Octane Ratings

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NeonTuning
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Post by NeonTuning » Tue Nov 20, 2007 6:37 am

racer12306 wrote:I was just asking because in the states we have the (r+m)/2 method. Holland must be on the ron method.

Ron numbers are typically higher than (r+m)/2 numbers.
sorry I dont really understand what u mean, what is r+m/2 method???
Love Redline Shifting......

racer12306
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Post by racer12306 » Tue Nov 20, 2007 8:33 am

(ron + mon)/2

i believe...
ron = research octane number
mon = mechanical octane number
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NeonTuning
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Post by NeonTuning » Tue Nov 20, 2007 9:09 am

ok and what is the difference??
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NOx_Concepts
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Post by NOx_Concepts » Wed Mar 05, 2008 2:56 am

coming from someone who went through 3 DAYS of fuels training to make $7/hr pumping gas, the difference is this. the "R" rating is the calculated octane rating of the fuel as it is "created" as they call it, in mathematical formulations, and the "M" rating is the octane rating that that same fuel is studied to have through thorough testing in a wide variety of engines, they actually try to get as wide a range as possible, going from something rediculiously small, like a lawn mower, all the way up to race engines and everywhere in between to get the mechanical rating, it takes something like ~10x as long for them (them being shell, not sure about the others) to get a federally approved "M" rating for the fuel, they then add these two numbers together and divide them by to to get the numbers we see on the pumps, thats also saying that 93 octane at sea level and the 92 octane we have in Portland (someplaces elevation of ~600-700 ft) is "R" wise, the same stuff, different atmospheric pressures will render differnet mechanical ratings there by changing the "pump" rating.

sorry, was kindofa science and math nerd, working on translating that into parts fabriation master :shock: 8)
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Post by jamaicangrimreaper » Thu Mar 06, 2008 2:16 pm

:thumbright:

NOx_Concepts
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Post by NOx_Concepts » Fri Mar 07, 2008 1:27 am

**thread hijack** im pretty sure with the build im doing ill be alright with chevron 92 (2.4, .020 over 10.5:1 comp, afx race ecu and long tube header, AMM ported indy manifold, 60 mm tb) I NEED CAMS, PLEASE HELP. I DONT CARE ABOUT LOPE, TO ME, THE MORE THE BETTER, THE PURPOSE OF THIS CAR IS TO BE A TOY, AND STILL BE STREET DRIVABLE, if anyone has a set of 22's or 24's i can buy from them, please lemme know .........
"If your primary path is everyone else's road less traveled, no one will ever be in your way." Nox

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Wolfemancola
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Post by Wolfemancola » Tue Oct 18, 2011 8:36 pm

i know this is an old post but i was wondering, why is it that when you switch to the Mopar performance PCM ypu need to start using higher octane gas?
My car:
1998 Plymouth Neon EX 2-door coupe DOHC 5-speed with Cruise Control
ATX Throttle body, 3.0 intake with K&N filter, Mopar PCM, mopar motor mount with inserts, Booger Bushings, Rear view mirror with dual lights.
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Ianguilly
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Post by Ianguilly » Tue Oct 18, 2011 11:34 pm

I have a mopar computer and run regular octane and it drives fine.
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-Neon #3 1999 Dodge Neon R/T, Flame Red, DOHC MTX, Goodies, "Christine X2"

-Neon #6 95 NYG sport coupe SOHC MTX, 1 0f only 527
jamieely wrote: There are 2 kinds of people here, those with coupes, and then the other guys. If srt4s were coupes I would have one.

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Post by 2drSRT4 » Wed Oct 19, 2011 12:41 am

Ianguilly wrote:I have a mopar computer and run regular octane and it drives fine.
What is regular for you? There are different "regular" ratings all around the country. I know when I visit houston, the only "regular" gas I can buy is like 89 octane, but here in my home town we can get as low as 86. 86 would knock like a bitch with the wrong timing compared to 89.
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jamieely
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Post by jamieely » Wed Oct 19, 2011 2:54 am

