No, you're talking about something else (not sure exactly what). The intercooler cools down the air after it leaves the turbo and before it enters the intake manifold / throttle body. It's an air to air heat exchanger. Top mounted intercoolers are easier to package, but suffer from heat soak at low speeds. Front mounted intercoolers don't have the heat soak issue, but require more plumbing and are harder to integrate. What's unique about the RDX setup is that they have a top mounted IC with a front mounted intake scoop.
I've been comparison shopping EX-L and RDX. Obvious difference is the turbo... but also wondered about AWD system. What is "normal" power distribution front vs. rear wheels on CR-V vs. RDX? How do the two systems differ?
Also, for anyone who has driven both, how does ride compare?
BTW, have seen posts that RDX is not selling big... have already seen a few CRVs on the road here in NYC area... have seen exactly ONE RDX!
I am in the same position -- almost wish I could mix features from both vehicles.
The AWD system is significantly different between the two. The CR-V's AWD system is totally reactive -- it is nominally FWD (100% front / 0% rear), but becomes AWD when the front wheels slip. It's a decent system to enhance traction on slippery road surfaces.
The RDX is nominally 90% front / 10% rear. Like the CR-V, it will react to front wheel slip and send power aft. However, it is also proactive and will funnel power aft (up to 55% front / 45% rear) on acceleration to avoid wheelspin. The bigger aspect of the RDX's AWD system is the "SH" aspect, which can overdrive the outside rear wheel when cornering to offset understeer and enhance handling.
I have not driven the CR-V yet, but the RDX handles very well.
The air within the inter-cooler has been heated in the process of being compressed. The air flowing through the inter-cooler cools this compressed air and in the process is of iself HEATED.
With a front mounted inter-cooler that same HEATED air is then used to COOL the condensor, A/C refrigerant, and then the radiator, engine coolant.
Putting the inter-cooler elsewhere allows the use of smaller and lighter condensor/radiator assemblies.
I think I see what you're getting at now, but generally the front mounted IC is not in series with any of the other heat exchangers (radiator, AC, possibly transmission). I know the others are often stacked in series, but the IC is usually not -- because it's an air exchanger, the internal volume is rather large and it takes up a lot of depth. They are usually at least 2X-4X deeper than a liquid exchanger.
Since,generally, John/Joan Q. Public would rarely make serious use of the turboes I have never understood why some of the A/C cooling capacity isn't diverted to cool the intake charge.
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"While looking under the hood, I noticed something new. The upper grille opening on the RDX is not really a traditional grille opening -- it feeds the top mounted intercooler through a duct. This is more analogous to the hood scoop on many turbo cars with top mounted intercoolers, but Acura disguised it to look like a grille. This is a somewhat clever way to package a top mounted intercooler, but one wonders why they didn't just go with a front-mounted intercooler for its potential advantages."
I assumed everyone already knew about the "grill-scoop". The little strakes in there are intended to suggest the functional aspect of the grill.
A front-mounted intercooler will get more air (and cooler air), but it will require more plumbing before it reaches its destination. While in transit from the cooler, the air loses any advantages it might have had initially.
The top-mounted intercooler in the Acura provides the shortest distance from cooler to compression chamber. But, of course, the whole area is heated by the engine.
The grill-scoop and integrated channel under the surface of the hood is supposed to provide the best of both worlds.. cold air channeled right to the cooler and a short distance to the combustion chamber. However, you'd need a dyno in a wind tunnel to test it.
BTW, have seen posts that RDX is not selling big... have already seen a few CRVs on the road here in NYC area... have seen exactly ONE RDX! The projections I've seen have Acura aiming to sell 40,000 RDX's in the twelve months post introduction. Assuming Acura is on pace, then in the first (roughly) two months of sales, they should have put about 6,666 RDX's on the road. That's ALL OVER the United States. It seems a bit early to expect to see them constantly.
I'd be cautious in drawing conclusions based on sighting a single RDX. For instance, the first RDX I saw in the DC/MD/VA area was piloted by a man in his 70s with a passenger in her 70s. I wouldn't rush to conclude that Acura is targeting the Cadillac crowd based on the age of one couple that bought the RDX, even though they were early adopters.
They sold 3065 RDXs through the end of September. At this point, I am seeing VINs in the 9000 range show up in inventory (ie, they have made at least 9000 units so far).
Interestingly, I just received an email asking to participate in a JD Powers survey about the RDX. Don't know how they actually got to me - I may have registered on the Acura site. Lots of questions about "have you bought a vehicle", "if not the RDX, why", "what don't you like about it", etc.
My gut says things aren't going as well as had been expected by this stage of the RDX launch. Nothing to base that on, just the survey and the info it was asking about.
