spare tire well removal

[matthewb]

I dont ever carry a spare tire in my car and am currently doing basically a full tear down, repaint and fix everything along the way type project. With some of the drivetrain modifications I have already done(putting in a ford 4.6 liter v-8 mostly) I can no longer remove my transmission without dropping the rear suspension... unless i removed the tire well. So anyway has anyone ever removed it completely as a weight savings or made it shallower so maybe it would just hold a couple of tools or jumper cables or something? How did it turn out? any pictures?

Through out this project I am looking for weight savings ideas too. I am already planning to do away with the rear seat and it looks as though each of the front seats are about 50lbs a piece (is that right? seems high). I thought about maybe the GT racing style rear bumper to loose 27 lbs acording to their site (though i would make one on my own though). Any input on these type things or any ideas for weight savings would be apprectiated. I know race seats will loose some weight but normally are pretty expensive. Are there any later style seats from another porsche (911 or something) that can easily be made to fit that might save about 20 lbs per seat? How many people have the GT racing rear bumper replacement? is it nice?

Thanks,

Matt

[flash968]

i've been thinking about it as part of an underbody aerodynamics project - i'd love to see what you come up with

i don't know that you will lose all that much weight in body panels - the polyurethane bumper cover of a 968 for example is only about 30 lbs - the fiberglass unit is about half that - not a lot of savings - fit and finish of fiberglass is generally not satisfactory for street cars, so keep that in mind

factory seats are upwards of 50lbs - there are many aftermarket seats that weight a lot less - width is the primary complication

prices range roughly from the inexpensive at about $300 to about $1800 for the recaro sportlines like i have in my blue car

[matthewb]

Flash, I am working with an 83' 944 so I do have that giant hunk of aluminum bumper out there with the bumperettes on it plus the bumper shocks underneath. I am a little concerned about the loss of low speed rear ending protection by getting rid of the big bumper and shocks but i dont know maybe i still want to do it... i mean afterall I dont plan to get rearended.
I would think the only other possible major body panel weight savings would be in the hood but finding a well fitting and structually sound hood to replace the steel could be quite a problem... maybe if someone made an aluminum hood for it. I dont know.

Somehow I think these cars are a little heavy for their size and maybe that is just what you end up with when you get a car that isnt a complete rattle box i dont know.

As far as the seats go, how much do your seats weigh and did you get them recovered to match your car? Looks like you did.
Is it typical to have issues finding seats the correct width for these cars or are you talking about finding a seat the correct width for the driver that sits in them?

I guess part of my big motivation for the spare tire well is for ease of removal of my transaxle not as much for the weight savings. I could only imagine it saving about 3 or 4 pounds.
as far as the earodynamics i would think i would need to make a panel at that point that would basically come down from the rear bumper and wrap all the way to the back of the floor pan and somehow have it not interfere with the suspension.

Thanks for your info

[flash968]

if the 968 hood is any example, it only weighs 39lbs - again, not a lot of savings to be had

if you are looking to save weight in bodywork, the rear hatch glass can be replaced with lexan and is good for a bit of very high mounted weight

the bumper removal may void your insurance policy, and is likely not legal in your state - i'd check that - that being said, there is about 20lbs there

these cars are indeed heavy - there are a lot of things that contribute to that - some can go away without real loss to creature comfort - some can't - i've pulled 240lbs from my blue car, and have not lost anything in the way of comforts

the seat wells in this car are narrow - it's hard to find seats that will fit - then you need to make adaptors for the rails for most of them to get them to line up - height is another concern - many aftermarket seats are designed for cars with a taller roof, and consequently sit too high - even the ones in my car required custom adaptors to lower them so they weren't putting my head in the roof (and i'm not that tall)

the weight savings of the well removal won't be much - but if you made a piece that went from the rear down over the transaxle and to the floor, you would create a nice exit for the air - most high speed cars do this - it would require building in a good exit for that air though - take a look at the back of a current ferrari for an idea of what i'm talking about - done right, this would seriously decrease drag and increase downforce

[speedracing944]

What about converting the spare tire well into a second radiator support for a rear mounted radiator. You could duct air from under the car, through the radiator and out the back of the car. You could even slot (mill out) the rear aluminum bumper and enclose the area so the hot air exits out of the slotted rear bumper.

