safe psi on 93 octane??
#1
Evolved Member
Thread Starter
iTrader: (41)
Join Date: Nov 2005
Location: Joplin, MO
Posts: 557
Likes: 0
Received 0 Likes
on
0 Posts
safe psi on 93 octane??
my question is 22-23 psi to mucH? I run 93 octane only unless the gas station has closed which they close at 10 pm so sometimse i cant make it there to get gas. So if i do have to fill up with 91 i usualy just put like 5 bucks in till the next day i can get some 93. WOuld it be alright to set it to 22-23 psi if i dont jump on the throttle with the 91 oct in there? Thanks for the help
Matt
Matt
#4
Evolving Member
Join Date: Feb 2006
Location: Virginia
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
Pump gas limits you to how much boost you can run. I have an 03 TB Evo w/stock turbo, 9.8 hotside and w/my mods and a custom tune, i don't run anymore than 22PSI on a warm day. You can get away w/running 23PSI on 93 but that's pushing your turbo. 21PSI is safe, 22PSI is ok.
#5
Evolved Member
iTrader: (1)
Join Date: Sep 2004
Location: Chicago
Posts: 1,121
Likes: 0
Received 0 Likes
on
0 Posts
It all depends on how you are tuned. 21-23 psi is the average on 93 octane. It depends on how much timing you run, knock count, intake temp and so on. I could run 24-25 psi safely if i really wanted to.
#7
Originally Posted by 03redtype-s
my question is 22-23 psi to mucH? I run 93 octane only unless the gas station has closed which they close at 10 pm so sometimse i cant make it there to get gas. So if i do have to fill up with 91 i usualy just put like 5 bucks in till the next day i can get some 93. WOuld it be alright to set it to 22-23 psi if i dont jump on the throttle with the 91 oct in there? Thanks for the help
Matt
Matt
Since you seem to be fairly cautious, here is one accepted school of thought:
Turning up the boost should be done in concert with doing something to lower the intake charge air. In otherwords, to simply turn up the boost is a hack's way of gaining power. Adding a higher octane (you're low on both grades at your altitude), a larger IC, upgraded fuel delivery system (Walbro helps a little on stock injectors), water/alky, etc are all ways of reducing your cylinder temps.
I didn't see anything in your mods about a cooler range of spark plugs. That's an easy first step to help gaurd against detonation - as to whether it will help with both kinds of knock, I forget at the moment. It looks to me like you could run an "8" range plug.
The manual recommends 98 oct (right ?) so you are starting out somewhere below the recommended octane but since you are a little higher than sea level, you're equivalent need is slightly less.
(However I'm not certain where they determined the fuel requirement, but it was likely at sea level.)
Altitude - affects - Air Pressure - affects - Cylinder Pressure - affects - Cylinder Temps - affects - your wallet if you get it wrong.
You also don't list a Wide Band in your mods, so if you are looking at running raised boost, that would be a consideration.
I said "all that" to make you think a little, now I'll tell you that I'm running 93 at 5280 ft and I'm ok at 23 psi, but that doesn't mean you will be. The guy from NJ in the above post is at a lower altitude than you, but to assume you'll be ok too without knowing more about the individual car (mod differences) seems risky to me - he might be right - but there also may be more factors to consider (does he have upgraded injectors, larger IC ? he has a larger turbo than you, so I don't think he is on stock injectors - just a guess- didn't do the math )
Check things out a bit more, True ,there is a certain amount of safety built into the stock set up, just don't be in the dark about how it will affect your car by changing things.
Good Luck
Thread
Thread Starter
Forum
Replies
Last Post
03redtype-s
Evo Tires / Wheels / Brakes / Suspension
22
May 12, 2007 05:15 PM
03redtype-s
Evo General
37
Jun 26, 2006 10:56 AM