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You answered your own question.

Even without exotic engineering highly-boosted turbocharged 2.0L street-car I4s can put out upwards of 500 horsepower at 7-8000 RPM. Formula One builders take things to the next level by building more advanced rotating parts and using pneumatic valve springs to allow the engine to spin all the way up to 15,000RPM with an almost linear increase in horsepower as they travel up the powerband.

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> Even without exotic engineering highly-boosted turbocharged 2.0L street-car I4s can put out upwards of 500 horsepower at 7-8000 RPM.

I'll call bullshit on that. After whatever you've done to a stock 4-cylinder motor to make it output 500 horsepower, you've got a racing engine, with all that entails. It's not properly a "street car" part anymore. :)

Not really, depending on the engine. Some engines are built sturdily enough that they can make that power without anything other than bolt-on modifications. For example, the Saab B204L turbo engines make 185 HP stock. Just by changing the mapping in the ECU, you can raise that to 225 or so. Add a new exhaust and intercooler, you're up to 280. Bigger turbo, now you can hit 300-330. Bigger fuel injectors, now you can hit 400. Keep adding more air (bigger turbo) and more fuel (bigger injectors) for as long as the engine can take it. I think the record is currently around 700 HP, which may have been done on an engine with aftermarket pistons, but still, 400HP or more is possible with only bolt-on modifications, no rebuilding of the engine internals.

That's impressive. How many miles would you expect to get out of a B204L motor making 400HP, assuming you were just keeping it on the street?

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