# maybe this can be added to the nitrous sticky?



## buffdaddy18 (Dec 16, 2005)

I saw ya'lls nitrous sticky and thought ya'll might wanna add this. I wrote it on another forum I am on.


Q: Will Nitrous affect engine reliability?

A: The key is choosing the correct H.P. for a given application. A kit that uses the correct factory calibration does not usually cause increased wear. As the energy released in the cylinder increases so do the loads on the various components that must handle them. If the load increases exceed the ability of the component to handle them, added wear takes place. Nitrous kits are designed for use on demand and only at wide open throttle. Nitrous can be extremely advantageous in that it is only used when you want it, not all the time. All NOS kits are designed for maximum power with reliability for a given application.

Q: Can I simply bolt a nitrous kit onto my stock engine?
A: Yes, Nitrous companies manufacture systems for virtually any stock engine application. The key is to choose the correct kit for a given application; i.e., 4 cylinder. engines normally allow an extra 40-60 HP, 6 cylinder. engines usually work great between 75-100 extra HP, small block V8's (302/350/400cid) can typically accept up to 140 extra HP, and big block V8's (427/454) might accept from 125-200 extra HP. These suggested ranges provide maximum reliability from most stock engines using cast pistons and cast crank with few or no engine modifications.

Q: What are some of the general rules for even higher H.P. gains?
A: Generally, forged aluminum pistons are one of the best modifications you can make. Retard ignition timing by 4-8 degrees (1 to 1½ degrees timing retard per 50 H.P. gain). In many cases a higher flowing fuel pump may be necessary. Higher octane (100+) racing type fuel may be required as well as spark plugs 1 to 2 heat ranges colder than normal with gaps closed to .025"-.030".

For gains over 250 H.P., other important modifications could be necessary in addition to those mentioned above. These special modifications may include a forged crankshaft, a high quality race type connecting rod, a high output fuel pump dedicated to feeding the additional fuel demands of the nitrous system, and a racing fuel with high specific gravity and an octane rating of 110 or more. For more specific information about your application, please contact the NOS technical dept.

Q: How does nitrous work?
A: Nitrous oxide is made up of 2 parts nitrogen and one part oxygen (36% oxygen by weight). During the combustion process in an engine, at about 572 degrees F., nitrous breaks down and releases oxygen. This extra oxygen creates additional power by allowing more fuel to be burned. Nitrogen acts to buffer, or dampen the increased cylinder pressures helping to control the combustion process. Nitrous also has a tremendous "intercooling" effect by reducing intake charge temperatures by 60 to 75 degrees F.

Q: How much performance improvement can I expect with a nitrous system?
A: For many applications an improvement from 1 to 3 full seconds and 10 to 15 MPH in the quarter mile can be expected. Factors such as engine size, tires, jetting, gearing, etc. will effect the final results.

Q: How long will the bottle last?
A: This largely depends on the type of nitrous kit and jetting used. For example, a 125 HP Power Shot kit with a standard 10 lb. capacity bottle will usually offer up to 7 to 10 full quarter-mile passes. For power levels of 250 HP, 3 to 5 full quitter-mile passes may be expected. If nitrous is only used in 2nd and 3rd gears, the number of runs will be more.

Q: How long can I hold the nitrous button down?
A: It is possible to hold the button down until the bottle is empty. However 15 continuous seconds at a time, or less, is recommend.

Q: When is the best time to use nitrous?
A: At wide open throttle only (unless a progressive controller is used). Due to the tremendous amount of increased torque, you will generally find best results, traction permitting, at early activation. Nitrous can be safely applied above 2,500 RPM under full throttle conditions.



Q: Is nitrous oxide flammable?
A: No. Nitrous oxide by itself is non-flammable. However, the oxygen present in nitrous oxide causes combustion of fuel to take place more rapidly.

Q: Will nitrous oxide cause detonation?
A: Not directly. Detonation is the result of too little fuel present during combustion (lean) or too low of an octane of fuel. Too much ignition advance also causes detonation. In general, most of our kits engineered for stock type engines will work well with premium type fuels and minimal decreases of ignition timing. In racing applications where higher compression ratios are used, resulting in higher cylinder pressures, a higher fuel octane must be used as well as more ignition retard.



