water/methanol injection

Water/alcohol injection is used for two reason. 1. To get every last little bit of performance on the drag strip. 2. To cover up a poor tune.

I have been running water and/or alcohol inject on my KB blown '89 Mustang for years. In a nutshell, yes it works, and it works very well. My advice is to leave out the alcohol and just inject water. It takes very little water to cool the intake air temperatures. Using water only will not affect the air-fuel ratio and makes it easier to tune the engine, IMO. Also, gasoline has a higher specific energy and per unit volume will generate more horsepower. Additionally, water has a higher heat of vaporization than alcohol so it is a more effective cooling liquid.

On a KB blown car it helps to make the "on" point of the spray both boost AND rpm dependent. This is due to the KBs providing full boost at a very low rpm. Spraying too much water at a low rpm can bog the engine because the water volume is too great for the the limited air flow. I use this setup and find it works well on my car:

I know the guy that owns SMC and he is great to work with. I don't hesitate to recommend him, and his product, to anyone. Just be sure to tell him you plan to run only water. He will use a pump that is designed for water. Typically, the turbo Buick guys run only alcohol so he uses a pump for them that will rust when water is present.

Just to let you know how effective water injection can be, I ran 16 psi with it and it worked very well. The problem I had was that on a stock

302 block the heads would lift at this pressure and it made the engine very prone to blowing head gaskets. If I had a better block I don't doubt that 16 psi, or more, is within reach. I backed the boost down to 12 psi and am able to run a very aggressive tune for that level of boost. It will take a little patience to get the water injection dialed in right but once you do you will love it.

One last thing, water injection can actually cool the intake air to BELOW ambient temperature. Try doing this with a standard air-air or air-water intercooler. :)

Your #2 doesn't apply to a KB blown 302 engine. There are no intercooler options for this setup so water injection is the only reasonable way to cool the intake air. It doesn't cover up a poor tune. It allows you to run a more aggressive tune for a particular boost level or just run more boost, period.

Also, water injection works very well on the street. It isn't a "drag strip only" modification.

about where are your spray-on set points, RPM and/or boost ? like the RPM would have to be about 1800 AND the boost would have to be about 2# or greater?

I did some design work with cooling buildings with spray water/filters, (upgraded type of swamp coolers) and I know it can cool down to within about

5 degrees of the due point, (up the humidity tto 85-95%) so in Texas summer day it can be 100 degrees out, but the due point is at 73 degrees, so it can cool down to about 78, that is 22 degrees below ambient. Phoenix is even better. Seems like water injection is just better than the intercoolers, except one has to carry water tank, but that's easy.

found this out there too;

of them little rice burners are running 22 pounds with water/alcohol injection

Mine is only boost dependent. It will bog slightly. My car has been laid up for quite some time so I have never upgraded the control box. My next step is a 427W engine swap. I have run the KB for a long time and want to go with a simpler more reliable setup. The 427 cubic inches should give me about all the torque i get from the KB.

Just go easy on the water. It doesn't take much at all. Using more than needed only robs power. A quart bottle of water will last quite a while. When spraying alcohol the bottle will drain rather quickly.

Here's some links I have accumulated over the years:

Here's an absolutely wicked OEM computer replacement:

You're telling me it's normal to have detonation at 5psi under routine driving conditions? And the only way to fix it is with water injection? I've never owned a KB, but I have owned and driven other forced induction applications. 8-10psi was normal before detonation on those vehicles.

Could be a poor tune, weather in his area, carbon buildup in the chambers, inadequate fuel delivery etc. Believe it or not the water and/or alcohol injection can cure all these problems. BTW, to me, "normal" driving conditions are non-boost driving. I assume he is talking about detonation while under boost. He can choose also to retard his tune but that only gets you so far and is counter productive to the reason the blower was installed.

I've two cars with forced induction that are otherwise identical need two radically different tunes to prevent detonation. I wouldn't automatically assume he has a "bad" tune. Maybe inadequate.

