Just wondering if regular gas (Shell 89 Octane) will harm the engine parts? I know the manual says to use premium, but I figured that was for performance reasons.

 

Do not run below the minimum reccomended rating. It will decrease performance but aditionally it will cause your car to continuously be running retarded timing. Under load this will increase the exhaust gas temperatures and potentially increased wear through things like degraded oil, etc. Plus, increased EGT values can degrade the catalytic converter. I've intentionally burnt and clogged cats before and anything above 1600 kills them quickly.

This is in an extreme example but why even tempt it. Stick with the manufacturers minimum specified octane.

 

It won't ruinin your engine (right away anyway), but it will cause your timing to be retarded and perform poorly.

 

I guess If you wanted to save money, you could use half a tank of 89 and half of 93. I use 93 here in FL on both my S's for top perfomance. My cars seem to perform best on Amoco.

 

Not to mention the deto that will occur before the ECU can back off the timing. Think of little men with large hammers pounding away inside your cylinders... A little won't huit imediately, but a little over time adds up.

 

Damnit, anyone know a place in LA to get 93?
-- Nihil

 

if you drive 20,000 a year and the CLS do avergae a worse of 20 MPG.. That is 1000 Gal/year @ 20 cents diffrence between Premium and regualr... You only save $200 per year, now if you can afford to pay $6000 per year for the downpayment for your CLS you can afford to pay $200 more!

Just does not make sense to go from Premium to regular to save some $200 per year...!!!

 

I have seen one in Pasadena, it's 76. Exit 710N and on your right. they carry 96 & 98 Octane!! It's about $3 a gallon (last month)

 

why dont you just use the cheapest gas (87 octane in my area) and then add a bottle of that octane booster stuff??? that would bring the octane back up to 93 or more! and its cheaper

 

jimcol, is there any data available to prove that? sounds like a good idea to me.

 

honestly, i dunno, i just pulled that idea out of my ass, but maybe some of the more technically inclined members could chime in on this topic, i mean if you buy a case of that octane boost, like 25 bottles for 30 bucks or something, each bottle is good for one tank, so fill up your tank with regular, you save approx. 20 cents per gallon, on a 16 gallon fill up that would mean you save $3.20 and the cost of the octane boost bottle is approx. $1.00-1.50 so you still save over a buck and a half per tank....it sounds good on paper, but is it safe to do? i dunno

 

Won't work Jim, when the Octane booster states it will increase the octane X points, these are normally tenths. Plus, some octane boosters are not O2 or catalytic converter safe.

The one's that do in fact increase the octane noticeably and will not hurt the O2 sensor or catalytic converter run in the $4 - $6 (or higher) range so it would end up costing extra.

Now there are some ways to make you own Octane booster for less. I forget the ratios but you can mix Xylene and transmission fluid to get a decent and safe octane booster. But who wants to keep cans of highly combustible Xylene laying around...

 

What sucks though is the new accord makes 240hp on regular gas and mine makes 225hp and I have to use premium.

 

so what if you put premium on an ACCORD? it will make more HP??.. maybe 245?

 

it all comes from the same focking tank under the ground anyway, octane #'s are a marketing ploy to charge more $$ for gas. how come ARCO 91 is less than Chevron 91??

 

cuz arco is garbage

 

Not necessarily. Maybe in some areas which are not regulated, but in areas with inspections and regulations the Octane value has to be at least what is specified.

I could tell the fuel grade in my old Typhoon, anything under 93 and it would knock like crazy during heavy loads.

 

The GAS question I see comes up again.
This topic comes up just slightly less than the tranny issue on the TL forum as well as this one. Here is my take on the issue as it has & will be again be beat to death. I am not an expert just your average car owner going by what I see on this forum & the TL forum as well as others. This also comes from reading all my car magazines like MOTOR TREND, CAR & DRIVER, ROAD & TRACK, & ATOMOBILE. some I have had subsrciptions to for over 20yrs. But back to the topic our cars required to burn 91 octane as the owners manual says. It also says 91 octane or higher so 93 or 94 would be okay. Depending on the station you go to or area you live there might not be a 91 octane sold. One of the car magazies even did test on premium gas & regular gas. This was cars design to run on premium only using regular & cars only needing regular burning premium. Some test results found that cars needing premium using less than there required octane rating were getting less miles per gal from a tank full of gas. This means the lower octane would be cheaper for you to buy at the pump but you would get less miles per gal by not using premium.
So you would in fact be filling your car up more often by not using the required premium fuel it was design to burn. More trips to the pump= more money.

 

I haven't seen this confirmed yet, but it's rumored +10 HP... Here's a thread about it:

http://www.acura-cl.com/forums/showt...threadid=76500

 

great timing for this post! i was about to ask you guys a question:

I lend my dad my cl-s, and he was feeling "generous" and filled up the gas for me. it turned out he put octane 87 gas in the car!

i've used about half-tank so far. i was wondering if there is anything to do to minimize the harm (if there is any) done to the engine?

thanks.
j

 

Gotta stick my nose in on this one. I work for one of the majors and have been in refining for too long.