Wolfemancola wrote:i know this is an old post but i was wondering, why is it that when you switch to the Mopar performance PCM ypu need to start using higher octane gas?
It is due to the advanced ignition timing, you can run less 90 octane and the car will run fine but you may have some slight pinging and possibly detonation if I remember correctly, and you will not be getting the performance out of it you should be. More than likely a mopar pcm on regular gas isnt making much more power if any at all over a stock pcm. Mopar didnt just want you to spend more money on gas they assume since you are spending the money for an aftermarket pcm you want it to run optimally as well. I would compare it to running a dohc motor on a sohc pcm, it will run, but not the best it could run.
1995 Highline Coupe SOHC MTX.
DOHC Mopar PCM
e85, 30lb injectors, LM-1, SAFC
Custom CAI, 60mm MPx TB, AMM Box Intake, DOHC pistons, built4race UDP
PT Clutch, 3.94 FD
AF/X LTH, High Flow Cat, Spiral Flow, 2.5" piping, Flowmaster 80 series

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Ianguilly
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Post by Ianguilly » Wed Oct 19, 2011 12:04 pm

I run it with 87.
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-Neon #3 1999 Dodge Neon R/T, Flame Red, DOHC MTX, Goodies, "Christine X2"

-Neon #6 95 NYG sport coupe SOHC MTX, 1 0f only 527
jamieely wrote: There are 2 kinds of people here, those with coupes, and then the other guys. If srt4s were coupes I would have one.

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jamieely
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Post by jamieely » Wed Oct 19, 2011 7:22 pm

Ianguilly wrote:I run it with 87.
:(
1995 Highline Coupe SOHC MTX.
DOHC Mopar PCM
e85, 30lb injectors, LM-1, SAFC
Custom CAI, 60mm MPx TB, AMM Box Intake, DOHC pistons, built4race UDP
PT Clutch, 3.94 FD
AF/X LTH, High Flow Cat, Spiral Flow, 2.5" piping, Flowmaster 80 series

P&P Magnum head, Crane springs, Crane 007, AEM 3-bolt cam gear almost ready to bolt on

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Ianguilly
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Post by Ianguilly » Wed Oct 19, 2011 7:39 pm

jamieely wrote:
Ianguilly wrote:I run it with 87.
:(
Money is tight, sometimes i get 89 when the price is right.
Image
-Neon #3 1999 Dodge Neon R/T, Flame Red, DOHC MTX, Goodies, "Christine X2"

-Neon #6 95 NYG sport coupe SOHC MTX, 1 0f only 527
jamieely wrote: There are 2 kinds of people here, those with coupes, and then the other guys. If srt4s were coupes I would have one.

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jamieely
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Post by jamieely » Wed Oct 19, 2011 9:56 pm

Ianguilly wrote:
jamieely wrote:
Ianguilly wrote:I run it with 87.
:(
Money is tight, sometimes i get 89 when the price is right.
I can understand that. Thats why I made the switch to e85, it is getting easier to get now too, at least around here. Even with the reduced mileage my gas card bill is still around $50 cheaper than it was. I have always been a firm believer in premium. I havent run anything less than premium in any of my cars since I was around 19 or 20 when I bought my first Subaru.
1995 Highline Coupe SOHC MTX.
DOHC Mopar PCM
e85, 30lb injectors, LM-1, SAFC
Custom CAI, 60mm MPx TB, AMM Box Intake, DOHC pistons, built4race UDP
PT Clutch, 3.94 FD
AF/X LTH, High Flow Cat, Spiral Flow, 2.5" piping, Flowmaster 80 series

P&P Magnum head, Crane springs, Crane 007, AEM 3-bolt cam gear almost ready to bolt on

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Post by 2drSRT4 » Thu Oct 20, 2011 12:08 am

jamieely wrote:
Ianguilly wrote:
jamieely wrote:
Ianguilly wrote:I run it with 87.
:(
Money is tight, sometimes i get 89 when the price is right.
I can understand that. Thats why I made the switch to e85, it is getting easier to get now too, at least around here. Even with the reduced mileage my gas card bill is still around $50 cheaper than it was. I have always been a firm believer in premium. I havent run anything less than premium in any of my cars since I was around 19 or 20 when I bought my first Subaru.
e85 is awesome =) Definitely what I want to run the neon on. But I know my range will be decreased quite a lot. What do you do to combat the lowered driving range?
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