[Longun]

I've got a F31 340i with a stage 2+ setup and what I think might be a very rare map.

The car is mapped in a way where by I have stock power in ECO/Comfort and 480(ish) in Sport/Sport+.

I need to stick a stock cat back on for the MOT but I'm tempted to leave it fitted and get an aftermarket exhaust. I like the idea of having a legal car setup this way with a nice exhaust thats not crazy loud as the CAT will take the edge off.

I'll have to get it remapped with the stock cat back on. Couple of questions off the back of this.

Any idea of rough power loss? I'm thinking 20-30bhp?

I'd need to get the pops removed as they'll kill a stock CAT. Any recommendations on settings like duration etc on the stock CAT?

If I was to remap with MHD or BM3 do either have the ability to save the existing map before hand? I've no clue how this map works but want the ability to go back if I change my mind.

Can I even put a map overtop with either of the above tools?

Tempted to take it back to the place that mapped it originally to keep this setup on the mode buttons as its neat but its a long old drive to get it over to them.

[ABall]

Originally Posted by Longun

I've got a F31 340i with a stage 2+ setup and what I think might be a very rare map.

The car is mapped in a way where by I have stock power in ECO/Comfort and 480(ish) in Sport/Sport+.

I need to stick a stock cat back on for the MOT but I'm tempted to leave it fitted and get an aftermarket exhaust. I like the idea of having a legal car setup this way with a nice exhaust thats not crazy loud as the CAT will take the edge off.

I'll have to get it remapped with the stock cat back on. Couple of questions off the back of this.

Any idea of rough power loss? I'm thinking 20-30bhp?

I'd need to get the pops removed as they'll kill a stock CAT. Any recommendations on settings like duration etc on the stock CAT?

If I was to remap with MHD or BM3 do either have the ability to save the existing map before hand? I've no clue how this map works but want the ability to go back if I change my mind.

Can I even put a map overtop with either of the above tools?

Tempted to take it back to the place that mapped it originally to keep this setup on the mode buttons as its neat but its a long old drive to get it over to them.

MHD user here, you cant save an existing map but yes you can put one over the top as you say, it clears the existing and re writes a new map. Stage 2 requires a sports cat, no idea on the power loss but its probably more because your limited with a stage 1 on a stock CAT, there may be people running stage 2 with stock CATs but I dont think its recommended. As far as pops go, MHD has 2 options, I have set mine to OEM, you wouldnt get anything on that setting with a stock exhaust and down pipe but because I have MPPSK and a sports CAT (400 CELL) OEM is perfect, you get little burbles on lift off at very slow speeds and pops are rare. If I wanted to stop them completely I believe the way is to enable them then slide the dials down to zero. You cant do what they have done with OTS maps, If they have linked the power increase to comfort and sport as you say then you cant do that with an OTS map in MHD, you would set the multi maps to the steeering wheel buttons and select a percentage of reduced power on the map position of your choice. I wanted control so I went with OTS, I can enable/disable cold start when I want, control the valves on the backbox and switch stuff around at my leisure, Im waiting for the cold start option to be integrated into the multi map but we have been waiting a while for that one, its been in the making for a long time.

When you use MHD a tuner can just send you update files that you can load yourself in the custom option, no idea on cost but it means you dont need to go back. If you dont use XHP on the transmissison then the gear box can limit power, MHD works with XHP, you set the transmission to manual, I dont think BM3 has that option.

Another option I like with sticking to OTS is I can change the Octane setting sat in a petrol station if I cant get Momentom/Shell 99.

[sunnys1ngh]

The jump from stock to stage 1 is more noticable then stage 1 to stage 2.
A stock cat on stage 2 will give increased egt and prob be slow and give timing errors. But if it can be run on stock cat. Id like to know because its good to be legal on the road. Mot are harder now. Loopholes closed
Stage 2 does make more heat may melt cat.

I ran stage 1 with mhd. Burbles i set to 0.5 duration in sport and medium. Sounded good.

On stage 2 running similar in sport. 0.3 duration in comfort. Ovs with decat it pops more.

To your question about feeling less power compared to stage 1. Low speeds like 0 to 60 not as much on road, as wheels are spinning more. But higher speeds it just flies.

[rossm]

Will damage the cat long term, just get it remapped and use MHD multimap to retain the power switching functionality, you just hold down the LIM button on the steering wheel and select the map, you can have up to 4

I use 95 ron comfort no burbles in slot 1, slot 2 is 98 ron no burbles, slot 3 98 ron with a few burbles and slot 4 is stock power, but you can set the power as a percentage eg 60% through to 100%

[ABall]

Originally Posted by sunnys1ngh

The jump from stock to stage 1 is more noticable then stage 1 to stage 2.
A stock cat on stage 2 will give increased egt and prob be slow and give timing errors. But if it can be run on stock cat. Id like to know because its good to be legal on the road. Mot are harder now. Loopholes closed
Stage 2 does make more heat may melt cat.

I ran stage 1 with mhd. Burbles i set to 0.5 duration in sport and medium. Sounded good.

On stage 2 running similar in sport. 0.3 duration in comfort. Ovs with decat it pops more.

To your question about feeling less power compared to stage 1. Low speeds like 0 to 60 not as much on road, as wheels are spinning more. But higher speeds it just flies.

You dont need a stock CAT to be legal, you just need one that will pass an MOT. I wouldnt run stage 2 on a stock CAT, I had an email chat with MHD, I asked if it would be ok to run stage 2+ with my Active Autowerk sports CAT, (400 CELL) they said NO! They said they design MHD on a catless down pipe, they didnt say they designed stage 2 plus on one so im guessing all there performance figures are based on 200 or less CELL. I would guess they would say the same for stage 2, dont forget an increase in boost wont just damage the CAT it could damage the turbo if theres too much back pressure.
Its been reported MHD have said stock CAT is OK with stage 2 as long as you dont drive too hard, nothing about burbles, things change with stock higher HP cars, they already have very good flow. Perhaps if you go fully open exhaust post CAT it would be fine but I like the option of quiet mode. Oh and ive just noticed MHD HAVE implimented cold start per map so I can turn that on when I leave the house!

[TurboWeasel]

Originally Posted by Longun

I'd need to get the pops removed as they'll kill a stock CAT.

Pops and bangs kills the turbo as well.

They aren't a controlled burn like combustion. As the name suggests, it's exploding fuel in the exhaust manifold. The shock and violence of that shatters cat converter matrices and turbo CHRAs, hence why you see so many Stage 2+ Golf Rs blowing blue smoke.

I think you will appreciate a calmer and smoother life with a cat and no bangs. Your local residents will probably thank you for it as well.

[Solenoidal]

Originally Posted by TurboWeasel

Pops and bangs kills the turbo as well.

They aren't a controlled burn like combustion. As the name suggests, it's exploding fuel in the exhaust manifold. The shock and violence of that shatters cat converter matrices and turbo CHRAs, hence why you see so many Stage 2+ Golf Rs blowing blue smoke.

I think you will appreciate a calmer and smoother life with a cat and no bangs. Your local residents will probably thank you for it as well.

Agreed. Pops and bangs just screams yob and chav to me.

The MPPSK setup is just perfect, not too much and not too little. Just right.

Although a sports cat might be on the books in the near future, looking at a 300 cell from HJS. The price I’ll worry about in the future