Acura and JD Powers are independent entities. Personally, I have never received an invite from JD Powers. They must have gotten the information from the same place they do for a few thousand other new car buyers.
I got 3-4 of those surveys a couple years ago, all asking about a particular car I had bought -- basically, they were tracking the initial quality with periodic updates on ownership. Each survey came with the $1, which I thought was a great idea (sure worked on me!).
They offered you one lousy dollar for filling out the questionaire?! I've heard dealers commonly bribe people to give them favourable marks on quality surveys, with free oil changes or at least $20.
Given the negativity circulating on the web after a number of major car reviewers reported bad fuel economy on the car, it's hardly surprising that the initial sales pace is half of that Acura was projecting for the car. But I think ultimately the word of mouth will mitigate all that. I've driven my new RDX (non tech pkg) 750 miles over two weeks and I AM IN LOVE WITH THIS CAR!!
First off, the avg. mpg I've gotten is 18-19 after 700+ miles, half hwy, half local. Yes I'm sure, both by the car's digital readout and my own old fashioned determination the miles and divide by the gallons @ the pump calculations. That's about what I'd expect for a car rated @ 19mpg city, 23mpg hwy by the EPA. The mpg will improve 1-2mpg once the engine breaks in too.
But magazine reviews and a couple of road tests didn't prepare me for how wonderful the RDX is. My other car is a 2004 Acura TL. I've had high performance sedans and sports cars all my life. I didn't want an SUV. This one works for me. Love the pleasant and roomy interior, just enough cargo room for my needs too. Sure it's a compromise, and yes it doesn't have the capabilities of many SUV's, but what I wanted was essentially an AWD wagon. And the car had to be Japanese. So this is the ticket. The handling is phenomenal, the power more than adequate for this kind of car (where this 'turbo lag' talk comes from is beyond me) and the overall sense of value is outstanding. Handling is UNREAL. You have to drive it a bunch to appreciate it. Very hard to get the sense during the road test @ the dealership.
So what's not to like? I didn't expect this car to get 25-30mpg? I'm near 20mpg (and over on the hwy) - and that's OK for a 3900 lb. SUV that goes 0-60 in 7 seconds - and outperforms sports sedans like the Acura TSX on the Road & Track slalom test.
You could certainly get the add-on Sirius receiver and connect it through the aux-in jack on the front of the stereo. That will likely be the easiest way to do it. And the bonus is that you can use it in other vehicles too.
I think that many overlook the marketing angle of the turbo 4. This engine is the Honda tuners' dream come true: factory turbo freindly compression and factory turbo control. There will shortly be some fast RDX's out there. That will lend some "coolness" to the brand to help keep its appeal to youger crowd.
And besides, this engine performs very well. I don't understand why people want more cylinders instead of more performance.
I think the issue is that, despite Acura's marketing hype, the engine still has noticeable turbo lag and the fuel efficiency is not that great. I drive a vehicle with a turbo-4, so I am not surprised myself, but if you look at all the marketing materials for the RDX, they make it sound like they licked the lag problem with the variable geometry turbo, and that they chose the turbo-4 for fuel economy. Clearly the vehicle is not a breakthrough in those areas, leading many to wonder "why not just put in a V6"?
As a point of reference, the larger, more powerful MDX gets only slightly worse MPG out of its big V6. Acura probably could have put a slightly smaller V6 in the RDX and gotten the same or better MPG as the turbo-4.
I do agree about the coolness factor of the turbo-4, and it does appeal to me (apparently I am the target market for the RDX, so no surprise there). However, I get the feeling it's not a great match for "typical" Acura shoppers, who tend to be older folks in their 40s and 50s with a decent income.
To be honest, I have not driven the RDX yet, so can't comment on the "lag" part. However, it may not all be due to turbo, some of it could be due to DBW. The throttle response does change with DBW as I can see between my '06 TL (DBW system) and '98 Accord (mechanical linkage). The latter, while a lot less powerful, gets up and moves right off the bat almost as quickly as the TL if not better (especially if I'm not too gently on the gas pedal).
As for small V6, well, all Acura/Honda V6 in market today are about the same size (use the same block, be it the 3.7/V6 in MDX or the 3.0/V6 in Accord). So, if 3.0 fits, 3.7 would too. However, going smaller displacement may not have been the best idea, especially as it relates to torque output. RDX's turbo-4 delivers torque output that only 3.5/V6 can match (Honda/Acura 3.0/V6 could deliver upto 220 lb-ft but thats quite low compared to 260 lb-ft that the turbo delivers).
BTW, average age of a typical Acura buyer is a year younger than Honda (43 versus 44), or at least it was in 2004. That also happens to be overall average age of a typical car buyer in America. So, the age demographics is quite young. RDX should appeal to even younger audience, although not many may be able to afford it.
