for mods see sig. i have a DP, MP, and greddy SP. I just replaced the MP with the rx7store one (which is awsome btw) because the MP was just way to loud and ive noticed im actually running quite a bit leaner. Im tuned pretty rich, but at around 4000-5000 rpm my max AFR was around 15-15.9 and now its going almost up to 18-18.9

Im also running with no filter on the turbo... new one is coming in a few days... and I know i run concideably leaner, but it wasnt as much. I thought i would run richer with the rx7store MP.

comments? oppinions? input?

 

It shouldnt run any leaner. The resonated pipe is just a midpipe with a straight thru muffler on it.

 

That seems to be a strange problem, Jason is right though, there should not be a difference. What are you using for engine management??

 

Is the pipe ID larger on the Rx7 Store midpipe??

 

Resonated pipes are often more efficient that plain pipe. This is because the dimple effect of the perforations reduces friction to flow. The effect is quite pronounced and easy to see on a flow bench. I have tested 2-1/2" resonator cores that will outflow an equivalent length of 3" pipe.

There are also dynamic tuning effects that result from the changes to the pressure wave front as a result of damping (at the resonator).

Bottom line is that leaner = better scavenging, which is a usually a good thing and a good indicator of the exhaust system performance.

One other thought: what is being used to measure AFR's? One must be aware that any leaks in the exhaust can introduce air and cause AFR's to appear leaner than they are. (As can the operation of an air pump.)

 

If you are running 15a/f at 5000rpm at wide open throttle I'm surprised you haven't poped your motor yet. That is way too lean. But the midpipe shouldn't affect your a/f ratio.

R.K.

 

I have the PLX 300-m wideband...... i welded the bung on the resonated MP where it use to be on the straight MP.... is there any calibration or anything i have to do?


Also... right now i have GReddy SP1... i want to switch to racing beat duals for noise. Is that a really bad idea? to much restriction? because the noise is still excessive.

T04R
Streetported motor
PFC
all supporting mods

 

WTF

tuned pretty RICH @ 15.9:1?




aren't you the same guy that overheated his engine to 350*F?

 

yea.. found out that was a sensor problem... it "wtf"-ed me too.... but yea.. it went up to like 210F


well at idle my AFRs were around 10.5, which is nothing close to lean

and also notice the "but" in the first post

 

15.9:1 is really lean... 10.5:1 is rich

 

i am aware of that