zguy36

The stock ecu will not automatically correct for larger injectors. The O2 sensor circuit has a max of 5-10% correction, and does not correct at higher rpm or engine loads. If you want to run larger injectors with the stock ECU, you will have to tighten the spring in your air flow meter. In my opinion, get a megasquirt. You can't beat the bang for the buck, and at $250 for the MSII, there isn't much money going out the door. -jeremy-

Caen fred, I understand the want to maximize the stock components of your car, but I'll tell you that it an uphill battle. I was running the stock turbo components to their maximum and you definatly sacrafice drivability for performance. Start looking into the megasquirt. You really can't beat the price $190 for MSI and $250 for MSII. This will provide you with full control of any injectors that you want to put in. The great thing is too, that you can keep all your stock components (sensors, distributor, injectors, fuel rail,....) I am also a bit confused as to why you are using a rising rate regulator. If it is the type that I am thinking of, it will only rise the fuel pressure under boost and will do nothing under vacuum. This type is used in conjunction with the stock regulator. Is this what you are using? -jeremy-

I don't get any boost spike or changes with gears. Just a constant steady 15psi with my homemade ball and spring controller. If you don't like your granger, make a bleed valve for $5. You won't have noticible changes in spool time and you can get rid of the problems you are having with your existing valve. I wouldn't recommend making changes to your wastegate, but just changing your controller instead.

I don't agree that the L28et has to run really rich at idle. I just finished putting in a megasquirt and Innovate wideband and it idles great at 14.5-15.0 I am not a fan of the stock fuel management, since it is very inconsistent.

The difference between using a ball and spring type controller and a bleed valve is boost response. The ball and spring completely cuts off pressure to the wastegate actuator until the ball lifts from its seat allowing pressure to the actuator. The bleed type just vents the pressure from the actuator but doesnt' completely restrict it, so it is always seeing pressure and will start to open the wastegate sooner than the ball and spring type. Now keep in mind, this is all theory. I have run both types and couldn't really see any difference between the two. The bleed valve does work well, it is just a pain to adjust. I used electrical butt connectors (they come in different sizes) as different orifice sizes. To get an in between size, just crimp it down smaller. I am currently running a homemade ball and spring type and have had very little trouble with it. It is just made from brass fitting from home depot and a spring that I found laying around. No boost spike and very consistent boost.

I did something similar to your cold start injector. I drilled out an injector bore in my throttle body and was running a 420cc injector wide open with an activation switch. I never got around to having it pressure activated since it was mostly just an experiement until I got the megasquirt going. It did help quite a bit, but had a ton of drivability issues. Hit the switch too soon and the engine would bog, hit it too late and have some detation. With water injection and the 420cc injector, I was able to run 16psi with no detonation. It was fun, but tough to use! -jeremy-

Check the other side of the coil, the positive side should have ~12v

You can pull your turbo without removing any of the manifolds. I've done this on several occasions, just get some wobbly extensions and you can get the turbo right off without pulling the intake. -jeremy-

the injectors won't do you any good unless you have a programable ecu. wait until you have to cash to do the work how you really want it.

what is an N/A turbo?

Just finished putting in the megasquirt and thought I would see what kind of temperature rise I was getting with my medium sized NPR cooler. At 15psi through first, second and third gear, the intake air temps rose from 62F to 68F

I just got done installing the megasquirt II on my '83 280zx turbo. The motor fires up okay but has no spark on cylinders 2 and 5. The other cylinders seem to be firing okay. This motor uses an optical distributor and I have this wired into the megasquirt using a 1k pullup resistor. I am also driving the coil with the direct coil control. I hooked up a scope to the output of the distrubutor (input signal to megasquirt) and it is a nice square wave with zero volt for the low and 5 volt for the top of the square. I am assuming this is the pattern that I am looking for. Any ideas why I am not getting spark to those two cylinders? Anything to do with the fact that those two cylinders are directly across from each other in the dizzy cap? Any help would be greatly appriciated. Thanks a ton! -jeremy- let me know if any more information is needed.

