Hemi - What Gas Grade

As a new Hemi owner I'm asking what grade gas does everyone put into their Hemi?

Here in the UK we have two grades 95 octane and 98 octane

I've been putting the 95 Octane in the tank...is this what should go in?

Cheers

As a new Hemi owner I'm asking what grade gas does everyone put into their Hemi?

Here in the UK we have two grades 95 octane and 98 octane

I've been putting the 95 Octane in the tank...is this what should go in?

Cheers

I may be way off here, but I always put the lowest octane possible (that'd be 87 octane here). I was told that the hemi is really a truck engine and it would run too hot on higher octane fuel.

Anyone else with some insight feel free to correct me.

:)

The hemi requires the mid grade here which is 89 octane. Have you looked in your manual to see what the required octane is for over there?

The hemi requires the mid grade here which is 89 octane. Have you looked in your manual to see what the required octane is for over there?

Well I'll be danged.... I really should read this thing *pointing at owner's manual* more often.....

:o

Well I'll be danged.... I really should read this thing *pointing at owner's manual* more often.....

:o

I would read it, but its 75miles away at home, I'm in the office killing time and thought I'd ask my forum chums a question!!!!! :p

Who's reads the owners manual anyway??? :D

Sorry for asking a question!!! :rolleyes:

you should be fine. isn't european gas octane different then USA gas grades. or am i missing something?

did you trade your CRD for the Hemi?

don't you guys still have leaded gas as well? i thought i saw leaded gas when i was there from 98-2000. we accidentally put it in out car. P-reg. vauxall corsa.

you should be fine. isn't european gas octane different then USA gas grades. or am i missing something?

did you trade your CRD for the Hemi?


Chrysler UK did a swap with the CRD. It had cost them so much to replace the transmissions, they wanted it off the road!!!

We have unleaded here now and have done for many years now!!!

I looked up the difference between US and European octane ratings, so we can compare apples to apples.

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.

There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

In most countries (including all of Europe and Australia) the "headline" octane rating, shown on the pump, is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON).

Wow! There you have it! Thanks Riddle!!!

Mmmmm....confused even more now! :confused:

Called the wife, she states the operators manual is US spec! :confused:

I'll have a look when I get home!!! :confused:

According the Riddle's writeup, you are good at 95 which is equal to our 90 here. The hemi's here require 89.

I would assume that if you have two octaine levels you will want to be running the higher level fuel for the HEMI. We have three levels and run the middle or upper depending on preference.

I've been using 87 octane in my HEMI since I bought it (new) with no problems. Tried a couple of tanks of 89 but could not tell any difference.

i run 85 in my 4.7L hemi

anyone going to dispute i have a hemi?????

http://en.wikipedia.org/wiki/Hemi_engine

i run 85 in my 4.7L hemi

anyone going to dispute i have a hemi?????

http://en.wikipedia.org/wiki/Hemi_engine

Yes, you have a Magnum/PowerTech: http://en.wikipedia.org/wiki/Chrysler_PowerTech_engine :D

The 4.7 liter version was the first of this family, appearing in the 1999 Jeep Grand Cherokee. The displacement is 287 cubic inches (4698 cc) with a bore of 3.66 in (93 mm) and a stroke of 3.405 in (86.5 mm). It has a cast iron block and aluminum "almost Hemi" heads :D with two valves per cylinder. It uses a chain-driven overhead camshaft. It originally produced 235 hp (175 kW) and 295 ft·lbf (400 N·m) of torque.

The PowerTech was on the Ward's 10 Best Engines list for 1999.

Applications:

* 1999-present Jeep Grand Cherokee
* 2000-present Dodge Dakota
* 2000-present Dodge Durango
* 2002-present Dodge Ram
* 2006-present Jeep Commander
* 2007-present Chrysler Aspen

"Almost" only counts in horseshoes, hand grenades and nuclear weapons!

