Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Mercedes-Benz SL Discussion Forum

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 10-21-2007, 12:09 AM
Graham's Avatar
Registered User
 
Join Date: Nov 2004
Location: Ontario, Canada
Posts: 3,460
Fuel for 4.5L (USA version)

Noticed my manual says to use 91 RON fuel for our '72 350SL.

So, what the heck is RON? Looked it up on Wikepedia:

In most countries (including all of Europe and Australia) the "headline" octane that would be 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, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).


So, it seems that 87 Octane regular in NA should be OK.

Timing instructions in shop manual say to retard ignition if fuel is less than 98 RON for "Standard version" for USA version it does not mention fuel. Presume the figures relate to regular fuel in USA? Says 5deg after TDC fat idle with vacuum. Mechanic set mine higher than that - says it's needed for old car??
Reply With Quote
  #2  
Old 10-22-2007, 11:13 AM
Registered User
 
Join Date: Mar 2004
Posts: 758
Although the "book" says regular grade is recommended, I use the 89 octane mid-grade fuel in my '72 SL. The small cost penalty is cheap insurance against detonation and knock. I also throw in a bottle of Techron every other tank to keep the FI system clean.

230/8
Reply With Quote
  #3  
Old 10-22-2007, 08:26 PM
Graham's Avatar
Registered User
 
Join Date: Nov 2004
Location: Ontario, Canada
Posts: 3,460
Quote:
Originally Posted by 230/8 View Post
Although the "book" says regular grade is recommended, I use the 89 octane mid-grade fuel in my '72 SL. The small cost penalty is cheap insurance against detonation and knock. I also throw in a bottle of Techron every other tank to keep the FI system clean.

230/8
I ran a bottle of Pennzoil cleaner through our SL. It says it cleans up injectors if applied to one tankful. It did seem to make a difference - Not sure if to injectors or to fuel pressure control valve, but it smoothed idle out.

Currently running mid grade which I think is 89 here too. Manual (under Standard Version, not USA version) says to retard timing a few degrees for lower octane and advance for higher octanes. I drive car no more than a few thousand miles each year, so no real cost to using 89 instead of 87 and local station gives me double Bonus-Bucks for buying coffees etc!
Reply With Quote
  #4  
Old 10-22-2007, 09:07 PM
meltedpanda's Avatar
Certified Benzaholic
 
Join Date: Mar 2003
Location: Central Ky
Posts: 6,130
i run 89 chevron ( with Techtron) timing at 7-8 ATDC
__________________
Ron
2011 Porsche Cayman - Bond,James Bond
99 E320 THE Queen Mary
62 220b - Dolly - Finally my Finny!
72 450SL, Pearl-SOLD
16 F350 6.7 Diesel -THOR
07 Lexus RX 350 - Lexi
14 38HP John Deere 3038E Tractor -Mean Green
84 300SD, Benjamin -SOLD
71 220 - W115-Libby ( my first love) -SOLD
73 280 - W114 "Organspende" Rest in Peace
81 380 SL - Rest in Peace
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 06:22 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page