arl240

I'm with Mach 1, and he made it easy to understand (better than my long *** writing).

carguycw

OK you said 3, guess I wasn't paying too much attention to the earlier post...

FWIW I doubt that any model of the Mazda3 will use any variant of the F-series engine. Reason #1: The whole reason for the design of the new MZR is to reduce the number of 4-cylinder engine families that Ford/Mazda produces. It's already an open secret that Mazda is discontinuing the B-series when the current Miata design expires, and it wouldn't suprise me if the F-series follows suit, esp. because Mazda does not make pickups anymore. Reason #2: It would make more financial sense to use a smaller variant of the MZR as the base engine because the same engine mounts, axles, trannies, etc. could be used in all variants of the Focus/Mazda3/Volvo S40, reducing costs. Reason #3: Mazda is pursuing a performance-oriented marketing strategy (Zoom Zoom!) and it makes sense to use a more powerful engine to make the base model more appealing. Mazda is not heavily dependent on fleet sales, so it doesn't make sense to build a dirt cheap, decontented, weak-engined base model that's openly aimed at rental companies and city motor pools... like the base Ford Focus.

That's what I think, anyways.

carguycw

Yeah, but it's not much cheaper when you add the expense of (a) pressed-in iron cylinder liners or (b) some sort of hardening treatment applied to the cylinder bores (such as Nikasil). One or the other is required to stand up to the abuse of internal combustion because aluminum is so soft. The cost of adding one of these features is dropping all the time, but it's still more expensive than just drilling several big holes in the d*mn thing, like an iron block.

dynamho

Isn't that self contradicting and hypocritical? You say the thread reacted with emotion and yet you yourself say you're passionate about your dissatisfactions. What's up?

obender66

Thanks God Mazda still has iron block closed deck design engines!
I don't know about you, but I knew about relatively low fuel efficiency, high rpm and "low"tech of FS loong before I got it. So what-less things to break and more reliability when turbocharged.
In city driving under "real" conditions Honda with non VTEC will have same fuel economy as PR5-I know for sure, because I have 1999 Civic sitting on my driveway. Same would probably be true for Corolla-why not?
Can somebody list ACTUAL weight of aluminum engine and iron block engine?
I am sure difference will be not material to substantiate efficiency claim.
What car weight has to do with rolling resisitance? Take shopping cart-you have to keep pushing it a little all the time when it's empty, but when it's loaded and got momentum, you actually need to hold it from slamming into another shoppers. Heavier car will get better fuel economy DURING CONSTANT CRUISING AT ANY SPEED compared to lighter, if they geared the same-Pseudo was right. Heavier car will get worse fuel economy in STOP and GO, same as you get more tired pushing heavy shopping cart from standstill and then halting it, pushing it hard again and so on.
Alex

Scarmiglio

That works great, until you try pushing the loaded shopping cart up a hill!

Unfortunately, the world is not perfectly flat and frictionless. There are uphills and downhills, and the added weight on the uphills (even gradual ones) will allow the lighter vehicle to get better mileage.

Scarmiglio

You say to argue the physics, not the people, and yet you are arguing with ME!!! And I am not wrong. If what you are saying were true, then a 2.0L in a Suburban would get better mileage than the same 2.0L in my P5 (at cruising speed, of course) and there is NO WAY that this is accurate. (It would be fun to try out though - maybe too much of a pain in the ***). Lots of automakers use the same engines in more than one car, and the heavier cars always have lower mileage ratings (you will argue that this is due to around town driving, but they have lower highway mileage ratings also).

How is drag from the road "more powerful" against a lightweight car? The heavier car pushes more weight down on its tires creating more friction and therefore more drag. Your theory is not based in fact, dude.

This is a silly argument regardless.

Scarmiglio

I did a little "scientific" research and here's some info for you:

A VW Eurovan with a 2.8L V6 and an auto tranny weighs 4228 pounds and gets 17city/20highway
A VW Jetta with a 2.8L V6 and an auto tranny weighs 3274 pounds and get 21city/31highway

Funny how that works, isn't it? I guess those extra 1000 pounds do make a difference after all.

another example:

A Ford Expedition with Auto and a 4.6 weighs 5267 pounds and gets 14city/19highway
A Ford F-150 with Auto and a 4.6 weighs 4655 pounds ad gets 15city/20highway

I don't know about the VW's, but the fords have identical transmissions and identical engines. In fact, the truck, becuase of its open bed, has more wind resistance to boot.

Where are the vehicles that weigh more and yet get better highway mileage? I didn't seem able to find any. I wonder why....

Scarmiglio

Let me use a better example. When a big rig is empty, it get halfway decent gas mileage and has no problem driving up hills or even mountain passes. When a big rig is full, no momentum in the world is going to stop it from using the truck lane to get up the hill and the gas mileage is going to suffer. The downhill on the other side does not make up for this.

What you're saying is that if I load up my car before I go on a long trip, I'm going to get better gas mileage. Believe me, this is not the case! That's like saying that a truck that's pulling a trailer gets better gas mileage than one that isn't because the "momentum" of the trailer is pushing the truck. We all know that this isn't true.

You're trying to tell everyone that you know more about weight/momentum than the automakers. Further, your argument is refuting the laws of physics. And then you just blow it off with a "believe whatever you want". Why don't you back up your statements with some FACT?!? Oh, wait, maybe because there ISN'T ANY.

fossil boy

1st - PLEASE cease "locking" threads... the old one was getting a tad bit interesting. C'mon, endless post-***** threads are allowed to continue until 10's of pages - those senseless ones ought to be extinguished, rather than threads which actually may yield insight and knowledge!

