[Autoaddict]

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Guys a question, I’m leaning more towards a mid pipe as it gives a nice deep sound without the breaking the bank. But which option is better, the mid pipe or full exhaust? And which one gives more of a HP/TQ gain? Or is it the same increase for both options? I just saw Valvetronics full equal length exhaust which looks pretty slick, but is it really worth it compared to just a mid pipe mod? Thanks.

[Scorviss]

I have the PSI midpipe on my car and love it, great sound and no drone, I originally looked at full systems but haven’t needed any louder sound. From my understanding for the most HP you’d want to look at downpipes instead of a full catback, though at this power level you really won’t notice a 10ish HP boost (unless you’re planning on tuning then that’s a separate conversation)

[AhsanU]

Depends on your downpipe situation and what you plan on doing with them.

If keeping stock downpipes, then an aggressive axle back paired with a midpipe will make for some loud fun. If going catless or 200 cell catted downpipes, then keep the axle back stock as it helps a tremendous amount with drone - ask me how I know.

The greatest amount of hp/tq gain will be from going catless downpipes. Any performance gained from a catback system will not be noticeable at all. Weight savings from the axle back is decent but again.. depends on what your goals are and downpipe situation.

[mike@x-ph.com]

It depends on your budget; a full exhaust offers a better sound upgrade.

But if your budget does not allow it, the midpipe offers a significant improvement

You can also start with a midpipe and decide if you need to get the rest of the exhaust.

[forcefed]

Originally Posted by Autoaddict

I just saw Valvetronics full equal length exhaust which looks pretty slick, but is it really worth it compared to just a mid pipe mod? Thanks.

Lol no, go with a midpipe first, or if you want to save some more $$$ get an exhaust shop to cut out the secondary cats and resonators for around $3-400.

[Info@mad-us.com]

Originally Posted by forcefed

Lol no, go with a midpipe first, or if you want to save some more $$$ get an exhaust shop to cut out the secondary cats and resonators for around $3-400.

Definitely don't cut up your stock midpipe. Most people aren't every happy with it and end up buying our midpipe spending more in the long run.

Our midpipe has the deepest sound when used with a stock rear and stock downpipe.

https://mad-us.com/mad-bmw-g8x-m3-m4...race-included/

[Autoaddict]

Originally Posted by Scorviss

I have the PSI midpipe on my car and love it, great sound and no drone, I originally looked at full systems but haven’t needed any louder sound. From my understanding for the most HP you’d want to look at downpipes instead of a full catback, though at this power level you really won’t notice a 10ish HP boost (unless you’re planning on tuning then that’s a separate conversation)

Thanks. I think I’m going to go with the PSI mid pipe. The sound has nice deep tone. Also, as you noted no drone. I just can’t see spending a ton of money on a full cat back exhaust system when the sounds are nearly identical. Also, I’m going to keep the stock down pipes. The MAD down pipes are nice, but holy hell, they’re loud.

[LuckyBrand]

Adding a new rear can doesn't add as much volume as one would think but in the asthetics department it really cleans up the back end of the car and just completes the package. Their are better ways to add volume but just depends on your goals for the car overall.

[mike@x-ph.com]

Originally Posted by LuckyBrand

Adding a new rear can doesn't add as much volume as one would think but in the asthetics department it really cleans up the back end of the car and just completes the package. Their are better ways to add volume but just depends on your goals for the car overall.

I did the downpipes, midpipe, and axle back separately.

Each upgrade adds volume on its own, but it's not a huge difference until you have 2 of the three mentioned.

[Nado]

Originally Posted by AhsanU

The greatest amount of hp/tq gain will be from going catless downpipes. Any performance gained from a catback system will not be noticeable at all. Weight savings from the axle back is decent but again.. depends on what your goals are and downpipe situation.

Unless the OP is wishing to do an actual tune, I dont think DPs are going to yield any real positive results. It definitely wont with the stock DME, and I dont think they are really adding anything with a piggyback. It looks like DP need an actual tune to get results.

Please correct me if I am wrong, as I cant seem to find any dyno plots stating otherwise.

[Info@mad-us.com]

Originally Posted by Nado

Unless the OP is wishing to do an actual tune, I dont think DPs are going to yield any real positive results. It definitely wont with the stock DME, and I dont think they are really adding anything with a piggyback. It looks like DP need an actual tune to get results.

Please correct me if I am wrong, as I cant seem to find any dyno plots stating otherwise.

We spoke about this in another thread but the jb4 with everyhing connected will yield power with a downpipe the other "tuning device" was just adding boost on top of ecu's boost target. Ecu flash will always be king but it's not an option for everyone.

[Nado]

Originally Posted by Info@mad-us.com

We spoke about this in another thread but the jb4 with everyhing connected will yield power with a downpipe the other "tuning device" was just adding boost on top of ecu's boost target. Ecu flash will always be king but it's not an option for everyone.

Hello - yes we did. Im just still looking for proof that is the case. Im searching for some dyno charts, etc...

[Info@mad-us.com]

Originally Posted by Nado

Hello - yes we did. Im just still looking for proof that is the case. Im searching for some dyno charts, etc...

I'll look through my vendors dyno sheets. What are you looking for
exactly jb4 stage 2 and a catless downpipes?

[Nado]

Originally Posted by Info@mad-us.com

I'll look through my vendors dyno sheets. What aree you looking for
exactly jb4 stage 2 and a catless downpipes?

Pretty much, yes. Im out there looking and just havent ran across anything. Its always been, an E tune, full tune, or dps and midpipe, or dps and exhaust,etc...

Seems like no one has done a JB4 map 2 with stock DP vs aftermarket DP. Which to me is very hard to believe. Someone has to have done it