hey i was just wondering if anyone knew.....if im turboing my rx7 13b would i want to run my motor rich or lean? i was talking with a guy the other day and he said that you must run rx7's very rich in fuel...anyone know what the common a/f ratio should be if doing so?

 

Let's start by saying that tuning any engine is a fairly complex issue. If you're tuning a turbocharged rotary at WOT, you'd probably want to be no leaner than 11.5:1. Some might suggest that you be even richer than that.

 

what is rich 12.1-14.7....i herd from an old guy that it should be around 12.5 and i said holy **** thats wayy too rich....any suggestions? 11.8 sounds good normal turbo runs 11.8-12.1 WOT...

 

12.1-14.7 would be lean. It's Air/Fuel ratio ie. number of parts of air per part of fuel. 12.1 A/F ratio would be 12.1 parts of air per part of fuel.

 

the safe mixture is based on a bunch of different things.



1. fuel octane

2. boost

3. air intake temps

4. oil and water temps

5. egt

6. etc etc



if you have a good intercooler, cool water and oil temps, moderate boost 10psi, 12.5 might be ok



but if you've got a small intercooler, and run 12+psi on a small turbo, it needs to be richer, they run it in the high 10's stock for that reason

 

14.7:1 means 14.7 grams of air to 1 gram of fuel. Not "parts". That seems to be a universal term which means absolutly nothing.

 

Air fuel ratio is the mass of air in a mixture to the mass of fuel in a mixture. You can use whatever units of mass you like. I'm fine with the term "parts" as long as we understand that its parts by mass and not parts by volume.

 

the closer you are to 1:1 the richer you are at Idle you should see 14.8 +-.2 and WOT depending on boost and other factors I don't like anything leaner then 11.1+-.2