Im currently in the process of trying to twin turbo my 89 lx that has a 351w in it right now. N/A im hitting 12.80's. Im just wondering who has a turbo 351w and what carb/ cam and turbos your using. Im just checking out my options right now.
hey thanks guys, but what im really trying to find out is some fuel options. Obviously its way cheaper to go carb so that is what im going with. Though its not as efficient, i have seen some impressive times even with a carb. The only real good source i have found is www.toohighpsi.com which i recomend everyone looking for a fast cheap turbo build go there. I would like to see some other builds though.
Seriously? No one else has any comments? Well then does anyone have any comments on nitrous? Im putting nitrous on my other 351W mustang. My main concern is Retarting the timeing. Dont the experts say about 2 degrees retarted for every 50 shot? so you would think that i would want to run 4 degrees retarded since that im going to run a 100 wet shot to start out?
So you bought yourself a nitrous kit, huh? Now what? Think you can just bolt it on and go? Well maybe, but how about making sure you understand exactly what you're getting into first. It just might save you some cash. I'm going to address some of the basics of tuning in your kit. I'm going to stay pretty general with this article so it will apply to the masses. There are a lot of common questions that get asked about using nitrous and a lot of misconceptions that I can probably shed some light on. Let's start off by getting a general idea of exactly what nitrous does when it's introduced into your engine and why it results in more horsepower.
1) Nitrous Oxide (N2O) is comprised of a ratio of 2 parts nitrogen to 1 part oxygen. N2O by itself is NOT flammable.
2) When it is introduced into the intake charge (the flow of air through the intake) it cools the charge. The colder the air is, the more dense it is. The denser the air is, the less space it takes up. The less space it takes up, the more you can fit in your combustion chamber. Your engine is nothing more than an over-glorified air pump. The more air it can move through it, the more power it will make.
3) Having more air in your combustion chamber increases your compression ratio when you're spraying. I'm sure you've seen or heard of people blowing head gaskets when they're spraying. Extra heat and compression are the causes of this. You need to have the right parts.
As I stated, I'm going to keep it pretty simple here. Now then, onto the most vital aspect of nitrous use, THE FUEL. If you think about the points I just made you'll understand why you need to supply more fuel to your engine if you're spraying nitrous. Dry kits (kits that don't also introduce fuel) are available but their power potentials are greatly limited because they don't introduce more fuel. You need to have more fuel introduced to support all that extra air you're running through your engine. Without it, you would get lean and start melting parts. It's no different than getting a carb dialed in when you think about it. If your carb is overly lean you're going to melt parts. Same deal here. You need enough fuel to support the amount of air you're pushing through your engine, no matter if it's naturally aspirated, blown, bottle-fed, or turbo'd.
Okay, onto the good stuff! Here's where I'll start getting a little more detailed to better help you understand the tuning aspects of a kit and all the variables that are involved. I want to make it clear that we use only NOS brand nitrous kits and all of our years of tuning are based on NOS kits and parts. Most of these principles however will apply to any kit. With any nitrous kit you should always start with the manufacturers recommended settings and jetmaps and dial it in from there. The addition of a data recorder to my car did a lot to help us better understand what was going on with our kits. I would highly recommend one to anyone who's looking to get more power out of their setup.
FUEL - The other white meat The delivery of extra fuel is THE most important part of any nitrous kit and it's the part that will take up most of your tuning time. Introducing N2O at 1000psi is pretty simple to accomplish. Introducing fuel in the neighborhood of 5.5psi reliably and consistently is not as easy. I can't stress enough how vital the fuel supply is. There are some pretty simple things you can do to greatly aid you in your tuning though:
1) A separate fuel system dedicated to the nitrous kit. There are some really good fuel pumps out these days that are capable of flowing enough fuel reliably to support both an engine and a nitrous kit but we're still firm believers in a separate system. A separate system keeps your kit "self-contained". You're not throwing engine components and engine fuel supply variables into the list of factors that will affect your nitrous tune-up. A small cell mounted at the front of the car with a filter and pump is all it takes. Keep the lines as short as possible and try to keep the fuel moving towards the rear of the vehicle as it makes it's way to your kit. This will help eliminate G-forces from being a negative factor in your tune-up. The cost of an extra fuel system is a lot less than a set of pistons, rods, rings, bearings, crank, etc.