There's no doubt in my mind it's turbo lag -- you get the accompanying "swish" from the turbo (which is pronounced in the RDX) to give audible feedback. There may be DBW lag as well, but the turbo lag is certainly there. There will always be some lag with the turbo, it's a fact of life, but I was hoping it would be less noticeable in the RDX. It is less noticeable compared to the CX-7 according to reviewers and people who have test driven both, but it's still there, unfortunately.
I was dissapointed that Acura didn't beat the lag issue as well. Honda considered a turbo for the S2000 during its development and rejected the notion because of lag. When the RDX was announced with a turbo, I figured it was because they'd figured out a way to beat the lag problem.
To their credit, there is far less lag than all of the other turbo-powered cars I've driven. But I can't say that I've sampled all that many. (I am an NA guy at heart.) Driving the RDX, I found relatively little lag. It was more like power delivery had a little turbulence. Strong, but not smooth.
One of the things I've noted is that most of the vehicles which posters claim have less lag also have more displacement and/or less weight. In other words, they have more torque or less weight to move when the engine is operating in naturally aspirated fashion. So, I really don't think the fault for the lag lies with the turbo design. It's simply a small engine moving a fairly heavy vehicle when it's off boost.
I think too many enthusiasts focus on what is here and now. It wasn't that long ago that Acura's best seller was the Integra - a youth car positioned very low in the market place.
Integra's were the darlings of the tuner world. Even the RSX, while not as popular, won awards for the K20 engine being so aftermarket friendly. Turbo-power was part of the car's culture.
Now, that association will probably play out better if Acura does what everyone is expecting - build a TSX with the same K23 turbo. But I see no reason why they shouldn't also use it in the RDX.
FWIW, Acura considers BMW's use of a V6 in the X3 to be a mistake. Sales of the more expensive (probably more profitable) X5 tanked when they introduced the cheaper, similar-looking little brother. Acura wanted to avoid having the RDX and MDX stealing sales from each other. So, they gave the RDX some different character.
Now, I dunno that this plan of theirs is working out. But I can understand what they were thinking.
And besides, this engine performs very well. I don't understand why people want more cylinders instead of more performance.
No question. The engine does perform well (once it gets going).
But there is also no question there is noticeable turbo lag, the gas mileage s*cks when you push the engine hard enough to peform like a 6-cylinder, and the sound the engine makes when pushed is not unlike a Waring blender.
The turbo lag affects buyers' perceptions of safety. The gas mileage affects buyers' perception of value. And the unpleasant engine sound effects affect buyers' perception of quality.
A 6-cylinder engine would likely have neutralized those issues, and it's difficult to imagine it would have been substantially more costly (witness the low price differential between the TSX/TL).
It's a shame the turbo-4 holds the RDX back, because Acura did manage to pack 90%-95% of the performance of an X3 into the RDX at about 75%-80% of the price.
I hate to sound like a know-it-all, but I think the turbo lag "problem" is one of perception. I think that it is not the lack of low end grunt but rather the rush of high end power that causes the impression of turbo lag on the RDX. I have not driven the vehicle, so this is just me musing. I drive a modified 2004 WRX, so I know all about turbo lag.
I am surpised the engine doesn't sound good. Most honda engines sound great.
I am considering getting either an RDX or X3 in a year or so. The X3 will not be considered if the new twin turbo is not offered. I want aftermarket potential, and nothing beats factory forced induction for that.
BTW, the RDX motor makes more torque than the TL motor. The new MDX motor makes more, but it is a 3.7L. I doubt a 3.7L would fit in the RDX, and all the other honda V6's are weaker than the new turbo motor in terms of torque.
Lag... I think one fix that all Acura SH-AWD vehicles need is a short-geared (low) and close ratio 6-speed transmission. THAT itself will help a lot off the line, turbo lag or not.
"So, I really don't think the fault for the lag lies with the turbo design. It's simply a small engine moving a fairly heavy vehicle when it's off boost."
I think you are beginning to hit the nail on the head. For that size and configuration of turbo engine, Honda has done the best it could. Its only fault is that it is a small turbo engine in a rather large car. If it was a twin-turbo V-6 people might not have that much to complain about, but as it stands, there is some delay before you "get what you paid for" and it can be annoying to the uninitiated.
"Sales of the more expensive (probably more profitable) X5 tanked when they introduced the cheaper, similar-looking little brother."
That had to do with a lot of things, but one of the biggest and most embarrassing is that the X3 was bigger inside than its more expenisve sibling. I suppose BMW learned a little between engineering the X5 and X3, but the fact remains that the X5 was always an inefficient, stopgap attempt at jumping into the SUV market. The next-gen X5 seems to solve some of that, and I would assume both it, the next-gen MDX, and RDX would all fit into their appropriate market slots more neatly.
