason

xxxBlakexxx · 03-10-2004, 09:51 PM

Jason:

I think the "experts" would say this: Make all your mods that you can, then do a custom chip! This way the chip takes into account all your mods.

In reality, who is ever done doing mods, right? Even the serious guys are always swapping turbos out and guess what, each time they need a custom program.

My suggestion (and I am not the smartest), go with a chip now if you want, but choose one of the following:

Jason1320 · 03-10-2004, 09:56 PM

Quote:

Originally posted by xxxBlakexxx
Jason:

I think the "experts" would say this: Make all your mods that you can, then do a custom chip! This way the chip takes into account all your mods.

In reality, who is ever done doing mods, right? Even the serious guys are always swapping turbos out and guess what, each time they need a custom program.

My suggestion (and I am not the smartest), go with a chip now if you want, but choose one of the following:

You left me hangin!

Following what?

xxxBlakexxx · 03-10-2004, 10:02 PM

(crap, my post got posted before I was done)

Anyway, go with ones of these style chips:

1 - a "Max Tuner" type device. This will allow you to make changes yourself without pulling the chip. If you decide to add gears later, then just re-program it! No installtion with a tuner and chips suck to install, but these things cost more. Super Tuner and Diablo make these that I know of (though Diablo's may just be for Cobras)

2 - Choose a chip that can be pulled and customized later. I chose this option. For $80 I can add a custom program, but I have to take it out and mail it.

Now for your big question "On a Stock GT will timing advance and using better gas add to performance?" On paper "YES". In reality, I think it depends on the car. There are too many factors I think. This is why a real dyno tune program is the ONLY way to ensure results. Diablo claims a 24 hp gain at the wheels with my chip. I can tell you as the driver, no way. Maybe 5 or 10 based on my "butt-o-meter".

For automatics, garden variety chips help a lot more, yet cost the same. If I had an auto, a chip is a must! For a 5 speed, well, I am not sure. I probably would have been better off buying gears or exhaust.

Hope this helps and I am sure there will be other opinions.

MiracleMax · 03-10-2004, 10:11 PM

almost forgot, effective or dynamic compression ratio also effects timing.

Hi-comp egnines also require less initial timing

Jason1320 · 03-11-2004, 06:42 AM

Execelent advice. I was looking in to the Max Tuner style boxes. Both Max Tuner and Diablo plug into the diagnostic port. Where is that exactly? Under the hood? Sounds like it does a lot better job than my jet chip ($300). The Diablo was only $399 and the Max Tuner ($314). That being said, anyone want to buy a slgihtly used Jet Chip? $200

Jason1320 · 03-11-2004, 08:43 AM

Last question, is there a difference between adjusting the timing via the computer and adjusting it via a manual T/A kit?

MiracleMax · 03-11-2004, 11:07 AM

Hmmmm.... If your using the T/A kitm you are physically adjusting the relationship between the sensor and its trigger but still using the same spark tables provided by the factory. I would hazarad a guess that by adjusting the timing with a T/A kit your firing on a cylinder when its effective compression ratio is higher (since it seems power is up across the board), but this changes the fuel requirements for the engine.

Using a chip could provide more aggressive timing tables as well as changing initial timing like a T/A kit so potentially a chip could offer more power in the way of ignition adjustments.

I dunno I'm old school when it comes to the chio stuff, it always seemed like you could get more out of a 5.0 per dollar spent if you ignored the chip

jaxter1 · 03-11-2004, 11:36 AM

Well, that's the big question.....pushrods with dist's you can turn by hand are out. I'd still go for as extreme advance as practical on a 4.6....I've mentioned it before, but I still wish laptop interfaces like Moto, Autotap, Scantool etc could actually adjust things on the fly. That would be so much better than using a chip....I've yet to see an OBD2 laptop interface that can prog/flash or modify on the fly.

xxxBlakexxx · 03-11-2004, 06:37 PM

The plug for the tuner is located uder the dash by the driver (I think).

03-08-2004, 07:05 AM	#1
Jason1320 Registered Member Join Date: Jul 2003 Location: Bowie, MD Posts: 45	Help me understand timing I know this has probably been posted a million times, but I can't seem to find the answers I'm looking for. Can some one please tell me where I can learn about timing? How does bumping the timing up help or hurt you? Retarding it? What is the difference between bumping the timing manually with a Steeda T/A kit and the spark advance I get from a chip? Thanks, __________________ 2003 Mustang Cobra (Sonic Blue) - Bone Stock!!! Best 1/4 mile - ???

