nvpscore

What difference does the 101 octane have on our car if I were to fill my my CL-S with this gas? Reportedly it was found at a local Texaco by my house. Shall I do this, just for a little bit to test it out? Has anybody done this?

Thanks

Nick

Tuboz

hey man i dunno know the specifics but go out and get an issue of the new "car and driver"

it has an article towards the end about premium vs. regular fuel

they tested cars such as
- BMW M3
- ACCORD V6
- SABB
and another.....

it seems like in all the other cars besides the accord performed better with premium fuel...

which made me think, since the closes thing to a CLS would be a V6 accord....i thought

so i'm considereing NOT putting in 94 octain from sunoco from now on to save a buck or two

moomaster_99

Was the Saab turbo?? Then it'll benefit....the M3 has a 11:1 compression ratio much like the Type-S..(10.5:1) meaning it'll allow more air in to mix with the fuel without worry of detonation. The accord has like a 9.5:1 compression...high but not high enough for extra octane to give it any performance advantages.

Pull_T

Stock, it shouldn't give you any more power, and most likely will cost you a small amount. Higher octane (101+) burns colder/slower and is meant for higher compression engines or forced induction engines.

However, when/if you get the blower, the higher octane gas would be of great benefit. It will allow your tuner much more flexibility and will enable him to get you more power. What I have seen on many blown Mustangs is a chip, be it Autologic, Diablo or whatever that gives you an aggressive tune for racing gas and a more conservative one for pump gas.

Pull_T

The other was a Mustang GT.

I read the article. They stated that the GT has knock sensors that pulled timing out costing hp when the regular unleaded was used. The GT has no knock sensors...therefore I do not trust the results they claimed.

IMO, at best, the results show the normal variances that occur in testing and inaccurate testing methods used by C&D.

tankmonkey

you've just opened pandora's box...

(as if this topic hadn't been done ad nauseum already...)

EricL

IMO -- if you are in California, it doesn't hurt to add a couple (or more) gallons of 100 octane to get the fuel octane up a point or two.

IMO -- You will waste your money filling a whole tank with the stuff and it is expensive.

However, I have finally done some GTECHs (under similar conditions) and I've now gotten a couple of tenths off in 0..60 runs on same street, two ways, temp within 5 degrees. Also, the Toyos -- that do not like to spin on hard takeoff (on the same rough surface) -- will spin with the octane boost. I've now tried 3-different runs (with GTECH) and there is a small increase (IMO). I've done 8 tests in total.

IMO -- the car with "goodies" could use the 92-93 octane. The car just hasn't been the same with the California 91 octane.

I noticed that article too and while it is true that higher than required octane can actualy hurt performance, using just enough to keep the knock sensors off is best (IMO). It would have been nice if they had tested OUR car and NOT the Accord. Finally, there is the issue of 91-octane fuel being crap *and* the 100-octane available from 76 probably has a "better" mix of fractions -- and this may account for the "measured" performance increase

UNTIL someone does a dyno of OUR car with 91-octane (for cal users), 91,92, and 93 (out-of-Cal.) vs. 100-octane, this will probably end up as flame city...

EricL

Yes, I still have the lash marks on my back (from the TL-Forum) for saying that it might help to diagnose pinging problems and that it seems to help adding a bit in CA...

tankmonkey

well, all blasphemers in the name of octane must be punished...

(kidding! )

acura_service

this has been discussed many many times before, the only reason you would need a higher octane fuel is if you are running a higher compression, with a higher compression cylinder temperatures increase causing detonation, a higher octane burns cooler and cleaner at a higher compression. putting it in your cl is a waste of money

EricL

Your not in CA... However, don't you find it interesting that they (Acura) spec'd 92-octane for the TLS ????


Here is the spec capture for a TLS (same engine yes/no/maybe?) from the acura web site:

DRM600

I remember that the cl's owner's manual states that a minimum of 91 octane should be used. At least the lowered octane in CA still meets our needs. The quality of the fuel is another issue. My car felt really sluggish when I was filling up with 91 over the summer as 92 was being phased out.

100 octane is nice stuff. I can't say that the car "has more power", but the engine definately felt smoother. I pay $3.25 in OH for that at Sunoco. Too much for any kind of regular use, but it's fine for experimental purposes. 94 octane at ~$1.40 is juuust fiiine.

EricL

Yes, and the acura site says 91-octane for the CLS (it came out first, before the crummy gas in CA). BUT, it says 92-octane for the TLS.

And a bunch of TLS owners are complaining about pinging with CA gas...

Hmmm...

BTW -- I'd be thrilled if I could get 94 here!

typeR

here's another area where i have just started educating myself...here's what i think i've learned...besides compression heat is another reason for pre detonation...california,florida,arizona,texas,soun d fimilar so far....sounds like 90% of the board...higher temps in the heads can cause predetonation and the ecu will,that's WILL retard spark to avoid this...10.5:1 and 90*temp+90* humidity could be leading to a retard situation on spark resulting in lost torque...I am adding water wetter,high pressure raidator cap and lower temp thermostat,to my cooling system,which BTW seems to be apart of the trans mission cooling,this can reduce head temps as much as 45* and overLL TEMPS by 20*....it's complicated if you want to find out more see www.redlineoil.com
watterwetter...10$ for one bottle which will treat you entire cooling system...
101 octane in any of the above situations MAY lead towards spark remaining advanced hence more power....flame away.

scalbert

Just to add another issue into the mix.... Yes, higher Octane does help to starve off deto but deto is brought about by different mechanisms. Is it spontaneous ignition due to compression, hot spots, etc.?? Octane is based on Ron + Mon / 2. Ron and Mon Octane handle different issues of deto (or rather the inability to self detonate or having an uncontrolled burn).

So if one blend handles an issue better another blend might not. So the tests done in the mag were decent info but now complete. They didn't define spark mapping based on knock history, nor did they define what gas was run in each car prior to the tests. This would have an impact if spark advance mapping is done.

Then we get to the area of which Octane rating is better for a car, is it heat generated, another or a mix. Because as the knock sensor system detects deto (through knock counts) it will pull timing. But when you pull timing your EGTs go up which in some vehicles (if the Ron is too low) will experience further knock. Kinda a catch 22.

This is a very dynamic issue and cannot be answered simply.

EricL

All true, including the increased temp rejected to the cooling system by the retarted spark (re: your remark about the increased EGTs). Getting back to the original question, perhaps this is best left to "experimentation" and let the experimenter consider ALL of the various factors involved.

As a note, could you image the problems that a manufacturer would have (here in CA) with "fussy and paranoid buyers" if they actualy put a requirement for 94-octane gas. in their sales literature. Perhaps, marketing gets into this as well -- who knows for sure?

I could just see some potential M3 buyer saying, "Hey, this thing requires 93 octane and I can't get it..." The dealer replies, "Don't worry the car will still run well on 91..." But, but, but how much power will I loose, will I still be able to beat that chipped S4 my rich neighbor has... I really, really need to know. I'm so worried now."


Perhaps the answer to the question at the top would be – just go out and try it – for fun!

scalbert

I wouldn't want to be that salesperson... Or would become the BEST car salesperson out there...

But fortunately I don't have to deal with THAT gas unless I'm traveling and in a rental (which the lowest grade goes in regardless)... We here in the south, for the time being, enjoy good fuel throughout the year thanks in part to Colonial Pipeline and others...

CO-CL-S

And don't forget that altitude also plays a part, the higher up you are the less octane your car needs.