Boxster Diet
 

It seems as though everyone is looking for performance enhancements (i.e. HP gains). Short of upgrading your engine size, most seem like a lot of spend for not much gain. The truly practical is to drop some weight. So, other than the spare tire (not mine) and maybe the wheels where do you guys trim?

The Under Drive pulley really does give you about 15HP. You can really feel it, but get used to it quickly.

Removed the spare, but I myself am the next biggest weight factor to trim down, sadly....

Relatively easy weight loss comes from:

1- Very heavy carpet mat over the top of the engine compartment (obviously you will hear the engine more.

2- Speaker console mounted on top of that heavy carpet mat (the lower speakers in the doors work pretty well without it - this is not a concert hall)

3- Low weight battery. Lots of options on this look around. The Deka and Odessy batteries are fairly light weight, and reliable if you put them on a trickle charger when not in use. Pegasus Racing was having a sale recently on some super light weight Lithium batteries. With any of these, you may need to fabricate some hold down means.

4- Light weight exhaust (Fabspeed, etc)

You can remove the carpet from the Frunk and trunk. The plastic over the battery and brake master cylinder. Any trim part you can do without.

After that pounds cost money just like motor upgrades. Lighter wheel $$, Sport exhaust $$, Coilovers $$, Race/sport seats $$ .

Boxster Diet
 

Thanks guys. Sadly I too could shed some pounds to help the cause. I'm surprised the under drive pulley contributes that much but 15 HP is nothing to sneeze at. That's fairly simply to do so why then is everyone chasing the plenum, throttle body, tuning which is $$$ and really doesn't add too awfully much more? Is it one of those "mine is bigger than yours" fixations?

A/C weighs about 40 pounds

15 HP from a Underdrive pulley? That sounds pretty optimistic to me. Please show me the make on that one, I think everyone would want one. The most claim I've seen is about 5HP

I would agree with you here. 5hp maybe stretching too. Lastly if you combine this setup with a lightweight battery the negative effects is not worth the effort for a street car. Under drive pulleys are meant for high rpm drivin, lightweight batteries doesn't have the required amp for typical street driving.

Be careful on your diet selection combo.

nothing so nefarious. different people want different things from their cars - some want to keep all the creature comforts, while others want stripped-out autocross weapons. so, for those unwilling to remove ac, airbags, carpet, etc., performance is found elsewhere. those who want/need 100% from their car do everyhting they can. and for some, getting the most out of the machine is a challenge, hobby, etc. been done with porsches (and cars) since the start.

to answer your question, anything can be removed from the car, or lightened - what are your personal limits - can you do without ac? would you drive without airbags? need a stereo? can you live with the added heat and vibration that comes with removing the carpets? are you ok with a manual roof? can you afford fg body panels? will your conscience allow you to remove the charcoal canister? remove your bumpers? drill holes in your radiator brackets?

My experience confirms this 4-5 HP., but it was the cheapest performance increase I have.

Want another cheap gain 3-4 HP buy a shorter serpentine belt and skip the AC pump

My light weight battery starts the car fine in street use my car see about 7,000 miles a year never had an issue. It's 18 months old never on a tender.

Got rid of my girlfriend @ about 105 lbs. and went on a vegetarian diet and lost 40 lbs, so far. 145 lbs weight loss and I feel like a new man and the car moves a little bit quicker.:dance:

stripped out autocross weapon, hell yeah!!!
Ok, carbon or fiberglass hood will drop 30lbs
Swapping full power seats for fiberglass race seats are worth 50+
Get a hardtop and lose the convertible top, then run around with nothing and you'll lose 70ish.

http://i765.photobucket.com/albums/x...psja6enhnq.jpg
I took all this out plus the foam insulation on the back of the carpets and lost 91.5 lbs. I've decided I'm also going to remove the airbags and speakers too.

Wow! never seen that kind of estimate before. That would be a big bang for the buck upgrade. Are there Dyno #'s to show that gain?

Rule of thumb...~15 pounds of weight = 1 HP gain.

I reduced the rolling weight of my car by 50 lbs using the eat-less-cheeseburgers mod. Made the sport seats much more comfortable too, not to mention the increased ease of entering/exiting the vehicle. Also upgraded to Girlfriend 2.0 for an additional 25 lbs of weight reduction and a significantly less bagged suspension.

Humorous references to the human cargo weight! I'm about 160.

When a friend of mine rides at his 6-4 and 260 weight, I can really feel the difference.

Not just negative effect on acceleration,but lopsided handling as well.

Problem with racing and weight loss is the class you race in. If your weight goes below the lower limit you end up in the next faster class.

Its really strategic weigh loss only to the bottom of your desired class.

I love when I get into a class and consistently win 2nd place or better. Note: only 2 cars racing in that class. :p

Lower weight however will always result in faster acceleration, and we all love pulling some G's.

To measure that you need a lateral G meter. (IE Smart Phone with the right App.)

For street use the lightweight batteries are typically sized so that equivalent capacity simply weighs less with the newer technology batteries. Racing sized batteries is another matter.