Momentary cut off switch for the alternator @ WOT

[Jakee]

Anyone know anything about this mod?

Fab a bracket that mounts on one of the throttle body bolts. The bracket will have a momentary cut off switch for the alternator. What you want to do is to locate the bracket in just the right position so that when at WOT the switch will be pressed, resulting in your alternator being temporally cut off. When the throttle is released, the switch is released and the alternator functions normally. The wire to tie into is green with a red stripe. This was proven to give a extra 7 HP on a mustang. Not sure about our engines but I'm sure it does something.

Current through the wire coil - called "field" current - produces a magnetic field around the core. The strength of the field current determines the strength of the magnetic field. The field current is D/C, or direct current. In other words, the current flows in one direction only, and is supplied to the wire coil by a set of brushes and slip rings. The magnetic field produced has, as any magnet, a north and a south pole. The rotor is driven by the alternator pulley, rotating as the engine runs, hence the name "rotor."

An alternator typically takes about 1 HP (horse power) for every 25 amps of power generated. So, a 100 amp alternator will require about 4 HP at full output. Most alternators do not operate at full output for very long.

Maybe it's worth looking into more. Any comments?

Yes, this is "digging" deep but it seems so easy to do. I'm wondering if there are any ill affects on the alt or anything else for that matter?

 

[biturbosport]

hmmm... that is an interesting idea. Wondering what that would do to the battery tho with alot of accessories that would normally be fine running off the alternator?

 

[Papa]

I think that would work. Have you considered using a vacuum operated cutout such as the on you A/C currently utilizes for that same purpose? I think you would find it easier to install and maintain.

 

[Jakee]

I think that would work. Have you considered using a vacuum operated cutout such as the on you A/C currently utilizes for that same purpose? I think you would find it easier to install and maintain.

Yes - I've talked to several people about this mod. They all say it DOES work. Just not sure how much the gain is exactly.

There was a guy that used a vacuum switch as well. He said it worked.

I'm just not sure about what sort of effect this has on the alt when turning on and off.

As for the accessories: It would be sort of like you sitting outside washing the car and listening to the car radio. You can do it for awhile but need to start the car every once in awhile to make sure you don't kill the bat. And if you're watching TV at WOT...well, I'd have to say you'd be an idiot.

As long as you don't go cruising around at WOT for along time, i'd say you'll be okay.

 

[sn0border88]

could you use a battery cutoff switch wired for the alt operated by a relay activated by WOT?

 

[BrooklynBay]

Keep in mind that the voltage regulator cycles the voltage on the rotor. It is not always applying full power to the rotor, just whenever there is a need for it. If your alternator cuts out, it will show a battery light on the dashboard, or your voltage gauge will fluctuate. A coil carrying a lot of current cycling on, and off will produce a large voltage spike. Diodes are used to clamp (suppress) this spike to prevent damage to the sensitive electronic components in your vehicle. The only way that the alternator could reduce HP is by extra drag from the rotor turning, and magnetic drag from the rotor's magnetic field attracting the iron casing. Without a clutch disconnecting the rotor like an A/C compressor, you would only reduce the magnetic drag, but not the physical drag from the rotor's weight. Many years ago, I took a Chrysler alternator, and added an AC Delco A/C compressor clutch to it. It works, but I have no dyno tests to prove how much HP is actually gained.

 

[biturbosport]

thats interesting- Really though I think it sounds like more work than it is worth. Might be better off to modify/upgrade the alternator casing with better bearings, or perhaps run 2 smaller diameter alternators to keep the spinning mass closer to the armature.

 

[Jakee]

Keep in mind that the voltage regulator cycles the voltage on the rotor. It is not always applying full power to the rotor, just whenever there is a need for it. If your alternator cuts out, it will show a battery light on the dashboard, or your voltage gauge will fluctuate. A coil carrying a lot of current cycling on, and off will produce a large voltage spike. Diodes are used to clamp (suppress) this spike to prevent damage to the sensitive electronic components in your vehicle. The only way that the alternator could reduce HP is by extra drag from the rotor turning, and magnetic drag from the rotor's magnetic field attracting the iron casing. Without a clutch disconnecting the rotor like an A/C compressor, you would only reduce the magnetic drag, but not the physical drag from the rotor's weight. Many years ago, I took a Chrysler alternator, and added an AC Delco A/C compressor clutch to it. It works, but I have no dyno tests to prove how much HP is actually gained.

