How much boost can a stock sti handle

The functions of a turbocharger cause it to produce heat, which plagues the intake side of the engine with hot, less dense air. The Subaru WRX and STI models equip an intercooler under the hood scoop to help cool the charge air from the turbocharger, and thus produce denser air for better combustion and more power. ETS offers the kit with options for factory or aftermarket turbo configurations, core thicknesses, and other customized items to make for the best fit and finish.

Since the STI will continue with the stock turbo for the time being, we chose the kit designed for the factory turbo configuration with a 3. We chose to pair the ETS Intake Kit without MAF for this setup, in order to create less air restriction as we prepare for more airflow down the road with a bigger turbo.

This larger hose offers a larger diameter opening than the factory equipment, plus it features a smoother interior opening as opposed to the factory ribbed hose.

As a result, this plug-and-play harness allows for more accurate tuning. This blow off valve is unique in that it can be configured to vent to the atmosphere, back into the air intake, or both.

This flexibility will come in handy as the car goes through changes down the road and we change the configuration of the Dual Port Blow Off Valve accordingly, without having to replace it with a different one. To this end, we turned to Gruppe-S Engineering for its popular unequal-length manifold. This 4-to-1 manifold is designed to maintain the classic Subaru boxer rumble in the form of T stainless steel piping, made with precise mandrel bends and CNC-cut flanges. The resulting power increases from all of this hardware led to significant clutch slipping during our dyno tests.

This design aims to ensure a positive engagement without feeling too aggressive. Given its design emphasis on rally and endurance racing, with a lb-ft capacity, the clutch was well up to the task of our Test and Tune.

This intake change and Speed Density Adapter Kit did away with the factory MAF and enabled air temperature readings to come from after the intercooler. This provided for more accurate tuning to wring the most out of the new hardware. Right away, the STI realized a This brought the peak numbers up to However, it also revealed the need for a stronger clutch. Likes Received: 1, Trophy Points: The OP is getting a nice response from his trolling.

I vote this thread for most pointless of the day. Depends on what year shortblock. AWDimprezaL , Dec 10, Likes Received: 47 Trophy Points: Air flow. The stock engine is only good for flowing a certain amount of air.

If you want a simple example of this, you look at the boost curve and then look at the torque curve on any given dyno chart. Flow restriction is when you have constant boost, but you see that torque curve die off. Then you see that hp curve flatten off and sort of stops at this certain maximum. In a very rough sense, 1. To make hp, you need an engine that can flow cfm. This means you need an intake that supports cfm, a turbo that supports cfm, heads, cams, exhaust, etc.

Now the car in its stock design was geared to flow cfm hp. How does this work? It doesn't. You pretty much need to re-engineer the engine to flow what you want it to just to make the power you seek. You don't just throw a big turbo on and pray to the car gods that hp will magically appear.

The big hp cars are the ones with actual re-engineering done. The intake's not stock. The cams are not stock. The exhaust is not stock.

You're modifying the engine to flow what you need. So let's say you can flow 10,cfm easy. What's next? Well, for a given fuel type and static compression, you can only shove so much into the combustion chamber before it blows up by itself. Let's say you're stuck at 21psi with a stock STI. We'll just pick ft-lbs at the crank. That's what 21psi produce. Then it becomes a matter of rpm. Then you run into a revving limitation. Pretty soon you're floating valves or something and not going any higher.

Again, let's say that's rpm as that max point. You can't make more than this without changing something. You simply can't shove more stuff into the combustion chamber without knock, and you can't rev any higher before you float valves.

So hp is it. Sure, if you can flow enough and rev enough. How do I make more? More stuff means more torque. More torque means more hp. If you can make ft-lbs, then you can make hp at the same rpm redline. You can also make it rev higher. Make it rev to 9k rpm and the same ft-lbs will produce hp.