What is the ideal A/F ratio???
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Joined: Oct 2001
Posts: 154
From: Stationed at Camp Lejeune, N.C. (But Going Home SOON!)- From New Jersey
I read (on ths board) that 12.7:1 is suppose to be the best A/F for Fuel injected cars. But on the Dyno the cars that I tuned made the most power with 13.1:1.
I was not running any Nitrous on these cars at the time, but I would think that it would be the same on or off.
The biggest problem with Nitrous is when you runn lean!
If you tune your car "off" the juice and than tune it "on" the juice and get the car about the same on and off- you should be doing well.
The only problem I ran into is tuning a Ram Air car on the Dyno. I tuned a Ram Air car on the Dyno and got the A/F Ratio where It made the most power(and perfect for the Juice) and than on the rosd it leans out. This is because you can not truely compensate for the air at higher speeds. The Cure that I am going to use- is to permanettly mout a WB O2 with display in the car and adjust the A/F Ratio on the road.
But that's just my opion- There are many Nitrous "experts" on the board that might be able to help you more. That's my 2 cents.
I was not running any Nitrous on these cars at the time, but I would think that it would be the same on or off.
The biggest problem with Nitrous is when you runn lean!
If you tune your car "off" the juice and than tune it "on" the juice and get the car about the same on and off- you should be doing well.
The only problem I ran into is tuning a Ram Air car on the Dyno. I tuned a Ram Air car on the Dyno and got the A/F Ratio where It made the most power(and perfect for the Juice) and than on the rosd it leans out. This is because you can not truely compensate for the air at higher speeds. The Cure that I am going to use- is to permanettly mout a WB O2 with display in the car and adjust the A/F Ratio on the road.
But that's just my opion- There are many Nitrous "experts" on the board that might be able to help you more. That's my 2 cents.
We tune for 12.5:1 for SC or nitrous and 11.5:1 for both. You also have to consider the conditions that you tune under v. the expected worst conditions the vehicle will operate under. There is a lot more O2 content on a cool, dry day with a high barometric pressure.
A little leaner makes a little more hp but may cost a lot more $$$. Remember, fuel makes hp, not nitrous. Nitrous is just another source of oxygen. You need fuel in excess of stiochiometric to be sure each O2 molecule has enough time to find a fuel molecule to oxidize. Excess fuel also cools and slows the combustion process which may inhibit detonation. This also costs a bit of power, but it is safer.
Rich Krause
A little leaner makes a little more hp but may cost a lot more $$$. Remember, fuel makes hp, not nitrous. Nitrous is just another source of oxygen. You need fuel in excess of stiochiometric to be sure each O2 molecule has enough time to find a fuel molecule to oxidize. Excess fuel also cools and slows the combustion process which may inhibit detonation. This also costs a bit of power, but it is safer.
Rich Krause
I will be tunning the car on the juice in the dead of a South Florida winter (i.e..70 degrees probably fairly high pressure). I do want to be very conservative since the car is driven mostly in summer (90 degrees, low pressure, and humidity in the 90% range at least). What do you guys think will be a conservative range to aim for? I am thinking about 12.1. On the motor the car is tunned for 13.1, not sure that helps much.
Thanks guys!!!
Thanks guys!!!
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