438 lbs gone in 5 days - My Build Story

[ShakinJoe]

Let's look at the actual numbers and what the weight loss does for the 911. You will find weights in "The Porsche Family Tree" and weights in your owners manual.

I believe the weights in "The Porsche Family Tree" are all dry weights, meaning that there is no fuel in the tank, and your owners manual lists them as wet weights. I will list a bunch of cars here, but the one I am working on is the 87 Carrera and I will list it first. I will calculate in 44 lbs of fuel, which is roughly 7.8 gallons, and a 200 lb driver.

Year Model Weight HP lb/hp
1987 911 2906 217 13.39
81-83 911SC 2796 180 15.53
78-79 911SC 2796 180 15.53


For comparison, look at the following later models:

• RS America - 11.78 lbs/hp
• 08 Boxster S - 10.63 lbs/hp
• 997 Carrera - 9.92 lbs/hp
• 997 Carrera S - 9.24 lbs/hp
• 02-05 996 - 9.56 lbs/hp
• 03-06 911 GT3 8.38 lbs/hp

My 87 Carrera is stock at 217 hp, and I have a SW Chip and Cat Bypass. I have not had it dynoed, but I think it is safe to estimate it at 230 hp. If I remove a net 200 lbs and use the 230 HP figure, my ratio goes from 13.39 lbs/hp to 11.76 lbs/hp. If I remove 300 lbs net, my ratio goes from 13.39 lbs/hp to 11.33 lbs/hp. To acheive these ratios with just engines mods would require about 260 HP out of the 3.2L engine. It comes down to dollars and sense, and what you are looking for in terms of "look" vs performance. I want a nimble car.

Either way, we are looking at RS America numbers, or 06-07 Boxster S numbers in terms of power to weight ratio. More importantly, the brakes will get better as you have to stop less weight, but I am hoping that getting out of corners will improve greatly.

Day 2 of my build will be posted tonight along with the beginning numbers of the weight loss project. Thanks for all of positive feedback and your subs.

[mca]

I think the numbers for the 81-83 SC are Euro specs.

US models still maintained 180 if I am not mistaken.

[ShakinJoe]

You are correct sir and I just corrected!

[KTL]

I've got a Blaupunkt Miami CD head unit that I can weigh for you.

I'd like to see what your total ends up being. I've pulled most everything I can out of my car, within reason, to keep it decent looking and streetable to drive to-from driving events. My car weighs 2495 w/out passenger seat and 5/8 tank of fuel. There's more that can be done, but i'm not sure it's worthwhile beyond where i'm at now.

I just "finished" my car about a month ago and hit the track with it- noticeable improvement. But there's some things i'd reconsider next time- not a big fan of 'glass hoods and the crash protection of 'glass bumpers is a bit scary. Nonetheless the car has quickness potential and is no longer the portly Carrera that some consider the G50 cars.

[ShakinJoe]

The goal for day two is to remove the following items.

• Back Seats
• Insulation
• Carpet
• All Seat Belts

I have my son helping today and it was nice have him in the cramped areas, as it was not cramped for him...just a little hot. We started taking out the harness bar, and the lap belts which used the factory bolt holes. I will have eyebolts installed along with disconnect latches for the lap belts. The back seats proved to be somewhat of an issue where they screw into the fender well area. I had to use the side part of the head of a screwdriver to get enough leverage for them to break free. This was by far the hardest fastener to remove. From there the rear seat insulation was removed and that was like 17 lbs!!! I was shocked at how heavy it was. I saved the rear deck insulation for the next day as a fellow pelicaner offered some advice...thanks William.

The carpet was simple to remove, it just took a lot of time as trim pieces, heater controls, center console all had to be removed. The funny part is when you remove those items, you really ask yourself if you need to put it back. Especially the center console. Now if it had a cassette holder...........

The day was done and instead of selling the seats, I called the PO and asked if he would like it for nostalgic reasons, which he agreed. 2 hours later he stopped by and offered 2 cases of Brad Penn oil of which my car gladly accepted. Now I had to go back inside and get the passenger seat to mount in to drive it back in the garage.



INTERIOR SHOTS AT START OF DAY






BREAKING CHILD LABOR LAWS!!







MID-DAY SHOTS








All tuckered out and will get a good night sleep. The very next post will start to reveal some of the real numbers as I have to take off the bumper shock tubes. I am very happy with my progress and start to realize that this, while time consuming, is a lot of fun! Nothing I have done has been difficult so far. My 8mm, 10mm, 13mm, and 17mm sockets are getting a lot of excercise though. I guess if you are doing a project like this, you would have to pay someone to deconstruct the stuff that I have done myself. My learning about this car so far outweighs the time I have put into it. Look for the next post Wednesday or Thursday of this week as I have to arrange pictures, edit etc.....

[snbush67]

Nice, to see someone working for their inheritance? I love this thread!

[911st]

I have stripped two early 911's and am trying to not to molest my new to me 85 Carrera w LSD, factory sport seats, and factory 7&8/16's.

You are making it very hard!

If it matters my car with half a tank of gas as delivered from the factory weighed in right at 2800 lbs.

Emptying the front trunk was of its spare, jack & compressor took 50 lbs off my car. Not sure what the cat bypass saved.

[RWebb]

Originally Posted by ShakinJoe

L
* * *
To acheive these ratios with just engines mods would require about 260 HP out of the 3.2L engine.
* * *

Wt. reduction also affects braking performance, as well as handling.