Varmint was pointing out at the fact that RDX's base engine is actually only 2.3 liters. Had it used a larger displacement, "lag" would be less of an issue since larger displacement would allow for more power/torque already before the boost builds up.
I'm not a tuner, far from, but it seems to me that a solution to turbo lag is a SuperCharger.
Were it me I would convert the RDX engine to the miller cycle wherein the energy needed to run the turbo never escapes the combustion chamber. A SuperCharger indirectly driven by the engine via a Prius type CVT. Lots, TONS of BOOST at the low end and NO OVERBOOST via the CVT reducing the "ratio" of the engine/supercharger coupling.
"I am surpised the engine doesn't sound good. Most honda engines sound great."
He's right. There will always be some who do not appreciate turbo whine. (I'm not a big fan.)
Having that said, there are plenty of young buyers out there who adore the sound of a good turbo powerplant. With the dual balancer shafts in the K-series engines (and even a slight drop in rotating mass), I didn't find the sound of the engine objectionable. It makes noise under a heavy foot, but it's not at all thrashy. When driving more sedately, it was quiet.
It's not as smooth as... say... the TL's V6, but it's easily as good as the last V6 Murano I drove.
The VQ is a solid engine, it's been on Ward's 10 Best list many times. In that application it's probably a lack of insulation, or even isolation, that makes it less than smooth.
Blame Carlos "le cost cutter" Ghosn for perhaps going a bit too far cheapening the interiors. Though newer Nissans are improving.
Nissan's VQ V6 does feel unrefined compared to Honda's J-series V6 engines. I've experienced it in two vehicles (friend's G35 Coupe that I drive regularly) and in Altima.
As for Wards, well, thats another story. I have never really cared for it and the criteria they seem to use. For instance, they picked Accord's 3.0 in 2003 as one of the best. In 2004, they changed it to Accord's hybrid's V6 (which is basically the same engine but somehow they like the hybrid better now) and in 2005 they changed it to RL's 3.5/V6.
As for RDX's turbo "swoosh", I read somewhere that sending it into the cabin was a part of the plan. The designers didn't want the cabin to be devoid of sportiness (some people are already complaining that Acura TL-S is just too quiet inside, and you must open the windows to hear the engine under acceleration).
I believe the VQ series has won several awards. However, they are usually awards for power output and mechanical sophistication. They are not awards for smoothness.
And I'm not suggesting that the VQ in the Murano is all that bad. I've driven V6s which are even worse. It's just not any smoother or invisible than the K23 in the RDX. Moving to a V6 does not guarantee smooth operation.
FWIW, Acura considers BMW's use of a V6 in the X3 to be a mistake. Sales of the more expensive (probably more profitable) X5 tanked when they introduced the cheaper, similar-looking little brother. Acura wanted to avoid having the RDX and MDX stealing sales from each other. So, they gave the RDX some different character.
Anybody who thinks there's turbo lag on an RDX hasn't:
• driven the RDX enough or at all
• driven enough turbo cars
Compared to the various turbos I've had over30 years, the RDX has as close to zero turbo lag as I've ever experienced. With the paddle shifters to keep the rpm's in the sweet spot, it's not an issue. Trust me on that fellas.
About the best handling car I've driven, and certainly the most confidence inspiring car I've owned. And I owned a 540i BMW a couple of years back...
The RDX is BIG fun to drive. Very happy after 2K miles. Would it be nice if it did better than 18mpg most of the time? Sure. Is it worth givng up a few mpg for an SUV that handles like a Le Mans car? Ummm... yes.
In my brief test drive, I did not detect much turbo lag, if any. But I also didn't find it all that quick. It was above-average quick, but not that quick. My main gripe actually was the noise -- way too much engine noise, and it was coarse-sounding to boot. Oh, and yes, I'm also not sure I can/want to live with the ultra-stiff ride. :sick:
Of course there's no lag when you're keeping it in the sweet spot. In the right gear, at higher rpm. That's when the turbo is in its element.
It's when you're loafing along at 2000 rpm and then need power suddenly that lag could come up (I say could because I haven't driven an RDX yet).
Generally you need 2 things for boost to occur: a load on the engine, and some rpms. Cruising along in no-load situations at low rpm is a recipe for lag, you have neither of the two things you need for boost. That's why you feel it more with automatics.
When you floor the throttle, first the transmission has to shift down, then the turbo has to spool up from scratch, since the pressure is bled off during the shift. So you're really waiting for two things, the shift and then boost build-up.
Go drive a Forester XT, you can get both manual and automatic transmissions. The difference is night and day.