2) The ability to be able to only run the good gas in your small cell and still be able to run cheaper, lower octane fuel in your main fuel cell used to be another one of our positive reasons for this setup. Recently we did some reflection to our past and problems that we used to have. What we came up with was pretty simple and one of those "humbling" discussions. We were wrong. The lower octane fuel is still going to detonate before the higher octane fuel, even if it's all mixed together. You can get away with doing this on lower hp kit settings but as you get over 200hp I recommend running the same octane fuel to your kit as you do to your engine. It's a bit more expensive this way but we attribute this very simple mistake to a lot of melt-downs on Jimmer's car over the years as we began spraying higher hp settings.
3) You can never have "too much" fuel pump. I can't tell you how many times I see guys spraying 350hp and only using a 140gph pump to supply the fuel to the kit. You're asking for trouble and you're not getting all the power out of your kit! Not only is volume (gph, or gallons per hour) a factor here, but psi is as well. A pump's volume will change with psi changes and vice-versa. When dealing with a drag car and G-force's the rule of thumb is to have 3 times the needed psi coming out of the pump. For example, if you're running your nitrous kit at 5.5psi, you would want to have at least 16.5psi out of the pump. This is a factor when choosing a pump. Make sure that the pump you choose can supply adequate volume (gph) at the psi that you're going to be running it at. The engine pump is very vulnerable to fluctuation if it's not putting out enough psi. On an 8 second car you're pulling about 3g's off the line and it tapers down throughout the run. 3g's means 3 times gravity. So if you placed a scale vertically on your passenger seat and put a 10lb weight against it, at 3g's that 10lb weight would register 30lbs on the scale. So how much fuel do your lines hold? 20 feet of -8 line holds just under half of a gallon of fuel. A gallon of fuel weighs approximately 7lbs. So just sitting there the pump is pushing 3.5lbs of fuel. At 3g's that fuel weighs almost 11lbs. Pick up 11lbs. That's a fair amount of weight for a pump to be pushing to the front of the car. I wouldn't spray over 250hp with a 140gph pump on any application. On anything over 350hp I would recommend at least a 300gph pump and if you're spraying in excess of 450hp you should be running a 500gph unit. But once again, make sure that the pump you choose flows the volume you want at the psi you're going to be running at. Many manufacturers mislead you with their advertised numbers.
4) Okay, enough about fuel pumps. Let's move on to the regulator (reg). So you've got the psi you need coming out of the fuel pump. Now all you need to do is regulate it down to a lower psi. Sounds easy! Wrong. I've mentioned how fuel supply is the most vital aspect of a kit. Well, controlling the fuel psi and keeping it stable and repeatable is the biggest tuning factor of the fuel supply. But there are some tricks to help you there too. You can go out and spend a couple hundred bucks on some wang-go, cool looking, rainbow-anodized regulator. Or, you could just go get yourself a Holley #12-803 for 20 smack-ola's and have the same one we use. We've found it to be the best of the one's we've tried. That's not to say that other's aren't good, but they're a lot more than 20 bucks and we're completely satisfied with the performance of ours for regulating our nitrous kit's fuel psi. Whatever regulator you choose has to control the psi of the fuel going to your kit with the least amount of psi fluctuation as possible. It also needs to be repeatable. You don't want to set it at 5.5psi and after a couple of times opening it all of a sudden is putting out 6psi or it's psi steadily ramps up or down during a run. This is often referred to as pressure "creep". It also needs to hold back all that pump psi. This is something to think about when choosing one. If you're putting out 20psi from your fuel pump, you want to make sure that your regulator can control that kind of psi reliably. Another common problem related to the regulation of the fuel is pressure spikes. When you engage your kit and start flowing fuel through the solenoid, the system goes from a stagnant state (the fuel isn't moving) to an active state (the fuel is flowing). The regulator needs to "catch up" with the change in it's environment. No matter what you do there will always be a drop and some fluctuation until the regulator flattens out but you can help make it flatten out sooner and minimize it's overall psi drop at the time of activation by running a return line from your nitrous kit's regulator back to the fuel cell. This keeps the fuel moving at all times so the change to the regulators environment isn't nearly as significant when you engage the kit. This return line should have a small jet in it to control the amount of fuel that's flowing through it. You don't want to just run a -4 line off the reg back to the cell, that would be wasting a lot of fuel supply and taking away fuel that your kit needs. We use a NOS brand jet in the neighborhood of .025-.030" in size. This line always stays attached. You shouldn't need to change the jet or ever disconnect the line. If you have a pump with it's own bypass you should still use it. The pumps internal bypass helps it function properly, the reg bypass helps the reg to function more efficiently and reliably.
