simplesimon

Acura recomends premium for the RDX, but will it be neccessary?

http://www.usatoday.com/money/autos/...emiumgas_x.htm

CGTSX2004

iTrader: (1)

Turbo engines should always be fed premium fuel.

CL6

It's maybe $5 extra per fill up. That's what, $20 more per month.

DHCLK06

No premium is not necessary. If you want to get the posted MGP that the EPA approved, use premium. If you're ok with loosing 5%-10% hp & MPG, and save your wallet, use regular. Modern cars have computers that will adjust the engines timing according to the octane level.

CGTSX2004

iTrader: (1)

Turbo-charged engines are more susceptible to detonation problems with low octane gas. To preserve the longevity of a turbo motor, you should always, and I do mean ALWAYS, run premium.

CL6

The money you "save" buying regular you will "lose" in gas mileage. Plus your engine won't be as happy. Penny wise and pound foolish.

RDX Groupie

Part of the bummer with this set up. It gets great mileage, but requires the expensive gas. 91 octane is premium in California. I still don't get why we don't get 93.

CGTSX2004

iTrader: (1)

California has its own fuel formulations that are different from those used in the rest of the country.

mrsteve

iTrader: (1)

"Expensive" gas? On average premium is only 20-25 cents more per gallon than regular. The RDX has an 18 gallon tank. Let's say you fill up 16 gallons every time.

$3.20-4.00 more every fill up is nothing. If you can afford a $30,000+ SUV you can afford a few extra bucks everytime you fill up.

CL6

Yeah people who bitch about 'premium' gas don't make sense. So it's 4 or 5 bucks extra? So what? Then you'll go into the gas station and pay $1.25 for a PINT of water when gas is $3.25 a GALLON!

simplesimon

Uhhh, don't see anyone bitching about it. I originally asked the question after reading an article in USA today. Was just curious. I won't put enough miles on the car to worry about gas, (about 7-8 k miles a year). I use my truck mostly.

Count Blah

If anything, the premium you pay for premium gas is less now than it was when gas was $1/gallon. It seems like there's always been about a $.20 difference. Back then that was 20%. Now it's just ~ 7%.

CL6

You're right. I'm sorry. Everyone but you then.

blnemec

Any guess on the useful life of the 'turbo motor' if I always use Premium gas?

Is 200,000 miles / 12 years reasonable to expect without replacement?

If not, any bets on turbo replacement cost?

CGTSX2004

iTrader: (1)

Too many other factors to take into account. Just putting premium gas into the tank alone isn't going to be a deciding factor.

With proper maintenance, there is not reason why a turbo motor can't run as long as a NA one. It's all about how well, and how often, you do your maintenance.

snorton48

In the turbo Subaru 4 cylinder, the engineers there insist that using regular gas all the time will damage the engine, and it is not an option. Hi-test is REQUIRED.

CGTSX2004

iTrader: (1)

I think you're confused. All of the brochures for Subaru list Premium as the recommended octane for their turbo models so I don't know where you're getting your info from, but it's wrong, as far as I can tell.

Colin

Our '87 Celica GT-S required premium, as did our '88 MR-2 Supercharged, and the '93 MR-2 Turbo used it too. All three Integra GS-Rs (94,97 and 99) used Premium, and all four of our S2000s.

This makes me wonder, what is this other cheaper gas everyones talking about? I didn't even know they made anthing like this.....

snorton48

That was from an email directly from a Subaru engineer, so I'm not making it up.

ArthurKnight

Honda/Acura always recommends premium with the v-tech engines. They don't require it though. The RDX not only has a v-tech engine but also a turbo charger.

From page 278 of the manual:

Fuel Recommendation
Your vehicle is designed to operate on premium unleaded gasoline with a pump octane of 91 or higher. If this octane grade is unavailable, regular unleaded gasoline with a pump octane of 87 or higher may be used temporarily. The use of regular unleaded gasoline can cause metallic knocking noises in the engine and will result in decreased engine performance. The long-term use of regular-grade gasoline can lead to engine damage.


Oh, and California gas no longer includes MTBE which has dropped the premium rating from 93 to 91.

RSXster

91+ guys. You dont want knock/detonation. Its a lot cheaper to fill up w/ the good stuff than to replace your engine.

If you use 91+ and get normal maintenance the engine should last 200,000+ no issue.

