Anyone had to re-tune A/F ratio after cutout install?
03-10-2003, 05:21 AM
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Anyone had to re-tune A/F ratio after cutout install? I've heard that an open cutout would cause the car to run a bit lean but I don't know by how much. Any one experienced such thing?
TIA <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />
TIA <img border="0" alt="[burn out]" title="" src="graemlins/gr_burnout.gif" />
03-10-2003, 02:32 PM
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Re: Anyone had to re-tune A/F ratio after cutout install? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Cal:
<strong> Is the cuttout installed before or after your cats? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No cats. Also there are no rear O2 sensors to worry about. I guess the only difference would be the exhaust back pressure. Would a difference in back pressure change A/F ratio?
<strong> Is the cuttout installed before or after your cats? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No cats. Also there are no rear O2 sensors to worry about. I guess the only difference would be the exhaust back pressure. Would a difference in back pressure change A/F ratio?
03-10-2003, 07:39 PM
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Re: Anyone had to re-tune A/F ratio after cutout install? Unless you have a squirrel caught in your exhaust then you are not going to see any significant difference in the a/f when you open and close your cutout.
Even if you do have a significantly restrictive exhaust (ie Flowmaster series 80) and you open your cutout, the a/f is not going to shift more than 0.1 air:fuel point. (ie 12.8 to 12.9)
Not a big deal. I wouldn't bother getting it retuned.
The only guys that I recommend that come in for a check/tune after installing cutouts are the turbocharged cars.
Good Luck,
Kevin
Even if you do have a significantly restrictive exhaust (ie Flowmaster series 80) and you open your cutout, the a/f is not going to shift more than 0.1 air:fuel point. (ie 12.8 to 12.9)
Not a big deal. I wouldn't bother getting it retuned.
The only guys that I recommend that come in for a check/tune after installing cutouts are the turbocharged cars.
Good Luck,
Kevin
03-14-2003, 12:45 AM
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Re: Anyone had to re-tune A/F ratio after cutout install? Here is my dyno with QTEC open vs closed...you can see the A/F actually gets a pinch richer with it open. <img src="http://www.netlinkapplications.com/aaron/images/dyno2lg.jpg" alt=" - " />
