mav238

move into the Acura line up.

The RDX turbocharged engine is a good engine, lots of torque and hgh end power, but lacks in the fuel efficiency area.

If Honda can bring in the direct injection (DI) technology into their cars and SUVs, that would be great.
Heck even Ford now has the twin turbo charged DI engine in some of their cars, like the Taurus SHO.
Direct injection sprays fuel directly into the piston top face, and hence can deliver a really dense cool charge, from a smaller amount of fuel, and yet generate equal power than a MPI engine.
This technology has been around for a long time now, so Honda should be able to easily incorporate it into their cars.

brizey

I think some of the fuel efficiency issue is because of an overly conservative tune, but indeed, DI would help by letting them lean it out more and still have a conservative tune. And at some point they need to advertise a more realistic hp number--the performance and 240 hp just don't add up. I think if they advertised a more realistic 260-265 hp, people would not gripe as much about the lack of a V6 and the efficiency.

trademark

As long as this doesn't involve something like the direct ignition cassettes on the Saab 9-3 turbo 4 that would overheat on top of the engine block and self-destruct. Took Saab years to initiate replacement program. Made for easy plug changes though . . .

BigHatch

fuel economy, schmuel schmeconomy... MORE POWER!!!!

cwepruk

I wouldn't hold my breath. Honda hasn't exactly been cutting edge in the engine department for a while.

MMike1981

eh...if anything, maybe a mpg or so improvement...

i could care less about DI...give me a more aggressive tune from the factory, and throw in maybe an economy mode to prevent high rpm in regular driving, i think that would help more.

Id rather see acura refine the power plant, do something with the tranny, and improve it vs trying to focus solely on MPG gains

mav238

That is the point of DI. It allows a leaner charge, but yet deliver an equal or more power delivery. A more efficient engine means better performance and not at the expense of fuel consumption.
The RDX turbo engine is a pretty refined engine already, smooth 4 banger, just not great in the fuel economy area.

brizey

I agree with the transmission part. I think replacing the 5 speed is the low hanging fruit right now, especially since a new six speed already exists. If Honda was too dumb to make it work with their four bangers, then I am buying an Infiniti next time.

MMike1981

after having the Mazda CX-7....im not sold on a company doing DI unless its been doing it for a while, on the consumer level, and its reliable

Im not doubting Acura couldnt do it, and do it right, but i wouldnt want anything to do with the engine if it was sporting DI on the first go around.

Mazdas DI claims were bullshit, and so far, they are the only company to try it in a 4 cyl turbo suv....their new model mpg gains are not due to DI but to more effective engine tuning. MPG attained was basically identical or worse to the RDX and thats w/6 speed.

Computer/engine tune first...ill worry about DI another time...im not saying it wouldnt be somewhat of an improvement..but its not THE improvement for me

cwepruk

The theory of DI is a good one, but so far, not much has occured. It seems to be a safer way to increase compression/boost and control knock, but it's not like the non-DI engines are lagging much.

XIS

I am happy with the RDX motor as is. Wouldn't mind an extra gear though...

I would like to see a turbo added to the six cyl TL and MDX though...

droooool.....

mau108

I hear DI motors require more maintenance especially with the current PCV exhaust setup. I've seen intakes off Porches that look awful. Sure you can setup a catch can but that's just more maintenance for the owner.



^ 2008 cayenne

I think it has been working well for Honda in terms of sticking with something that works and works well. Turbo 4 Cyl was new for them in the RDX and was a huge leap and so far I'd say its been great, I'm sure once they fix the design flaws other manufacturers have had with their DI motors Honda/Acura will release another bulletproof motor.

stevel

some things are overrated.... including direct injection at this time. maybe not in the future, but it's not ready yet...... with audi we have countless issues with it......

and as far as mau's picture...... audi has a significant problem with carbon buildup on the valves because without a fuel injector to keep them clean, well........... they don't have an answer for that yet, other than a tsb on how to clean the valves.......

and as far as a six speed a/t, nice idea, but in the mdx it gains 1mpg rating? that's nothing to be excited about........... again, something that is overrated. it's not a bad idea, it just doesn't pay off as well as some may think.

mav238

These are interesting observations... but DI has been around for a long while now, starting it's introduction in Europe and Japan and in Asia... It has only recently surfaced in North America, but the technology has been around for a bit now... it is definitely not in it's infancy as some here would think it is...

Regarding the issues with carbonated valves... well... even in a MPI engine, the valves do get carbon deposits on it as well, if we do not maintain it regularly and use quality gasoline regularly... The engineers who design these engines are not idiots, who only think in a single dimension... So this issue of potential carbon deposits on valves are probably well known to them...
The main thing is regular maintenance of your engine, regardless if it is MPI or DI... I put in a bottle of Chevron Techron fuel system cleaner every oil change (only $8), which will help keep those engine parts adequately clean of carbon deposits...

Yes, Honda can definitely do more in the area of better tuning of the current RDX engine and also including a 6 or even 7 speed autotrans. But a MPI engine will still never be as efficient as a DI engine in fuel combustion, just the fact of thermodynamics and engineering perspectives... Sure the current DI engine design is not perfect... what is??? The more perfect solution I guess would be a significant advance in using plasma gas technology to drive the car, much like star trek... to infinity and beyond! But then... it is not perfect is it? it could have a plasma containment issue and explode!

cwepruk

I too have heard of the carbon build up. I used to think that was because there is fuel being injected on to the valve, but it's likely PCV crud.

I've also heard a lot about fuel dilution in the oil with DI. Seems to be a big problem. I remember reading a Nissan study on it and I'm guessing that is why they still use port injection.

I do like the throttleless engine technology VVEL, Vanos, etc.

MMike1981

carbon buildup was an immense problem on the CX-7....some people even had issues with Mazda not covering it under warranty

BigHatch

I imagine the 6 spd would do very well in the RDX due to the variable vane turbo and decent boost/ more TQ down low. then again, more boost + more gas... it would drive nice though..

neo1738

when the hondata first came out a lot of people said the rdx runs to rich and that is a big part of the fuel waste. Make it a little more lean get more power, less fuel consumption, but run the engine a little hotter and in the end the 1st ever Honda turbo would have a shorter life span. I think most of their reasoning is to keep reliability. After over 60k miles on my RDX (Btw just now have to replace brakes) not 1 unusual sound from the engine bay and runs like the day I bought it. So far very happy with that aspect.

cwepruk

Most cars only run rich under boost though. They should be running Stoich on the highway or under most cruising. I think the Hondata was referring more to leaning out the mix slightly under boost, so in more aggressive driving, you might see a bit more economy.

A 6th gear would help, but that's more of a highway issue.

wwest

What is needed is an adoption of DI AND Toyota's extended VVT-i used on the new HSD generations. These new HSD engines remain at a 13:1 static/native compression ratio with low to moderate engine loading/loads, but then delay the closing of the intake valves with high throttle openings in order to reduce the effective CR to 10:1.

Can you imagine the absolutely STELLAR FE one would get with a small DFI/I4 and a static compression ratio of 15:1..?? Reverting progressively to as low as 10:1 as boost rises..??

mau108

Is that how the new Equinox can get 1100km on a full tank of gas highway

MMike1981

wow look who decided to return...hopefully no one has forgotten about the nonsense you spread over this board, and every other car board on the net.