The manual is a bullet, ridicuously fast, really. For whatever reason even at low rpm, it doesn't seem to matter, boost builds so fast you'd better hand on when you touch the throttle. 0-30 was quicker than the Ferrari Enzo in Car & Driver tests. Poor Ferrari. :sick:
Before anyone talks about fried clutches the 5-60 time was still remarkably fast, not just for its class, fast even among sports cars under $40 grand.
Then go drive an automatic. It feels like a different vehicle. Under boost it's quick, yes, but it's just not nearly as responsive to the throttle.
Floor it and it pauses, shifts down, then begins to build boost, and the slushbox seems to allow more slop so even then the boost doesn't build as quickly as it does in the manual.
The ability to select gears manually helps, 5 close ratios help, and the geometry of the RDX's turbo probably help, too, but you still have to wait for (1) a downshift and (2) boost to build from scratch when you stab the throttle in those situations.
Juice said it better than I could, and I agree. The RDX definitely has "classic" lag in those situations when starting from no boost. When the engine is already boiling it's quite responsive, as are most turbo engines. Not unlike the basic VTEC effect you feel in many NA Honda motors -- if you can keep the RPMs up with a close-spaced transmission, the engine stays in the sweet spot.
If you're feeling the rush of power when the turbo kicks in, then you're also feeling lag before that happens. Two sides of the same coin.
The car is blistering fast for an SUV. Period. Hell, R&T got the RDX to 60mph in 6.3 secs. Most road tests are coming in @ about 7 seconds, and that is very fast for a SUV, crossover vehicle, truck, whatever you want to call the RDX. It's NOT a sedan/coupe car, it can't compete with cars like that for quickness, so that type of comparison is a bit silly.
What's not so silly are concerns about the ride. Very stiff. Doesn't really bother me, but I don't live in an are with nasty roads. But that's a resonable concern. I'd rather have my car than a plusher riding SUV that wallows in the twisties, but to each his own.
Perhaps, but "for an SUV" is faint praise. And trucks have low ranges and skid plates. OK, it's half car, half truck, but it ain't a truck the way you're implying.
0-60 tests are missing the point entirely.
R&T uses brake-torque starts to spool up the engine before the launch, something noone does in everyday, normal driving.
Anyone: what was C&D's 5-60 time? That's more telling.
They address the lag issue, normal driving doesn't.
Don't get me wrong, I'm a fan of turbos. Off boost you get gas mileage that you just could not match in a big V6, while on boost you have power. At elevation the engine doesn't wheeze with the thin air like normally aspirated engines do.
That doesn't come without trade-offs, lag being the primary one.
And that's just fine with many, many people. Me, for example. I like the Dr. Jeckyl/Mr. Hide split personality. You can drive slowly and get peak fuel efficiency, yet still have power when you want it (at least when you plan ahead).
Blistering fast in aggressive driving conditions, sure, but you have to qualify that statement.
My issues with the RDX: it's a bit heavy, and it only comes with an automatic. Give us a Type S with a 6MT and say bye-bye to the lag.
I gotta get outta here. 95% of this is car weenie forum hand wringing. FW bias, RW bias, oh man. You're kidding me. What are you dudes, Road & Track editors? Not me. I'm just a consumer who likes to blast through the twisties every now and then even though I need AWD and a bigass hatchback. I'm driving the car. It's GREAT.
The amount of pantiy twisting over theoretical nuances of handling on these boards that wouldn't bother a Ferrari engineer is truly astonishing. The RDX is about the best handling car I've driven. This after 25+ cars, most of them pricey imports.
Comments
Also, for anyone who has driven both, how does ride compare?
BTW, have seen posts that RDX is not selling big... have already seen a few CRVs on the road here in NYC area... have seen exactly ONE RDX!
The AWD system is significantly different between the two. The CR-V's AWD system is totally reactive -- it is nominally FWD (100% front / 0% rear), but becomes AWD when the front wheels slip. It's a decent system to enhance traction on slippery road surfaces.
The RDX is nominally 90% front / 10% rear. Like the CR-V, it will react to front wheel slip and send power aft. However, it is also proactive and will funnel power aft (up to 55% front / 45% rear) on acceleration to avoid wheelspin. The bigger aspect of the RDX's AWD system is the "SH" aspect, which can overdrive the outside rear wheel when cornering to offset understeer and enhance handling.
I have not driven the CR-V yet, but the RDX handles very well.
With a front mounted inter-cooler that same HEATED air is then used to COOL the condensor, A/C refrigerant, and then the radiator, engine coolant.
Putting the inter-cooler elsewhere allows the use of smaller and lighter condensor/radiator assemblies.