Q: Is it a good idea to use an aftermarket computer chip in conjunction with an NOS System?
A: Only if the chip had been designed specifically for use with nitrous oxide. Most aftermarket chips use more aggressive timing advance curves to create more power. This can lead to potential detonation. You may wish to check with the manufacturer of the chip before using it. The top manufacturers, such as Hypertech do make special chips for use with nitrous.



Q: Does nitrous oxide raise cylinder pressures and temperatures?
A: Yes. Due to the ability to burn more fuel, this is exactly why nitrous makes so much power.

Q: Are there any benefits to chilling the nitrous bottle?
A: No. Chilling the bottle lowers the pressure dramatically and will also lower the flow rate of the nitrous causing a fuel rich condition and reducing power. On cold evenings you might run on the rich side. For optimal running conditions, keep bottle pressure at approximately 800-900 psi. If you live or operate a nitrous system in colder climates, it may also be a good idea to purchase a bottle heater kit, part #14161. Generally, ambient temperatures of 70-90 degrees F. will allow for best power potential of NOS kits.

Q: Are there benefits to using nitrous with turbo or supercharger applications?
A: Absolutely! In turbo applications, turbo lag is completely eliminated with the addition of a nitrous system. In addition, both turbo and superchargers compress the incoming air, thus heating it. With the injection of nitrous, a tremendous intercooling effect reduces intake charge temperatures by 75 degrees or more. Boost is usually increased as well; adding to even more power.



Q: What effect does nitrous have on an engine with considerable miles on it?
A: This depends largely on the actual condition of the engine components. Any performance modification to an engine that is worn out or poorly tuned will have detrimental effects. However, an engine in good condition, with good ring and head gasket sealing, should be able to use nitrous without any abnormal wear.

Q: Will the use of nitrous oxide affect the catalytic converter?
A: No. The increase in oxygen present in the exhaust may actually increase the efficiency of the converter. Since the use of nitrous is normally limited to 10-20 seconds of continuous use, there usually are no appreciable effects. Temperatures are typically well within acceptable standards.

Q: Will the percentage of performance increase be the same in a highly modified engine compared to a stock engine when using the same nitrous kit and jetting?
A: Not really. In most cases the percentage of increase is greater from a stock engine because it is not as efficient as the modified engine in a normal non-nitrous mode. However, since the effects of nitrous oxide magnify the output of any engine, the total power output will be much higher in the modified engine.

Q: Can service station fuel be used for street/strip nitrous oxide applications?
A: Yes. Use of a premium type leaded or unleaded fuel of 92, or greater, octane is recommended for most applications. Many systems are designed for use with service station pump gas. However, when higher compression or higher horsepower levels are used, a racing fuel of 100 octane, or more, must be used.

Q: What type of cam is best suited for use with nitrous oxide?
A: Generally, cams that have more exhaust overlap and duration. However, it is best to choose a cam tailored to normal use (when nitrous is not activated) since 99% of most vehicle operation is not at full throttle. There are special cam grinds available for nitrous competition which have more aggressive exhaust profile ramping, etc. Since cam selection depends largely on vehicle weight, gearing, etc., it is best to stick to cam manufacturer's recommendations for your particular goal.

Q: Should I modify my fuel system to use nitrous oxide?
A: Most stock fuel pumps will work adequately for smaller nitrous applications. It is important to check to see if your pump can flow enough fuel to your existing fuel system (whether carburetor or fuel injected), as well as being able to supply the additional fuel required by the nitrous kit under full throttle conditions. It may be a good idea to dedicate a separate fuel pump to the nitrous kit.

Q: Which is the best position to mount a nitrous bottle?
A: bottles come with siphon tubes and, in order to maintain proper nitrous pickup, it is important to mount the bottle correctly. It is recommended mounting the bottle at a 15 degree angle with the valve end higher than the bottom of the bottle. The valve end of the bottle should point to the front of the vehicle and the valve knob and label should face straight up.

Q: How important is it to use nitrous and fuel filters in a kit?
A: Some of the most important components of any nitrous system are nitrous and fuel filters. To keep contaminants from attacking the solenoid or plugging up a jet, NOS nitrous filters feature a special stainless steel mesh element from the aerospace industry.


