Weight reduction; it works.

[UltimateLurker]

Last weekend a few friends and I removed the front and rear bumpers from my '05 STi, along with the subframe. Total weight removed: 88.2 lbs

I have 74 passes at the track in the STi, in all kinds of temperature/humidity/barometric pressure, and I take copious notes.

Here's a screen-cap of my times from last night...

60' / 330' / 594' / 8th ET / 8th MPH


From previous runs under nearly identical conditions I can say I definitely averaged a mid 8.1, but this time I averaged a mid 8.0, so there's no question in my mind that the weight-loss helped tremendously (remember, this is only an 8th mile).

The very best part was running 11 times (most with no cool-down whatsoever, and within 3 minutes of each other), and 9 of them being 8.0 runs. Bracket-racers, eat your heart out...lol. I beat every Camaro/Firebird/Mustang at the track except 2, and by the end of the night they were all crowded around my car like mourners at their own funeral .

Mods: Helix catted down-pipe + professional tune (Jorge / RiftsWRX).

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[JustinsWRX]

Hows the car handle with the subframe removed? I've already removed the front and rear bumper beams and was thinking about removing subframe aswell but wasn't sure how it would effect the handling. Thanks

[UltimateLurker]

I honestly can't tell any difference at all, I'm sure there is some if you're cornering super aggressively, but I corner at 7-10ths at most.

[pharo]

OO this is very interesting. So did you remove the front and rear bumper beams as well? Also, do you think it is due to the fact that the weight removed was on the outer edge of the car that it made more of a difference.

I think it would be interesting to see how much the jack + rear spare (roughly 33 lbs) and having 4 gallons of gas (since each gallon weighs between 5.8-6.5 lbs).

Thanks for posting this up, as I have been feeling this might be an interesting route to try.

[PaulRex]

sure it works man.. ive tried to do everything i can for weight reduction in my car without losing my interior. or radio. i did ditch the a/c though.

your notes are very copious.. nice driving!

did you remove the whole bumper?

[UltimateLurker]

Pharo: I removed the re-bars and styrofoam. As far as the difference, it didn't help my 60' at all, but as I went down the track the engine simply had less weight to haul, so my time was better, and my trap was faster. Since the car is AWD, I think any sort of weight removal is good, and the less the car weighs the more difference each weight-reduction mod makes (PTWR). I've removed 136.2 lbs from the car in total, and there is a huge difference from stock.

Paul: The re-bars.

Here's a couple pix for you guys.

Rear re-bar with styrofoam


Front re-bar with styrofoam


Subframe


Bolts for everything

[UltimateLurker]

In doing this removal I had to fabricate a small bracket for the rear bumper-cover to keep it from flapping at the very bottom, as 3 clips that hold it steady go into the re-bar itself. The two on the sides can be held by a couple of zip-ties, no problem, but the one in the middle looks like this now...



The bracket is made from one of those blank slot covers from the back of a computer , hey it was the perfect size, and aluminum!

[PaulRex]

^ nice.. I wouldnt daily drive my rex like that, but for the track that is sweet. i have thought about a jdm front bumper beam though, you should consider that as a more permanent solution. at least for the front bumper.

ive gotten my rex down under 3,000lbs. without me in it and 1/4tank of gas! about 2960lbs. last time i checked, but ive added coilovers since then maybe its lighter now.. but my rims are alittle bit heavier now so maybe not lol. i still want to add a lightweight battery, and considering the front bumper beam.

paul

[Earl]

I usually just take a dump before a trip to the strip and loose about 10lbs. LOL

Just keep an eye out for tank driving soccer moms on her cell phone in the rear view mirror Drew.

[UltimateLurker]

I'm pretty lucky, I drive 2.5 miles to work, and the car rarely sees the Interstate. Of course, an accident can happen anywhere, but that's the chance I'm taking.

[SilverSurfer04STi]

Wow - that's awesome info.

I'm a firm believer in weight reduction. I'm in the process of trying to do mods to remove weight from my MY07. I have about 60 lbs off now and I haven't even taken out the heavy azz spare tire, tools, and jack. That would put me roughly at 100 lbs for a track day.

[verc]

ah interesting. I've got subframe and the front support off but haven't thought of the rear support. I'll give it a try sometime, though I don't want the fuel tank to be exploding the next time I get rearended

[verc]

Originally Posted by UltimateLurker

from the back of a computer , hey it was the perfect size, and aluminum!

I was about to say! "hey that bracket looks familiar..."

[xdrian]

wtg on the weight reduction :thumbsup:

[xdrian]

get the weight of the subframe bolts too, i know those are at least another pound

[UltimateLurker]

Originally Posted by xdrian

get the weight of the subframe bolts too, i know those are at least another pound

[B16A2NR]

Throw in an Odyssey / Braille Battery and lose even more with little sacrifice in cost and no sacrifice in safety or stability.

[UltimateLurker]

I wish I could, but it gets pretty damn cold here, and those things won't hold up to it.

Man, I knew weight-reduction worked, I just didn't think 88 lbs would drop a 10th off of my 8th mile time. I guess I should have paid more attention to anorexicsti.

[dug-e-fresh]

I've been running the same Braille in my car for 3 years now... no issues. And Maryland winters are 10-30 degree winters.

I will say this though... don't by FROM braille... braille batteries are motorcyle batteries they relabel and resell for double the price. Do a search... there's TONS of info on this out there.

BTW- in the drag racing world, its commonly known that ~100lbs = ~0.1 seconds... so you just proved something we already knew

That said, I'd replace the front brace with a GTSpec unit or something similar... VERY nice unit.

def

[AZScoobie]

This is great.. For a race car. I dont sugget anyone do this on a street car. Those bumper beams and that subframe could save your life or your passengers life. You never know when that Starbucks drinking, cell phone talking, Socker mom is going to plow through an intersection and nail you. Or worse a head on.

Clark

[UltimateLurker]

Originally Posted by dug-e-fresh

I've been running the same Braille in my car for 3 years now... no issues. And Maryland winters are 10-30 degree winters.

Thanks for the info

Originally Posted by dug-e-fresh

BTW- in the drag racing world, its commonly known that ~100lbs = ~0.1 seconds... so you just proved something we already knew

Actually, the old rule that dropping 100 lbs takes .1 off of your ¼ ET is pure folly. 100 lbs is meaningless without context. Think about it, taking 100 lbs off of a 5,000 lb Bently will have a lot less of an effect than taking that same 100 lbs off of an Elise, it's all about power-to-weight ratio. For how heavy the STi is, I didn't expect it to be such a large improvement, but I'm certainly happy with the outcome.

[UltimateLurker]

Originally Posted by AZScoobie

This is great.. For a race car. I dont sugget anyone do this on a street car. Those bumper beams and that subframe could save your life or your passengers life. You never know when that Starbucks drinking, cell phone talking, Socker mom is going to plow through an intersection and nail you. Or worse a head on.

Clark

While I appreciate your concern, I believe the beams and subframe do little, and know for a fact that the car was designed without them. I'm sure they help, but only to a minimal extent.

[boozy04]

the bumper beams do a lot actually... look at any subaru with a FMIC that has been in a fender bender. You can total the car at 10mph without that front bumper beam.

[HndaTch627]

Originally Posted by UltimateLurker

While I appreciate your concern, I believe the beams and subframe do little, and know for a fact that the car was designed without them. I'm sure they help, but only to a minimal extent.

are you kidding?

[LastResort]

I know the impreza in other countries has a different bumper beam, but that's far from being designed with nothing. And I don't get the subframe comment at all.