[dakotap80]

Hi all! I've been running MHD stage 1+ on my car for about a year now, and its been great. I'm thinking of switching to a catless downpipe so I can run Stage 2+ but I've heard all the horror stories about how much that job sucks on an xDrive N55. Just wondering if anyone has gone from Stage 1+ to Stage 2+ and how much of a difference you noticed? If its not a huge improvement like going from stock to Stage 1 I think I'll just save the myself the time and money and not do it. Thanks!

[GrannyShiftG80]

I'm actually doing this exact change on Wednesday. I'll let you know how it goes and how much the install runs me.

[dakotap80]

Great, thanks! I'll be DIYing for sure if I do end up doing it.

[ttthai]

I went from JB4 to mhd2+, I noticed a slight difference in power. I used to run JB4 on map 2 or that learning map, i forget the number. I feel more comfortable with a flash tune rather than a piggy back.

[mweisdorfer]

Originally Posted by dakotap80

Hi all! I've been running MHD stage 1+ on my car for about a year now, and its been great. I'm thinking of switching to a catless downpipe so I can run Stage 2+ but I've heard all the horror stories about how much that job sucks on an xDrive N55. Just wondering if anyone has gone from Stage 1+ to Stage 2+ and how much of a difference you noticed? If its not a huge improvement like going from stock to Stage 1 I think I'll just save the myself the time and money and not do it. Thanks!

I can't speak for the N55. I can say there is a noticeable difference on an N54.

[Achappell8]

I went catless and stage 2 after about a year in the car. 100% worth it unless you don't like smiling.

[dakotap80]

Allenssmart, how did the install go/how does the car feel now?

[mweisdorfer]

Originally Posted by dakotap80

Allenssmart, how did the install go/how does the car feel now?

Get 3"SS catless downpipes made by MMP.

If your o2 sensors are 100k or older replace them.

https://mmp-e.com/collections/produc...2008-2009-2010

Easy install.

[924er]

For me, stage 2 to stage 2+ was a huge difference and I'm running 91 lol

[GrannyShiftG80]

Originally Posted by dakotap80

Allenssmart, how did the install go/how does the car feel now?

Had it installed for $300 canadian dollars (227 USD). They told me it was a pain in the ass as expected. Took them 2.5 hours of labour. Car sounds pretty amazing now. At highway speed normal driving there is no drone, and it basically sounds the same as a stock downpipe which is incredible.

Give it a little bit of gas and you can really hear the difference. Exhaust is a lot more throaty and it the car is louder during acceleration but nothing like a fart cannon. I really enjoy it. MHD burbles also get A LOT louder.

Somehow I don't know what happened but my MHD cable either broke or I fucked something up and now I can't flash my car to stage 2 from 1+, but even without a tune I can feel a big difference with my butt dyno.

The turbo spool sound is about 4x louder, I thought I had a boost leak the first time I accelerated.

One downside though, wastegate rattle is a lot louder.

I haven't noticed any difference in smell.

[dakotap80]

Originally Posted by Allenssmart

Had it installed for $300 canadian dollars (227 USD). They told me it was a pain in the ass as expected. Took them 2.5 hours of labour. Car sounds pretty amazing now. At highway speed normal driving there is no drone, and it basically sounds the same as a stock downpipe which is incredible.

Give it a little bit of gas and you can really hear the difference. Exhaust is a lot more throaty and it the car is louder during acceleration but nothing like a fart cannon. I really enjoy it. MHD burbles also get A LOT louder.

Somehow I don't know what happened but my MHD cable either broke or I fucked something up and now I can't flash my car to stage 2 from 1+, but even without a tune I can feel a big difference with my butt dyno.

The turbo spool sound is about 4x louder, I thought I had a boost leak the first time I accelerated.

One downside though, wastegate rattle is a lot louder.

I haven't noticed any difference in smell.

2.5 hours doesn't sound bad at all, I was just worried because I had seen some posts saying it took 6-8 hours and the subframe had to be dropped. Thanks for your advice, hope you get the flashing issue figured out!

[joshe92]

You should be doing catless downpipes for your exhaust note, benefits of mhd 2+. you need an intercooler (suggest vrsf 5'" stepped). Shop around for the install, go to someone that knows how to do it. Should be 2-350

[mweisdorfer]

Originally Posted by joshe92

You should be doing catless downpipes for your exhaust note, benefits of mhd 2+. you need an intercooler (suggest vrsf 5'" stepped). Shop around for the install, go to someone that knows how to do it. Should be 2-350

Downpipes aren't hard to install. The hard part is getting the old cats off, if they are rusted to the exhaust flange. Nothing a Sawzall with a carbon tipped Diablo Blade can cut off in literally 2 min.

You can DIY them on Jack stands.

You don't even need to take out the O2 sensors out prior to removing the Cats. You just gotta be more careful to not break them when pulling them out between the subframe & engine block. At least that's what I'd do, if the O2 sensors weren't coming out after a few pulls. It's easier to put the cat into a vice and then pull it out, if need be.

Biggest thing is replacing the flange bolts & nuts with grade 8 ones and a lot of Nickel based anti-seize.

The v-clamps on the other end can be a little tedious at a times; you should take a picture of their locations regarding the bolts. The main thing there is that they don't interfere with the wastegate moving.

[GrannyShiftG80]

Originally Posted by dakotap80

2.5 hours doesn't sound bad at all, I was just worried because I had seen some posts saying it took 6-8 hours and the subframe had to be dropped. Thanks for your advice, hope you get the flashing issue figured out!

dunno what the flashing issue was, i just tried it a few days later and it worked. now i'm stage 2+ i can really feel the power difference. definitely worth!!

[mweisdorfer]

Originally Posted by Allenssmart

dunno what the flashing issue was, i just tried it a few days later and it worked. now i'm stage 2+ i can really feel the power difference. definitely worth!!

The DME is very sensitive. To flash it without hick-ups, you really need at least a 30amp battery charger/ maintainer. 60-70amp is even better but they tend to run $200.00 or so.

You can't open doors, turn stuff on/off etc. the lights, radio & air should all be off.

I'd say to even wait until the water pump gets done cycling coolant in/out of the turbos after driving too.

Any sort of power surge with flashing MHD & the DME doesn't like it.