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## buffdaddy18 (Dec 16, 2005)

Q: What are the advantages of using nitrous compared to other performance options?
A: The cost of many other performance options can put you in the poorhouse. Dollar for dollar, you can't buy more performance with less money than nitrous. With a nitrous system, performance and reliability can be had for a much more reasonable price while retaining the advantages of a stock engine during normal driving. And, nitrous offers tremendous gains in torque without having to rev the engine to excessive rpm's. These factors help your engine last longer than many other methods of boosting horsepower.


Q: What kind of pressures are components subject to in a typical nitrous kit?
A: Pressures often exceed 1,000 psi.

Q: How do I know how much nitrous is left in the bottle?

A: The most reliable way is to weigh the bottle to determine how many pounds remain. When a bottle is near empty (about 20% or less nitrous remaining) a surging effect is normally felt.

Q: What is the function of the blow-off safety valve on the bottle?
A: It is very important not to overfill a bottle; i.e., a 10 lb. capacity bottle should not be filled with more than 10 lb. of nitrous oxide by weight. Over-filling and/or too much heat can cause excessive bottle pressures forcing the safety seal to blow and releasing all the contents out of the bottle.

Q:Will I have to change my ignition system?
A: Most late model ignition systems are well suited for nitrous applications. In some higher HP cases, it may be advisable to look into a high quality high output ignition system.


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## buffdaddy18 (Dec 16, 2005)

Here is some more helpful info for newbies to nitrous

Triggering the System

Of course, you don't want the system to be running all the time - a 10lb bottle will last you less than a minute, if it's open. Typically, you want the system triggered on while you're at the track, at WOT (wide open throttle), and at relatively high rpm's (see "Safety" for why). To make that happen, you'll typically want to wire, in sequence, several switches. I won't describe the specific wiring here, but you'll have some or all of the following:


* A Master On/Off switch
* A WOT switch, which is installed on the actual throttle, that closes the circuit only when your foot is on the floorboard
* A pushbutton in the car, probably on the shifter
* A "window switch" (see "Safety" for details) that closes the circuit only when the engine RPM is between a certain range (like 3000-6000) that you decide is acceptable
* A fuel pressure switch 

More Esoteric Controllers
The system to trigger described above is a basic "single stage" setup. The nitrous is either on or off, and when it's on, the full volume dictated by the jets is sprayed into the engine. There are all sorts of reasons you might want a nitrous system which was a bit more intelligent, and I'm not going to define every possible option here. Suffice to say there are "multiple stage" systems (like those from Venom, which may be completely overboard) where separate flows of nitrous are added at different times, rpm-based systems which add more nitrous at higher rpms, time-based systems, which delay the nitrous flow for some time after you launch, etc. Practically any setup you want can be built by a computer-controlled box.



Safety
I'm a firm believer in using all the safety mechanisms you have available. Clearly, they aren't absolutely necessary, and some folks run nitrous systems without any of these devices. But for my money, they're well worth using.

What Can Go Wrong?

Well, a lot can go wrong, but hopefully you'll have adequate safety mechanisms built in to protect your motor when it does. The main thing that can go wrong is adding nitrous into your engine without compensating fuel. This extreme lean condition is disaster for the engine, and you're not likely to get a second chance - at least with the same engine. Conversely, adding extra fuel without nitrous is not particularly bad for the engine, so you can imagine, it's safer to start with the car running rich (too much fuel), then lean it back from there. Some examples of problems you might encounter include:







Fuel pump fails
A failed pump will lose pressure immediately, causing an extreme lean condition

Fuel injector failure or lockup
Using stock fuel injectors with a dry nitrous kit can cause the injectors to lock up and not flow fuel

Solenoid failure
A failed fuel or nitrous solenoid can cause serious damage 

Ignition RPM limiter

On a stock computer, the rev limiter is implemented by cutting the signal to the fuel injectors so the cylinders have no combustion. If you're running a dry system, which depends on the fuel injectors to provide compensating fuel for the nitrous, losing fuel this way is the ultimate disaster. An aftermarket ignition will typically implement the rev limit by cutting off spark rather than fuel, which is a much safer implementation of the rev limit. Typically, you'd get your stock PCM programmed to set the rev limit up higher than you'll ever expect to go (like 7000RPM), and use the setting on the aftermarket ignition as your actual rev limit.