To those ends, we will be shutting down the general make/model discussions and work exclusively with specific issues. This requires us to populate the make/model subsections with relevant, interesting and timely topics. Rather than having the hosts simply create boilerplate topics for each make/model, we feel that you, the owner, the make/model enthusiast and the prospective buyer can best judge what those topics should be.
You can help by adding a discussion (it's easy!) or suggesting one here.
To add a discussion, click on the last link in the "You are here" line at the top of this page. That will take you to the topic page for this make/model. Review the list of topics and click on the "Add discussion" link when you've decided what topic you'd like to add. Follow the directions and you're done! Feel free to add more than one. Just avoid duplicating existing topics and try not to make it TOO specific!
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I assumed everyone already knew about the "grill-scoop". The little strakes in there are intended to suggest the functional aspect of the grill.
A front-mounted intercooler will get more air (and cooler air), but it will require more plumbing before it reaches its destination. While in transit from the cooler, the air loses any advantages it might have had initially.
The top-mounted intercooler in the Acura provides the shortest distance from cooler to compression chamber. But, of course, the whole area is heated by the engine.
The grill-scoop and integrated channel under the surface of the hood is supposed to provide the best of both worlds.. cold air channeled right to the cooler and a short distance to the combustion chamber. However, you'd need a dyno in a wind tunnel to test it.
-juice
The projections I've seen have Acura aiming to sell 40,000 RDX's in the twelve months post introduction. Assuming Acura is on pace, then in the first (roughly) two months of sales, they should have put about 6,666 RDX's on the road. That's ALL OVER the United States. It seems a bit early to expect to see them constantly.
I'd be cautious in drawing conclusions based on sighting a single RDX. For instance, the first RDX I saw in the DC/MD/VA area was piloted by a man in his 70s with a passenger in her 70s. I wouldn't rush to conclude that Acura is targeting the Cadillac crowd based on the age of one couple that bought the RDX, even though they were early adopters.
My gut says things aren't going as well as had been expected by this stage of the RDX launch. Nothing to base that on, just the survey and the info it was asking about.
Oh d'oh, you said email. Ok, is there an offer to pay you via PayPal or something? I expect some swag for filling out surveys. :shades:
-juice
First off, the avg. mpg I've gotten is 18-19 after 700+ miles, half hwy, half local. Yes I'm sure, both by the car's digital readout and my own old fashioned determination the miles and divide by the gallons @ the pump calculations. That's about what I'd expect for a car rated @ 19mpg city, 23mpg hwy by the EPA. The mpg will improve 1-2mpg once the engine breaks in too.
But magazine reviews and a couple of road tests didn't prepare me for how wonderful the RDX is. My other car is a 2004 Acura TL. I've had high performance sedans and sports cars all my life. I didn't want an SUV. This one works for me. Love the pleasant and roomy interior, just enough cargo room for my needs too. Sure it's a compromise, and yes it doesn't have the capabilities of many SUV's, but what I wanted was essentially an AWD wagon. And the car had to be Japanese. So this is the ticket. The handling is phenomenal, the power more than adequate for this kind of car (where this 'turbo lag' talk comes from is beyond me) and the overall sense of value is outstanding. Handling is UNREAL. You have to drive it a bunch to appreciate it. Very hard to get the sense during the road test @ the dealership.
So what's not to like? I didn't expect this car to get 25-30mpg? I'm near 20mpg (and over on the hwy) - and that's OK for a 3900 lb. SUV that goes 0-60 in 7 seconds - and outperforms sports sedans like the Acura TSX on the Road & Track slalom test.
Thanks,
dmg
And besides, this engine performs very well. I don't understand why people want more cylinders instead of more performance.
As a point of reference, the larger, more powerful MDX gets only slightly worse MPG out of its big V6. Acura probably could have put a slightly smaller V6 in the RDX and gotten the same or better MPG as the turbo-4.
I do agree about the coolness factor of the turbo-4, and it does appeal to me (apparently I am the target market for the RDX, so no surprise there). However, I get the feeling it's not a great match for "typical" Acura shoppers, who tend to be older folks in their 40s and 50s with a decent income.
As for small V6, well, all Acura/Honda V6 in market today are about the same size (use the same block, be it the 3.7/V6 in MDX or the 3.0/V6 in Accord). So, if 3.0 fits, 3.7 would too. However, going smaller displacement may not have been the best idea, especially as it relates to torque output. RDX's turbo-4 delivers torque output that only 3.5/V6 can match (Honda/Acura 3.0/V6 could deliver upto 220 lb-ft but thats quite low compared to 260 lb-ft that the turbo delivers).
BTW, average age of a typical Acura buyer is a year younger than Honda (43 versus 44), or at least it was in 2004. That also happens to be overall average age of a typical car buyer in America. So, the age demographics is quite young. RDX should appeal to even younger audience, although not many may be able to afford it.
