flar

I think that's probably what happened as well, but the fact that they were coming from a platform based on a 4 cylinder engine may have had as much or more to do with the constraints as weight considerations.

Potentially, but according to the specs on the Toyota web site the weight cost of the V6 on the Rav4 is less than 200 pounds more than its normally aspirated 2.4L I4 version. Perhaps the Toyota engineers know something that the Honda engineers don't about making a light V6, but it suggests that a V6 doesn't have to add a lot of weight. You then have to factor in the weight of a turbocharger and associated plumbing to make the I4 perform well which then mitigates the weight gain of choosing a V6. I think the RDX would do just fine with a V6 with its sporty suspension and SH-AWD to manage the chassis dynamics.

terdonal

I guess I am one of the luckier ones as I find the gas mileage to be what I expected for this type for vehicle. Go to other forums, X3, X5, Cx7, MDX, etc. what have you, there is the same kind of postings. Some get good, some what they expected or some crap just like here.

Imo, it depends as much on how you drive as to the driving conditions you drive in, temp conditions, A/C use etc.. On my last 700+ km's I my averaged 11.2/100L or 21 US mpg. That was probably 35/hwy/20/rural/45/city. Volume from light to heavy in all of those areas and more than normal A/C use for me. I have never had it on the freeway for any lengthy distance to this point (maybe 10 km's) but do know the faster you go the lower the gas mileage as the OP's post shows.

I use the paddle shifters a lot myself and in particular up shifting from 4th to 5th and as a result my vehicle has learned to shift into 5th at a lower speed than when I first got it. When I first got it and for sometime after it would not shift into 5th until it was at 65-66 km/h now it will shift into 5th at 60-61 km/h. What that does for my gas mileage I don't know for sure but I am sure it has some impact. I don't run up peoples butts, I drive ahead as far as I can see, I drive according to the conditions, gauge street light changes and I let the vehicle momentum work for me. This is not something I do specifically for this vehicle I have done if for years.

For instance there is one 4 way stop I go through every night on the way home than can have up to 20 vehicles in front of me. As I wait in line I let the vehicle in front move 10-20 ft ahead and then take my foot off the brake and let the car move itself and most of the time I can make it to the 4 way stop without touching the gas pedal/brake more than a couple of times. (That usually depends on how busy the 4 way stop is and how many are turning left or right vs going straight.) What's the point I can't go past those vehicles in front of me anyway.

The most fun I have in this vehcile is on the twisties and curves yet it can move well on the straight. Not quite up to the 6 sec 0-60 referred to above with the twin turbo but still very respectable. I have yet to have anyone hang with me on these if I don't want them to and that includes a wide variety of vehicles but some of them will blow by me on the straights at stupid speeds for the conditions and leave me in their dust even though I maybe going up to 20 km's over the speed limit.

Some of us also forget that it is not just weight, awd, turbo, 4 cyl vs 6 cyl that impact gas mileage but aerodynamics and the physical size of the vehicle as it moves down the road that impact the gas mileage. So what is the point of me for eg, trying to compare the gas mileage of my RDX vs the gas mileage of my RSX typeS or my TSX 6 spd? For a point of reference yes but that is all imo.

737 Jock

Older Audi quattro was 50/50 torque biased with up to 80% to either end using the older Torsen system. But, they switched to Haldex in 1998.

Haldex is 100% front drive, but can transfer 50% to the rear. Haldex obviously, is more fuel efficient, but it imparts a front drive feel (and limitations) to performance driving. So your 2000 S4 should have had the Haldex quattro system. Most notably, Haldex is re-active and there is a delay in torque re-distrubution.

The RDX SH-AWD is pro-active and employs more rear torque earlier and longer than Haldex which may help explain the greater fuel burn over the very similar weight Audi -- more driveline friction.

My MID is within 1/2 mpg of gross calculation -- and it's high -- but that may be due to the computer's continuous calculation vs gross. At any rate I'm getting 25 mpg on the highway at 65, and 27 to 28 on two lanes at about 50.

Steady state cruise eliminates the driver induced variables. Have you had the car checked?

castor

Well, yesterday I went on a 500 km trip.

Car HAD 256 kms, now almost 800.

Reset, filled up and went out.

Averaged 9.8 l/100km over the trip, 90% Hwy at 120-130 km/h.