03-10-2004, 12:59 AM	#3
xxxBlakexxx Registered Member Join Date: Sep 2003 Location: Mountaintop, PA Posts: 634	Higher octane fuels burn slower than lower octane fuels. If you put 93 Octane in a stock GT, there is no performance gain, in fact, you can loose power if too high of an octane is used for the motor. If you put 87 Octane in a car designed to run on 91/93, the fuel will/can actually ignite early. This is called "knock", "ping", or "pre-mature ignition". When this ocurrs, the car looses power and damage can/will be done to the engine. In a bad case, it can sound like marbles rattling under your hood. Think of "octane" as meaning "resistance to knock". Most modern cars are equipped with knock sensors. My Ford servive manager told me that this is the case with my Mustang ('00) as well. These devices use a special pressure device that can sense knock before it ocurrs and adjusts the timing (advance, I think). Most cars can experience conditions that would cause some knock or ping from time to time. These conditions can ocurr because of other factors such as load on the motor and outside temperatures or fuel that is not quite what it is rated. So as you can see, modern cars are constantly "thinking" and making adjustments. In theory, a chip will allow you to advance your spark to take advantage of higher octane fuels. But if you use a chip you MUST always use high octane fuel. In my case, with my Diablo chip, it has a switch so I can turn it off and stay with 87 for those moments when gas hits $2.50 a gallon. I agree, though, if you are going to add gears, wait for the chip. It will save you some bucks and a lot of time pulling the chip out again. Chips will also give you a little more top-end in your power as they generally raise your rev limiter a little and I believe most of the spark advance happens at higher rpms too. I suppose this would not do much for the low-end power issue that you complained about in a previous post and may even make it feel more pronounced. I can say that my car pulls much better from about 4,000 rpms + that it did when stock. Although I have other mods that impact this. Despite all the hoopla about mods, my favorite two mods so far on my Steedia Shifter and my rims. Both do crap for performance. Kind of funny huh? When I add my exhaust, I am sure that I will love that more than my "power adding" mods too. The more I learn, the more I wish I just stuck with wheels, exhaust, shifter, and gears. Throw in some nitrous and you have a quick machine. __________________ "Children should not get cancer, but they do!" Help a child with cancer at www.homeoftheirown.org My Stang: 2000 Mustang GT Vert - Steeda Tri-Ax Shifter; C&L Plenum; BBK 75 mm TB; Steeda Strut Tower Supports; Black "Deep Dish" Bullet Wheels; FRPP 4.10's; Steeda Subframes; SLP Catback & SLP Catted X-Pipe; SCT 4 Position Chip with 3 custom tunes; Steeda CAI; Venom-1000 Nitrous; Roush Stage 3 Body Kit; Bullet Suspension Package (on the way)

03-10-2004, 09:05 PM	#4
MiracleMax Registered Member Join Date: Apr 1999 Location: Hayes, Va, USA Posts: 798	Ignition timing encompasses two things total advance and intial timing which can be retarded or advance. Initial timing is set via its relationship to the position of the piston and top dead center (TDC). This is affected by a great many things; quality of fuel, combustion chamber design, engine operation tempeture, fuel homoginezation, ect. and in the case of Ford the assumed operating parameters of the engine. Ford apparently uses a conservative ingnition seting to avoid possible damage to the engine (I assume due to the quality of available fuels and the tinker factor). Anywhosit that aside, intial timing is usually set so that the ignition fires sometime before top dead center giving the charge time to burn across the cylinder creating maximum pressure on the piston as it crosses over from top dead center to after top dead center (IIRC its like 4 to 6 degrees after TDC you want maximum pressure on the piston). Again the amount of intial advance depends on fuel type and engine design. Typically a more efficent design combined with fast burning fuels requires less initial advance. total ignition timing is the range of advance that the ignition system can move through so that precise timing can be adjusted based on speed and load (basically). As engine speed increases it requires more ignition advance to precisely fire the plug so that maximum pressure can be placed on the piston. The chief reason is that the psiton is moving much faster and the charge doesnt have as much time to complete its burn as the piston approaches TDC and then begins to move away. I once had a shop teacher that swore up and down (and probably to his grave) that no engine could rev past 6000 rpm. his reasoning was based on the notion that gasoline burned at a constant rate (wrong) and that it took a defined amount of time for a air/fuel charge to burn no matter what type of engine if it was using gasoline. I'm no guru and he might have been right about a single droplet of regular gas but he was completely wrong about the the time it takes to burn across the cylinder. Physical size of the cylinder has alot to do with this, so does the the combustion chamber shape and the piston shape. As well as the quality of the air/fuel mixture (small droplets burn faster and big droplets burn slower or not at all). Take a look at an F1 engine, very small bores with extremely compact combustion chambers. Want the best sort of combustion chamber, make it a small bore/long stroke hemi with a centrally located spark plug and a flattop piston. __________________ 2002 5M GT (99% stock) 1991 5M LX (30% stock) patiently awaiting my satin silver 07 Mach 1, and don't forget the shaker

