Weight savings cost/benefit benchmarks

WCH wrote

I think the seats are going to be hard to remove. The airbag sensors are located there and the seats are an important part of the design for the safety of the car.

True.

Epacy wrote

Odyseey.





Good thread Lucid. I will stay tuned.

I am familiar with the effects of over-moding and the impact on the ride. I hope to steer clear of that with this car.

How much is it? I couldn't see price info.

I have no intention of tearing up my car either.

lucid wrote

I have no intention of tearing up my car either.

This is all about reasonable weight saving modifications...bolt-on, bolt-off, No?

OC kid wrote

This is all about reasonable weight saving modifications...bolt-on, bolt-off, No?

Exactly. Nothing that would be a pain in the ass to undo.

OC kid wrote

This is all about reasonable weight saving modifications...bolt-on, bolt-off, No?

That is all I am interested in. Nothing too much where the character of the car is changed. Although, from my test drive, I didn't exactly bond with the character of the car.

Epacy wrote

That is all I am interested in. Nothing too much where the character of the car is changed. Although, from my test drive, I didn't exactly bond with the character of the car.

I think the character of the car would be very nicely changed if it were to lose 150lbs. That's like driving around with a passenger, which is noticable to me.

Plus the exhaust would increase hp at high rpms, and others would decrease rotational inertia (we should start reporting "I" numbers). Regardless, all differences will be small, and I am not sure that they will make financial sense. Hence the point of doing the bechmarking and the thread...

lucid wrote

I think the character of the car would be very nicely changed if it were to lose 150lbs. That's like driving around with a passenger, which is noticable to me.

I am not debating that point. I am talking about too many mods resulting in a much harsher ride and a noticeable decrease in civility within the cabin.

OC kid wrote

BBK
This is a big one that you missed. The stock brake assembly is very heavy. The benefits are multiplied in that it reduces the unsprung weight as well. I will be posting the results after install of the Brembo kit w/ differences in weight. Brembo just took measurements last week and I should have them in before Bimmerfest. TBD.

I'm not so sure. I have not done any weighing of brake components but consider these facts.

-The OEM brake caliper is aluminum.
-The OEM rotors are composite and floating with aluminum hats for less thermal stress and less weight.
-Rotating mass is bad indeed but having sufficient mass in your braking system is crucial for not cooking things.
-BBKs are just that BIG. This means larger and potentially heavier calipers and larger diameter and again potentially (likely) more rotor mass.

I am quite keen to hear about an apples to apples weight comparison of the OEM brakes vs. Brembo.

Epacy wrote

I am not debating that point. I am talking about too many mods resulting in a much harsher ride and a noticeable decrease in civility within the cabin.

We agree then. Now try to go to sleep if you can with your car in the dealer's lot!

Epacy wrote

That is all I am interested in. Nothing too much where the character of the car is changed. Although, from my test drive, I didn't exactly bond with the character of the car.

I know what you meant earlier about brutalizing the car. You'll get the feel for her after the first few 100 miles... and definitely wait till after the first 1000 mi. before you soil the virgin with a mod.

lucid wrote

I think the character of the car would be very nicely changed if it were to lose 150lbs. That's like driving around with a passenger, which is noticable to me.

+1 100lbs is very noticeable, and I can imagine how much swifter and tighter she would be! I seem to feel a big difference, in terms of acceleration and response, between having a full tank of gas vs. a close-to-empty one, due to the weight.

swamp2 wrote

I'm not so sure. I have not done any weighing of brake components but consider these facts.

-The OEM brake caliper is aluminum.
-The OEM rotors are composite and floating with aluminum hats for less thermal stress and less weight.
-Rotating mass is bad indeed but having sufficient mass in your braking system is crucial for not cooking things.
-BBKs are just that BIG. This means larger and potentially heavier calipers and larger diameter and again potentially (likely) more rotor mass.

I am quite keen to hear about an apples to apples weight comparison of the OEM brakes vs. Brembo.

swamp:

I am just commenting from my experience when I removed the suspension, the brake assembly felt much heavier than any I have handled before. (I had to double-up on it to keep it from falling to the floor.) I will have more info later because I will be weighing each component (stock and Brembo BBK) to compare the real numbers.

Epacy wrote

I am not debating that point. I am talking about too many mods resulting in a much harsher ride and a noticeable decrease in civility within the cabin.

Kreissieg F1 idea is out the window...

OC kid wrote

Kreissieg F1 idea is out the window...

The only thing that would put that out of the window is the $5k muffler they supposedly charge.
The sound is simply the best.

coil overs
empty the trucnk floor and tire goo kit
remove rear seats
lightweight tires
lightwieght flywheel

This is a great thread. I am conscious of the weight also and would love to shave 100 lbs or so and get closer to the E46 M3 weight. The mods would have to be tasteful aesthetically and fully reversible though.

I wish it were possible to get identical front seats, but fully manual and without any motors. Also, does anyone know how much the BBS sourced(?) concept wheels for E90/92/93 weigh compared to the stock 19s? I would love to save 12 lbs there if possible. Exhaust would be another area I would consider, but I like the sound of the stock setup. I wonder how much weight EDC adds? I don't see how it could be that significant.

I don't know if you are in shape, but the most cost-effective thing to do is to reduce the weight of the driver!

Seriously though, IMHO wheels and seats are going to bring about the biggest weight savings.

lucid wrote

Body Fat
Stock: ?
Sculpted body: ?
Cost: ?
Weight savings: ?
cost/benefit: ?

Don't forget to count the wife too if you are married.

ILC32 wrote

I don't know if you are in shape, but the most cost-effective thing to do is to reduce the weight of the driver!

Seriously though, IMHO wheels and seats are going to bring about the biggest weight savings.

Yeah, I have lost about 20 lbs since last summer. I was 6'-0" 200 lbs and now I'm very low 180s. Getting lean like that 4 liter!

mkoesel wrote

Don't forget to count the wife too if you are married.

Fortunately, I don't have that "problem".

RandyB wrote

Yeah, I have lost about 20 lbs since last summer. I was 6'-0" 200 lbs and now I'm very low 180s. Getting lean like that 4 liter!

Wait, how much did that cost you? I need to enter the cost/benefit ratio in my benchmark table.

Porsche really deserves kudos for their emphasis on out of the box track readiness. Standard seats are manual adjustment and comfortable with good support. I would pay to have a manual seat option in the M3 over the heavy and less reliable electric chairs. Porsche is now offering carbon fibre buckets from the GT2 on all their cars. Expensive option, yet saves in the neighborhood of 40lbs on the chairs alone.

Porsche brakes are legendary for their fade free attributes. No need to opt for the over the top expensive ceramic option unless you are a track junkie with gobs of money.

The M division simply cut corners on their brakes, likely as an effort to keep costs down. I would of gladly paid more for multi piston/fade free brakes. Is the M division the only performance company to stay the course with single piston stoppers? The 1 series getting fitted with multi piston brakes should tells us something.

It appears BMW has finally ran the numbers and surmised they can make lots of money by offering performance parts. In theory this is exciting but in reality it will be more expensive for us the customers than if they simply offered the options straight from the factory as Porsche does. It will give the stealerships another avenue to bilk the customer with high installation costs and provide more room for intallation error.

ILC32 wrote

Seriously though, IMHO wheels...are going to bring about the biggest weight savings.

A cursory check has shown the opposite, the stocks are already pretty light. As lucid mentioned, I would expect only ~10-15 lbs. with all four swapped out.