Of Curb Weights and why this car will not weigh under 2600lbs

[Eldorian]

Originally Posted by Sully

Most people don't know much about cars.

edit: Not to mention, a lot of other partnerships with mechanically identical cars have one that is a clear winner loser: GM/Toyota, for instance. Geo/Toyota. People might be leery of the BRZ because the toyota version has ALWAYS been better when they partner with somebody else.

Time will tell if the BRZ is different.

I like the Vibe over the Matrix.

[AE86XGC8]

Haven't Subaru and Toyota both cut weight on the current Impreza and Camry over previous models? That's got to count for something.

here is what I found about the 2012 Impreza

http://www.motortrend.com/roadtests/...k/viewall.html

It's lighter, yet safer. In addition to new knee airbags and a brake override system, Subaru includes an expensive, hot-pressed-steel center roof brace to improve chassis stiffness and strength. This, along with additional reinforcements to the junctures of roof rails and pillars, bumps up the roof crush strength to four times the Impreza's weight (the federal standard requires three times).

At just under 2950 pounds, the new Impreza 2.0i weighs 164 pounds less than the outgoing model, thanks to such improvements as redesigned seat frames, a smaller gas tank, and a switch to electric power steering.

[Aki]

Originally Posted by Kostamojen

You can't compare the Miata chassis to the FT86 because well, its entirely a different style of chassis using completely different components

And you just made my point for me. A 90s Impreza is a totally different car with than the FT86, as is the Miata. If anything a Miata would be closer, because it's a RWD architecture.

Originally Posted by Ikaros

@Aki was the news about the aluminum hood in the training manual? I know that aluminum saves weight but it is also very good at conducting heat. Which means that if you have been driving for a long time and accidentally put your hand on the hood you are in for a surprise. That being said it also acts like a heat sink for the engine. So I guess it's a hood idea as long as nobody touches the hood after a track run without gloves on.

Yes, the aluminum hood bit is actually in the training manual. Middle pic of the second page says so.

[Kostamojen]

Originally Posted by Aki

And you just made my point for me. A 90s Impreza is a totally different car with than the FT86, as is the Miata. If anything a Miata would be closer, because it's a RWD architecture.

Uh, no. The Miata shares no similarities to the FT86. The chassis had to be reinforced at different locations due to the convertible design, and the car itself has a "backbone" to support the drivetrain something the FT86 chassis does not have or need to have. There are no shared components or anything remotely comparable between the two.

The closest chassis in terms of actual design, would be a 2012 Impreza chassis. The rear suspension is nearly identicle as is the drivetrain layout excluding the front axles. I don't have any cutaways of a 2012 Impreza, but here is a Forester which shares architecture with the Impreza:




The reason for using the early imprezas is because of how light the chassis is and the fact it has the same drivetrain layout. It also came with two doors (which is irrelevant, the 2-door and 4-door versions only had a 10lbs weight difference). The newer Subaru chassis are bigger cars that weigh significantly more, although the 2012 DOES weigh under 3000lbs.

[Aki]

Originally Posted by Kostamojen

Uh, no. The Miata shares no similarities to the FT86.

Uh, I never said the Miata is similar to the FT86, I'm saying relative to a FWD car from the 90s it's probably more similar (and not by much)... you know, my original point that you can't compare two completely different chassis and draw conclusions? I only bring up the Miata because it's a light RWD car, which debunks the (very) speculative notion that a RWD can't be below XXXX lbs.

And simply showing a top-down drawing of the suspension says nothing as to the chassis design relative to its weight.

The reason for using the early imprezas is because of how light the chassis is and the fact it has the same drivetrain layout.

Last I checked, the 1st-gen Impreza was FWD... not exactly the same drivetrain layout as an FT86.

[old greg]

Originally Posted by Aki

Last I checked, the 1st-gen Impreza was FWD... not exactly the same drivetrain layout as an FT86.

No, it was available as both FWD and AWD. In either case the engine and transaxle were mounted longitudinally, the FWD transaxle simply lacked the center differential and driveshaft output. The AWD arrangement was exactly the same as it is on current Subarus, which is very much like a traditional FR except that the transmission contains a ring/pinion gearset, two differentials, and two stub axles. The original posts references an AWD Impreza, and makes allowances for the weight saved by the exclusion of those components.

[Kostamojen]

Originally Posted by Aki

you know, my original point that you can't compare two completely different chassis and draw conclusions? I only bring up the Miata because it's a light RWD car, which debunks the (very) speculative notion that a RWD can't be below XXXX lbs.

First, I never said RWD CAN'T be below X amount of lbs. What I am saying is that this car with this drivetrain and these components being used in this price range, won't be below a certain amount.