Window Switch

This electrical device provides an open or closed circuit based on the engine being between two RPM values (hence "window") that you chose, so that you'll only flow nitrous in this range. Why would you do that? Well, for two very different reasons.


At low RPM, think about what's going on: you're spraying nitrous into the intake at a constant flow. That is, the nitrous bottle and solenoids have no idea what RPM you're at, and they're just pushing it into the intake at a constant volume. Inside the engine, though, the nitrous and fuel combination is being sucked into the cylinders during every stroke. The net result is that at low RPM, you're getting far more of the mixture into the cylinders. At 3000 RPM, for example, you're getting twice the amount as at 6000 RPM. So, you can imagine that running nitrous at, say 1000 RPM, is far more stressful on the motor as at 3000 RPM, and typically causes a "nitrous backfire" - meaning that the nitrous/fuel combination can explode in the intake manifold (rather than the cylinders) - a bad thing. So that's why you don't want the system triggered at low RPM.


At high RPM, the situation is easier to explain. Given the discussion of the rev limit above, you may just want the nitrous system to cut off before hitting that rev limit. If you've got a ignition, you certainly want a window switch. If your rev limit is implemented by an aftermarket ignition, it's perfectly safe for the motor to run nitrous during the rev limit. It's not particularly easy though, on your transmission or clutch to have all that power during the shift, which may be a reason to keep the window switch set a bit before you shift. 

Fuel Pressure Safety Switch (FPSS)

This is a device that's plumbed into the fuel system, and provides an open or closed circuit based on availability of fuel pressure. It can be used in the triggering circuit to make sure the system isn't on when you've got a fuel problem. Typically, you only use it to switch off the nitrous solenoid; turning off the fuel solenoid as well can start a cycle of switching the solenoids on and off while the pressure raises and drops in the fuel system when you're switching the solenoid on and off. Let the pressure build up in the fuel lines when you open that solenoid, and when it's high enough, the nitrous solenoid will open. The switch can be used whether you've got a wet or a dry system. You can adjust the pressure at which it triggers by using an allen wrench on the back of the switch (loosen the screw lowers the pressure threshold).


To set the threshold pressure, you've got a few options"


1.



Connect enough plumbing so that you can have the FPSS installed at the same time as a fuel pressure gauge. Turn the key on to pressurize the fuel system, then turn it off. As the fuel pressure bleeds down, monitor the continuity across the FPSS contacts (disconnect them from the rest of the nitrous system) and when the pressure reaches the level you're interested in, adjust the screw on the back so it just balances back and forth between the continuity signal.


2.



You could use an air compressor, with the appropriate fitting for the FPSS. Remove the FPSS from the car, and thread it onto the compressor. Set the compressor for the pressure of interest, and measure continuity as above.


3.



If you can't do option #1 above because you don't have two available ports, first thread in the pressure gauge, and cycle the key. Then time how long it takes for the pressure to bleed down to the correct level. Then disconnect the pressure gauge, install the FPSS, and do the process against the clock rather than the pressure. 

Timing Retard

A nitrous/fuel mixture increases the burn rate in the cylinder, and typically adding a few degrees of timing retard is recommended for safety. A rule of thumb is two degrees per 50hp of nitrous, but this will also reduce the power generated. When I tune my system, I monitor engine knock, and retard the timing only enough to eliminate the knock, which is usually about one degree per 50hp. At the track, under harder conditions (actually pulling the weight of the car, possibly higher outdoor temperatures, etc) you can add a degree of retard.


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## buffdaddy18 (Dec 16, 2005)

this maximum character thing is killin me. lol

High Octane Fuel

High octane gas (e.g. 100 or more, unleaded) will also slow the burn rate in the cylinder. This will provide another way, similar to retarding timing, to avoid knock. I only use nitrous on a 50/50 mix of 92 octane pump gas and 100 octane racing gas. Make sure it's unleaded, of course, or you'll destroy your O2 sensors.

By the way, watch out for Octane Boost claims. Typical claims are "8-10 points of octane boost for a tank of gas." You should be aware that these "points" are tenths of a point of octane as you'd purchase at a gas station. So the above example will raise your octane from 92 to 92.8 or 93, not 100-102 as you might think.

Don't assume that if high octane fuel helps on nitrous motors, that it'll help your naturally aspirated motor too. A naturally aspirated motor is tuned for a particular octane of gas; adding more doesn't help one bit. Save your money.

