bimmertech said:
who's still in buisness? nuff said!
With a comment like that you obviouysly don't know the situation. The original owner passed away and the new group were a bunch of idiots and ran it into the ground. Its still a superior product. Pro-M's employees are supposedly buying the company and trying to restore it to the way it once was... we shall see.
OK, here's my take on the meters...
I do not like C&L. Let me first give a little detail as to how a meter works, as it will help explain why I don't like them. A MAF is nothing more than devise that tells the EEC how much air is flowing into the motor. It does this by a very thin wire that acts like a resistor with a small amount of voltage passing through it. The more air that flows over it the cooler the wire gets and since it acts as a resistor the voltage will change with the temp. That's all it does, nothing more and nothing less. Since the incomming air can be at different temps the EEC also used an ACT (Air Charge temperature) sensor. With these two sensors the EEC can determine what amount of air is coming in and adjust the injector pulse wdith accordingly. When we get larger injectors we need a "re-cal'd" MAF. What this means is that in order to maintain the correct fuel delivery per certain amoutn of air the voltage will need to be altered. Pro-M did this with NEW electronics. Basically the MAF will send a "tricked" voltage to the EEC and tell it that LESS air is coming into the motor than there really is. The EEC sees this voltage and shortens up the pulsewidth on the injector... BUT since the injector is larger than stock more fuel is supplied for that pre determined pulsewidth. This is a problem for 94-95 cars because they are the MAF voltage to determine LOAD. The old fox's were more of an RPM based EEC, ours is more of a LOAD based EEC. The EEC uses LOAD for damn near every table in it, includind the fuel and timing maps. This is also why our cars are more sensative to MAF's than the 93-older cars. Now that I've explained a little on how it works, let me tell you why I don't like C&L.
Pro-M accomplishes it "tricked" voltage through new electronics in the MAF itself. This is good because it is CONSISTENT, meaning that you know exactly what the meter is going to do. Now the C&L take an a different approach. Instead of tricking the voltage by electronics, it simply alters the amount of airflow that reaches the MAF wires. It retains the stock electronics, but there are different "sampling tubes" which are nothing more thna a small piece of aluminum with a hole through the middle of it which air passes through. The problem is that there is a LOT that can effect the amount of air that passes through the metereing tube and can cause issues. Some of those are tubulent air, areas of higher or lower air velocity within the meter itself etc. The pro-m is vulnerable to this as well, but since its relying on electronics its more consistent as to what it does.
My dad went with a C&L 76mm MAF on his 91GT. On the dyno we could not make 2 consecutive pulls with repeatable results. He had the C&L tube with a conical filter on the end inside the engine bay just like I used to have with my Pro-M in my 95 without any problems. No matter what the tuner did he could not get the A/F ratio to remain the same on every dyno run. It was a wasted trip because they could not tune the car. We then put the stock airbox back on with a
K&N panel filter and went back to the dyno... this cured the problem and made it repeatable, but it shows how sensative the C&L can be due to the way it meters the air.
How was that Striped?