Not too bad.

Same as my old Subaru.

overall so far I am averaging 11.1 l/100 km combined.

Lrpba300

I just wanted to hear some more details Flar, that's all. It brings up some interesting views & info from everyone. I agree with lots of what you said, some I don't. I'm also sure the Acura marketing guru's helped "plug" the numbers in & then the engineers had to make it happen.

It's just hard to compare "apples & oranges" type differences. Was the Audi better then the Acura RDX? Maybe... All I'm trying to say is that with how the RDX is setup, it does a pretty good job of all around power, handling, good in snow, great interior, mpg that isn't that bad. If I take for just that, I'm happy. If I compare to past vehicles, some were better, some were worse, (COMPAIRED to their posted / rated mpg on the sticker!). Maybe yours is at the low end of the manufacturing curve, someone's is at the high end of the manufactured curve. It is kinda sad that EPA(?) had to re-rate the RDX. Set to high. Maybe Acura screwed up? All I can say is I'm very happy with my RDX. It fits my needs perfect & COMPAIRED to other vehicles mpg stickers, it's still decent mpg. It's still better than my MDX's I had. They didn't get NEAR what the sticker said. Does this make me mad at Acura? No. I blame the "ratings system" more! Maybe your mad at Acura, I don't know. Is it worse than your Audi? Obviously. Have your RDX checked out. I just hope you still like your RDX, I know I do.

XLR8R

I get 211 pounds from my Rav4 brochure, between the Base AWD I-4 and V-6.

But consider the location of this 200 some pounds; at the extreme front, entirely forward of the struts and axles. This creates a very high polar moment and shifts the weight distribution from 57/43 in the four (= to RDX) to 60/40 in the six. A similar effect could be achieved by strapping four 50 pound bags of cement to the hood -- increased understeer.

Turbo-chargers are much lighter now. The burst containment housings are typically aluminum bonded to a ballistic Kevlar-like material. Turbine wheels are super-alloys and compressor wheels are composites.

I don't have info on the material or weight of the RDX turbo unit, but it should not weigh more than 18 pounds in cast stainless. The intercooler should not weigh more than 8 pounds. The top-mount minimizes duct length. All components of the charge air system should not exceed 30 pounds and they are mounted aft and above the engine for lower polar moment.

I agree; a V-6 would satisfy many people looking for more grunt and refinement at the expense of some handling, but I don't think Honda's V-6 would fit.

flar

So do I, but that is an apples to oranges comparison. The base I-4 is a stripped down model. The base V-6 includes some "all V-6's have these" options - bigger wheels, full-sized spare. The higher end models represent a fairer comparison since more of the "V-6 value added" options become standard with the higher end packages so the difference in weight is due more to the engine. If you look at those models the weight difference gets lower: base - 227/211, sport - 176/163, limited - 176/163. Even on the higher end there appear to still be some "V-6 standard" options...

True, and the SH-AWD system (perhaps with a little tuning) could help with that as well.

Perhaps, but that would still reduce the cost of a V-6 down to potentially 133 pounds?

I'm not arguing that the V-6 would come for free, but some posts here seem to exaggerate the cost of it.

Also...

I'm sure it would be a more satisfying experience, but that isn't where it ends.

The increased control over power delivery from a (normally aspirated) V-6 would also have tangible benefits for the handling. When you have to submit a request in triplicate via a telegraph to your engine compartment to get power to the wheels because the I-4 can't deliver until it downshifts and spools up the turbo there is a lot less you can do with the great suspension and torque distribution that the RDX offers.

OK, so I'm employing some hyperbole there, but coming from a car with a beautifully flat torque curve it's pretty amazing how much that can make a difference in the handling. The RDX handles great up til that point when the power delivery matters and then it gets really clumsy. The S mode helps a bit there, but not as much as a good V-6 could.

I think that is the real sticking point here. It may not even be possible, but it's nice to dream...

flar

I'm not "mad" at Acura, but I'm not going to help rationalize why they couldn't have done better. I'm not bringing up these points because I'm angry and want my old car back - the RDX meets my needs in so many ways that I am happy about and I appreciate it as a really incredible piece of engineering and technology - but I do feel that I have experience which speaks to the issue of whether or not the RDX could do what it does and eat less gas while it is at it.