I removed my fog lights awhile back to make room for a cold air mod so my switch for the fog lights is doing nothing. I wonder if I could use the switch to control the alt manually to find out what sort of gain were talking about? When I dyno, I could make one run with the switch off and one with it on. What do you think?

 

[BrooklynBay]

You could try this with a relay. It will disengage the wiring, but you will still have the drag of the rotor.

 

[boominXplorer]

Another thing to think about is what about all the hype about having full power to all sensors and ignition for optimum performance. The second you turn off an altenator you go from about 14.4 to 12.6 almost instantly.

Just my $.02

 

[BrooklynBay]

That's why some companies make those 16 volt active inverters that take 14.7 vdc, invert it to 16 vac, then rectify it to 16 vdc. They use them on fuel pumps, and ignition systems to push them to the limit without burning them out.

 

[Jakee]

You could try this with a relay. It will disengage the wiring, but you will still have the drag of the rotor.

I wonder if using Royal Purple in the bearings would do anything?

 

[spindlecone]

I wonder if using Royal Purple in the bearings would do anything?

I would think royal purple on sealed bearings would do nothing

 

[shamaal]

If I understand this correctly, the theory is that by reducing the load on the alternator you will be reducing the horsepower necessary to drive it. With that line of reasoning turning on electric utilities such as lights, blowers and electric windows reduces the available engine horsepower; something easily checked on a dyno.

This would mean that changing the load on an alternator affects the torque, I suppose it's possible. I would think higher gains would come from installation of an A/C compressor type clutch.

As I recall, the 25 amp = 1hp rule of thumb is for sizing during design. A 25 amp unit uses 1 hp. A 100 amp unit would use 4. This would come from the difference in the mass of the rotors, resultant torque to spin them and perhaps the weight of the large stator, casing and regulator. I don't think it refers to the current draw.

A good litmus test is, what do racers do?

 

[spindlecone]

What the mod is if it works at all is deminishig returns, in a daily driver, that wgts 2.5 tons.
Is just not worth it.
you wanna see the real story about what you get with E-fans, electric water pumps etc.
For those rabid Dyonists on this site, Get hooked up, remove your serp belt, make a run.
Replace your serp belt, make a run, what you see as far as a diff will amaze you as it is not worth worrying abouthave a nice day

 

[Jakee]

If I understand this correctly, the theory is that by reducing the load on the alternator you will be reducing the horsepower necessary to drive it. With that line of reasoning turning on electric utilities such as lights, blowers and electric windows reduces the available engine horsepower; something easily checked on a dyno.

This would mean that changing the load on an alternator affects the torque, I suppose it's possible. I would think higher gains would come from installation of an A/C compressor type clutch.

As I recall, the 25 amp = 1hp rule of thumb is for sizing during design. A 25 amp unit uses 1 hp. A 100 amp unit would use 4. This would come from the difference in the mass of the rotors, resultant torque to spin them and perhaps the weight of the large stator, casing and regulator. I don't think it refers to the current draw.

A good litmus test is, what do racers do?

Good thoughts.

I think the only thing left to do is try it. If there's a gain, then good.

I believe this idea was conceived by racers.

 

[Jakee]

What the mod is if it works at all is deminishig returns, in a daily driver, that wgts 2.5 tons.
Is just not worth it.
you wanna see the real story about what you get with E-fans, electric water pumps etc.
For those rabid Dyonists on this site, Get hooked up, remove your serp belt, make a run.
Replace your serp belt, make a run, what you see as far as a diff will amaze you as it is not worth worrying abouthave a nice day

I would like you to try this at your next dyno. Let me know how that works out for you.

 

[spindlecone]

Good thoughts.

I think the only thing left to do is try it. If there's a gain, then good.

I believe this idea was conceived by racers.

Any gain is good, racers do not drive EXs
If I wannna race, the other car in my sig is what i use

 

[Jakee]

Any gain is good, racers do not drive EXs
If I wannna race, the other car in my sig is what i use

That's the whole challange bud. Do something that can't be done or that's totally crazy. Or, be like everyone else and get lost in the croud.

Yeah - I've had a faster car before. A lot faster.

What "other" car in your sig? I don't see nothing.

 

[Jakee]

What's more impressive.

A mustang doing 12's Or an X doing 12's?