03-10-2004, 09:14 PM	#5
Jason1320 Registered Member Join Date: Jul 2003 Location: Bowie, MD Posts: 45	Thanks, that was very informative. There is still one question left unanswered. How does this affect performance from a tinker's point of view. For instance, on a basicly stock GT with my few mods, could I see a gain from advancing the timing and running better gas? Would it be in best intrest to lose the Jet Chip (cuz it sucks anyway) and go with a Steeda T/A kit? Or would a programable chip and dyno tune be the way to go? Thanks, Jason __________________ 2003 Mustang Cobra (Sonic Blue) - Bone Stock!!! Best 1/4 mile - ???

03-10-2004, 09:51 PM	#6
xxxBlakexxx Registered Member Join Date: Sep 2003 Location: Mountaintop, PA Posts: 634	Jason: I think the "experts" would say this: Make all your mods that you can, then do a custom chip! This way the chip takes into account all your mods. In reality, who is ever done doing mods, right? Even the serious guys are always swapping turbos out and guess what, each time they need a custom program. My suggestion (and I am not the smartest), go with a chip now if you want, but choose one of the following: __________________ "Children should not get cancer, but they do!" Help a child with cancer at www.homeoftheirown.org My Stang: 2000 Mustang GT Vert - Steeda Tri-Ax Shifter; C&L Plenum; BBK 75 mm TB; Steeda Strut Tower Supports; Black "Deep Dish" Bullet Wheels; FRPP 4.10's; Steeda Subframes; SLP Catback & SLP Catted X-Pipe; SCT 4 Position Chip with 3 custom tunes; Steeda CAI; Venom-1000 Nitrous; Roush Stage 3 Body Kit; Bullet Suspension Package (on the way)

03-09-2004, 11:28 AM	#2
jaxter1 Registered Member Join Date: Sep 2000 Location: il Posts: 10	Suprised nobody replied.....yep, the stock 4.6 is retarded, set to run 87 octane, there's a good 5 HP gain if it's set to accept high 90's, I bet, at least with a better intake. Your next thread is interesting, about lo-end torque.....If you swap gears, and plan on running an advance, get the Diablo or Steeda setup. I plan on this soon. You will need to reprog for timing and gears, why not do both at once? A stock vs bumped timing and gears would be an interesting poll.......seems the smartest mod to me, any thoughts out there?

03-10-2004, 10:02 PM	#8
xxxBlakexxx Registered Member Join Date: Sep 2003 Location: Mountaintop, PA Posts: 634	(crap, my post got posted before I was done) Anyway, go with ones of these style chips: 1 - a "Max Tuner" type device. This will allow you to make changes yourself without pulling the chip. If you decide to add gears later, then just re-program it! No installtion with a tuner and chips suck to install, but these things cost more. Super Tuner and Diablo make these that I know of (though Diablo's may just be for Cobras) 2 - Choose a chip that can be pulled and customized later. I chose this option. For $80 I can add a custom program, but I have to take it out and mail it. Now for your big question "On a Stock GT will timing advance and using better gas add to performance?" On paper "YES". In reality, I think it depends on the car. There are too many factors I think. This is why a real dyno tune program is the ONLY way to ensure results. Diablo claims a 24 hp gain at the wheels with my chip. I can tell you as the driver, no way. Maybe 5 or 10 based on my "butt-o-meter". For automatics, garden variety chips help a lot more, yet cost the same. If I had an auto, a chip is a must! For a 5 speed, well, I am not sure. I probably would have been better off buying gears or exhaust. Hope this helps and I am sure there will be other opinions. __________________ "Children should not get cancer, but they do!" Help a child with cancer at www.homeoftheirown.org My Stang: 2000 Mustang GT Vert - Steeda Tri-Ax Shifter; C&L Plenum; BBK 75 mm TB; Steeda Strut Tower Supports; Black "Deep Dish" Bullet Wheels; FRPP 4.10's; Steeda Subframes; SLP Catback & SLP Catted X-Pipe; SCT 4 Position Chip with 3 custom tunes; Steeda CAI; Venom-1000 Nitrous; Roush Stage 3 Body Kit; Bullet Suspension Package (on the way)