Benefits;
1) more cooling for your V8
2) better aerodynamics by directing the under vehicle air into the normal low pressure turbulent wake

Speedy

[m73m95]

Tony G over on RL cut his spare tire well out, and put in a huge trans cooler.

He did the LS1 swap, so his tranny needed the extra fluid, fan, and exchanger.

With your 4.6 swap, you might think about the same thing.

TonyG LS1 He also has a writeup on the setup he's using. Search RL

[Cocacolakidd]

Another thing for weight savings that most overlook are the huge hunks of tar under the front carpets. Yes there is insulation and sound deadening material there in a form of tar sheets. Now that our cars are twenty plus years old these sheets are closer to black peanut brittle and chip apart like that - there is probably 30 pounds there for easy removal and replace with a more modern and better insulation that is lighter and better. When I replaced mine I also found almost three dollars in change under the seats/carpets.

[Capt Squid]

My old 944 turbo race car had the spare well removed and an aluminum panel pop riveted over the hole. The PO said that it saved 10 lbs.

I have a light weight aftermarket fiberglass rear bumper off that race car. I will take $125 plus shipping from San Diego. If you are interested, PM me and I will weigh it and send some pictures.

[matthewb]

Speedy, am right there with you on the cooling. While doing this project i was planning to add some auxilary coolers by way of heater cores possibly alongside the radiator in front. I had considered doing a rear one but didnt really like the options for running the cooling lines. it is a little limited. i wonder how much the heat from the front radiator and the heat from the hot road is going to hurt the effectiveness of a rear setup.

I had considered the sound dedener under the carpets and looking at it it doesnt look like there is really that much there. I have gone through on a different car are removed a bunch of that and it was only maybe 5 pounds worth and a lot of work getting it out. It was an early 90's car so maybe you are correct in saying the newer stuff is lighter I am just not sure if I will much from that or not.

Capt squid, What condition is the rear bumper in? I am in hamilton, Ohio (45013) I can't imagine it being cheap enough to ship to make it worth while. I had considered trying to lay up my own fiberglass rear bumper so we will see.

[rickharrison]

Let's see some pics of your engine!

[Sterling Doc]

I did this in my build thread - look here: 944SPEC - Low cost wheel to wheel racing - Re:Budget Build 944 Spec racecar - Updated 1/25/09 - 944-SPEC

[matthewb]

Here is a picture of my engine finally for you guys. obviously right now I am in the middle of full revamp.

[matthewb]

I guess nobody was interested in the picture?

[Cocacolakidd]

Where did the battery wind up? Neat way of doing cowl induction there -

[matthewb]

The battery is in the passenger side rear well by the marker light. Its a good spot for them.

[Cocacolakidd]

Did you run a 4ga. cable and ground the batt back there - or?

[matthewb]

I do not have the battery grounded in the rear. i ran the ground straight from the battery to the block and have a wire continue directly from there to the frame. 4Ga. is not enough. I think i ran single "0" size. It is right aroud a 15 foot long run. The voltage drop with that much current over that disatance would be way too much with 4ga.

[ideola]

More pix than you can shake a stick at here:
924Board.org :: View topic - Body Work for Ideola's Ultra Wide Body 931

This thread chronicles everything I've done to my chassis to lighten it, including removal of the rear bulkhead area for the installation of a fuel cell. Feel free to send me a PM if you have any specific questions.

[matthewb]

Does anyone know the difference I weight between the early steel fuel tank and the late plastic ones? I like the plastic idea because it is bigger and won't rust out and the fact that I have one laying around but I don't have my steel one out to weigh yet.