Octane road test
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Don't know about L98s, but when the LT1 stock program detects knock it goes into "low octane mode" where it pulls a significant amount of timing and the car runs like crap under WOT. Stays in that mode until you restart the car. I could definitely see someone saying that it feels like it is missing in that situation.
There is no such "optimal" octane for all 10.25 cars. You can make a 10.25 engine in so many ways that it could be optimized at 85 or 105. For starters, DCR is what matters, not SCR.
In most cases, what matters is not SCR or DCR, or any engine parameter, but rather what octane the _tune_ was optimized for.
91 is considered optimal (although often hard to find) for a 10.25:1 car.
In most cases, what matters is not SCR or DCR, or any engine parameter, but rather what octane the _tune_ was optimized for.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by CFI-EFI
You guys didn't read the opening post very carefully.
His complaint wasn't of knocking or detonation, which can be caused by low octane, but one of missing, which has nothing to do with octane. It was an invalid test with a Bubba conclusion.
RACE ON!!!
His complaint wasn't of knocking or detonation, which can be caused by low octane, but one of missing, which has nothing to do with octane. It was an invalid test with a Bubba conclusion.
RACE ON!!!
He didn't say it was missing.
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
Originally Posted by Vis Croceus
There is no such "optimal" octane for all 10.25 cars. You can make a 10.25 engine in so many ways that it could be optimized at 85 or 105. For starters, DCR is what matters, not SCR.
In most cases, what matters is not SCR or DCR, or any engine parameter, but rather what octane the _tune_ was optimized for.
2. its a no sh!tter that you can build an engine with a wide range of outcomes. this has nothing to do with the OP.
3. the owners's manual says premium, and when our cars were built, "standard" premium meant 91 octane. 93 is overkill for a 10.25:1 stock car which includes factory tolerance stack. 91 is conservative, takes that into account, as well as being in any altitude in the country with a road.
So apparently you didn't read the OP carefully.
He didn't say his engine was "built" with a set of parameters different than stock.
Last edited by Red Tornado; Nov 7, 2006 at 12:05 AM.
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by Hot Rod 90
1. i didn't see anything in the OP or his profile that indicated anything other than a factory, stock setup. who was talking about "making an engine"?
Originally Posted by Hot Rod 90
91 is considered optimal (although often hard to find) for a 10.25:1 car.
Assuming that the OPs car is stock then 91 is optimal for his car.
Guess you didn't read your own post carefully...
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Vis Croceus
You didn't read the OP very carefully.
He didn't say it was missing.
He didn't say it was missing.
Originally Posted by Bubba91
So, a couple of weeks ago I got a full tank of 87octane gas(sunoco). The vette ran like crud(like it was missing a cylinder).
RACE ON!!!