I am not a physicist, but here's my take on the situation:

While F = m(a), what is not considered is Frictional resistance, which may seem to affect a lighter vehicle greater, b/c of the larger ratio of resistance to weight, BUT, the heavier vehicle actually will generate more resistance since Gravity has greater affect on larger mass. Thus, while it may seem that the heavier vehicle, due to inertia would be more efficient, I don't think this would be observed, unless we were operating in a Vaccuum!

Furthermore, who cares about Force (unless you have a head-on crash)? Force is NOT a measure of efficiency, but rather, the sum of energy generated. Thus, an object requiring less force (F) to maintain the same velocity actually would be lighter (less mass), and require less energy to attain that velocity.

What would be an improvement is lighter internal components such as pistons, crank and flywheel - and I'm thinking titanium here - since these internals are the inital objects of mass which must be moved for any motion to occur or be maintained.

Insofar as Al v Fe blocks
1) Ceramics and/or polymers probably are a better route anyway.
2) All I want for Christmas is Titanium Front Teeth, then I'd be able to jump through the screen and chew your face off!!

fossil boy

You are beginning to perk my ire!

According to your posted mandate, this Forum is supposedly about the exchange of FACTUAL information. I've seen all too many posts/threads that spend a great deal of time delving into minutia concerning Mazda VIN #'s, engine designations, gear ratios, etc. These discussions center about the fact that, "Truthful, valuable information must be dispensed" rather than someone's uninformed "opinion". I agree with that pretext. But when your moderators incorrectly spew information, and then lock the threads, I become a bit aghast.

"when a thread is closed, discussion ends.
when its over, its over. get over it
stop beating the dead horse


__________________
TheMAN
'01 BJFP MT

Nothing is more pertinent to our cars than Physics.
PsuedoRealityX may indeed have vast expertise and excellent knowledge of an automotive nature, but, apparently, not in Physics (or Algebra). By posting inaccurate info, and then locking the thread (see "2.0 engine"), you have denied yourself and other Forum members from advancing ideas and knowledge. Is this truly what we want here?

Considering how much extraneous babble is allowed here, along with the plethora of whoring (post- and otherwise), I don't see how you have any valid right to ban folks, lock/delete threads, etc., merely b/c YOU, as a moderator choose to do so.
The free exchange of information ends when members opinions and ideas are denied. And certainly, this isn't an issue of thread length (ex. "I've got proof"), or in the case of the "2.0 engine" discussion, it isn't about offensive behaviour, language or personal attacks. While i wasn't necessarily concerned with the original intent of that thread, indeed, it had morphed into issues which I do find interesting. Thanks for denying me the opportunity to enjoy and share knowledge

So do tell me, what exactly caused the demise of that particular thread? I'm not sure, but I suspect the reason lies within the fragile egos of the "Mods".

You say stop beating a dead horse - well that's YOUR perception/opinion. To some, it's dead; to others, it's dinner; and yet to others, it could be a sad loss!

arl240

Since you reopened this proverbial can o'worms, I thought I would include my PM to Pseudo, just to clear it up:

After finishing the pissing contest that was going on in that 2.0L post, I thought I would finally give you the physical reason why heavier vehicles are less efficient than lighter ones:

First, your inertia argument - everything wants to keep going unless acted upon by an outside force - this is well and good in space, but here we have wind resistance and rolling resistance.

Fw = force on the car by the wind = ugly fluid formula related to cd, fluid props, velocity, etc - has nothing to do with weight

Fr = rolling resistance = related to friction and materials, among others - Ff = force of friction = u*[B]m/[B]*a = coeff of friction x [B]mass of car/[B] x gravity

In rolling resistance we can see that the weight of the car will directly affect the rolling resistance of the vehicle.

Now, both of those forces act backwards on the car, even on flat surfaces. Unmolested (like when we are in neutral), the car would slow down and stop. To counteract this slowing, the engine must transmit a torque (which get converted to a force) to the wheels. This cruising force (remember the car is actually perpetually slowing down, we give it a micropush to get it back to its original speed) is Fc. Now as you stated earlier F=ma, therefore, the bigger the mass the more force needed, even if the acceleration is infinitesimally small. And no acceleration is not zero, if it were there would be zero cruising force, and the wind and rolling resistance would slow you down.

Pseudo, you know cars and driving really well, but stay humble when it comes to Free Body Diagrams.

UCSBgeek

If I understand correctly... a heavier weight requires more force to propel than momentum is gained... please don't flame me if I'm wrong, I don't know

LOS-323

Acceleration IS zero.... meaning "constant velocity"... it it slowed down, then acceleration would be negative. Check any physics book and you´ll see what I mean.

Perhaps you mean that the cruising force is zero. In that case the car would slow down, because the forces against it would be greater than those forward, resulting in negative acceleration.

An object is accelerating if it is changing its velocity... and slowing down or speeding up is accelerating (negative or positive). So, constant speed is zero acceleration.

Acceleration: "The rate at which an object changes its velocity."

Hope this helps.

VagaBond-X

HeHe...

I understand and like what LOS-323 said

from my first year of physics....his reply seems right...

but then again...I've only taken one year of physics...next one is next semester