Anyone notice less mpg once they put their exhaust on? I swear my mds doesn't come on as much as it used to with my mbrp system? I'm wondering if the lack of back pressure on my mbrp system is hurting my mpg? Anyone noticed this?
Since I put my K&N drop in filter with my 18' Magnaflow muffler, plus grounding my throttle body. I have better throttle response plus my MDS comes on sooner and stays on alot more. As with any combustion engine you just have to make it breathe. My next mod is to do away with the funky Y pipe!
Yep, grounding the throttle body, it sets in plastic. The intake is plastic and the intake hose coming in from the airbox is plastic. Grounding the throttle body helps clean up the signals to the PCM, seeing how everything is drive by wire. Found out about this on another forum and gave it a try, quicker acceleration and tranny has smoother shifts and doesn't hunt for shifting points as much. Ran a #12 ga wire from throttle body to body ground on passenger side by the hood hinge. For about $5 it is the cheapest mod you can do.
On this grounding of the throttle body, aren't there a couple of extensive threads on this subject already posted elsewhere on the forum that came to the conclusion that there was no effect at all with this mod. I haven't done it, but some of the posters were some long-time, knowledgeable folks who came to this conclusion. Might be worth checking out. I know one of these longer posts was on the 5.7 custom mods section.
On the MDS not engaging as easily with a modded exhaust, I haven't noticed a change since doing a Borla muffler on mine. It stll goes into MDS exactly the same. I've even been surprised that it will engage occasionally while pulling a travel trailer on the slightest downgrade when the tow/haul mode isn't engaged.
I am an electronics tech with a govt agency and have extensive knowledge and years in the electronic field, I did see a differance in throttle response and tranny response, like I have said, for $5 you can't go wrong. I am not going into a tit for tat on this, all I said is it has worked for me.