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This subject confuses me. When I first got my 03, I did a baseline dyno run with no mods whatsoever. The A/F on that run had a hump at 3,000 RPM's where A/F hit 13:1. That's the stock computer and 3,000 RPMs is where a lot of driving happens.

With the chips and tunes, we try to targed low to mid 11's. But I know that the more lean the tune, the more power is made.

Like everyone else, I wouldn't want to run a dangerously lean mixture just to make more power...it's not worth the risk.

But I'm wondering if 13:1 really consititutes a dangerous A/F mixture.

The latest 5.0 Mag has the Kenne Bell article. This is a direct and exact quote out of that article:

"While the 451 peak horsepower reading was OK, nearly the rest of the power curve came with a dangerously lean air/fuel mixture. Up high, at peak power, the stock electronics in the Cobra had the A/F ratio at a respectable, power-producing 13.5 to 12.5:1. But in the lower rpm ranges, the A/F ratio was a scary 16:1. Obviously, we needed to richen the bottom of the fuel curve..."

This section of the article describes what happened to the Kenne Bell prototype vehicle (Randy's car) with a Lightning pulley, Bazooka test inlet tube and no chip.

Can an article in 5.0 Magazine done by experts be THAT off-whack? I'm thinking it's correct and accurate information.

The article declares that 13.5 to 12.5 A/F ratio is "respectable and power-producing". This also supports what I have been told by a tuning expert.

In our chips, we target 11.5 to 1 A/F. Is this ULTRA conservative to the point of paranoia in order to avoid problems?

I like the idea of a conservative A/F tune, but not if it is unnecessary and costing me 40-50 RWHP!

Isn't 12.5:1 conservative and safe enough? And wouldn't it yield at least 20 RWHP more than 11.5:1?

Many of us have tunes in our car from the extreme heat of summer (that was the time when we got the chips and tunes). Now, in the extreme cold of winter, the air is cold and more dense. A/F goes way lean - we saw it over and over again at the last dyno day. But many of us have been running those same summer tunes all winter. Has anyone had a problem? Anyone notice any pinging or detonation? I have not. But I have noticed that my car feels like it's 50 RWHP stronger than it did in the summer. Is that because of the cold air or because of the change in A/F due to the summer tune run in the winter?

I've also seen some cars have EXTREMELY rich tunes - like 10:1 A/F. I know that either extreme is dangerous. At too lean, you risk detonation. At too rich, your mixture is too thin and you end up with cylinder wash - which ruins ring seal in the cylinder.

Anyway, I just wanted to initiate a discussion about this subject. What REALLY constitutes safe a/f range? Because we all want to be safe but not sacrifice HUGE amounts of RWHP by being overly paranoid in the tune.
 

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Hey Hammer head, :) Jim bell is correct , BUT tuners need to tune in the 11.4-11.8 range , other wise people will be blowing ther shet up. I run lean and mean, but I aloways need and run good fuel.
bottom line is street cars- 11.8- 12.2 is super fine.
weather has a big part in this, so a little higher in af will be fine in cold weather.
As long as NO PING :shocked peace
 
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I agree Hammer....

Just run good fuel and check the a/f here and there. That way the car is producing as much power possible without spilling its guts:vomit:

Hot Rod(I too run lean and mean with 100 octane fuel)Harry
Of course things change when the spray comes into play :D
 

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Harry , Do you work or what , :rolleyes:
 

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My tune has me running 11.5 at the tail pipe.

According to a post from a few days ago the tailpipe reading is consistantly .6-1 leaner than a bung reading.

Sooooo....after reading this post here's what i'm thinkin'. My true a/f reading would be between 10.9 and 10.5.....which means; I am way to safe on a/f, givin' up some hp because it's burning so fat, i'm makin' those plugs work to burn all that fuel being dumped on em', and.......obviously getting my moneys worth out of that rediculous gas guzzler tax I paid.:) :) :)
 

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Pete's right I like it in the low 11's because when we added fuel (around12.0) the cars slowed down. Also at 12.0 with this gas you will be at 13.0 a/f. Better keep them safe.

Rick
 

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I'm assuming you're all talking about the wide band reading, at the tail pipe during the dyno run.
 

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OK, dumb question time. A lot of people seem to be running lean with mild mods. I have a catted x, catback, and CAI. Should I be worried about leaning out. I sure can't afford to break anything. Any advice? T
 

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TxSnake said:
OK, dumb question time. A lot of people seem to be running lean with mild mods. I have a catted x, catback, and CAI. Should I be worried about leaning out. I sure can't afford to break anything. Any advice? T
From what I have seen if you have an early build(1st run) car you may be OK.....but If you have a second run car you should get it checked.

I have a second run YDHO (PCM code) car and with a CAI, K&N, L pulley and cat back it was WAY lean.

It's cheap insurance to do a dyno pull with a/f to be sure.
 

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4sfed. I really don't like the tailpipe method. To many things can cause a bad reading. I do all my programs with a wide band in a bung right after the header on drivers side. If you really want to be sure use this method, because 7&8 go lean first and a tailpipe is an average of all 8 cyl. The main thing with these cars is good gas. 3.10 pulley guys should be fine unless there tuner likes to run the car around 12.0 and above a/f.
Txsnake I don't think they use winter gas in your area so you should be fine.

Rick
 

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Thanks for the info guys. My car is YDHO, but I feel a lot better now after reading Rick's post. :) He seems to be the man with the plan on tuning these things. Trmn8r, I have no plans on a pulley but I am curious how lean you were. T
 

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TxSnake said:
Thanks for the info guys. My car is YDHO, but I feel a lot better now after reading Rick's post. :) He seems to be the man with the plan on tuning these things. Trmn8r, I have no plans on a pulley but I am curious how lean you were. T
I don't have the dyno sheets here at work but I was around 14.5-15 at WOT with a tail pipe sniffer.

I only gained 5 peak hp with the chip tune but gained 68 tq and 15 hp at 2600 rpms. The biggest thing the chip did was get my a/f down to 11.5.
 
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