Tannji, Yes, it would be really interesting to compare both systems on a similar setup. The problem is that both systems don't use the same size turbos (STS uses smaller due to more density of incoming charge) so you really can't get a comparable result. You seem to be quite supportive of the STS systems, so maybe you can answer the most confusing of all questions. Why go to all the extra work to plumb the turbo in the back, if there don't seem to be any clear cut advantages? Taking your oil lines and pressure side of the intake clear to the back seems more difficult than just putting it all under the hood. It is all good stuff if you can make it work, more boost=more fun. -jeremy-

Tannji, Well done in your support for the STS systems, I enjoyed reading your post. My beef on here isn't with the STS system, just with the people who don't understand how the conventional turbo works concerning heat issues. I actually find the STS system quite intruiging. It just seems like a lot more work to me to plumb all that piping in, but in a car with a tight engine bay, that is pretty much the only option. You did hit the nail right on the head by not saying that the STS system is more efficient. I have done some more reading and found some interesting stuff in Advanced Engine Technology by Heinz Heisler "A measure of the energy transformed from the exhaust gas to the compressor turbine-wheel is the amount the exhaust gas temperature drop on its way through the turbine blades. In its simplest form, the thermal energy absorbed by the turbine wheel can be given by the fomula Q=mC(T2-T1) Q= rate of energy transfer (kJ/min) m=gas flow rate (kg/min) C=specific heat capacity T1=temp at turbine inlet © T2=temp at turbine outlet©" I have been trying to think of how this equation would apply to the STS system, since the inlet temperatures are so much lower. The answer is that the outlet temperatures are a bunch lower too. It can be equated to releasing compressed air from a cylinder and the cylinder getting cold. In a conventional turbo system, the temperature changes go from really hot to hot... but the sts systems temperature drop goes from not so hot to cold. Just some food for thought.... Moby, Interesting thought on water injection. Adding more material to the combustion chamber doesn't always "allow more energy to be transferred to physical force. " This is only the case when you add more combustibles. Like you said about nitrous, adding more mass to the chamber that will either burn (fuel) or aid combustion (nitrous) will add more energy. Water injection inhibits combustion. In the combustion chamber, water is inert (combustion wise) and really only gets in the way. It doesn't help at all if you only add water to your setup. The only reason that it helps is because it cools down the incoming charge and internal surfaces of your engine that you can turn up the boost without detonation issues. The extra power comes from the extra boost that was previously detonation limited. On my current (or at least before I tore it out yesterday) of stock ECU and a supplemental fuel injector, I could run 15psi on 85 octane with water injection. I could only do this on days where it was 10-20F outside, but without the water I had detonation issues at 11 psi. Anyway, this wasn't on topic so much for this post. At least I hijacked my own post this time! -jeremy-

For those who want to know what actually makes a turbocharger work and the theromdynamics behind its operation, please read. The other posts that concerned this topic turned into more of an arguement with people that only half understand the topic at hand. If you do not think that I am qualified to write this post, then I will let you know that I am taking this information from someone who is much more qualified than I am. I will be referencing the following book: Thermodyamics An Engineering Approach by Yunus A. Cengel and Michael A Boles This is a great book on thermodynamics that covers the cycles of an internal combustion engine and also the operation of a turbine. If you want to read up on it, by this book. I'll start out with the cycles of an engine. I don't want to insult anyone's intelligence, but I think that there are a few key points that might be misunderstood. The following diagram shows the cylces of the engine and what is happening. You can see the difference between the actual engine and the ideal cycle that is shown. The upper half of the actual engine cycle does closely resemble the idea cycle, just with the corners rounded off. This is due to losses of heat into the cooling system and also due to internal friction. Once again, these losses don't matter for understanding the topic at hand. Just realize that the equations that follow don't take into account these losses and can't be used directly without taking a measured efficiency into account. For the purposes of how a turbocharger works, I am going to focus on the part of the cycle that goes from points 4-1, or the exhaust cycle. A more illustrative figure on the energies involved in the cycles of an engine is displayed in the following figure: In this diagram, T is temperature and s is entropy per unit mass (kJ/kg*K). The definition of entropy would take a lot more explanation for what is necessary here. In short, to understand, entropy is a measurement of heat transfer divided by the temperature the transfer takes place at. Other terms of interest are u and q. u is internal energy with units of kJ/kg. This is the energy stored in a certain mass. q is heat energy with units of kJ/kg. These two terms are very similar. To find the work output of an engine, we need to know the internal energies of the air inside the cylinder at each point in the cycle. A point that seemed a bit shaky is from points 2-3 of the cycle, or the heat addition. When fuel is burned, it releases its stored chemical energy as heat. This is why heat is not a inconsequential byproduct of combustion, but in fact the only part of combustion that means much at all. When fuel is burned, the air in the cylinder is superheated which causes it to expand which builds pressure. Without this heat, the air would not expand and cause the pressure to push the piston in the cylinder. The equations for work output of an engine are: q_out=u_1-u_4 q_in=u_3-u_2 work=q_in-q_out efficiency=work/q_in q_in is the heat energy added by combusting the fuel. q_out is the heat energy released from the exhaust to the atmosphere. In order to maximize efficiency and work of an engine, we want to maximize q_in and minimize q_out. The more heat we add with fuel and the less we lose by dumping it out of the exhaust, the more power we can make. The problem with an internal combustion engine is how thermally inefficient it is. According to the text, "thermal efficiencies of actual spark-ignition engines range from 25-30 percent." If you think about it, you can easily see why this is true. Think of all the heat lost to the atmosphere out of the cooling system, exhaust, and also heat radiating from the engine itself. This is all heat energy being dumped that isn't being converted to kinetic energy. By using a turbocharger, some of the heat energy lost through the exhaust can be recovered. This is the part that everyone is interested in. Next I will explain the turbine section of the turbo. Terms for this section are: m = mass into the system (kg) h = enthalpy (kJ/kg) Enthalpy is very similar to u (internal energy) and I will not cover the differences here. It gives the energy values for the state that the air is in. Enthaply for a gas depends on its temperature and pressure. Values for air can be found in tables in the back of this book. Higher pressures and temperatures give higher values of energy. The work transfered from the compressor to the turbine is found by: work=m*(h_in-h_out) Higher temperature and pressure going in and lower temperatures and pressures going out maximize the work in the turbo. The fact that the exhaust expands as it goes through the turbo causes it to cool and the pressure to drop. The more pressure drop, the more temperature drop and also more energy recovered. This is where things have been controversial regarding heat. Looking at the tables for enthalpy, it can be seen that there is a larger amount of energy transfered into the turbo with higher temperatures going into it. The function that defines the values of enthalpy for air has exponential decay as temperatures get closer and closer to ambient temperature. With the sts turbo systems, they rely on pressure alone and waste the heat energy that is available. I am starting to lose focus on what people are confused about, so please ask me some more questions so I can clarify.

Maybe I just missed it, but I didn't see the results of how the thing worked out. How much sooner did the boost come in? -jeremy-

Scottie, The point I was trying to make is that there is a diminished return as you make your intercooler bigger and bigger. I am very pleased with this setup. With a much smaller intercooler setup, the entire core will get warm during long boost runs. With mine, only parts of the intercooler get warm, and most of it doesn't get any warmer than ambient. Heat is transfered when there is a temperature gradient between two parts and this grows exponentially as that temperature gradient changes. If over half of my intercooler is ambient temperature during a long boost run, then that portion of the intercooler is not transferring much heat. It is a case of competing equations. Smaller intercooler gives less restriction and a larger intercooler gives more temperature drop. In my case, 20% of the intercooler is warm and the other 80% is near ambient. Yes it is functioning properly, but might be a bit bigger than is needed. -jeremy-

I actually found that picture searching this forum to see if anyone else had done this mod. I can't really tell what actuates the flap though. I can see that it is cable operated, but is it actuated at a certain boost level or at a certain throttle opening? I plan to open mine with a boost operated diaphram that opens the flap 2-3 psi before the wastegate opens. Is that setup on your engine, or did you just find the picture? I am interested in how much sooner the turbo gets to full boost and with what turbo. -jeremy-

http://album.hybridz.org/showphoto.php?photo=5186&cat=500&page=1