Nitrous Filter
A simple part, but essential in any nitrous system. This filter is added in-line to your nitrous line, between the tank and the solenoid. Install it as close to the solenoid end as is convenient. It will trap any small particles that may come through the line, much like a fuel filter. A common solenoid failure is due to some particle jamming it open.

Fuel Systems

Your fuel system is the most important part of the system. As I hope is clear by now, the worst scenario in a nitrous system is a lean air/fuel mixture. The solutions to a good fuel system depend on the type of nitrous system you're using.


On a wet system, you simply need to ensure that your fuel system can supply adequate fuel, at standard (~45psi at WOT) pressure. A stock f-body fuel pump can usually supply enough fuel for around 450 total horsepower to the motor; any more and you want to get a larger pump. Much more than 650hp and you'll want larger fuel lines as well.


On a dry system, not only do you want adequate fuel like the wet system, but on an regular setup the fuel is added by raising the fuel pressure, which forces more gas through the injectors. In this scenario, it's typically recommended that you replace the stock fuel injectors with better quality (not higher rating, just better, like Bosch) injectors. These injectors are able to handle the increased fuel pressures necessary.

Spark Plugs
Generally you want to use copper spark plugs as opposed to the stock platinum ones. You also want to reduce the gap from the stock 0.050" down to 0.035"-0.040". I've received a couple notes on why you use a smaller gap. "The reason you want a smaller gap is because of ionization. If you change from the typical air (78%nitrogen, 21% oxygen)/fuel ratio, a given gap requires more energy to ionize the mixture, resulting in less energy in the spark, if you even get a spark. You could also increase the coil voltage instead of decreasing the gap, but I think using a smaller gap would be preferential since the spark time will be smaller." and also this message: "The reason that you will close the gap on your spark plugs is because when nitrous is added, it raises the cylinder pressure, much like a supercharger. Therefore "blowing" the spark out. When you close the gap it cannot put out the spark as easily."
Testing Solenoids
I mentioned failed fuel or nitrous solenoids doing damage. Some of the issues here may be hard to cover with only other safety devices. I recommend you wire your solenoids with spade clips, so you can easily disconnect them, and test them on a regular basis. Simply disconnect them from the rest of the wiring, then ground one side, and connect the other side to 12V, and listen for the click-click to make sure they open and close. Some folks will also use two nitrous solenoids, in-line, which will ensure that both would have to fail before the flow would fail to stop. Of course you still need to test this setup, to ensure one isn't stuck open.
Tuning

All of the kit systems will come with a couple tuning setups, labeled "50-shot", "100-shot", etc. These are tuned to provide 50, 100, or other horsepower amounts, usually measured at the crank (i.e., measured on a chassis dyno you'll get a bit less). I consider these a starting point, and certainly good for your first passes (hopefully you'll make these with the lowest power, until you tune the system up). Once you've got the system installed and functional, though, tuning it is paramount, before running any serious power through it. I really recommend you do this tuning right away, even though the temptation will be strong to just go out and enjoy the power. This is the time you're very likely to do some serious damage to the motor, so it's important to get it set up right.

Getting Started

I'm not going to go through a bunch of details on tuning here, other than to mention some ideas. You've got a plumbing system to test, as well as an electrical system. You'd like to test each component of both systems, to verify that it's correctly doing it's job. I suggest doing most of this in your garage, with the nitrous and fuel lines removed from the intake, and pointing (or held) into a rag. Keep in mind the nitrous line will give a good kick under pressure, so don't just leave it loose to whip around. You can test your WOT switch easily enough, your window switch (maybe set the window range at a lower rpm for the test, so you don't have to rev up to your red line). To test your fuel pressure switch, you'll need to verify it's got a closed circuit when the engine is running (showing adequate pressure), but you'll also want to verify that it opens the circuit as fuel pressure drops. There are a couple ways to do this. On my car, the fuel pressure bleeds off at about 2psi per hour. So if I switch the engine off, I can use an ohm meter to check continuity across the FPSS connections, and within a couple hours it should switch off. You can also test the FPSS on an air compressor, by generating the pressure you want for the FPSS, and monitoring that it switches at the right point.