03-10-2004, 10:11 PM	#9
MiracleMax Registered Member Join Date: Apr 1999 Location: Hayes, Va, USA Posts: 798	almost forgot, effective or dynamic compression ratio also effects timing. Hi-comp egnines also require less initial timing __________________ 2002 5M GT (99% stock) 1991 5M LX (30% stock) patiently awaiting my satin silver 07 Mach 1, and don't forget the shaker

03-11-2004, 06:42 AM	#10
Jason1320 Registered Member Join Date: Jul 2003 Location: Bowie, MD Posts: 45	Execelent advice. I was looking in to the Max Tuner style boxes. Both Max Tuner and Diablo plug into the diagnostic port. Where is that exactly? Under the hood? Sounds like it does a lot better job than my jet chip ($300). The Diablo was only $399 and the Max Tuner ($314). That being said, anyone want to buy a slgihtly used Jet Chip? $200 __________________ 2003 Mustang Cobra (Sonic Blue) - Bone Stock!!! Best 1/4 mile - ???

03-11-2004, 08:43 AM	#11
Jason1320 Registered Member Join Date: Jul 2003 Location: Bowie, MD Posts: 45	Last question, is there a difference between adjusting the timing via the computer and adjusting it via a manual T/A kit? __________________ 2003 Mustang Cobra (Sonic Blue) - Bone Stock!!! Best 1/4 mile - ???

03-11-2004, 11:07 AM	#12
MiracleMax Registered Member Join Date: Apr 1999 Location: Hayes, Va, USA Posts: 798	Hmmmm.... If your using the T/A kitm you are physically adjusting the relationship between the sensor and its trigger but still using the same spark tables provided by the factory. I would hazarad a guess that by adjusting the timing with a T/A kit your firing on a cylinder when its effective compression ratio is higher (since it seems power is up across the board), but this changes the fuel requirements for the engine. Using a chip could provide more aggressive timing tables as well as changing initial timing like a T/A kit so potentially a chip could offer more power in the way of ignition adjustments. I dunno I'm old school when it comes to the chio stuff, it always seemed like you could get more out of a 5.0 per dollar spent if you ignored the chip __________________ 2002 5M GT (99% stock) 1991 5M LX (30% stock) patiently awaiting my satin silver 07 Mach 1, and don't forget the shaker

03-11-2004, 11:36 AM	#13
jaxter1 Registered Member Join Date: Sep 2000 Location: il Posts: 10	Well, that's the big question.....pushrods with dist's you can turn by hand are out. I'd still go for as extreme advance as practical on a 4.6....I've mentioned it before, but I still wish laptop interfaces like Moto, Autotap, Scantool etc could actually adjust things on the fly. That would be so much better than using a chip....I've yet to see an OBD2 laptop interface that can prog/flash or modify on the fly.

03-11-2004, 06:37 PM	#14
xxxBlakexxx Registered Member Join Date: Sep 2003 Location: Mountaintop, PA Posts: 634	The plug for the tuner is located uder the dash by the driver (I think). __________________ "Children should not get cancer, but they do!" Help a child with cancer at www.homeoftheirown.org My Stang: 2000 Mustang GT Vert - Steeda Tri-Ax Shifter; C&L Plenum; BBK 75 mm TB; Steeda Strut Tower Supports; Black "Deep Dish" Bullet Wheels; FRPP 4.10's; Steeda Subframes; SLP Catback & SLP Catted X-Pipe; SCT 4 Position Chip with 3 custom tunes; Steeda CAI; Venom-1000 Nitrous; Roush Stage 3 Body Kit; Bullet Suspension Package (on the way)