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I have a stock 2015 E63S with the M157 engine. I am wanting a little more throatier exhaust note and am considering a RENNtech tune to achieve it. I am not interested in a lot of crackling, popping nor a constant overly loud exhaust sound, just a little huskier than stock. I'm planning on the ECU tune and then either the RENNtech downtubes and/or the RENNtech mufflers. I'd appreciate any comments from those who have experience with a RENNtech tune. Of particular interest is downtubes versus mufflers - one or the other or both? I notice that the RENNtech Stage 1 tune includes their mufflers but not the downtubes.
You could also remove the exhaust resonator and replace it with an H-pipe if you just want a little more exhaust sound; any reputable exhaust shop can handle doing the work.
A tune will not make the exhaust notes any louder unless you get a burble tune in which you said you are not looking for. So the best and most economical way without breaking your bank is to get a resonator delete with straight pipe. Its the best $200 you will spend to get more V8 sound out of your beast.
Catless downpipes paired with any setup will be really loud. The Renntech sport mufflers with stock downpipes is not too loud at all. I have a resonator delete with stock mufflers, stock cats & in my opinion its a tad louder than the Renntech mufflers. The Renntech mufflers are deeper & bassy sounding, while the resonator delete sounds just like stock but louder & definitely makes cracking noises every time I shift at redline.
Last edited by BiturboSF; Dec 12, 2020 at 03:01 AM.
I figured that the ECU tune alone wouldn't really impact the exhaust note. I actually started my line of thinking with the RENNtech downpipes might get me the improved exhaust note. And then I thought as long as I was going to install the downpipes, I might as well do the ECU tune as its not invasive, so it became a no-brainer add-on to the pipes. But then I saw the RENNtech R2 package which includes the RENNtech mufflers but doesn't include the downpipes and it threw my thinking a little off course. So now I'm debating whether to do the R2 package or stick to the original plan of downpipes+ECU tune.
I figured that the ECU tune alone wouldn't really impact the exhaust note. I actually started my line of thinking with the RENNtech downpipes might get me the improved exhaust note. And then I thought as long as I was going to install the downpipes, I might as well do the ECU tune as its not invasive, so it became a no-brainer add-on to the pipes. But then I saw the RENNtech R2 package which includes the RENNtech mufflers but doesn't include the downpipes and it threw my thinking a little off course. So now I'm debating whether to do the R2 package or stick to the original plan of downpipes+ECU tune.
If you have the money to spurge go for the R2 package. Also, to keep in mind when installing the Downpipes the installer will need to drop the engine to get it in I believe.
Thanks for all the advice, the R2 package is looking more attractive. It should certainly be less invasive than the downpipes, however my quote for the downpipes included just 4 hours of labor to remove and replace so I'm not thinking that they'd be dropping the engine in that amount of time. And it's from the local RENNtech Euro Automotive shop here in the Dallas area, so I'd like to think they are familiar with the effort. But you do make a point that it would be a bit more intrusive than the ECU tune, mufflers, airbox and high performance filters would be. When I called RENNtech with some questions, they told me they were out of stock on their CF airbox though due to COVID issues in manufacturing and shipping (they are made in Europe and there's currently a carbon fiber shortage). But that should hopefully improve in 2021.
Renntech only sells catted downpipes currently, and I think that might give a louder exhaust than there mufflers, the engine doesnt need to be dropped for this.
Their mufflers as mentioned above arent loud and change the tune mostly. I think a R1 pack with their catted downpipes would be nice package. I dont believe they support or will make a tune for a complete catless downpipe any longer if you wanted even louder, only catted but I may be wrong.
Here's the info I managed to find about the RENNtech downpipes: "Our performance downpipes replace the restrictive stock exhaust with high flow, 200 cell sport catalytic for improved performance, greater exhaust gas volume and better sound.
Combined with RENNtech's ECU software, our downpipes create an incredible sound with performance to match.
Our downpipes mate perfectly with the stock Mercedes Benz AMG exhaust system and include all necessary mounting hardware and clamps. High strength 304 stainless steel construction with high flow, 200 cell catalytic ensure lasting quality and a rich, consistent sound."
So you're right in that they are catted and they at least suggest that the exhaust note will be improved. It was this description that led to my initial plan of getting the downpipes together with an ECU tune.
My local RENNtech installer also suggested, that since this plan would greatly improve the exhaust output capability, I should also add a high performance air filter to improve the air intake capacity to match (although the RENNtech CF airbox is quite pricey, but there are alternatives).
If you have the money to spurge go for the R2 package. Also, to keep in mind when installing the Downpipes the installer will need to drop the engine to get it in I believe.
Motor does not have to come down. The m157 has mini downpipes that connects to turbo and then the longer downpipes. Replacing the little ones require engine drop, the longer downpipes does not
Motor does not have to come down. The m157 has mini downpipes that connects to turbo and then the longer downpipes. Replacing the little ones require engine drop, the longer downpipes does not
they're called Bridge Pipes.
On the AWD cars, the front sub-frame(at the least) must be dropped, but most people just drop the subframe/eng/trans all together to get it done.
On RWD cars, the Bridge Pipes can be installed with the motor in place.
Last edited by nota_amg; Jan 24, 2021 at 12:57 PM.
I detect from your message that you might could be kinda happy with the result. I'd be interested in your impressions of the ECU+ tune. Did you have RENNtech do the tune or a local Indi shop? Does the ECU+ tune impact all driving modes, e.g., including the comfort mode? Or just the S+ and AMG modes? Did you notice much impact to your gas mileage?
I'm planning on doing the R1Package (which has the 638 HP ECU tune) together with the RENNtech downpipes in February.
I can't really offer a review yet....just installed the tune yesterday. This is the ECU+ HHT. It's a "canned' tune loaded on a OSBll dongle....along with the stock tune so you can switch back and forth. Took 2 minutes to load the tune. Took the wagon out...tooled around to get everything warmed up...headed over to a quiet 1/2 mile stretch of road near my house and experienced one of those great Holy S##T moments. Really tickled the butt dyno. My only other mod is an airbox spacer. Not intending to do any other hardware mods, except intercoolers, (famous last words), I just wanted to wake the engine up a bit and Boy! did this do it. Will report again after more time in the saddle.
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