User Tag List
Results 1 to 15 of 56
Thread: Fuel/compression
-
12-07-2021, 03:01 PM #1
Fuel/compression
What kinda fuel or real octane booster , or mix of fuels do I need to run 170lbs compression? This will b a 1st for me and don't wanna burn her up
-
Instigator liked this post
-
12-07-2021, 03:47 PM #2
https://youtu.be/JWOevmVGwY8
I finally figured out video to put on here. These are not the tight headsLast edited by Merc 2.5; 12-07-2021 at 03:50 PM.
-
Keaten thanked for this post
-
12-07-2021, 04:02 PM #3
Have an airport near by?
-
-
12-07-2021, 04:06 PM #4Screaming And Flying!
- Join Date
- Jan 2004
- Location
- Los Angeles Cal.
- Posts
- 4,831
- Thanks (Given)
- 2
- Thanks (Received)
- 405
- Likes (Given)
- 3032
- Likes (Received)
- 5318
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
170 psi cranking on a 2.5 25° timing should be good at 95.5 to 96 octane. Been running that mixture for years with no problem. Mix avgas with pump premium or 110 race fuel with pump premium, works for me.
-
12-07-2021, 04:24 PM #5
VP110 is rated up to 12:1 compression. Not sure what 170 works out to but if thats not enough go higher
https://vpracingfuels.com/product-category/marine/Hydrostream dreamin
-
12-07-2021, 05:35 PM #6
-
Instigator liked this post
-
12-07-2021, 05:35 PM #7
-
12-07-2021, 06:50 PM #8
Two stroke “compression ratio” doesn’t jive with what the fuel companies talk about for four stroke engines.
like said above…..go to the airport and get some 100LL and you’ll be plenty safe for 25-26 degrees of timing. For the most part, Any engine is going to make its most power on the lowest octane fuel you can run before detonation so if you want to get picky you might pick up a few mixing down to 96 octane or so. In my experience the gains aren’t worth the risks so I’d rather be over and safe…just my opinion…
'95 STV "The Blue Goose"
-
-
12-07-2021, 07:22 PM #9Screaming And Flying!
- Join Date
- Jan 2004
- Location
- Los Angeles Cal.
- Posts
- 4,831
- Thanks (Given)
- 2
- Thanks (Received)
- 405
- Likes (Given)
- 3032
- Likes (Received)
- 5318
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
If you want to know how to compare your 2.5 two-stroke in automotive four stroke engine terms like 10:1 compression ratio. Go online and look at compression ratio explained, however in my opinion doing that on your two stroke would be a waste of time.
As far as mixing goes. 2.5 gallons of 91 pump premium = 227.5 + 2.5 gallons of 100 aviation fuel = 250 Total they equal 477.5. Divide that total by number five because it’s 5 gallons = 95.5 octane.
-
12-07-2021, 10:39 PM #105000 RPM
- Join Date
- Oct 2015
- Location
- Kentucky lake
- Posts
- 480
- Thanks (Given)
- 31
- Thanks (Received)
- 6
- Likes (Given)
- 15
- Likes (Received)
- 60
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
The Air port I work at sells 100LL .I get to smell it burning in Airplanes all day long.. Smells great !! Right now it's 6.00 a gallon. I use it all the time in my boats/ ATVs /Sport Bike love it !!
-
Capt.Insane-o liked this post
-
12-07-2021, 10:47 PM #11
I ran 100ll av for years at 175-180 psi.
-
H2OPERF liked this post
-
12-07-2021, 10:54 PM #12Supporting Member
- Join Date
- Apr 2003
- Location
- New Smyrna Beach, FL./LOTO
- Posts
- 6,645
- Thanks (Given)
- 606
- Thanks (Received)
- 923
- Likes (Given)
- 1699
- Likes (Received)
- 7151
- Mentioned
- 3 Post(s)
- Tagged
- 1 Thread(s)
It has a much better shelf life to. I run it everything that isn't used on a weekly basis and I put hundreds of gallons thru my X motors over the years.
Joe
-
12-07-2021, 11:09 PM #13Screaming And Flying!
- Join Date
- Jan 2004
- Location
- Los Angeles Cal.
- Posts
- 4,831
- Thanks (Given)
- 2
- Thanks (Received)
- 405
- Likes (Given)
- 3032
- Likes (Received)
- 5318
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
-
12-07-2021, 11:18 PM #14
-
12-08-2021, 08:18 AM #15Screaming And Flying!
- Join Date
- Jan 2004
- Location
- Los Angeles Cal.
- Posts
- 4,831
- Thanks (Given)
- 2
- Thanks (Received)
- 405
- Likes (Given)
- 3032
- Likes (Received)
- 5318
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Similar Threads
-
Compression And Fuel
By seansbaja1982 in forum Technical DiscussionReplies: 24Last Post: 08-20-2019, 12:33 AM -
2.5 compression and fuel
By ActivatedSludge in forum Technical DiscussionReplies: 12Last Post: 10-07-2012, 03:32 PM -
Compression And Fuel
By seansbaja1982 in forum Technical DiscussionReplies: 1Last Post: 08-01-2012, 12:26 AM -
Fuel/compression/timing
By 850cc racer in forum Technical DiscussionReplies: 5Last Post: 11-02-2011, 07:59 AM -
Compression / fuel
By JTS Racing in forum Technical DiscussionReplies: 9Last Post: 07-29-2002, 06:29 AM