To answer the question "Is it worse than my Audi?" the answer is yes on a couple of fronts. First, my Audi beat its sticker from fairly early on in its life span, soon after break in. Second, my Audi got better mileage than the RDX (I've already spelled out most of the info on whether or not that represents a fair comparison - it's not perfect "apples to apples", but it's close enough to raise my eyebrow). Finally, my Audi got similar mileage at 60 as it did at 80-85 and even with me driving it for all it was worth all the time. I got around sticker at 80 even, and I got noticeably (but not dramatically) better mileage at 60, and I could play with the turbo to my pleasure without dramatically hurting the tank to tank average.

The RDX mileage seems much more susceptable to nudging the accelerator pedal or pushing the speedo up a little. I once watched the MPG gauge drop an entire MPG, averaged against the previous 100 miles since the last reset, just going up one on-ramp onto the highway. I was not gunning it, but the turbo did come on in order to manage the slope of the on-ramp. My jaw just dropped - it was like my tank had sprung a leak.

Some good news here. I've done some cruise control experiments in the past and they were disappointing, but I haven't done one in a while. I think the last one I did was right around when I got my A1 service done - 5K miles or so. I'm at 8800 miles now and tonight I set the cruise control on 65 for my commute back up 101 around 11:30. The good news is that I managed 25 MPG shown on the computer! That's a first for me in this car. Experience shows that it can read arond 1MPG high, but even 24 MPG would be a nice. Hopefully this indicates that the mileage is on a good track for the better.

And, on the down side, this was a surprise for me as I have not seen any improvement in my day to day combined mileage outside of that experiment. Maybe that will improve as well now given a little more time.

mav238

Yup the RDX turbo is a thirsty one... reviews galore have pointed this out... I read those reviews before I went out and purchased the vehicle anyway... Why, because I don't believe those reviews? No... but the RDX fitted the bill for which I was looking for in the new vehicle...
I knew going into the RDX, meant a somewhat heavy vehicle with full-time AWD, plus a turbo that is always ready to spool up even at low rpms... almost like a supercharger... so no more of the hype that SAAB turbos used to claim, "power only when you need it, and not there if you don't"...

Supercharged engines are quite thirsty, since power and boost is always on tap... but it does not have turbo-lag...

Could Acura have done better with the RDX turbocharged engine, in terms of better gas mileage... i don't know... but if they could drop gas consumption in the turbocharged engine by 30% and lose power only by 10%, I bet they would do it... why wouldn't they? it would be a great marketing ploy...

You can argue why toyota can do it in their V6.. well, one's a normally aspirated engine, one's a high performance turbocharged engine... why didn't Acura go with the V6? *scratching head*... go ask the Acura Executives...

The argument that Audi could do it... well... yes, it is not really apples and oranges, but even with apples, there are many different variety of apples... there is always the weight issue and also the aerodynamics of a vehicle that significantly affect the gas consumption...

The Audi S4 is a sedan, with aerodynamics that presents a significantly less frontal surface area in comparison to the RDX, less drag... The Audi S4 is a purposed designed sports sedan, minimize factors that can affect it's overall performance... drag and weight are some of them...

Ultimately, when we all walked into the dealer to buy the RDX, I think, we are all reasonably intelligent and car savvy people, did our research somewhat, knew what we were getting into, knew that the gas prices were not the most ideal...
There is no perfect car out there...period... if there was , we would have bought it, and be done with buying another car for the rest of our lives...
In the automotive world, as in many other aspects of life, there is always room for improvement...

BMW, Mercedes, Lexus, all have their issues with their cars too... super high priced, more than the Acuras anyway, and yet, if you check the respective forums, there are dissatisfied owners there too...

We are not driving a Yaris or a Suzuki swift... enjoy the RDX we have now, and know that Acura will probably come out with new technology that will be better, performance wise and also gas consumption... they have to, to survive in this highly competitive automotive industry...

JMHO...

flar

Just in case it isn't coming through from the details of my recent postings I think the RDX is an amazing piece of engineering and the Acura/Honda engineers did a great job of bringing a refreshing new take on the CUV to market that embarrasses the competition in so many ways. And the turbo 4 in it is a really amazing piece of engineering that produces some rather unexpected performance.

