Actually, he asked a specific question of how to add 30hp to a base 997. Pretty sure he'll get nothing close to that with the mods you suggested.

 

Well you'd be pretty sure wrong. The 82mm TB and plenum along with the headers will have the car breathing far better.

Nonetheless I'll modify my list with the following just because I saw the dynos to back up these claims:
Headers (no cats) 15 hp $1500
X-pipe with 200 cell cats 18 hp $2000
IDP plenum with 82mm TB 13 hp (but helps across the entire curve)

The 3.6 liter motor is detuned to keep power down, specifically choked by use of a smaller more restrictive TB. There's power in that motor, just need to increase air/fuel flow and exit of exhaust gases.

You'll get your peak power over 30 hp somewhere in the powerband, but the new curve should all be above the stock one, and throttle response will be significantly improved. Software of course would help too by smoothing out the curve.

Cheers!

 

Almost 50hp for less than $4,000? Who posted the dynos you refer to? Wouldn't be the guys selling those parts by chance? Yes....I am skeptical of all those numbers.

 

Doesn't mean you simply add the numbers and that's what you get. Most likely the mods collectively would amount to something under since the curve is affected in different locations by individual mods. But real power is gained by these mods, especially the bigger TB which flows significantly more air and fuel once the ecu adjusts to it.

Headers have a tendency to change the curve in ways which rob from some points along the curve and add to others. The larger TB and plenum add power across the curve. High flow cats allow the exhaust gases to escape much more efficiently which helps quite a bit. Some Porsches have 2 sets of cats, which is restriction overkill.

Not sure why you think dramatically increasing air and fuel, and allowing a greater flow of exhaust gases won't make a big difference. If I stated fuel economy would be the same then yes be skeptical. Power is always at the expense of more fuel.

Porsche typically places smaller TBs in the base cars, to limit power. Often the hose opening diameter exiting the airbox is larger than the TB intake diameter. Makes me think the smaller TB was an after thought to reduce power. Porsche is very particular to ensure performance gaps in their cars. They engineer these gaps, but by simple means. Easy to correct.

I would most likely be happy just doing the plenum and bigger TB, keeping costs way down. You won't close the gap, but you'll feel the difference and make the car much more fun to drive.

 

I don't doubt that. I'm just focusing on the OP's original question which was how to add 30hp to a base car and I don't think your formula will reach that goal. I stand by my response (which you ridiculed) that increasing the budget and buy an S instead of a base is the best and least expensive way to get there. Especially since you also get bigger and better brakes and better suspension too.

 

I don't disagree that buying the S is better option but that isn't what was asked. I wouldn't considering a base 997 for obvious reasons, although a base 991 is a different story. Can't cry about brakes there.

 

I've been around this forum for a long time and I've seen two guys on here spending upwards of $8,000 on bolt on mods only to yield less than a handful worth of hp. They used to come here and tell you it's not worth it but they either brought another car or isn't active on this forum anymore. Can't think of their names right now. I haven't looked but I would assume an S model isn't that much more than a base in the used market.

 

You can definitely overspend (i.e. full exhaust) when the most benefit is found just by removing the restrictive cats. I think you're underselling your point though as in a handful of power for $8000. That cash will gain power, but whether that power is worth $8000 is another story.

Most people think in terms of peak power like that's the goal. It's not and it's really meaningless to a discussion on what changes to the power curve are actually accomplished. It's the power gained across the entire power band that matters, not peak, and bolt-on mods will give you this.

On my 997.2 S I simply changed the center and side mufflers and felt quite a bit more usable power and less peaky torque. In fact it was almost overkill as the car was too eager to break traction from standing starts.

I'm not one to toss $8000 or even $5000 after gaining a bit of power. But I recognize derestricting the motor will result in noteworthy gains. Some just enjoy the added noise you get with more air and a freer exhaust. Modding in general is an expensive undertaking with little return.

 

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