To their credit, there is far less lag than all of the other turbo-powered cars I've driven. But I can't say that I've sampled all that many. (I am an NA guy at heart.) Driving the RDX, I found relatively little lag. It was more like power delivery had a little turbulence. Strong, but not smooth.
One of the things I've noted is that most of the vehicles which posters claim have less lag also have more displacement and/or less weight. In other words, they have more torque or less weight to move when the engine is operating in naturally aspirated fashion. So, I really don't think the fault for the lag lies with the turbo design. It's simply a small engine moving a fairly heavy vehicle when it's off boost.
Integra's were the darlings of the tuner world. Even the RSX, while not as popular, won awards for the K20 engine being so aftermarket friendly. Turbo-power was part of the car's culture.
Now, that association will probably play out better if Acura does what everyone is expecting - build a TSX with the same K23 turbo. But I see no reason why they shouldn't also use it in the RDX.
FWIW, Acura considers BMW's use of a V6 in the X3 to be a mistake. Sales of the more expensive (probably more profitable) X5 tanked when they introduced the cheaper, similar-looking little brother. Acura wanted to avoid having the RDX and MDX stealing sales from each other. So, they gave the RDX some different character.
Now, I dunno that this plan of theirs is working out. But I can understand what they were thinking.
No question. The engine does perform well (once it gets going).
But there is also no question there is noticeable turbo lag, the gas mileage s*cks when you push the engine hard enough to peform like a 6-cylinder, and the sound the engine makes when pushed is not unlike a Waring blender.
The turbo lag affects buyers' perceptions of safety. The gas mileage affects buyers' perception of value. And the unpleasant engine sound effects affect buyers' perception of quality.
A 6-cylinder engine would likely have neutralized those issues, and it's difficult to imagine it would have been substantially more costly (witness the low price differential between the TSX/TL).
It's a shame the turbo-4 holds the RDX back, because Acura did manage to pack 90%-95% of the performance of an X3 into the RDX at about 75%-80% of the price.
I am surpised the engine doesn't sound good. Most honda engines sound great.
I am considering getting either an RDX or X3 in a year or so. The X3 will not be considered if the new twin turbo is not offered. I want aftermarket potential, and nothing beats factory forced induction for that.
BTW, the RDX motor makes more torque than the TL motor. The new MDX motor makes more, but it is a 3.7L. I doubt a 3.7L would fit in the RDX, and all the other honda V6's are weaker than the new turbo motor in terms of torque.
I think you are beginning to hit the nail on the head. For that size and configuration of turbo engine, Honda has done the best it could. Its only fault is that it is a small turbo engine in a rather large car. If it was a twin-turbo V-6 people might not have that much to complain about, but as it stands, there is some delay before you "get what you paid for" and it can be annoying to the uninitiated.
"Sales of the more expensive (probably more profitable) X5 tanked when they introduced the cheaper, similar-looking little brother."
That had to do with a lot of things, but one of the biggest and most embarrassing is that the X3 was bigger inside than its more expenisve sibling. I suppose BMW learned a little between engineering the X5 and X3, but the fact remains that the X5 was always an inefficient, stopgap attempt at jumping into the SUV market. The next-gen X5 seems to solve some of that, and I would assume both it, the next-gen MDX, and RDX would all fit into their appropriate market slots more neatly.
Were it me I would convert the RDX engine to the miller cycle wherein the energy needed to run the turbo never escapes the combustion chamber. A SuperCharger indirectly driven by the engine via a Prius type CVT. Lots, TONS of BOOST at the low end and NO OVERBOOST via the CVT reducing the "ratio" of the engine/supercharger coupling.
He's right. There will always be some who do not appreciate turbo whine. (I'm not a big fan.)
Having that said, there are plenty of young buyers out there who adore the sound of a good turbo powerplant. With the dual balancer shafts in the K-series engines (and even a slight drop in rotating mass), I didn't find the sound of the engine objectionable. It makes noise under a heavy foot, but it's not at all thrashy. When driving more sedately, it was quiet.
It's not as smooth as... say... the TL's V6, but it's easily as good as the last V6 Murano I drove.
Blame Carlos "le cost cutter" Ghosn for perhaps going a bit too far cheapening the interiors. Though newer Nissans are improving.
-juice
As for Wards, well, thats another story. I have never really cared for it and the criteria they seem to use. For instance, they picked Accord's 3.0 in 2003 as one of the best. In 2004, they changed it to Accord's hybrid's V6 (which is basically the same engine but somehow they like the hybrid better now) and in 2005 they changed it to RL's 3.5/V6.