I'm an engineer. If I like something, then I start thinking about how it could be better. My comments here, though they are in response counter to some comments that are praising the RDX are not meant to indicate that I think that the RDX doesn't deserve praise, but that the praise should come from a position of not being based on mistaken assumptions.

Unfortunately I often forget to provide the full balance of view when I compose a post.

Lrpba300

Hey Flar, good write! Now we know a little more about you. It's good to hear ya say some POSITIVE things about your RDX, not just "they shoulda's!" Engineer huh? Well that figures(no put down intended!) It does explain some things though! I'm a Technician, & I fix things. I also don't try to fix things that are working good! You leave them alone. Mistaken assumptions is a double negitive! If Acura made a mistake on the MPG's, they didn't make any assumptions!! They we're fudging it like many do, as I've said in many of my posts before this.
Compairing the RDX to the Audi is human nature, but def. not an exact science! Audi has done AWD, turbo's, (in production) visciuos slip differentials for a long time. Some of this stuff, (Turbo in prod., sh-awd) in a CUV is new to Acura! Maybe they fudge on sticker MPG's more than others do. I guess all my Acura's (except the TL) put the mpg on the sticker higher than "real life numbers!"
All I was saying is this is one FINE SUV/CUV! If the mpg's aren't up to snuff, it doesn't make me dwell on it, b/c there are too many other great qualities to off-set that negative. As someone said in another post, some of us didn't buy this vehicle for the great mpg! I'm glad you gave some insite into your reasons. I ain't trying to bust your b@lls., just love to discuss the finer points of personal views about the vehicle we all purchased!

XLR8R

Flar, all very good points, so I'll just respond to this one:

This is where the paddle shifters come into play. Just as with a real manual trans; one paddles down entering the turn, in order to achieve the desired gear/RPM combination at the apex, and power out with the engine on boil.

I would submit that the RDX does not have a Manually Selectable Auto because it is the latest cool feature -- but because it is neccessary to extract the promised performance from the little four-banger.

XLR8R

How's this for dreaming. VW/Audi's masterpiece: the Vee/Reihen engine in say 3.6 liter, with an aluminum block instead of iron, putting out 280 hp.

I daresay, with the 10.6 degree narrow Vee, it might fit in the RDX, and I absolutely love this engine in my Mark 4 GTI.

mav238

You are definitely entitled to "venting" your frustrations regarding the apparent "deficiencies" in the RDX...

We all have our wish-list in a car, and at the end of the day, we just need to realize that we are never gonna get the "perfect" car... Heck, even the Bugatti Veyron will have things that reviewers and owners wish were there or were absent...

Even if a car manufacturer can theoretically build a "perfectly engineered" performance vehicle, with the balance of performance and economy, I bet they would not do it, for pure economics reason... who would buy any more cars from them?

XLR8R

Yeah, what he said. No one should find it neccessary to balance their viewpoint in order to appease the faithful.

Honda is a multi-national mega-corp (Acura is just a badge) and although I'm very pleased with their products, I check every one against the competition and buy accord-ingly (little joke there). If they ever start taking customers for granted, as Detroit has, then they should be given the same consideration Detroit has.

XLR8R

Like a place to go 252 mph. Where are ya Sideswipe?

Lrpba300

good one XLR8R

flar

I guess my point was that I wasn't really "venting" because I wasn't really frustrated with the RDX. Or, more accurately, I was frustrated, but it was because of mistaken assumptions here, not the RDX itself.

I saw people saying "the RDX could not be this or that because the sky is green" and I was trying to give some perspective that while it may be appropriate for the RDX not to be this or that, it's probably not related to the sky which generally appears blue. Unfortunately, I was only presenting the "sky isn't green" side of my viewpoint and not the "but that doesn't mean that the RDX isn't doing fine on its own" side.

As a result it seemed that some were responding to me as if I had something against the RDX. True - I'd love to see better mileage and I think it is probably more achievable than most think. But I still love my RDX and I'd like to challenge some of the assumptions without necessarily contradicting that overall impression.

(And, mixed in is a little bit of me not getting the same results from my RDX as others have been getting, but that could be changing...)

optik_rdx

Thanks for the advice on the attorney. I did hire one. My first court apperance was postponed on the advice of my attorney, i'll be back in court in August I'll let you know how it turns out.