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Logan #34's Dad
08-09-2009, 05:28 AM
Can someone tell me what octane of fuel performs the best if you have around 140 psi for compression? I know that somewhere someone broke it down.
I know if it is too high you can double ignite.
Thanks
08-09-2009, 05:47 AM
Ron Kersey always told me to get Turbo Blue and mix it 50/50 with 93 octane. Thats the best fuel mixture as far as I know. Just what Ive been told Rocky.
Team-Ty
08-09-2009, 06:41 AM
140 isn't high at all I run 114 with my sons, only reason he is at 227 psi. 140 is fine to run with 93 anything higher will not help only hurt.
LT80
08-09-2009, 07:08 AM
150 is my target and 105 octane ran the best.
Team-Ty
08-09-2009, 09:11 AM
http://www.qrckarts.com/store/index.cfm?
fuseaction=product.display&Product_ID=313 (http://www.qrckarts.com/store/index.cfm?fuseaction=product.display&Product_ID=313)

Found this if it helps
08-09-2009, 10:51 AM
Nice Go Cart info,
Team-Ty
08-09-2009, 11:34 AM
Yeah but the chart at the bottom has compression ratio to octane recommendations which relates to his question
riding4fun
08-09-2009, 12:05 PM
Originally posted by Team-Ty
Yeah but the chart at the bottom has compression ratio to octane recommendations which relates to his question

OK, I'm a dummy. what compression does 11:1, 12:1 and 13:1 equal in terms of compression.
wvspeedfreak
08-09-2009, 12:37 PM
Originally posted by riding4fun
OK, I'm a dummy. what compression does 11:1, 12:1 and 13:1 equal in terms of compression.

Compression ratio is the relationship of cylinder volume (or displacement) with the piston at BDC to cylinder volume with the piston at TDC. If the volume of the cylinder with the piston at BDC is 10 times greater than the volume of the combustion area with the piston at TDC, then 10 units of volume get squeezed into 1 unit of space, and the compression ratio is 10.0:1. There are five factors that affect compression ratio: cylinder swept volume, clearance volume, piston dome or dish, head-gasket volume, and chamber volume.
riding4fun
08-09-2009, 12:47 PM
Speak English Jason. LOL
OK so what octane should I use if my motor is at 190 psi
08-09-2009, 01:45 PM
Originally posted by Team-Ty
Yeah but the chart at the bottom has compression ratio to octane recommendations which relates to his question

I meant nice chart not beeing a smart ***. Its neat to actually see what you should use. Thanks for your post.
wvspeedfreak
08-09-2009, 01:54 PM
Originally posted by riding4fun
Speak English Jason. LOL
OK so what octane should I use if my motor is at 190 psi

I can't take credit for that....I copied and pasted it.I thought you were asking what the actual numbers represented in compression ratios :p

I would run 110 octane.
rookiewrench
08-09-2009, 02:28 PM
Where's I-Zapp when you need him!
Team-Ty
08-09-2009, 02:39 PM
well if you guys want me to go in depth with compreson ratio let me know here is the formula

http://www.rbracing-rsr.com/compstaticcalc.html

actually I found this that might help you guys seems to be more user friendly then me just spitting out the formula.
Team-Ty
08-09-2009, 02:41 PM
riding4fun I would run 110 octane.
riding4fun
08-09-2009, 04:14 PM
Sorry to keep going with this but would running an octane that is lower than it should be make it run hot or hotter than normal.
LT80
08-09-2009, 05:30 PM
Originally posted by riding4fun
Sorry to keep going with this but would running an octane that is lower than it should be make it run hot or hotter than normal.

Hot! (at the wrong time) LOL
It'll cause detonation. Sorta like advancing the timing big time.
A hole in the top of the piston will follow. :)
Ryko racing
08-10-2009, 12:43 PM
140 psi turbo blue or any 100 octane 50/ 50 w sunoco prem 93

we have dynoed many engines and found this works best most of the time.