Guest Mikey Posted May 21, 2007 Share Posted May 21, 2007 It's true...East of the Missippi, the gasoline has 93 Octane instead of the 91 Octane that we have out West. We discovered this fact to be true while driving round trip to Bowling Green two weeks ago.So...How many horsepower does my 400hp LS2 engine loose by using our 91 octane? I realize that we can use any octane rating we want and the computer will retard/advance the spark accordingly, however, doesn't that process involve a loss of ponies? I didn't notice any difference in the "Giddy-up Factor", so I assume the difference to be fairly small. BTW...We paid $3.02 a gallon for the 93 octane!! Link to comment Share on other sites More sharing options...
Eddie44 Posted May 21, 2007 Share Posted May 21, 2007 My guess would be you wouldn't loose enough to notice unless it was put on a dyno. Maybe 0-5 HPBTW, I'm not a scientist but I did stay at a Holiday Inn Express last night Link to comment Share on other sites More sharing options...
Guest Kens06 Posted May 21, 2007 Share Posted May 21, 2007 It's all in the tune!!The factory tune is so fat [rich] that you won't have any problems with knocking which pulls timing!!Now when you start modding, you have to get the fuel and timing tables adjusted, i.e. a tune!!Ken Link to comment Share on other sites More sharing options...
knkayotte Posted May 21, 2007 Share Posted May 21, 2007 Only time I put 93 octane in my C5 was when the wife and I drove to see the BIL in Texas. I did notice a seat of the pants difference, but he lower altitude probably had a bunch to do it with it as well. 93 octane at near sea level altitude felt like a good 20-30 hp difference, it was quite noticeable! Even the wife commented on how much faster the car felt.Also been to Lompoc CA (only 91 octane) which is at sea level as well. Didn't feel as quick as it did in TX with the 93 octane. I'd say the temps and humidity were about the same in TX and CA, probably slightly higher humidity in CA.What sad is were paying the same for 91 octane as those guys are paying for 93 octane. Could of really used the 93 octane with my S/C Toyota. Link to comment Share on other sites More sharing options...
Guest Kens06 Posted May 21, 2007 Share Posted May 21, 2007 I thought we have already been through this...............Higher octane has a lower flash point.........A lower flashpoint means the fuel ignites quicker.........If the fuel ignites quicker and the timing hasn't been set to fire earlier in the power stroke, you don't burn all the fuel and lose power, not gain!! Now you have more hydrocarbons for your cats to burn and lower their life cycle!!Pig rich factory settings and a lower DA would have given you the same feeling with 91!!Ken Link to comment Share on other sites More sharing options...
knkayotte Posted May 21, 2007 Share Posted May 21, 2007 I thought we have already been through this...............Higher octane has a lower flash point.........A lower flashpoint means the fuel ignites quicker.........If the fuel ignites quicker and the timing hasn't been set to fire earlier in the power stroke, you don't burn all the fuel and lose power, not gain!! Now you have more hydrocarbons for your cats to burn and lower their life cycle!!Pig rich factory settings and a lower DA would have given you the same feeling with 91!!Ken"Higher octane has a lower flash point........."Ken, it's the exact opposite! Higher octane = higher flash point which means it tolerates higher temps and burns slower. Do a quick Google search on this....I'm right. Reason you want it in higher compression vehicles and with forced induction, it won't pre-detonate on you causing treaded PING. C5 and C6's were designed to run 93 octane (higher compression and more aggressive timing then your average car) , they compromise their computer settings to run on lower octane crap (usually backing out some timing). Being at a lower altitude gave me denser air then at 3-5k feet where I normally drive. 93 octane allowed the car to run a more aggressive timing map (which C5 were designed to do) which all equated to more power. Having said that, you shouldn't run higher octane in daily drivers like Toyota's, Tahoe's, etc. These vehicles were designed for 87 octane and run at much lower compression (for the most part). Running higher octane in low compression engines leads to carbon residue and your cats working a lot harder then they need to burning off the fuel that didn't burn off in the combustion cycle (due to higher flash point of the fuel).Couple links to back me up: Octane InfoOctane Info Link to comment Share on other sites More sharing options...
ChadC Posted May 22, 2007 Share Posted May 22, 2007 oooohhhhhh SNAP! Ken you just got Burrrrend Link to comment Share on other sites More sharing options...
nort99 Posted May 22, 2007 Share Posted May 22, 2007 oooohhhhhh SNAP! Ken you just got BurrrrendThere goes another 12 pack. Link to comment Share on other sites More sharing options...
MOTV8 Posted May 22, 2007 Share Posted May 22, 2007 Some good info there. My bike (not one, but four 40mm Keihin carbs...) and 12.2 to 1 compression doesn't like this 91 swill in AZ, but runs like a scalded ape with the VP 101! And Uvettya has me in the habit of adding some 101 to the 'vette before a track day apparently for the WOT mapping. Does anyone know how much, if any, horsepower/lb-ft of torque you can theoretically pick up with race gas? Every tenth is sacred, so why not add the good stuff? Edit: Got curious and went to VP's website, depending on which race gas of the bazillion they sell they are claiming like a 5 to 10% increase in horses over pump gas. "Which is nice...." - Carl Spangler, Bushwood Country Club Asst. Greenskeeper Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now