Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Discussion Forum

What octane gas for what compression?

Welcome Guest, Log in or Register
Author 
JohnDeere2Cylinder

07-19-2002 11:04:28




Report to Moderator

I have seen many posts on this subject, but no answer to my question: What octane gasoline for what compression in psi? My gauge only shows psi, not compression ratio and the engine is an unknown ratio. For examples, if under 100 psi, what octane is recommended or if 100-125, or 150-200, or 250-300, what octane? Does anyone know of an accurate chart? Thanks.




[Log in to Reply]   [No Email]
G Taylor

07-19-2002 19:37:19




Report to Moderator
 Re: What octane gas for what compression? in reply to JohnDeere2Cylinder, 07-19-2002 11:04:28  
It isn't the pressure but air/fuel mixture getting above it's ignition temperature. A 3 to 1 compression engine with 50 psi compression will detonate on 100LL aviation fuel if the mixture is heated by glowing carbon,too hot plug,glowing overhanging gasketor glowing exhaust valve. High rpm automotive race engines often retard timing near redline as more heat from compression ends up in the air/fuel mixture than at lower rpms. Same as diesel has to be cranked fast enough to start.

[Log in to Reply]  [No Email]
The Happy Hooker

07-19-2002 13:46:06




Report to Moderator
 Re: What octane gas for what compression? in reply to JohnDeere2Cylinder, 07-19-2002 11:04:28  
If you get above 175 or so psi you better run some good stuff. We have 2 old As running 215 to 235 and we run 110 octane or better. One of them has been known to ping on that.



[Log in to Reply]  [No Email]
G-MAN

07-19-2002 12:13:19




Report to Moderator
 Re: What octane gas for what compression? in reply to JohnDeere2Cylinder, 07-19-2002 11:04:28  
I don't think there are any hard and fast rules pertaining to octane requirements and compression ratio. There are too many variables within each engine. Things like bore diameter, piston shape, timing, valve location, plug location, engine temp and many other factors determine what octane is required, along with compression. Two engines could both have identical compression, but they could require completely different octane ratings, based on all of the different factors.

[Log in to Reply]  [No Email]
MMpuller

07-19-2002 19:28:42




Report to Moderator
 Re: Re: What octane gas for what compression? in reply to G-MAN, 07-19-2002 12:13:19  
I agree , dont forget that a multiple spark will also help but their is nothing cast in stone for octane to psi



[Log in to Reply]  [No Email]
JOhn

07-19-2002 15:49:24




Report to Moderator
 Re: Re: What octane gas for what compression? in reply to G-MAN, 07-19-2002 12:13:19  
I would say that if you get above 225psi, you better come up with a different motor. We have a G that runs at a bout 205psi, and we have to run 110, 103 octane aircraft fuel is too little for it to handle.
John



[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy