Hey I did a search but couldnt find anything, Im looking at a new Computer for my 90 tt zed Im looking at getting a well known brand like apexi or motec but I am looking at gettin one that does'nt run a AFM, is there any pros and cons about doing this? Thanks Tye
Microtech LTX-12 is probably the most adaptable and familiar aftermarket ECU for the Z32 that can use a MAP sensor and the price is reasonable as well compared to others.
Cons: MAP sensor is inferior to MAF. Motec/PowerFC are exxy. UAS is the only people doing PowerFC installs that I know of. Pro's: Urmm... you can run bov's with less hassle.... :/ More people know how to tune the PowerFC than the stock computer.
Debateable And greatly depends on your tuner and the MAP sensor used. If the Map is the correct range for your vehicle and is setup and tuned properly you have no problems. To run a map sensor reliably you need to make sure your car doesnt leak boost as this will adversley effect your cars performance as far as the MAP sensor is concerned. MAF's on the other hand can injest water and the like which can interfere with the hot wire. Also a dual pods setup is a lot harder and more expensive if using MAFS. I have been running Apexi dual MAP sensors with the power FC now for nearly 12 months without 1 single issue apart from when I had a bad boost leak the car ran a little rough until it was sorted Dual Maps are better on the VG30dett due to the twin intake setup even though there is a balance pipe it is not big enough to adequately equalise the pressures properly for a sinlge map on either side to work effectively.
This is interesting. Perhaps the maf is not as inaccurate as some of us think, and is user friendly. There are three ways to measure the fuel requirements for the engine. These methods are most often referred to as Mass Air Flow (MAF), Speed Density, and Throttle Position Sensing (Alpha-N). Each system has its own benefits and disadvantages. Mass Air Flow is perhaps the most commonly used of all the systems on current production automobiles. MAF utilizes some form of device to measure the actual volume of air entering the engine. Early forms of this system used a box with a flapper door connected to a spring and sensor mounted in the air stream. The flapper door opened up further with increasing airflow. It was not highly accurate and was not very sensitive at low airflows. More recently an electronic metering device has been developed to find the flow of air into the engine with very little restriction to the airflow and it does it with near laboratory precision. It requires also measuring the air temperature and engine rpm to calculate the precise amount of air entering the engine each revolution. The big advantage of this system is that it can measure any change in engine performance caused by wear or modification and adjust the fuel mixture accordingly making it very flexible. It does have the disadvantage of requiring an extra component in the air stream to restrict airflow. It also is very sensitive to air leaks in the intake tract. Speed Density takes a slightly different approach to measuring airflow. It uses the universal gas law PV=nRT to calculate airflow in the engine. By measuring the Vacuum in the intake manifold, the airflow can be determined using the gas law. Measuring engine RPM is not necessary and the Air temperature has less of an effect on the measurement since the density change of air with temperature also effects the amount of vacuum in the intake with a specific throttle opening. The greatest advantage of the speed density system is that it can run with only 1 sensor to measure manifold absolute pressure (MAP), and thus does not have an air flow sensor to restrict air flow. Fuel required in an engine is directly proportional to the manifold pressure. It also does not care if there is a vacuum leak since changing the vacuum would just change the fuel and make the engine speed change. The big disadvantage is the fuel requirement may change if changes are made to the engine such that for the same pressure, more fuel is required since the engine produces more power. This makes it difficult to make major modifications to a speed density engine. The Throttle Position sensing system uses the engine rpm, air temperature and throttle plate position to determine airflow. It is by far the simplest system but also requires the most tuning. Since airflow is strictly assumed by calculation, a very accurate map of the engine must be made for tuning. However, this system is virtually the only way that a high performance engine that carries little vacuum can be tuned. Even though MAF measures airflow, high lift and overlap cams can cause pressure reversions that fool the MAF sensor into making false readings. Throttle position is used widely on motorcycles and ultra performance engines like Indy and F1. It is very sensitive to changes in the engine and would require a complete retune if even such things like exhaust were changed. Some early production car systems did use this type of control but were very dependant on the oxygen sensor to fine tune the engine and quickly gave way to more accurate ways to calculate airflow.
Evil Tye you really need to realise why you would want an aftermarket ECU in the first place. If your getting one because you've read that they are the most effective way to increase power then you have missed it completely. The factory ECU when tuned properly is well capable of handling just about any power figure you could throw at it. The biggest issue is the limited amount of people capable to tune them which in my opinion should be the only reason to look at aftermarket engine management. Personally I don't go for MAP sensors purely because the technology is inferior in comparison. Most if not all car manufacturers use MAF sensors because of their accuracy. Just for an example, if you had a restriction in your exhuast for what ever reason, the ECU will still fuel the engine the same because it is looking at manifold pressure all though the total air flow has reduced. I also work with a guy with a Skyline R34 GTT and converted over to MAP sensor and has regreted it ever since for their inability to maintain constants with changes to atmospheric conditions.
Unless you are running larger injectors and/or turbos then probably the best value for money way to go would be to stick with the standard computer and get an SAFC to tune the fuel.