5) Now let's talk about how you should set the psi on the reg. You want to do this with the fuel "flowing" the same way it is when your kit is engaged. That means you want to be flowing the same amount of fuel as your kit flows when it is engaged. To do this you need a flow gauge. There are several companies that make these. You need to calculate the overall jet area of your kit and place that size jet in your flow gauge. There are a couple of formulas that you can use to calculate this jet size and you can find them in our "Tech Tips" section under "NOS Jetmaps". Once you figure out what jet you need, place it in your flow gauge and hook the flow gauge up to your regulator. If you have an extra port you can hook up there. If you don't have an extra port off your reg, simply disconnect the feed line to the solenoid and hook up your flow gauge there. Remember not to remove the return line, that never comes off. Turn the pump on and set your reg psi where you want it by reading the flow gauge. Simple as that. Now when your kit is engaged you'll actually have the psi that you want. Be sure to hook up your flow gauge often to make sure your psi is still where you want it. We check ours almost every pass.
That pretty much covers the fuel supply to your kit. Following these guidelines can save you a lot of tuning headaches. Now we'll move on to the nitrous...
NITROUS - Adrenaline in a bottle As I stated earlier, introducing the nitrous is pretty simple but there are some things you should know:
1) You can never have too big a supply bottle! For any applications spraying under 300hp a 10lb. bottle will work just fine. There are advantages to a larger bottle though. On a 300-350hp setting you'll use about 3/8 lb. of nitrous per second. So do some math. On a 9 second car you'd be using about 3 3/8 lbs. of nitrous per pass. That's about 33% of your bottle. As nitrous leaves the bottle, bottle psi is lost. The lower the percentage of nitrous that leaves your bottle is, the more stable your psi would stay throughout the run. In the same scenario with a 15lb. bottle, you'd only be using about 22% of the bottle's capacity. The same scenario with two 10lb. bottles would only use up about 17% of the capacity. It doesn't seem like much..but it is. Another reason for the larger bottle is what has come to be known as "Sweet Nitrous". It is theorized that only about 1/3 of a bottle is actually good horsepower-making nitrous. The rest of the contents are negatively affected by "phase change" as the bottle is drained. I'm going to save more details on this for a later article. It's based on Butch Schrier's experiments and years of R&D with nitrous kits.
2) Keep your supply line as short as possible! You don't want to have supply line coiled up and zip-tied together. Just like the fuel supply lines, you want to keep your nitrous supply line as short as you can. Some classes have rules that require a minimum line length so check the rules to be sure your setup is legal. The longer the line is, the more pressure you will lose by the time it reaches the plate or nozzle. The line is an extension of the capacity of the bottle once the valve is opened. If you increase the capacity, you decrease the psi.
3) "What psi should I run my bottle at?" This is one of the most common questions associated with using nitrous. Let me start by telling you that all the manufacturers that I know of base their standard jetmaps at a bottle psi of 950psi. There is no "magic" number. It's yet another tuning variable of your kit. But....nitrous oxide flashes from a liquid to a gas at 760-780psi and makes no power. Considering the psi that is lost while making a pass, you definitely don't want to start a run with less than 850psi in your bottle. I try to have mine at about 1050psi at the start of a run. A safe range is 900psi to 1100 psi. Whatever psi you run and tune your kit with needs to be the psi you stick with. If you run at a different psi you will get different results out of your kit. This is where those bottle heaters come in. A bottle heater is a MUST HAVE item. You should NEVER use a torch to heat your bottles and every bottle should have a psi gauge so you know exactly what psi it's at!! Invest in one of the various bottle heaters that are on the market, you'll be glad you did. A 5 minute wait in staging on a cool night can be the difference between a good pass and a wasted one without a bottle heater.
