[NNJCarGuy]

I'm looking into exhaust options and the new Dinan x-pipe. I started thinking, how hard would it be to have my local shop make one for me?

Here is just one of many x-pipes I found on the net during a quick search.

https://www.summitracing.com/parts/mpe-10792

Can someone with experience chime in here with your opinion? I realize the Dinan has great looking welds however beyond that why would my idea be bad/ good? Obviously I don't want any codes or check engine lights and definitely don't want any drone. The x-pipe will ensure no drone when compared to going with straight pipes?

Thanks in advance!

[Boosted_8]

My car is having one fabricated as we speak. I opted for an X rather than straight pipes for two reasons. Firstly it has a chance of making a little of bit power with the pulse overlap pulling gasses from each bank. Secondly It sounds smoother and is less likely to cause an annoying resonance at certain RPM.

[NNJCarGuy]

Thank you! That's the exact feedback I was in search of. Getting mine done in a week. Please keep me posted as I will.

[choppedliver]

I spoke to a few exhaust shops and most just make their own. Where I got mine done they had pre-made stainless ones on the shelf and they were the cheapest. Also did x-pipe for same reasons as Boosted_8.

[NNJCarGuy]

Originally Posted by choppedliver

I spoke to a few exhaust shops and most just make their own. Where I got mine done they had pre-made stainless ones on the shelf and they were the cheapest. Also did x-pipe for same reasons as Boosted_8.

I appreciate the confirmation, looks like I'm making the smart choice here.

[Superjackson]

The dinan one is not just an x-pipe, it's an entire midpipe that is wider than stock (3" vs 2.75"). That would cost a lot more to make than just fitting in an x pipe, although an exhaust shop can still make it for half the price of the dinan midpipe.
Also, you don't need to worry about drone if you still have mufflers.

[choppedliver]

Originally Posted by Superjackson

The dinan one is not just an x-pipe, it's an entire midpipe that is wider than stock (3" vs 2.75"). That would cost a lot more to make than just fitting in an x pipe, although an exhaust shop can still make it for half the price of the dinan midpipe.
Also, you don't need to worry about drone if you still have mufflers.

I spoke to my exhaust shop and the euro cars use 2.75” so the entire x-pipe and replacement piping on mine is 3” as that is more common. I also got the x-pipe set towards the back in case I want to put a resonator back after doing catless downpipes later on.

Cost $350 AUD.

[NNJCarGuy]

Originally Posted by choppedliver

I spoke to my exhaust shop and the euro cars use 2.75” so the entire x-pipe and replacement piping on mine is 3” as that is more common. I also got the x-pipe set towards the back in case I want to put a resonator back after doing catless downpipes later on.

Cost $350 AUD.

Should I be requesting 3" over the 2.75", is there an advantage?

[choppedliver]

Originally Posted by NNJCarGuy

Should I be requesting 3" over the 2.75", is there an advantage?

It won’t do any harm. I’m in Australia and they said they either had 2.5” or 3” pipes and didn’t carry the euro sizes. You may find the same in the US.

[Boosted_8]

Originally Posted by NNJCarGuy

Should I be requesting 3" over the 2.75", is there an advantage?

This is just my opinion as I haven't tested on this vehicle but have on other platforms.

If the rear muffler is the bottle neck at 2.75", larger piping beyond the downpipe attached to the turbo doesn't really change pressure across the whole system.

On an NA car it can help with harmonics to run a larger midpipe after the headers collector at certain RPM but I wouldn't expect any HP on a turbo.

I don't know exactly what the impact on sound or tone is but I would guess based on other experiences, off boost the larger mid pipe makes more gargles and is deeper in tone.

[NNJCarGuy]

That is good information and my hunch too, thank you.

[Boosted_8]

Well, the good news is the exhaust shop made me a lovely X pipe. It sounds refined and high end. No rasp, drone or unwanted resonance. However, I am throwing a CEL and limp mode at half throttle 3000rpm. I can reproduce it without fail. Low throttle and full throttle is fine. I suspect its the OPF pressure sensor in open loop ECU mode picking up a new pressure value after the filter. I have a new OBD scanner coming tomorrow to check for sure. If so I will need to spend a bit more money on the OPF sensor jackers from Germany to stop it from limping. I suppose on the bright side this means that the X did lower pressure across the system and make some power.

[NNJCarGuy]

Thanks for the follow up! No rasp nor drone, sounds good to me! I'm sure you'll figure out the blip. I just flashed my car with the bootmod3 stage 1 on 93 octane. Can't wait for the exhaust work to complete the job.

[Boosted_8]

I'm running a damn EU spec 2021, completely tied up with ECU and emissions BS

[choppedliver]

Originally Posted by Boosted_8

Well, the good news is the exhaust shop made me a lovely X pipe. It sounds refined and high end. No rasp, drone or unwanted resonance. However, I am throwing a CEL and limp mode at half throttle 3000rpm. I can reproduce it without fail. Low throttle and full throttle is fine. I suspect its the OPF pressure sensor in open loop ECU mode picking up a new pressure value after the filter. I have a new OBD scanner coming tomorrow to check for sure. If so I will need to spend a bit more money on the OPF sensor jackers from Germany to stop it from limping. I suppose on the bright side this means that the X did lower pressure across the system and make some power.

That sucks. I’ve not seen anyone else report this, but then again I’m not sure if any of them are 2021s.

[Boosted_8]

Bimmerlink confirms its the OPF leak error code causing limp. The internet tells me quite few M2 Comp owners with EU spec OPFs have the same issue with any exhaust changes.

The good news is I have a mitigation measure on the way from Deutschland, hope to test it out next week postman permitting. If it works out, hello downpipes and bye bye OPF...

[BolomM550i]

Here's what I did to my car.... X-Pipe, resonators delete
https://g30.bimmerpost.com/forums/sh....php?t=1780816

[NNJCarGuy]

Originally Posted by BolomM550i

Here's what I did to my car.... X-Pipe, resonators delete
https://g30.bimmerpost.com/forums/sh....php?t=1780816

Your shop did a great job!

[BolomM550i]

Originally Posted by NNJCarGuy

Your shop did a great job!

Thanks - not exactly DINAN or REMUS quality, but I'm super happy with it.

[Boosted_8]

Forgive the 'hand under the car blind' photo but here's the X I had made. All mandrel bent with some nice welds. Sorted the CEL out with the LEIB engineering OPF plugs as well.

[Lancelot]

Originally Posted by Boosted_8

Forgive the 'hand under the car blind' photo but here's the X I had made. All mandrel bent with some nice welds. Sorted the CEL out with the LEIB engineering OPF plugs as well.

Looks good! How much was it? (Not including OPF plug)
Thanks

[Boosted_8]

I paid £700 for the work. This is the company that produced it: https://www.jpexhausts.co.uk/bespoke-custom-exhausts