For the plumbing, you of course want to verify that there are no fuel or nitrous leaks in the system. You should be able to leave your nitrous bottle open for hours without losing bottle pressure. On the fuel side, of course a fuel leak may be the most disastrous possibility, so check this first by pressurizing the system (turn the key to "acc" but don't start the car) and feel around all the fittings. 


I haven't listed all possibilities, but hopefully given you an idea of where to start testing. Once everything seems to check out, put in a set of 50hp jets, and move out on the street...

Jets

All nitrous systems use "jets" inserted in the fuel or nitrous lines to limit the flow. These jets have openings of a specific size, measured in thousandths of an inch. So a "35 jet" is a jet with a hole drilled 0.035" through it. Increasing a nitrous jet size will make the system run more lean, increasing the fuel jet size will make the system run more rich.


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## buffdaddy18 (Dec 16, 2005)

There's also a good web site with a jet size calculator on it for a wet setup (where you're metering the fuel and nitrous yourself). It will give you jet sizes based on desired horsepower, fuel and nitrous pressure. I recommend you use these as a target, maybe start a bit richer than shown.


I don't have information here on the use of a jet to apply vacuum pressure to a fuel pressure regulator, as in the NOS 5176 kit. The use of jets for this purpose, and calling them "fuel jets" is NOT related in any way to the normal use of fuel jets in a wet system, and I'm not aware of algorithms that would allow you to select these jets in combination with nitrous jets, to create a certain amount of horsepower. Contact the nitrous kit vendor for recommendations.

Scanner Tuning

A PCM scanner (Diacom, Autotap, etc) is crucial to successful tuning of your nitrous system. I run most of my nitrous passes while logging with an Autotap, and also use it at the dyno. You'll be monitoring the oxygen sensor voltages, knock, etc, and adjusting the jets to provide the best combination. Note, though, that the stock oxygen sensors are not particularly good, and a wideband O2 sensor (say, at a dyno) is much better to use if you have access to one. Typical O2 values should be around 860-880mv (higher is richer) when running the motor normally aspirated, and I try to tune mine to 900-940 on nitrous. As mentioned above, you'll adjust jet sizes up or down to enrich or lean out the mixture. You'll probably see some knock during a shift, but should see none otherwise. You can add timing retard to reduce knock.

Dyno Tuning

Doing your scanner tuning at a dyno provides another benefit, since you can see the power the engine is generating, while you tune the system. It also makes the whole tuning process

Miscellaneous Options
Purge

Most nitrous systems are build with a purge feature. The purpose of a purge is to get liquid nitrous oxide up to the front of the car, filling the hoses with nitrous rather than air. To do this, another solenoid is used, but rather than shooting the nitrous into the motor, it's usually shot up over the hood, so you can purge until it creates a nice fog. It also looks real cool . Of course, no fuel is used during a purge.

Bottle Heater

It's virtually mandatory that you install your nitrous system with a bottle heater, which is used to raise up the temperature of the bottle, and therefore increase the pressure at which the nitrous is delivered. If you don't use one, your pressure will quickly drop and won't supply the volume of nitrous your vehicle was tuned for.

Remote Bottle Opener

Normally, your nitrous bottle should be kept closed, with no pressure in the nitrous lines. But when you're lined up against that guy that just looks a bit too fast, you'd hate to say "excuse me, do you mind if I hop out and open my bottle in the trunk?". Easy solution, get a remote bottle opener! Most vendors have such a device, which allows you to open the bottle electrically via a switch on your dash.



Collateral Damage

You can break tons of other parts on your car by running nitrous, or any other large power adder. Running slicks at the track will just accelerate the damage. Here are a few things to keep in mind.

Clutch

The huge torque spike at low rpm's is particularly hard on clutches. I had to buy a new clutch as soon as I made my first pass with nitrous on slicks. Keep in mind, on a manual transmission car, you're likely to need one too.

Tires

With all the extra power, you'll have trouble hooking up with any traction, especially on street tires. You'll probably have to use drag radials at least, or slicks if you're adding any significant power.


Note: Running nitrous oxide in your engine can be very dangerous, and the above document is intended on helping you understand generally how it's done. My recommendation is that you not do it at all, unless you can afford a new motor if something goes wrong. In either case, the information above is just my recommendations, and in no way is a guarantee, or acceptance of any responsibility on my part.


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