Originally Posted by wydopnthrtl
Bob is right in one respect. Or I should say that he's *most likely* right in one respect. And that's testing. It's called "DV testing" in the oem realm.
Design Validation testing on the OEM level is done not only in the lab (SAE standards) but they also put the parts in vehicles that go all the way around the world. From northern canada / Alaska down to the deserts.
Having worked in both the aftermarket and OEM auto parts realms (in engineering) I definately would say that its unlikely the screamin demon coil is up to OEM reliability standards.
Now having said that. I think something that escapes Bob often times is that cars guys like to experiment and modify. Often times it is indeed a waste of money. Such is many areas of life. I'm sure that if Bobs spending habits were shown to all.. we'd find some areas of waste. Camera equipment maybe?
As far as OEM performance. I'm pushing my stock coil pretty hard with a 50shot of nitrous. It's doing fine so far. Maybe when my truck gets up into the 125k mile range I'll try a screamin demon.
When it comes to electronic components testing (or qualification) there are 2 parts:
1) Functional Characterization
This is when the component is characterized to check how robust the design is. Voltage, temperature, and frequency are the three main parameters that would be varied to see if the component will still operate. Typically, these parameters are varied outside what would be seen in the application.
2) Reliability Testing
This is the one I've previously posted about, and the lack of this testing on the aftermarket products is why the failure rate will be higher. There are three stress tests that are done that also exceed the application conditions
that give an acceleration factor, that tests for long term reliability.
A) HTOL stress: High Temperature Operating Life
In this stress, the components are put in a temperature chamber to heat the components up (beyond the application temps) and are powered up statically, or operated dynamically at voltage levels above the application conditions.
B) TC stress: Thermal Cycle or Thermal Shock
In this stress, the components are placed in a chamber with a cold, and hot region, and the components are constantly cycled from cold to hot, and back to cold. This test checks for differences in materials that will result in conductor cracks, causing an open in a circuit.
C) T&H stress : Temperature & Humidity
In this stress, the components are put in a chamber at elevated temp and humidity. (85 degress C / 85% humidity are industry standard conditions).
Another type of this stress is call "Pressure Pot" which would be like a pressure cooker. This stress looks for defects like packaging cracks, or other
materials issues that would cause failures from corrosion.
The functional characterization and reliability testing conditions are all called out in SAE standards. The same standards exist for the Japanese, and European automotive industries.