Secondly, the point of this thread was to compare cars that were not completely different.

If you don't want to use the first gen Imprezas, then try this formula with the 2012 model. You will come up with a similar result.

And simply showing a top-down drawing of the suspension says nothing as to the chassis design relative to its weight.

Gives us a damn good idea of what components are being used on the car.

Last I checked, the 1st-gen Impreza was FWD... not exactly the same drivetrain layout as an FT86.

You obviously don't know much about Subaru's, so it might be best if you leave yourself out of this one.

[Aki]

Originally Posted by old greg

No, it was available as both FWD and AWD.

Of course it's offered in AWD. And no, just because the engine is mounted longitudinally doesn't make it close to RWD. The big difference with longitudinal FF layouts from FR is that the engine almost always has to be mounted in front of the front wheel center line. That substantially changes the packaging of the vehicle. That's the case with Imprezas. It's the case with Audi's--which is why they're seen more as FF platforms even with the AWD.

Originally Posted by Kostamojen

If you don't want to use the first gen Imprezas, then try this formula with the 2012 model. You will come up with a similar result.

Sigh, the point is "formulas" don't work because even when based on a similar platform the engineering that goes into it is very different. Different engine, different rigidity requirements, different use of alloys, different weight distribution priorities... different a lot of things.

Gives us a damn good idea of what components are being used on the car.

Since when does eyeballing pictures provide good indications of curb weight?

You obviously don't know much about Subaru's, so it might be best if you leave yourself out of this one.

I know enough to know that you can't draw conclusions of weight based on comparing a yet-unreleased car--which you have very limited tech info on--to a car that's two decades old.

[Kostamojen]

Originally Posted by Aki

That substantially changes the packaging of the vehicle. That's the case with Imprezas.

The packaging of the vehicle is NOT substantially different, thats my point!

The engine moved farther back yes, but that didn't magically make the car lighter. Removing the front axles does make it lighter, but everything else still has to stay the same!

The only thing we don't know in terms of weight is the chassis itself. The engine weight we know because its just a modified FB motor, we know the weight of the suspension components because they are the same, we know the weight of the drivetrain will basically be the same excluding the parts for the front axles as mentioned, so the only thing that is the question is the weight of the chassis.

And the entire point here is that the chassis isn't going to be significantly lighter than old chassis of roughly the same size that were made of less materials and had less structural rigidity than any new car. And because this is a cost-effective car, its not going to use exotic alloys to keep the weight down.

[fatoni]

Originally Posted by Kostamojen

The packaging of the vehicle is NOT substantially different, thats my point!

The engine moved farther back yes, but that didn't magically make the car lighter. Removing the front axles does make it lighter, but everything else still has to stay the same!

The only thing we don't know in terms of weight is the chassis itself. The engine weight we know because its just a modified FB motor, we know the weight of the suspension components because they are the same, we know the weight of the drivetrain will basically be the same excluding the parts for the front axles as mentioned, so the only thing that is the question is the weight of the chassis.

And the entire point here is that the chassis isn't going to be significantly lighter than old chassis of roughly the same size that were made of less materials and had less structural rigidity than any new car. And because this is a cost-effective car, its not going to use exotic alloys to keep the weight down.

moving the engine back kinda changes the weight of the car

[Sony]

Originally Posted by fatoni

moving the engine back kinda changes the weight of the car

It doesn't change the weight...it changes the "weight distribution" they are two VERY different things. Unless you are talking about the incredibly insignificant weight loss due to a slightly shorter driveshaft...other than that it barely changes the weight at all.

[Kostamojen]

Originally Posted by Sony

It doesn't change the weight...it changes the "weight distribution" they are two VERY different things. Unless you are talking about the incredibly insignificant weight loss due to a slightly shorter driveshaft...other than that it barely changes the weight at all.

What he said.

[fatoni]

Originally Posted by Sony

It doesn't change the weight...it changes the "weight distribution" they are two VERY different things. Unless you are talking about the incredibly insignificant weight loss due to a slightly shorter driveshaft...other than that it barely changes the weight at all.

people spend thousands of dollars buying carbon fiber this and that and light weight components to save ounces. a shorter drivetrain shaves pounds. and in cars that are light the weight removed is a larger percentage of overall mass. it may not be that much when simply looked at objectively but in context it is a move that is worth thousands of dollars and may provide significant benefits.

you are saying its insignificant and i am saying its significant. those words are subjective so i dont think we will agree but small things like that kinda add up

[chulooz]

Unless you are moving the engine over 6" you may as well just skip a meal and drinks to save the same amount of weight.