You paid $35,000+ so you can afford to pay .25 cents more at per gallon

Gadgets

Not all v-tech engines require premium, the CR-V, Pilot, and 4 cyl Accord to name a few. They are designed to run on 87 octane.

Gadgets

I'd rather not if I didn't have to. Lots of MDX owners run their SUV's on 87 without problems. I agree that if it's required, then pay the extra for premium, but if it's only recommended, you can spend the extra money, what little it may be, on something else if you choose.

Boon

Like some have mentioned above, I think the difference is the turbo engine. Turbo's are a little more sensitive to the knocking issue and can be damaged more easily than the other cars you mentioned.

But I hear what you're saying. I'd personally love to see a Deisel engine here in North America. The 2007 BMW X3 has a new deisel in Europe and it can produce 286 hp and 427 lb-ft of torque....all this with an efficiency of roughly 28 mpg!

CL6

If you bring your RDX in because there is an engine problem they will test the gas and if it is not 91 octane good luck getting a warranty to cover it.

And any money you 'save' on using regular gas will be 'spent' getting lower mileage so, if you do the math, you save no money.

And it is required, not recommended.

jcg878

I have yet to hear one person ever say that this has happened to him/her. I hear plenty of speculation about it, but never heard a 1st person experience. Anyone?

CL6

To the best of my knowledge, Acura has never sold a turbo powered car before. Care to be the first to have your engine blow?

s4iscool

It is speculation and assumptions that not running premium will destroy the rdx turbo engine. If the car manufacture specs Premium, its best to use it, because its been mapped (read, best performance) to run on 91+ oct. Now as others mentioned, due to modern day ECMs, you can run lower than 91 and higher than 93 and your car will adapt. The theory is that you can run the lowest octane before your engine knocks...i would bet that the rdx would run just fine on 89, but its probably not worth the few cents savings to take any risk on a new turboengine from honda.

Anyone buying the RDX is taking some form of risk, because the honda turbo setup is completly new...it is not unusual to see turbo saabs volvos with 150k+ miles without any turbo problems. On the flip side, there are other turbo applications that see frequent failures, usually from heat related failures (poor turbo driving habits, not wamrning up the car right, not cooling the turbo down, neglecting oil changes, not using full syn oils with the right weight, etc) . Thats just the risk you take with a turbo car.

13+/boost on the RDX is quite a bit on a little tubro straight from the factory, so its definetly not a low boost application. Im sure some tuner will come out with a bigHP/huge tq chip using crazy boost pressures, but I would never touch it in this car. Something like a VAG 1.8T/2.0T yes, but only because its been proven to handle (read, drivable, reliable) increased boost from tuners.

Just cross the fingers and hope that honda would not risk its reputation for reliability by putting out unreliable engine/turbo. If I had to place a bet, I would say the RDX will be just fine in the powertrain dept. (if kept stock).

btw, is there a turbo timer in the RDX?

RSXster

I see your point in terms of Finances, but just dont take the chance. Turbo engines that are tuned for 91+ octane NEED it, or else they will go boom. It doesnt just reduce performance it literally causes knock and potential detonation.

It is not speculation, it is a fact that higher octane prevents knock. Knock kills engines. Turbo cars require higher octane.

The RDX will not run on 89 octane as it is tuned for 91+. Please dont give people an excuse to use inferior gasoline and then effectively kill their engines.

Honda would not produce an engine that was not designed correctly. Yes this is their first production Turbo engine in a car, but they have used FI in watercraft and other products before.

13.5 psi is not a lot. The Stock WRX comes w/ 13.5psi (11psi on 06 due to 2.5L) and they can be safely tuned to well over that. I run 19psi w/ a custom tune and all supporting modifications including a larger Turbo. 13.5psi on the stock turbo is not maxing it out at all.

Modern turbos do not require turbo timers b/c they are coolant cooled. You dont need to let the car idle before turning it off.

jcg878

I am sure I'd put premium in it since that is what it recommends, and that's what I put in my TSX. I see the logic of using higher octane in turbo engines, but whether it's an Acura-mandated necessity or not is the question. Shall I assume you don't know anyone personally who has had his warranty revoked by using regular? I am curious if anyone does.

s4iscool

How can you make such statements without even knowing the exact specs of the RDX turbo? 13.5 can be fine on a WRX or 1.8T turbo, but that doesnt mean you can automatically assume that 20psi will be ok on the RDX. Im sure honda did its homework and put the rdx boost right in the turbos efficiency range, but we dont know if they are pushing the upper limits of the setup or being extremely conservative.

