Octane and Boost (no meth)
Octane and Boost (no meth) How much octane is good for how much boost? I.e 91 octane up to Xpsi, 93 octane up to Xpsi, and 101 octane up to Xpsi? What do you guys think? Any rule of thumb? No meth in the equation?
I'd say it would be tough to develop a rule of thumb. I've see both 93 and E85 up to and over 30psi making anywhere from 1200 to 1400rwhp. It all depends on the set up.
Way too much of a loaded question. There are just too many variables to say X octane with support Y psi. The possibility of talking about this is on a complete stock car and a specific make/model head unit.
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Need to look at a few extra factors
1) static and dynamic compression
2) IAT and intercooler choice
3) timing
4) AF
5) Turbo or SCing
6) trans type and converter (if auto)
For example you can run easily 15#s boost or more on 8:1 comp with pump gas if things are setup right.
1) static and dynamic compression
2) IAT and intercooler choice
3) timing
4) AF
5) Turbo or SCing
6) trans type and converter (if auto)
For example you can run easily 15#s boost or more on 8:1 comp with pump gas if things are setup right.
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9 Second Club
Joined: Feb 2002
Posts: 985
Likes: 7
From: Lake Orion, MI
You won't scrape by on 89 octane. So you run the highest that you can get on a regular basis and tune to it. Then you don't have to worry about what's in your tank when you hit the track. Rick
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How about tuning the car on 101 octane pump from that shell on 63rd/western and not go WOT in it when putting around on the street on 91 oct? Do that and don't fool with meth...would that be a feasible option?
so let me get this straight, You are telling me that you can roll around with the potetial of 700hp and not have the temptation to wack it just once? LOL! We all know that you will jump on it at least once and we all know it will detonate and kill itself in a matter of seconds. I for one do not have that kind of discipline! JMHO
LOL, just a thought! As little as this guy drives this car - I'd just get it tuned on 101 and run it all the time. Either spend the money on 101 all the time or meth when you need it. Or tune on 91 and see if you can hit seven hunge. Or you could be like some of the import crowd and tune on a 'blend'...like half 91 and half 101...and run that all the time to save a lil dough, and when you're gonna be out at the track or out flogging on it when its really hot out, run straight 101 to be on the safe side.
Last edited by Photochop; Feb 11, 2009 at 03:05 PM.
That is like playing Russian Roulette with 6 rounds in the chamber.
Haha, well the real debate in my mind is between 93 and 101, but you have a good point, I RARELY drive it. 101 will be right around $104/tank from empty, which isn't bad, assuming 1 tank a month.
Need to look at a few extra factors
1) static and dynamic compression No, idea, it is a 9.5:1 motor
2) IAT and intercooler choice - 80*, twin 4.5"s
3) timing - 20*
4) AF - 11.0 - 11.2
5) Turbo or SCing - D1-SC
6) trans type and converter (if auto) - 4L60E w/PI 3200 triple disc
For example you can run easily 15#s boost or more on 8:1 comp with pump gas if things are setup right.
1) static and dynamic compression No, idea, it is a 9.5:1 motor
2) IAT and intercooler choice - 80*, twin 4.5"s
3) timing - 20*
4) AF - 11.0 - 11.2
5) Turbo or SCing - D1-SC
6) trans type and converter (if auto) - 4L60E w/PI 3200 triple disc
For example you can run easily 15#s boost or more on 8:1 comp with pump gas if things are setup right.
TECH Apprentice
Joined: Sep 2004
Posts: 377
Likes: 0
From: Kona, Pearl Ridge
why not just use the same timing table as your 93 tune in your 110 tune and just up the boost. SD tuned and crank the boost when your tanks got the good stuff and keep 6-8 lbs on the low stuff. How fast do people really need to go on a daily basis anyways? I could live with 1 night a week on the 110 
if im tuned for speed density @9 psi on 91 octane(whats around here) could i throw in 110 and upp the boost a couple lbs w/o touching the tune?
also... if im at 600hp on 91 at 9 psi and i put in a tank of 110 w/o upping the boost or messing w/ the tune will i feel a noticable performance difference (approx how much rwhp would i be looking at?)
thanks, Gary
also... if im at 600hp on 91 at 9 psi and i put in a tank of 110 w/o upping the boost or messing w/ the tune will i feel a noticable performance difference (approx how much rwhp would i be looking at?)
thanks, Gary
I've found that gas can be different between fill ups which is very unsafe when you are running on the ragged edge. I have pushed mine a little but it is usually at night when it's really cool out. i have found that 3rd gear in my t400 right when i shift is when it may start to knock. this is because of the load on the engine.
anyway i can run around 14 psi in good conditions on 91.
anyway i can run around 14 psi in good conditions on 91.