blownC6

Do you guys think 11:1 is too much for Arizona(we have 91 octane gas and 110F summer days are common)? I'm about to buy some AS 5.3's and I'm deciding on the compression ratio to go with. I know the LS6 runs 10.5:1 with no problems, and Jay told me he could go as low as 10.8:1 with the 5.3's. I'd like to run 11:1, just wanted to see what you guys thought. Thanks.

Damian

iTrader: (89)

It will GREATLY depend on your tune how much compression you can run. Being in AZ and only using 91 octane, I would go on the safe side and run 10.8:1. The difference wouldn't even be 5 HP between that and 11:1, and it'd be worth the security. Not really worth it when you take a step back and realize it'd only be a couple more HP and more risk of detonation....JMO


josh

4thGENRETARD

It depends hot and dry or hot and humid?? The higher the humidity the less chance of detonation (Kinda like a water injection. Also depends on your timing.

blownC6

Damian
Thanks for the information Josh; this is exactly what I was looking for. As you can see from my choice of cam(TR220), I'm not looking to set any hp records, just to have a dependable daily driver with same extra teeth. Looks like the 10.8:1 is gonna be my choice. It was tuned after the cam install and will be tuned again after the heads go on. The shop is local(Xtreme Motorsports) and they understand I'm not looking to push the envelope with the tune.


4thGENRETARD
I'm in Arizona so it would be seriously dry , thanks.

Pro Stock John

iTrader: (34)

I'd stay 10.5:1, with the double limitation of the heat and the 91 octane you don't want problems.

JZ'sTA

iTrader: (23)

Id move.......
J/KI live in some shatty weather myself during the summer.
However we do have 93 octane at every gas station.

2001CamaroGuy

iTrader: (6)

I have been running 11.1:1 CR for the past year without any problems. I would run a gallon or two of 100 unleaded (in a full tank of 91) durring the summer if I was going to go out "hunting" on Bell but other than that I just ran straight 91. One guy I know is running 11.2:1 and another had 10.8:1.

AZ isn't that big of a deal 90% of the year if you have the car set up to run cool (colder T-stat, fans set lower, etc...). The only real time I had problems was August (and thats a no duhhh).

blownC6

LOL, I remember one summer about 15 years ago or so, it got up to 122(no BS) that would have been the summer to move.

2001CamaroGuy
We have to run Sunoco 110 in my son's goped(15:1 comp) and I usualy buy it 5gal at a time so it would be easy enough to buy extra to mix with the 91 during the hottest months. I do run a 178 stat, redline water wetter, and the fans are set to come on at 194 and 204.


Thanks to all for your input, I ordered the AS stg2 5.3’s today.

2001CamaroGuy

iTrader: (6)

I run straight distilled water and water wetter (no need for the "anti-freeze" out here ) and have my fans set to come on about 170 and 180.

SSEUL8R

Could a guy run 93 octane with 11:1 without problems?

4thGENRETARD

Antifreeze is also a coolant in the Summer. you would get better results with a 50/50 mix and water wetter.

2001CamaroGuy

iTrader: (6)

it says right on the bottle "for better cooling in non-freezing environments, run straight water and water wetter"

I started doing this and the car runs cooler than it did with 50/50 and water wetter

blownC6

Yep, the water wetter works better with no antifreeze. When I first used it I had a 50/50 mix of water and antifreeze, didn't see much of an improvement. I then went with 20% antifreeze(don't need much protection in Arizona) 80% distilled water and 2 bottles of water wetter, the result was about 10 degree cooler temp.

Here's a link to Redline's tech data on Water Wetter, interesting reading. http://www.redlineoil.com/redlineoil/wwti.htm

verbs

10.8:1 here and 91 Octane....I run a bigger cam though which helps bleed off some of the compression so I don't have to worry as much. WOT all day long when its 115 degrees and no problem

I personally wouldn't run 11:1, but if I did I'd mix a little 100+ octane gas like 2001CamaroGuy said.

I'd also recommend an EWP.