BLACK ROCKET

I am currently experimenting the benefit of using higher (91) octaine gas for the winter.

It prompted me that winter time my car gets flooded easily, unlike nice warm or hot day.

My theory is this: Combustion is better on higher octaine gas, therefore, evaporation rate should be higher than lower octaine gas.

It's been about a week since I started my experiment and not sure wether psycologically or functionally to my satisfaction that my car does not flood with normal cooling off period (3-4 min of music listening pleasure while being parked in front of a store).

While I was using normal grade gas (87) during winter season, no matter how long I cool off the car. it's 50/50 chance of being flooded.

Yes, I'm done with tune-up, oil change, etc. prior to commencement of my experiement.

My car is fine during temperate weather season, but, winter time really SUCKS.

Has anyone else tried the experiment as such?

I will update you on my experiment as data compiles for longer period.

Madrx7racer

what kind of car do u have? Turbo? NA?

BLACK ROCKET

turbo

MountainTurbo

Yah, I'm interested to see how that goes for you. The TII I'm buying floods kinda bad right now, but it might be because of some other issues.

Keep us informed!

1987RX7guy

iTrader: (3)

AFAIK lower octane means easier burning. Higher octane resists detonation more which means harder to light up.

bingoboy

yeah what he said.

Wicked_razor

i use 91 all year long

1987RX7guy

iTrader: (3)

Your also wasting your money if your doing it on an N/a. There is no need to run anything higher than 87 octane on an N/a.

Santaigo


PS- The lower octane you can run the better.

BLACK ROCKET

Check this site: 4.11.1)volatility:
http://www.repairfaq.org/filipg/AUTO...l#GASOLINE_011

1987RX7guy

iTrader: (3)

That talks about regions not octaine. From what I could gather all octanes would be changed equally given your region.

Also may I ask what your using to test your theory?

Elysian

you use 87 in ur TII? that just doesn't sound right to me... i've never used less than 91.... and that was driving thru cali... WA has 92, and Dallas area has 93....

1987RX7guy

iTrader: (3)

My comments are refering to N/a's TII's are generally better off with higher octane. But they run just fine under normal driving situations with 87 or 89.

BLACK ROCKET

I live in Northern Nevada, where summer is at around 100 and winter average is teens at night and maybe 30-40 during a day (in exception of overcast winter days).

Theory began when my rex's been sheltered in the garage for the most part of early winter and one decent day I was going to take her out for a spin and my deep cell battery was low (my fault for not maintaining during winter season) I put charger on my battery and began driving even colder weather to primarily charge up my battery.

I, then, noticed flodding incidents began to occur even after my NORMAL 4 minutish idle before shutting my engine, as I explained initially.

So, I was close to 1/8 of a tank (intentionally for my experimental purposes) and filled her up with 91 instead of my normal 89. I know it's not much of a difference, but, just to satisfy my curiosity, I began to notice the difference in not flodding as during my summer (temperate) months of enjoyment.

This theory backed by fact via site mentioned above, may not apply to So Cal or generally temperate reigions, but, seemingly working for harsher temperature variance area like N Nevada.

As I mentioned in my first post this experiement has just barely began and I won't be able to give you a conclusive statement, yet.

But, so far so good.

BLACK ROCKET

The following states are mandated to use RFG (Reformulated Gasoline) i.e., federally mandate gasoline that is specially processed and blended to reduce the emission of pollutants) CA, TX, VA and DC.

RFG has seasonal "adjustments" for winter and summer use. During summer months less evaporative RFG is being used.

Therefore, based on my findings higher evaporative gas ((higher octaine), confirmed by petrolium co)) should be required during winter season for the rest of the area where RFG is not automatically being adjusted for the season.

Based on the factual findings stated above my "experiment" was not a loss cause, but, previously noted and confirmed by petrolium companies.

I hope this info will enlighten forum members for assuring better performance of 7's throughout the year.

1987RX7guy

iTrader: (3)

Ok so can you break it down how this is going to make higher octane gasoline better?

glorthu

FYI, most everywhere there are different gas blends for summer and winter. I don't know whether there is generally a difference in evaporability for non-RFG summer and winter blends though.

Also, another factor in your experiment is the additive blend of the gases you are using. Generally, when you switch between say Shell and Mobile, or between 89 and 91 octane at a single gas station, the additives are different. Most gas companies buy their gas from the same pool and add detergents and whatever else before it gets to the pump. They often try to give added 'value' to their higher octane gas by using more additives.

Cheers and best of luck on your experiment!

BLACK ROCKET

I thought my privious post kinda explained the reason why and I wouldn't call it "better" in this instance. I would refer to it as EFFICIENT utilization.

Anyhow, in this application, characteristics (sp) of higher octaine gas' (faster evaporative quality compared to lower octaine gas) there's a logical connection not causing FLOOD in a chamber especially in a harsher (colder)environment.

Tristan Bull

Indeed. I used 87 all through my break-in. I didn't start using 91 until I started driving the car a bit harder. I noticed knocking after 4k rpm or so, or about when I started to make full boost. I've used 87 some since then. I just don't drive the car hard. I'll probably be using it more as this $1.80/gallon 91 is killing me.

Anyhow, on the flooding topic, my car still floods about as frequently no matter what type of gas I use. It doesn't really happen much anymore. Maybe once every few weeks or once a month. I haven't been driving it much in the winter though. I don't drive in ice/snow or if there's salt on the roads after the ice/snow is gone. So that might be why I don't notice it happening much anymore as when I drove the car every day.

1987RX7guy

iTrader: (3)

BLACK ROCKET



What is the condition/status of your fuel injectors? Was that part of your "tune-up"?


My car started up fine all month. We have had lows of 28* F and highs of 101 in the past month. There isn't anything wrong with using low octane in different weather in my experience. Btw I live in TX

Terrh

iTrader: (7)

STOCK TII's have NO PROBLEM running on 87.

I discovered this halfway through the summer instead of in the spring, unfortunatly.

BLACK ROCKET

When I pulled my stock 13B about a year ago with J spec rebuilt, every thing (all the important STUFF, including injector) have been replaced.

And few months ago I had my injector cleaned

I'm telling you living in NV sucks as weather is so volatile and fun time is limited and I don't go skiing anymore.

Not sounding arrogant or anything but, in my opinion, my vehicle is in as optimal condition as 88 TII could possibly be.

1987RX7guy

iTrader: (3)

I see I neglected to see that you had a TII. In that case carry on. I thought you had an 88 N/a but then I looked at your post up top where you stated you had a TII. In that case if your boosting you should use high octane.


Santiago

BLACK ROCKET

Yeah, but on the other hand during summer months lower (usually mid) octane gas and it's just perfect 4 me.

And you save whole $0.01 per gallon and I'm planning on continue this experiment in hot (100+ temp) summer condition.