Those are the fundamentals in regards to introducing the nitrous. Now let's talk about tuning in your kit:
IT'S GOING TO RUN THE NUMBER OR I'LL BLOW IT UP TRYING!! I've said that a few times! Fortunately, I've never over-stepped my kit's boundaries. If you do, you're asking for trouble. Before you start tuning your kit you need to be sure that your combination is tuned in when not running the bottle. If it's not tuned in properly off-the-bottle, then tuning it on-the-bottle is going to be much more difficult. Tuning a kit in really isn't as hard as many people believe it is. The manufacturers have spent a lot of time and money to come up with their recommended settings and that's where everyone should start. Those recommendations are "safe" for almost every application. Start with a standard jetmap and the recommended fuel psi. and timing retard. Also, start on a lower hp setting. Don't go out and set your kit at the maximum setting and then start tuning. See how it's working on your combination at a lower hp level first. Every application is different and will need to be tuned in. SO LET'S TUNE IT!
1) Okay, your kit is on a low hp setting and you just made a good pass. Now what? Well, the most important part of tuning your kit in is reading the plugs. To get an accurate reading try to have your car towed back to the pits. Shut it down immediately following the run. Driving back to the pits can completely mess up the plug reading. If towing back isn't possible, drive it the least amount possible and then check them. I'm not going to get very involved on plug reading in this article. I'm going to do an article this Summer dedicated to plug reading but to do it properly I need pictures so that's going to have to wait. If you don't know how to read a plug simply find someone who does, preferably someone with nitrous experience. They'll be happy to help. Here's where I should point out that no question is too dumb to ask. If you don't know...ASK! It's the only way you're going to learn...well...you could blow up a few engines and learn too I guess.
2) There are many tuning variables associated with your kit but here is the most commonly tuned one...the amount of fuel vs. the amount of nitrous. There are a couple of options to get it where you want it. A very common approach is to adjust the fuel psi. If your plugs are reading rich you would take some fuel psi away. If your plugs are lean you would increase the fuel psi. This is the most widely used method of tuning. It works, but it's not the best way to do it if you need to lean down the kit. The problem is when the kit is rich and you take away fuel psi, you can often end up at a pretty low psi. Earlier while I was discussing fuel supply I referred to the spikes and drops that inevitably occur when the kit is engaged. If your kit is at a psi below 5lbs, one of these drops or fluctuations could prove to be pretty expensive. A better approach is to adjust the nitrous jet and leave the fuel at a constant. Sound scary??...it's not. It means taking very small steps though. Don't ever go more than a couple of jet sizes on a plate kit or one jet size on a Fogger. Re-check the plugs and tune again if necessary. If you find yourself having to make drastic jetting changes...STOP! There is probably something else wrong. Get some advice from someone experienced with nitrous. If you doubt what they're telling you, get a second opinion. Tuning a lean condition is a little bit easier. If the plugs are lean...bump up the fuel psi. Once again take small steps, like 1/8lb. increments. Having too much fuel can cause just as much damage as not enough. The reason you bump the fuel psi when the kit is lean rather than adjust the nitrous jet is so you can have as much fuel psi as possible. The more fuel psi you have, the less the percentage of change is when the kit experiences any possible spikes, drops, or fluctuations. This is why high psi tune-ups have become so popular these days. I have yet to see any horsepower advantage to the higher psi tune-up, but the safety and consistency that come along with higher fuel psi makes it the ideal tune-up. If you're new to nitrous, save the high psi stuff for later. Get a grip on tuning your kit at or near recommended settings first.
3) My plugs look great! I'm ready to set it on kill!! Hold on there Speedy...don't assume you can just max it out and be safe because you dialed in that low hp setting. Each new jetmap will require the same tuning steps. But, thanks to what you did on the lower hp setting you now have a general idea of what your combination likes. Before you bump it up to the next hp setting, see what kind of actual hp you're getting based off your timeslips. Compare your off-the-bottle runs to your bottle passes. Do the gains look close to what they should be? If not, you may not have it tuned in as well as you think you do and you might want to spend more time at this level before bumping up. When you do bump up, go with the recommended jetmap again. Then tune from there. Be sure to keep track of all your settings and changes on a computer or notebook so you know where it ran the best at each hp setting. This is valuable information that you can reference later on. It also helps to have that info and timeslips when you're talking to someone about tuning your kit.