To be fair, you have a point. He could probably fix his detonation issue without W/A injection but the results might not be very rewarding. Also, the fact his KB does not have a bypass is likely the main reason for his detonation at low boost pressure. The bypass lets the blower spin free under non-boost driving thus letting it stay cooler. The bypass feeds the engine air without the need for it to pass through the blower. Under boost the bypass closes and the blower provides boost to the engine. Without the bypass the blower is always compressing the intake air under all driving conditions and this, in turn, heats up the blower and the intake air. It also makes the blower hotter when it first delivers boost and only gets hotter the longer it is in a boost condition. Hot air causes detonation and requires timing to be retarded a great deal. So, in a way, water injection might be the only way for him to successfully resolve the detonation problem at 5 psi with his current setup and driving conditions.

The KBs are tougher to tune, IMO, than a centrifugal blown engine and just a little harder than a turbo setup. The reason is that with a centrifugal the rpm window of full boost conditions is relatively narrow. Low to mid rpm tuning can mostly be handled with the near stock settings. A KB provides full boost from idle to redline so tuning has to occur throughout the entire rpm range and numerous engine load conditions. It really takes a tuner that has worked a lot with KB setups to get it right. Plus, without a bypass, it makes tuning the engine that much harder.

With a KB, 6 psi is fairly detonation free but any more can bring on problems and depending on the given engine and associated mods the problems can be severe and difficult to resolve. The KB kits for the

5.0L engines have no intercooler option due to their design. KB hasn't improved their kit for the 5.0L in over 15 years and any advances are done at a grass roots level. Me and several other KB users pioneered the use of W/A injection for these kits 4-5 years ago and, in the beginning, many laughed at us for trying and said it could never work. When these people, including KB, started seeing boost levels that were not seen before they finally took notice. I personally ran 16 psi with a tune I bought from Chris Johnson when I ran 8 psi. That is how effective water injection can be.

So in a way, W/A injection might be the only way the OP can solve some of his issues. The fact he is running his car in Texas without a bypass makes it about the only option to running high boost for his setup in the heat of the summer. The only down side I encountered when running water injection was the need to top off the bottle every 3-4 tanks of gas but the cost of that was very cheap. ;)

I bet it is carbon buildup, and also Heat Soak. I did a compression check 10 years ago when I got the '93 car, and all cylinders read the same in a narrow range (45 I think). It has 135K miles now. Before that, I had a 5.0 '87 and did the compression check and two cylinders were too high, about 60 and the rest varied around 45 was the lowest (mileage was about 155K). So I sold that car and got the 93, so I could put a supercharger on a good car. (Both cars are ex cop cars bought at the auction, (about 95K) stiff suspension, rough ride, 87 was really fast). I could do another compression check and find out.

When the '93 car is cold it can do 8#, no problem. It takes about a hour at

90 degrees and det starts at lower boost levels about 4-5. I drove the car from Phoenix to Austin in the summer, 110 or so, and after 3 hours on the road, it was det with just 2#, which really sucks, can't pass car much.

I have meter for Air Fuel ratio for both O2 sensors, and boost/vacuum meter, and fuel pressure meter (45-50 then goes to 75-80 in boost, just one step, ). I could move timing from 10 to 8, but that looses HP all the time, but with water, should be OK.

There is a fuel regulator bypass unit that has an adjustment, it just bypasses the fuel regulator and the fuel pressure goes up on the rails, and more fuel goes in with standard 24 # injectors, and the computer adjusts the width down on the injectors via the O2 sensor. (what I remember) That adjustment did not seem critical, 10 years ago, could tune that one.

Car is really fast in town, works great in winter time, no problems, but summer over 85 degrees first hour is OK, then.... Have a 180 thermostat (second 180), new waterpump, could go to 160 and a high volume pump, but the gains may be too small, this is the 3rd radiator in the car, replaced original, the replacement did not cool as well, got a more efficient one. Spark plugs are one range cooler, new fan clutch (well 5 years ago)

Can't find much to tune on the car, just the fuel regulator bypass, what else can I tune? Any other ideas, are welcome, I'm getting rusty at this stuff.

Here are my suggestions. First, you should get the car to a good tuner and have a custom tune done using actual dyno runs to log the data. If you are using the stock computer alone then that might be your biggest problem. Do this after you have installed all the mods and are running your ultimate boost level. Some chips have multiple program settings so you can have one for summer driving, one for winter and maybe one for

100+ octane fuel. Second, seriously consider getting a bypass. It does wonders for reducing the heat soak in the blower case. It you want to do it right then get the Flowzilla manifolds from KB or buy them used. It has a bypass and much better airflow and that alone will probably gain you another 20-30 rwhp at the same boost level. Third, if you want to up the boost to double digits then do the water injection and get a tune with it operating during the dyno runs.