The Allpar article said that the only difference is that the cylinder head has a flat wall on one side, but that everything else is the same as a Hemi. I just wish they'd redesigned the engine for the 2006-2007 years, that extra power would be nice. But there is a supercharger for our engines, hmmm...

I also run the low grade in my HEMI and have had no issues. I did try the "good stuff" and I think I actually lost MPGs and performance (and $$$)!

My HEMI is at 45k miles now... Been using Octane 87 for 75% of the miles. I'll put in Chevron 91 Octane once in a while (contains Techron for cleaning purposes)

just stick a bottle of seafoam in your tank if you're worried about a dirty motor. it'll clean it up fast, and you'll notice a mileage increase afterward. i do it to all my used cars i buy. its about $8 for a can.

As I recall all of the Chevron grades contain Techron... right?

I've been using 87 octane in my HEMI since I bought it (new) with no problems. Tried a couple of tanks of 89 but could not tell any difference.

Same with me. 87 with no issues.

Just went back to 85 from 91 in my 4.7, and the mileage seems to have increased. I was getting ~14-15 on the highway before, coming back from wheeling yesterday I was getting ~19.

Just went back to 85 from 91 in my 4.7, and the mileage seems to have increased. I was getting ~14-15 on the highway before, coming back from wheeling yesterday I was getting ~19.
What was the reason behind you going up to 91?

Because we run lower octane out here due to altitude and I thought with the CAI, exhaust and iridium plugs it might make a difference, but it only lightened my wallet.

maybe thats why mine doesn't seem to care, we are at about 5000 ft. here.

i was at 10892 ft last night.

We were at 12k+ on Saturday, truck ran just fine on 85.

So does anyone think that using 87 may hurt the engine in some way? I would like to use 87 but I didnt want to take the chance of messing something up for $5.

I've been running the mid 80s since I got it and have had no issues.

So does anyone think that using 87 may hurt the engine in some way? I would like to use 87 but I didnt want to take the chance of messing something up for $5.
........No.......

I looked up the difference between US and European octane ratings, so we can compare apples to apples.

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.

There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

In most countries (including all of Europe and Australia) the "headline" octane rating, shown on the pump, is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON).

Really good info!! Thanks!

Really good info!! Thanks!

I am regularly impressed by the knowledge, skill and genuine good humor possessed by the members of this forum, my chance to contribute in meaningful ways are few. I pounced on the opportunity when I saw it. Alas, wikipedia was the source and 'cut and paste' was the means. But glad I could help.:o

So....Bottom line is...

No one has had issues with 87 in the Hemi.

I have religiously put in 89 for the past 16 months of ownership. Here in Atlanta, we've been out of gas EVERYWHERE...one station only had 87...so I put it in. A few days later, the "check engine" light has illuminated.

My wife thinks it's the gas...I say...NO WAY. Probably just pure coincidence. Driving appears normal.

NOW...I have to find a station with fuel so I can drive across town to another Jeep dealer since MY dealer (3 miles away) closed. UGH.

I changed to 87 about a month ago and have had no issues. Why are your gas stations running out of gas? I haven't seen any gas stations here running out.

...CNN an FoxNews say that supply lines damaged from Hurricane's Gustav and Fay are still running at reduced capacity. Plus...enter the "panic mode"...everyone fills up any chance they get.

Counted 7 stations on the drive home from Hartsfield yesterday...NO gas.

...CNN an FoxNews say that supply lines damaged from Hurricane's Gustav and Fay are still running at reduced capacity. Plus...enter the "panic mode"...everyone fills up any chance they get.

Counted 7 stations on the drive home from Hartsfield yesterday...NO gas.

Back in 1973, the first "shortage" To stop the people from running on the pumps we made a minimum purchass.
You paid for 5 gallons, even if you only got 2.
It was rather rough in the beginning, but, the public slowed down on their unneccessary purchasses, and refining capacity caught up in about 2 weeks.
It might have to come to that by you folks.

.........Rob