First, required octane is generally a function of compression ratio. The higher the ratio, the higher the octane required to prevent pinging (pre-ignition). Back in the muscle car days, compressions were real high and required 100 octane gas. The 74 oil embargo changed all that and manufacturers went for 4 bangers at low compression to boost mileage. Plus cost of refining and clean air regulations make manufacturing high octane gas a thing of the past. (High octane = high aromatics = really bad engine emmisions)

They have been creeping back up since then and electronics controls, better engine materials and such allow you to get a lot more power out of a moderate compression ratio. In the past few years Acura, Toyota and Nissan have all introduced 200+ HP 6 cylinder engines that require premium gas because they have raised the engine compression ratios beyond mid grade or regular (CL 1st Gen 3.0 engines took mid-grade)

The genera rule of thumb is that you can use the lowest octane that your car will run on without pinging. This is a moving target as the threshold can vary with outside temperature, engine load, and other stuff you can't control. The manufacturers recommend an octane that will prevent pinging under almost all conditions, and such its conservative and probably more than you might need on a "normal" day (but not in mid August climbing into Sequoia or up the Kingsbury Grade). I suspect that mid-grade will work quite well if you aren't putting the engine under a lot of load on hot days. But don't expect my word to stand up to a dealer who is trying to get out of a warranty repair. Using less than the manufacturers required octane can get you out of warranty. I tend to stick with Premium for my CL-S becsue the cost isn't really that much more compared to the car itself. (Beside we make more on premium).

Now for gas -- gas is gas. Everybody makes about the same base product - it meets local clean air composition specs and octane rating. In fact each refiner usually sends his gas out to a terminal via a common carrier pipeline. So you might have 10,000 Barrels of ARCO followed by 10,000 barrels of Chevron, followed by 10,000 barrels of Shell, all ending up in the same tank at the terminal. In fact, the companies all have exchange deals for base gasoline so they can supply stations in areas where they don't have refineries.

The companies draw their stocks and take the gas to their own truck terminals where the prorietary additives (commonly known as foo-foo juice) at added which make a branded gasoline. The independents usually have a generic addtive package, but the branded stations have their own (Chevron Techron for example).

One thing to know about is who is giving away octane -- you tend to make a slightly higher octane gas than its labeled as because you cannot afford the bad press, fines and general hassel of being caught selling sub-octane gas. So it may say 89 on the pump, but you are probably getting 89.5 to 91. How much give away you have to provide depends upon how good you are at blending at the refinery. In southern California, ARCO and Shell (Texaco) had the lowest giveaway, which the word is that Chevron has the most (for now -- its an incentive to ugrade your blending facilites at the refineres).

Now why are ARCO and Chevron prices so different. The basic reason is the cost of refining and marketing. ARCO (Now BP) has a far more efficient operation than their competetors have, along with a lower cost marketing structure. ARCO does not have their own credit system (not since the early 80's) and the stations tend to be older and on smaller lots. Chevron goes in big to provide "convenience". So to make the same profit Chevron has to charge more at the pump. But they really don't make more money. In the past 10 years or so, ARCO has always been the highest in profit per barrel (what you sell it to a dealer for vs what is costs to buy the crude, refine it, and transport the product to the stations). Gas is also priced according to supply and demand (despite what the politicians say - there is no conspiracy). ARCO prices are lower because that's what it takes to get people into the stations. Chevron's are higher because they have to get it, and their target customer is more affluent and less likely to be concerned about a few cents a gallon as long as the stations aren't crowed and they are spacious and new...

 

A Honda engineer stated that if you use premium gas in your 2003 Accord, your HP will jump to 250. There was a thread a few months ago regarding that. Most everyone here thought it was bullshit through.

 

Since CL is my beater, I always use 87. I tried both 87 & 91 on my 01 CL. I actually get better mileage using 87. Yes, 87. I tested many times and get the similar result. For a full tank of 91, avg I get around 320 miles. For a full take of 87, avg I get around 350 miles. I don't feel any power lost either. I use 87 for more than 2 years and the car still going strong. Btw, I know a friend use 87 on his 00 Maxima for 2-3 years and w/o any problems.

 

Openloop, now that was informative!

 

Yeah, no kidding.

Uh oh . . . :thinking: . . . I think I may have learned something.



Good post.

 

I agreed, gas is gas. I've a friend who's a engineer at Mobil. He told me that sometimes they sell gas to 76, Shell & Chevron.

 

Open Loop, that was beautifully written. Thumbs up.

I have kept records on my fuel consumption from Day One. My habits are 80 City/20 Highway. I average approximately 25 miles total per work day (morning drive - go to gym - back home).

From June 6, 2000 to November 1, 2002, my average MPG (CLS '01) is 22.35 using 93 octane over 26,922 miles. Median value is 20.98 MPG. I average 5.67 days per fill (or 174.9 miles between fills). This is very much in-line with predictions: I remember reading 19 City/29 Highway/23 Combined.

Shell was used almost exclusively, but I have had to use 66 and Amoco. Had to use 87 octane once. I haven't bothered to truly manhandle the data, but can actually give you the brands, date of purchase, station locations, &c. if you are curious.

This is all with mineral oil. Valvoline -- if I can trust my dealer. I don't, so I've pretty much struck out the oil column. I will be switching to synthetics at 30,000, and continue my spreadsheet analysis.

 

I find this hard to believe as is with other statements. And your testing method is?? Have you monitored the potentiometer reading from the FLS and then compared it to the miles driven??

Nor should you; the decreased power will be in the amount of about 2%. It takes more than 5% to really feel a difference.

A 2000 Maxima for 2 - 3 years is possible. But it would have been simpler to say, since the day he bought it. Please stick to your day job and refrain from ignorant comments...

 

And thank you for doing so...

Having worked with Colonial Pipeline here in the Southeast US I can appreciate your comments...

 

So whats your point?

 

It wasn't apparent...

 

:shakehd:

Don't know why someone would even try this

 

Chief any new news about the CC OBX headers? was it replaced?

 

Haven't done anything about it yet-waiting for my temper to cool down so my logical side reappears!