Most cost effective HP+ modifications?
 

Does someone have a list of the most cost effective modifications to boost HP? That is, which mods have the higher HP to $ ratio?

De-amberibg and airbag sticker removals do not count. ;)

Most cost affective? Take **************** out... Enough said.

See that spare tire? Get rid of it... Have your bowling ball/ golf clubs from last weekend still in there? Take them out.

50lbs doesn't sound like much, but if you pull out that much, or more, I promise you'll feel the difference. When you go to the gas station from an empty tank to a full tank, i know i can feel the difference. 10 gal of gas is only 80lbs. Now take that to perspective when you take out another 100lbs

And for how much? FREE! Unitl you get serious and start putting on light weight wheels/seat/steering wheel/ battery/ etc.

An Underpully is a mod you truly feel, I don't know how it would be in a place like Az where you need max AC but other than that you truly feel the difference.

+1 on the underdrive pulley.
The one I bought from Flat6 fitted perfectly and you can feel the difference in the low to medium rev range where 90% of your driving is....

Here are some thoughts from a previous thread:

1. A comprehensive and methodical approach to revamping the vehicle's exhaust system; i.e. headers, cats, cat back ect...
2. Light weight under drive pulley
3. Larger throttle body and plenum
4. ECU re-programming
5. Lighter wheels (a potentially faster and better performing vehicle by means of
reducing unsprung weight and rotational mass)
6. Reducing weight in general; i.e. spare tires, oem seats, lighter battery ect.. (this is
more aimed toward tracking your boxster .
7. Suspension upgrades (though not a direct increase in power, a faster vehicle can be
had by means of better handling and performance .
8. Increasing airflow to the engine, i.e. cold air intake or filter replacement
9. A divorce (a major reduction in weight by means of one less passenger, as well as financial freedom to do more mods)

and the list goes on ...........
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My current thoughts on the matter in terms of cost effective performance improvement:

1. Under drive crank pulley.
2. Weight loss (fly-weight buckets, remove AC equipment, remove spare, light weight back box). Will probably also remove and store the remove roof motors and transmissions - roof works really well manually when disconnected from the transmissions, oddly enough!

Even that won't be cheap if you buy everything new. But a used back box might not be too pricey, ditto buckets.

Question I have - is there any reason to be wary about fitting the underdrive pully? Don't think the factory one is damped, but even so...?

To add a bit more to Johnny's #8 (edited, previous reference to #9 was incorrect), I'd say smoothing out this airflow will also be a benefit. The stock plumbing could be better, as well all know, so one could consider replacing the hoses with smooth, straight tube and a couple of smooth elbow pieces, and that'd be a cheap and effective DIY. I'm sure, depending on your level of perfectionism, you could make it look very clean and like it belongs there.

Buy a used 911TT :D

I've got a UDP for sale in the classifieds:

http://986forum.com/forums/boxster-parts-sale-wanted/30366-fs-4-underdrive-crankshaft-pulley.html

I think everyone pretty much agrees it's at the top of the list for most cost effective hp modifications.

Ya know he says it jokingly, but in reality, if you want a fast car, you're probably better off selling your boxster and buying like an older C5 corvette or something, because unless you do an engine swap it's never going to be fast. And even if you do that, you would have been better off spending your money on a stock, faster car...:ah:

I said it half jokingly. For the exact reasons you list, you'll be spending thousands of dollars to chase 30 to maybe 50 extra HP.

I think the rule of thumb is $50 ~ $75 / hp
I think the max you can reach with "all tricks" is maybe an additional 50 hp = $3 ~ $4k
After that it gets real expensive with either an engine transplant > $15k or a turbo, also > $15k, so at this point it really might be cheaper to get a different car....

You turbo or supercharge your boxster and it will blow up.... I promise you... You may get even a full year out of it, but this engines will go out on you unless you fully build them... And again, Naturally Asperated is the way to go if you want fast, useable power..

For my money, a turbo Boxster would be ghastly anyway. For me one of the core appeals of these cars is the finely honed driving dynamics - and that includes sharp throttle response and linear, progressive power delivery Then there's the clarity of induction and exhaust notes.

An S-charger might be just about tolerable. But a turbo? Faggadaboutdit!

Something to consider .

$1,000's and $1,000's later = 25 or so hp at the wheel .

Totally agree - I had an Audi TT a while back, and while a total hoot, the dynamics are completely different. I briefly considered another TT, then test drove the Boxster, and never looked back.

I looked at all the power adding mods available for the Boxster and added the HP claims all together. I excluded superchargers and turbochargers.

I got $90 per HP. Parts include performance intake, low temp thermostat, underdrive pulley, headers with sport cats, secondary bypass pipes, performance muffler, ECU upgrade, Pedro's Plenum upgrade, added 2HP for desnorkel and iridium sparkplugs.

I say most cost effective mods are ECU upgrade combined with performance intake and bypass pipes. $1700 for 20-25HP according to claims. That is about $78 per HP.

I'll say it again... A car with 200hp that weighs 3000lbs is a lot slower than a car with 200hp that weighs 2500lbs.... Like WAY slower...

Granted, unless you totally strip your car you're not going to get 500lbs out. But even 100lbs is feelable... Just take stuff out of your car! It will be faster..
And thats like $0 per hp lol. Cuz you're not gaining any horspepower or spending any money!! lol

If you want a car in a fast line, boxsters are not the car for you. If you want a great handling, fun, gorgeous car, then you should buy a boxster... Enough said.

I can assure you that the above mentioned equipment alone will not achieve 20-25 hp . Not at the crank, wheels or otherwise .