Go Back  Offshoreonly.com > Technical > General Q & A
Can I get away with 91 Octane with a 525SC >

Can I get away with 91 Octane with a 525SC

Notices

Can I get away with 91 Octane with a 525SC

Thread Tools
 
Old 09-14-2009, 07:45 PM
  #11  
Registered User
Gold Member
 
bcfountain's Avatar
 
Join Date: Apr 2007
Location: prince george,va
Posts: 1,474
Likes: 0
Received 0 Likes on 0 Posts
Default gas

gas is the cheapst part of boating..burn good gas.i found out the hard way early this year.detionation is a mother.
bcfountain is offline  
Old 09-14-2009, 07:58 PM
  #12  
Registered
 
Back4More's Avatar
 
Join Date: Feb 2002
Location: Lake Michigan
Posts: 6,627
Likes: 0
Received 0 Likes on 0 Posts
Default

I have run 89 for 6 seasons when had the 525SC's... Just make sure your timing is set at no more than 35*@4500rpms.
Don't waste your time on an innercooler.
Attached Thumbnails Can I get away with 91 Octane with a 525SC-oldpower.jpg  

Last edited by Back4More; 09-15-2009 at 09:18 PM.
Back4More is offline  
Old 09-14-2009, 08:23 PM
  #13  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,558
Received 1,821 Likes on 907 Posts
Default

I'm 99% sure you will be fine running the 91 octane on a stock 525SC. I ran 92 octane in mine and had the boost cranked up to almost 8# with no chiller. Never any problems at all and it had over 400hrs on it. Stock boost on a 525SC is 5.5#. Maybe dial the timing back 2 degrees to be 100% safe, but I highly doubt you really need to.

BTW, full advance on the timing does not come in until about 4500rpms.

Last edited by Griff; 09-14-2009 at 08:40 PM.
Griff is online now  
Old 09-14-2009, 09:14 PM
  #14  
Registered
Thread Starter
 
Join Date: Sep 2009
Location: Lexington, KY
Posts: 38
Likes: 0
Received 0 Likes on 0 Posts
Default

Dont run the Piss out of it??? NO WAY!!! I'll Hi-jack a Tanker first!
Kid Cumberland is offline  
Old 09-14-2009, 09:34 PM
  #15  
Registered
iTrader: (7)
 
Join Date: Feb 2009
Location: NW Michigan
Posts: 8,302
Received 1,492 Likes on 807 Posts
Default

Originally Posted by JasonSmith
I don't think 91 would hurt it at all. They are setup so rich out of the box anyway.
Run it hard for a few & then shut it down & pull some plugs to take a look if you feel like you need to.
I'd run 91 & not think twice about it if it were mine.
correct they are rich and from my own experience 91 has worked fine with no signs of detonation however i would never keep it pinned for more than about 15 to 20 seconds.

running them rich doesn't really help in the detonation though. you still need sufficient octane to with stand the combination of heat and pressure.

Last edited by getrdunn; 09-14-2009 at 09:49 PM.
getrdunn is offline  
Old 09-15-2009, 02:15 AM
  #16  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,558
Received 1,821 Likes on 907 Posts
Default

Running a little rich will help keep cylinder temps down and help avoid detonation. They are plenty rich from Merc and have #98 jets squared. I had ran mine up to about 5 mins at WOT, buit mostly only 2-3 mins. The water temp would creep up about 5-10* and I would back off.
Griff is online now  
Old 09-15-2009, 07:54 AM
  #17  
Registered
 
Back4More's Avatar
 
Join Date: Feb 2002
Location: Lake Michigan
Posts: 6,627
Likes: 0
Received 0 Likes on 0 Posts
Default

Some info...http://www.blowerdriveservice.com/techcharts.php
Back4More is offline  
Old 09-15-2009, 08:22 PM
  #18  
Registered
iTrader: (7)
 
Join Date: Feb 2009
Location: NW Michigan
Posts: 8,302
Received 1,492 Likes on 807 Posts
Default

an extra burst of fuel by cracking the throttles always helps cool the temps. every performance engine i run i always have an exhaust temp probe / gauge. just a little extra insurance.
getrdunn is offline  
Old 09-16-2009, 12:07 AM
  #19  
Rob
VIP Member
iTrader: (6)
 
Strip Poker 388's Avatar
 
Join Date: Aug 2001
Location: Ms
Posts: 21,632
Received 6 Likes on 6 Posts
Default

Mississippi math

say you burn 300 gallons a month , the differance in gas price 91 to 93 at $2.75 is usally 10 cents,thats $30 dollars a month you save.

But being thats all ya have there, like Biggus says,Ive never liked running timming real low,exhaust temps on pump gas

thats my $30.00 worthGoodluck
Rob
Attached Thumbnails Can I get away with 91 Octane with a 525SC-bearing-sand-12-10-08-003-large-.jpg   Can I get away with 91 Octane with a 525SC-bearing-sand-12-10-08-001-large-.jpg  
__________________
.

The Only Time You Have To Much Ammo Is When Your Swimming Or On Fire.

Last edited by Strip Poker 388; 09-16-2009 at 12:13 AM.
Strip Poker 388 is offline  
Old 09-16-2009, 01:18 AM
  #20  
Registered
 
Join Date: Jul 2007
Location: San Diego
Posts: 988
Likes: 0
Received 2 Likes on 1 Post
Default

Originally Posted by Strip Poker 388
Mississippi math

say you burn 300 gallons a month , the differance in gas price 91 to 93 at $2.75 is usally 10 cents,thats $30 dollars a month you save.

But being thats all ya have there, like Biggus says,Ive never liked running timming real low,exhaust temps on pump gas

thats my $30.00 worthGoodluck
Rob


Unfortunately we can't even get 93 at the pumps where I boat in SOCAL. 91 is tops. I would gladly spend the extra 30 bucks for the added protection.


Darrell.
DMOORE is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.