Also, if the ecm can account and adjust for the 89 oct, and the car does not knock, it is fine. Sure you will lose optimum performance, but it doesnt mean that turbo is going to explode is some catastrophic failure . But im not advocating the use of sub 91 oct in the RDX, in fact I clearly said it is not worth the minute savings in gas price to use sub 91 oct.

As for your last statment that modern turbo cars are coolant cooled..the last 3 turbo cars Ive had in the last 5 years were oil cooled and some in part with water cooling as well. So it does help to let the car idle before shutting off if it has been driven hard.

RSXster

It says use Premium in the manual, we all know that Higher Octane reduces Knock, and knock kills engines. If you dont follow Acura/Honda's suggestion of Premium gasoline you have intentionally damaged the car and they will not replace your engine underwarranty.

Company's dont like to lose money, and warrantying YOUR mistake is not something they like to do.

Is there documentation of Honda refusing an RDX warranty due to sub-91 octane gasoline? probably not yet. Will there be? i am sure. Frankly, Acura needs to do a big Information campaign with the RDX. I would say more than half of current or near-future owners have never had a Turbocharged vehicle and will mistreat it. Most of the people on this forum have no clue about forced induction.

How can you make the statement that 13.5 is at the Turbo's peak? Most likely it is a happy medium of the two. It is an efficient power output to allow the car to perform under normal and emergency conditions. I didnt mean it was good to 20psi, I just meant that 13.5psi is not a radically high number as you made it sound. Yes, VW's run like 9psi, but that's b/c their turbo is tiny. The RDX I would assume has a turbo sized where 13.5 is not maxing it out at all.

The ECU will pull timing, but it will eventually knock and that will eventually degrade the engine.

I know you arent advocating it, but I have seen that a lot of people on this board are VERY new to Turbos and if one of them reads "hey it is ok to run 89" they might do it, and then IF their car dies it will be b/c of this thread.

s4iscool

OK i get your point to. Good points.

But from what I have been able to gather on this forum, and other resources online, the RDX turbo is quite small, so without knowing its specifications, we are all still speculating. If the rdx tuners are able to boost it up and make somewhere around 300hp, with great drviability and reliability...Id be all over the RDX. Unfortunately we wont know until some people serve up their cars for the greater good

neo1738

I dont know about the RDX, but FYI the new STI does in fact idle the car to let the turbo cool down, my best friend showed me his last week. I would say for the amount you would save on puttin in under 91oct your gonna pay more in engine parts later, be a man/woman, and put in the higher oct gas.

RSXster

What are you talking about? Subaru's do not idle their cars. The Stock STi Turbo is an IHI VF-39 which by definition is Coolant cooled. It doesnt NOT require a turbo timer or any time after driving to be cooled (besides the natural coolant cooling).

I dont know what he showed you, but it was not a turbo cool down.

s4iscool

Im curious, does the STi or WRX have a coolant pump that ALWAYS runs (for a short time) after engine shut off? To the other guy, after engine shut off, a lot of people confuse the radiator fans and coolant pump running to be the engine.

RSXster

Subaru actually uses a overflow reservoir above the turbo with a feed line designed to allow overflow water to circulate and absorb some heat after the motor is turned off as well. It's pretty ingenious. It's not really a heat exchange device in the conventional sense; the idea is to actually allow heat to create a coolant current.

jcg878

Is there documentation of any company voiding any warranty for this reason? Again, I'm a premium user myself. I'm just looking for proof... haven't seen it yet. It almost seems like an urban legend to me.

CL6

I have not personally witnessed this happening I have only heard this is what would happen. But the RDX has not been out that long and Acura used to say 'Premium Recommended' not it says 'Premium Required.' V6 engines can take the gas much better than 4s can, particularly if it's a turbo 4.

RSXster

After using Google.com for like 10min I cannot find documentation. BUT, there is documentation showing companies that will void a warranty due to modifications, and using an octane less than 91 does go against the Manual. It states that you must use 91+ therefore they have no legal obligation to pay for your mistake.

Can anyone find documentation showing an Octane related warranty voiding, or acceptance?