As for RDX's turbo "swoosh", I read somewhere that sending it into the cabin was a part of the plan. The designers didn't want the cabin to be devoid of sportiness (some people are already complaining that Acura TL-S is just too quiet inside, and you must open the windows to hear the engine under acceleration).
And I'm not suggesting that the VQ in the Murano is all that bad. I've driven V6s which are even worse. It's just not any smoother or invisible than the K23 in the RDX. Moving to a V6 does not guarantee smooth operation.
That might be interesting ... if it were true.
Year - X5 Sales // Total X3 & X5 Sales
2002 - 42,742 // 42,742
2003 - 40,715 // 40,715@
2004 - 35,225 // 69,828
2005 - 37,598 // 68,367
ALL the dropoff in X5 volume was in the 8-cylinder segment. Year over year sales of the X5 3.0 increased from 2003-2005
And, "FWIW," BMW didn't use a "V6" in the X3; it's an I-6.
But don't let facts get in the way of a good story.
So all things being relative, the VQ is smooth as buttah.
-juice
• driven the RDX enough or at all
• driven enough turbo cars
Compared to the various turbos I've had over30 years, the RDX has as close to zero turbo lag as I've ever experienced. With the paddle shifters to keep the rpm's in the sweet spot, it's not an issue. Trust me on that fellas.
About the best handling car I've driven, and certainly the most confidence inspiring car I've owned. And I owned a 540i BMW a couple of years back...
The RDX is BIG fun to drive. Very happy after 2K miles. Would it be nice if it did better than 18mpg most of the time? Sure. Is it worth givng up a few mpg for an SUV that handles like a Le Mans car? Ummm... yes.
It's when you're loafing along at 2000 rpm and then need power suddenly that lag could come up (I say could because I haven't driven an RDX yet).
Generally you need 2 things for boost to occur: a load on the engine, and some rpms. Cruising along in no-load situations at low rpm is a recipe for lag, you have neither of the two things you need for boost. That's why you feel it more with automatics.
When you floor the throttle, first the transmission has to shift down, then the turbo has to spool up from scratch, since the pressure is bled off during the shift. So you're really waiting for two things, the shift and then boost build-up.
Go drive a Forester XT, you can get both manual and automatic transmissions. The difference is night and day.
The manual is a bullet, ridicuously fast, really. For whatever reason even at low rpm, it doesn't seem to matter, boost builds so fast you'd better hand on when you touch the throttle. 0-30 was quicker than the Ferrari Enzo in Car & Driver tests. Poor Ferrari. :sick:
Before anyone talks about fried clutches the 5-60 time was still remarkably fast, not just for its class, fast even among sports cars under $40 grand.
Then go drive an automatic. It feels like a different vehicle. Under boost it's quick, yes, but it's just not nearly as responsive to the throttle.
Floor it and it pauses, shifts down, then begins to build boost, and the slushbox seems to allow more slop so even then the boost doesn't build as quickly as it does in the manual.
The ability to select gears manually helps, 5 close ratios help, and the geometry of the RDX's turbo probably help, too, but you still have to wait for (1) a downshift and (2) boost to build from scratch when you stab the throttle in those situations.
That's turbo lag.
-juice
If you're feeling the rush of power when the turbo kicks in, then you're also feeling lag before that happens. Two sides of the same coin.
What's not so silly are concerns about the ride. Very stiff. Doesn't really bother me, but I don't live in an are with nasty roads. But that's a resonable concern. I'd rather have my car than a plusher riding SUV that wallows in the twisties, but to each his own.
And God save us from CVT's.
0-60 tests are missing the point entirely.
R&T uses brake-torque starts to spool up the engine before the launch, something noone does in everyday, normal driving.
Anyone: what was C&D's 5-60 time? That's more telling.
They address the lag issue, normal driving doesn't.
Don't get me wrong, I'm a fan of turbos. Off boost you get gas mileage that you just could not match in a big V6, while on boost you have power. At elevation the engine doesn't wheeze with the thin air like normally aspirated engines do.
That doesn't come without trade-offs, lag being the primary one.
And that's just fine with many, many people. Me, for example. I like the Dr. Jeckyl/Mr. Hide split personality. You can drive slowly and get peak fuel efficiency, yet still have power when you want it (at least when you plan ahead).
Blistering fast in aggressive driving conditions, sure, but you have to qualify that statement.
My issues with the RDX: it's a bit heavy, and it only comes with an automatic. Give us a Type S with a 6MT and say bye-bye to the lag.
-juice
The amount of pantiy twisting over theoretical nuances of handling on these boards that wouldn't bother a Ferrari engineer is truly astonishing. The RDX is about the best handling car I've driven. This after 25+ cars, most of them pricey imports.
See ya.