It looks like you need to spend a lot of time tweaking the tune and installing some further mods. You might get by with just the custom tune but if you want to run more boost than 5-6 psi then the bypass is almost a requirement. The W/A injection is a requirement, IMO, for

11-12 psi and above.

Another thing to remember that every time you increase the boost you will need to spend more money to make the car reliable. This means fuel delivery upgrades, custom tuning, cooling sytem upgrades, transmission swaps/upgrades etc. It is a vicious circle. I have completely replaced the entire fuel system in my car, installed a T-56 tranny, use a TwEECer for DIY tuning, J&S Safeguard timing retard, A/F meter, SMC alcohol injection, rebuilt the rear end, upgraded the brakes and the list goes on to include things I can't even remember. This is why I am simplifying matters with the 427W swap. Don't get me wrong, there is nothing like the torque generated by a KB on a 302 running at 16 psi. It will give you a new benchmark for fantastic throttle response. All this though comes at a price and a high level of frustration for a 5.0L car.

The newer KB kits for the 4.6L Mustangs are light years ahead of our kits. They are complete, come with intercoolers, custom tunes and all the fuel enhancement needed to support the hp levels. Plus, they deliver fantastic hp/psi numbers. As you are finding out, us 5.0L guys have to do all this on our own.

Thanx, Mike, that was very concise and iformative. I had no idea these set ups were so tough to tune. The last turbo vehicle I had was pretty easy to tune, ran 6-8psi on pump gas, and had a boatload of torque. And that was an air cooled V-twin (H-D).

I'v been reading nothing but good things about the KB over the years. Seems to be the hands down favorite for the 302. But since it's that difficult to tune, why are they so popular? Sure, racers will go to any lengths to make an additional 5hp. But the average street guy isn't usually so quick to do that.

Now that must have been a thrill ride. :)

Maybe I stressed the term "hard to tune" a little too much. They are different and it takes someone that understands the power delivery of a twin screw blower to get it right. The reason I think most people would prefer a twin screw over a centrifugal, and even a turbo to a lesser extent, is the way it delivers power. If you were put in a car with a twin screw blower and couldn't hear the blower whine you would be very hard pressed to tell if there was a blown smaller engine or a large displacement V-8 under the hood. There is absolutely no throttle lag, big power surge like a centrifugal or turbo can create anywhere in the rpm range. You can also modulate the power very precisely with the throttle just like you can with the large displacement V-8.

Basically, it is the torque curve that hooks most KB users. I can be rolling along in third gear at 2000 rpm and roll into the throttle and it will immediately set me back in the seat and accelerate to redline in a rush with absolutely no power lag or surge. I can enjoy the additional power from a KB in any gear and at any rpm. This isn't true for a centrifugal. I guess the same kind of feel can be had from a Root's blower but they are much less efficient than a twin screw. Lastly, twin screws are as durable as Root's blowers and can typically last the life of the engine.

As I mentioned elsewhere in this thread, the new KB kits for the 4.6L engines are great. KB has taken all the hassles out of installing and running the blower. They give you everything needed from new injectors, fuel pump boosters, custom tuned chips etc. right in the box. Plus, KB really stands behind their products and R&Ds every kit they sell very heavily. They won't sell it until it is ready. So all the above is why I think the KB kits are so popular.

I'm sold on KB, the others all have to spin up, quite a delay till 4,000 rpm or more. The KB in my '93 5.0, I bought from a guy that parted out race cars from North Houston, cheap in a box, and had lots of extra parts, some that did not belong, wasn't new. KB support helped me get one missing part, they were great, put a 5# pulley on, but it still makes 8#. But installing it was easy, fired up without any tuning, and would get rubber all first, all second and part of third gear. So I'm running 8# without retard, which is not recommended, but I just don't slam on the gas hard, when hot. stock computer, injectors, fuel pump, etc The acceleration is really great, but is scary to most normal folks. I don't want to put much money into the '93, save up for new mustang (if they take off the stupid torque limiter) and KB blower. So on the '93, low cost, I could put retard on, or water injection, and turn on the WI in the summer time, drive till it drops.