itacud

300hp, 340hp, and 360hp.

True, it's more than a software change, but there's plenty of potential in a stock N.A. engine.

GIACUser

look for mods that improve performance but do not raise boost do things that segragate the intake track from engine heat. Improve air flow across intercoolers (consider aquamist system for intercooler). The only way you will receive the big increase is to raise boost, anything else short of nitrous will not really net you much and you probably are better off just leaving it stock unless you just want to try for the heck of it.

2.7tDallas

That is what I was afraid of. The engine is already highly tuned, so there is not much more I can do

GIACUser

getting more power out of any engine is a matter of getting more fuel/air into the cylinder, compressing it as much as possible, then getting it out as quick and completely as possible. Getting 40hp - 60 hp out of the 300hp version is obviously possible, but the cost makes it prohibative. You are talking about thnigs like taking the engine apart, replacing pistons, cams, valves, intake manifolds, exhuast manifolds etc. With a turbo you can get the power for about 600 dollars without taking anything apart, it really is almost too good to be true. Also as chipped cars are subject to greater risk from failure by simply adding more power, so would an NA engine be subject to greater risk without working on cooling systems, and the bottom half of the motor.

2.7tDallas

It is so cheap to over engineer the bottom end, that most german car companies just do it. Adding 20%-30% more HP by improving the tope end and breathing is probably well within the basic spec of the bottom. Just a gues, but i almost never see or hear of bottom end problmes on german cars

itacud

and a lot of that has to do with maintaining reliability. But it isn't really cheap to tune a turbo with equivalent reliability, either. Using the optimal engineering argument, manufacturers would do it themselves (and charge us for it), without fear of warranty claims -- if simply increasing boost was risk free.

For either engine type, the software is still plenty important. You can bolt on parts all day, but the engine needs to be optimized to use everything correctly. This means software tuning, unless there's a carb on there somewhere =).

I'm not sure I see how a cooling system upgrade is needed for a N.A. engine, and not for a Turbo. More, or bigger explosions in the cylinders cause heat, no matter what technique is used to make it possible.

Sorry for my rambling... =)

Bollinger

And isn't more boost the simplest way? I mean, you've already got this fan ready to do it, you just have to tell it to do so.

Frankly, I see little difference in impact upon reliability whether you add 10% more air with and intake/exhaust or more boost. The engine works harder and hotter in each case, the only difference is the turbo rotation speed. And possibly not even that.

Oh also note that you can flow more air without adding "boost", because "boost" is really a measure of how much pressure over ambient you produce. If you get 10% more air though, it may not be at a higher pressure, but you bet it is at 10% more turbo revs. And revs are half the killer (boost being the other).

itacud

The stock exhaust must be tuned for decent emmisions... and turbos are responsive to exhaust changes. I'd guess that improvements could be made there, w/o increased boost.

No promises on cost efficiency =)