Originally Posted by ramo
if you actually read the thread owners question instead of my comment, you wouldve noticed he said a stock car. that means stock turbo, stock injectors, stock intercooler.
The OP specified "stock internals", which means stock rotors, eccentric shaft, and associated gears, seals, etc., inside
the engine. The turbo, injectors, and intercooler are external.
Originally Posted by ramo
thank you for clearing that up, what if you have an ECU and then other items that improve performance? is 12 psi a solid number no matter what
Excellent question. No, 12 psi is not a solid number. See below for more...
Originally Posted by Silver Comet
The block itself and internals (Rotors, apex seals, ect.) Excluding things such as turbo's, intercoolers, fuel, ecu, ect. I don't know how to be any clearer, is it making sense what I'm asking? haha sorry
A boost gauge is not a very good limit indicator. There are two main factors that limit the amount of boost pressure: 1) The point at which the engine fails mechanically, and 2) The point at which the engine detonates. Since the engine will most likely detonate before it bursts from pressure or strain, let's look at some of the factors that affect the detonation threshold:
- Fuel octane rating
- Intercooler efficiency
- Compressor efficiency
- Air pressure (yes, altitude affects this)
- Air temperature
- Air humidity
- Engine temperature (affected by radiator, oil cooler, thermostat, etc.)
- Engine load (driving up a hill, rapid acceleration, pulling a lot of weight, etc.)
- Compression ratio of the rotors
- Fuel/Air ratio
- Ignition timing
For example, if your engine has 9.7:1 rotors, no intercooler, and a crummy Mexican Ebay turbocharger, and you live in Death Valley, use 87 octane fuel, and attempted to tune the engine yourself, then the engine will detonate at a low boost level. However, if your engine has 8.5:1 rotors, an efficient front-mounted Spearco intercooler, an efficient Garrett GTR turbo, you live in Aspen Colorado, use 115 octane race fuel, and paid for professional tuning, then the engine will be able to run much more boost before it detonates. This is why you need to take it with a grain of salt when forum members chime in about how "My engine runs ten million psi boost with no problem".
Given that, see this below website for some good general guidance. It is a bit out of date, so check with this forum before you buy anything that may have been superseded by a better product. For example, the FCD has been made obsolete by the Rtek ECU upgrade.