The improvements in handling relate to total wt., to the F/R wt. distribution and to the polar moment of inertia.

A good figure of merit to use is to measure the distance from the Cg (center of gravity) to the centroid of the item removed. Then take the X, y, and z components of that distance and multiply each by the amount of mass removed.

That will give you a decent comparison of the effects on roll, yaw, and pitch.

Or maybe use the distance to the roll center rather than to the Cg.

The bottom line will be to remove wt. from the rear and from the highest parts of the car.

[ShakinJoe]

Originally Posted by 911st

I have stripped two early 911's and am trying to not to molest my new to me 85 Carrera w LSD, factory sport seats, and factory 7&8/16's.

You are making it very hard!

If it matters my car with half a tank of gas as delivered from the factory weighed in right at 2800 lbs.

Emptying the front trunk was of its spare, jack & compressor took 50 lbs off my car. Not sure what the cat bypass saved.

911st,

Keep posted as I will start showing all of the areas of weight loss. I want it to be somewhat complete, but here is a detailed answer for you! The cat By-pass is a GHL that is listed.

[ShakinJoe]

In order to get all of the weights, I need to have all of the parts which included the Bumper Shocks. The right rear B Shock by the oil tank is a bear, but I found a pretty easy way to remove it. See the following link:

http://forums.pelicanparts.com/porsche-911-technical-forum/423728-right-rear-bumper-shock-removal-pictures.html?posted=1#post4104400

Tomorrow's Post?

F&R Bumper assy final removal and weights
Interior final removal and weights
Rear Condenser removal
Engine compartment blower motor removal

[fintstone]

What you really need to do is buy a midyear and shoehorn in a bigger engine. It starts out lighter and the jack, spare, compressor, tool kit would have all been lost or thrown out long ago. No heavy power windows, doors, mirrors, power steering, brakes, catalytic converter, air pump, door speakers or rear speakers etc. If you are lucky, lots of the sheetmetal will have already rusted away...making it so light that those fiberglass pieces just are not needed.

[ShakinJoe]

Originally Posted by fintstone

What you really need to do is buy a midyear and shoehorn in a bigger engine. It starts out lighter and the jack, spare, compressor, tool kit would have all been lost or thrown out long ago. No heavy power windows, doors, mirrors, power steering, brakes, catalytic converter, air pump, door speakers or rear speakers etc. If you are lucky, lots of the sheetmetal will have already rusted away...making it so light that those fiberglass pieces just are not needed.

LOL!! I hear that, I have had a few "get away" including this one.



Thanks for viewing. A lot of awesome stuff is on the way.

[Bill Verburg]

Originally Posted by RWebb

Or maybe use the distance to the roll center rather than to the Cg.

There are 2 roll centers one for the front suspension and one for the rear. they define the roll axis.

The roll center is a point the moves up and down depnding on the motion of the suspension, it tells you something about how well the suspension is working(ie the kinematics of the suspension) not the Newtonion dynamics.

For dynamic calculations like polar momment, yaw moment, pitch moment etc you use the distance to the cg(or cm)

[KTL]

Blaupunkt Madision CD127 detachable face CD head unit (with CD still in it I believe) weighs in at 2 lb 15-3/4 oz. on my digital baking scale from Ikea. It measures up to 6 lb. 9 oz., so it's quite accurate for light items.

So for simple figuring, call it 3 pounds.

[911st]

I have seen an offering for euro crush tubes to replace our bumper shocks and they make it sound like you can save 20 lbs by changing out all four.

However, you note they only weigh 3.5 lbs each.

Something dose not add up. Is this a case of misrepresentation of did your car possably have the euro crush tubes instead of US bumper shocks?

I have never looked forward to a post like I do this one...

[javadog]

Originally Posted by 911st

I have seen an offering for euro crush tubes to replace our bumper shocks and they make it sound like you can save 20 lbs by changing out all four.

However, you note they only weigh 3.5 lbs each.

Something dose not add up. Is this a case of misrepresentation?

Yep. Hard to lose more than exixts in the first place. That's what will make this thread so useful. For once, we'll have real data, not guesses or internet wisdom.

For what it's worth, a ROW crush tube is a little under 2 lbs.

JR

[KTL]

You're not saving 20 lbs by switching to Euro crush tubes. My weights agree with Joe's 3.5 lb each measurement. I measured both USA shocks together when tracking my weight losses and my notes tell me they weigh 7 lbs combined.

Therefore, the USA shocks are 14 lbs total for all four. So you can't save 20 lbs by switching to Euro tubes, since the Euro tubes would have to weigh negative 1.5 lbs each, or negative 6 pounds total! Is gravity different in Europe?

[brcorp]

This is great, fits into my upcoming plans!

[RWebb]

Thanks, Bill.


If you cannot find a light wt. head unit, then one with a mp3 type input could be gutted of its CD drive mechanism to save some wt. - I'd guess no more than a single lb. and it would be in a poor place to save.

BTW - do you have elec. windows? One thing we have never been able to nail down is whether they weigh more or less than manual (and if that is based on the different guide rails or not)....

[dracb]

what happened to the tar sound deadening material on the floor of cockpit?.....I have been doing the exact projecton on my 87 targa. Using sparco seats, rs door panels, and rs carpet set. I removed the center consule and air cond controls. Debating removal of door lock acctuator, and instaltion of door speakers and retention of radio. Interested in your plans for these items.