4) My jetting is great, what else can I do? Another tuning aspect of your kit is the timing. Check what the manufacturer's recommendations are. Most will recommend retarding the timing 4 degrees for every 100hp of nitrous (1 degree per 25hp). This is a safe setting. But it's not necessarily the best one. Although I've never seen any combinations that required taking out more than 4 degrees per 100hp of nitrous, I've seen plenty of them make big gains by taking out less. BE CAREFUL! Once again, take small steps with this. Never more than a couple of degrees at a time. I can't verify this theory, but we have found that higher-domed pistons seem to be capable of having less timing taken out than flat-tops can. We believe it has to do with the flame travel over the dome but once again we can't verify it. We've had my car all the way down to only taking out 8 or 9 degrees on a 350hp setting and not had any problems. I don't recommend this though!! Tuning the timing in is something you shouldn't do until you're very familiar with your kit.
5) Make sure your parts can take the hp!! I can't tell you how many times I've seen people throw a 350hp kit on their stock engine and then they wonder why they're breaking parts. Don't overstep your boundaries! While it's very tempting to throw those bigger jets in and go for a better number, it sometimes ends up costing you a lot of money. Be sure your parts are designed to take the extra power. It sounds easy enough but it's often not paid attention to. Use your head!
That pretty much covers the tuning basics. It should be enough to get you started anyways. Now I just want to go over a couple more things that are often discussed with people new to nitrous and some of the mistakes made. Firstly is activation. How should you activate your kit? If you're not ready to have the nitrous on for the full pass or if you're simply adding it so you can use it if you have to, a button is for you. Preferably one mounted to the steering wheel so both hands are on the wheel when the kit is engaged. If full nitrous passes are for you, then use a throttle switch. No buttons to mess with and simple. Next comes that RPM limiter you've got hooked up. You don't want to hit that while your kit is engaged. Ever see someone miss a gear and have a fireball at half track that sends their hood into the farmers field? It's common. Either disconnect the limiter or be REAL sure you don't hit it when you're spraying. Same goes for a two-step. Don't be on a two-step with the kit engaged...big fireball. The fans love this stuff but it's a lot more fun when you're in the stands watching it than if you're in the driver's seat of the car it's happening to. A good ignition is mandatory for nitrous use. If you spend a little extra money on the ignition you can get one with features like RPM switches built in. This comes in handy. If you have RPM switches you can wire your kit through them and you can set it up so the kit automatically shuts off before the RPM limiter is reached. I definitely recommend it. Another thing is when you actually arm the power to your kit. Don't do it until after you've completed your burnout and you're about to stage!! Ever see someone do a burnout and kill the engine in the process? Well...they have to hold it to the floor to get it to start and they just happen to have a throttle switch on their kit. Mind you, they're kind of embarrassed right now because everyone is watching them and they forgot that they turned their kit on before the burnout and right now while their foot is to the floor it's pumping fuel and nitrous into their engine. As soon as it sparks...KABOOM!!!...I mean BIG fireball! Once again...fun to watch from the stands but not so fun if you're in the car. This is one way to get all kinds of people over to your pit area though so if you're longing for attention you might want to try it. If you're content with the amount of attention you're receiving already, just don't turn your kit on until you're about to stage and you've cleared out the engine after the burnout. RPM switches would help in this scenario as well. Not only can you set the RPM that the kit turns off at, you can also set the RPM that it turns on at. With it wired this way there is no chance of the kit introducing fuel or nitrous into your engine if the engine hasn't reached the RPM you set it at. Well, I think that's enough for now.
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Reggie
Real Racers Don't Street Race
PERIOD.......
'88 LX Hatch With A Little Of This & A Little Of That...... 10.39 @128 MPH Soon to be faster....
Lets talk BOOST on 351w 
