craigdiver
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| posted on 26/2/18 at 10:15 PM |
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exhaust porn
Want this look on my straight-6 BMW haynes roadster but need to accomodate 2x O2 sensors (one on each bank of 3 cylinders), any ideas?
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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Nickp
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| posted on 27/2/18 at 07:10 AM |
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Seems ambitious, who are you paying to make that for you? 
I'm pretty sure the O2 sensors wouldn't work right. Each one takes a reading of the mixture for those 3 cylinders and adjusts the fueling
accordingly. You could line one up just after cyl3 and that may work OK but the other will be reading all 6cyls so I don't see it working right
and may not even pass emissions.
I'm happy with my 6-2-1. Works correctly, sounds amazing and cost peanuts to make 
[Edited on 27/2/18 by Nickp]
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theduck
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| posted on 27/2/18 at 07:37 AM |
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Why do you need 2 o2 sensors? I assume you are on aftermarket management? You should be fine running one o2 sensor that reads all 6
cylinders.
Not sure why there would be an issue with emissions...
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Nickp
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| posted on 27/2/18 at 07:39 AM |
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quote:
Originally posted by theduck
Why do you need 2 o2 sensors? I assume you are on aftermarket management? You should be fine running one o2 sensor that reads all 6
cylinders.
Not sure why there would be an issue with emissions...
I use the BMW management (remapped) which uses 2 sensors (for 1-3 and 4-6). I think he's planning to do similar.
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theduck
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| posted on 27/2/18 at 07:45 AM |
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oh i see, i assume the OEM ecu has some kind of trim table then to adjust for the banks running differently. In which case you could probably get
away with running them both reading all 6 cylinders. In fact, you could possibly even get away with running 1 and splicing the signal to both inputs
on the ecu. Or switch to aftermarket management and just run 1 wideband
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nick205
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| posted on 27/2/18 at 09:05 AM |
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That is certainly a rather tidy looking fabrication!
Do you know what car it's on?
I'm guessing something where the exhaust system is fairly visible and it enhances the overall look of the vehicle.
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craigdiver
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| posted on 27/2/18 at 11:38 AM |
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It does look good but I agree probably not sensible due to the likely cost and issue with the O2 sensors. This exhaust system was on a V12 with this
exhaust mirrored on each side.
The OEM ECU had 4 O2 sensors - 2 before and after the cat on each bank of 3 cylinders. The ECU has been altered to delete various things including the
post cat sensors to make the engine usable without ABS etc.
These engines with dual-vanos (variable valve timing on both inlet & exhaust) are tricky setting up with aftermarket engine management.
[Edited on 27/2/18 by craigdiver]
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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coyoteboy
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| posted on 28/2/18 at 03:12 PM |
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It's also a dodgy header design - it's basically just a log with long runners.
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Mr Whippy
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| posted on 1/3/18 at 07:03 AM |
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oh lovely....if your are a fan of chitty chitty bang bang
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craigdiver
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| posted on 1/3/18 at 07:58 AM |
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Original post is how I imagine it would look fabricating it myself, how it would actually turn out..... ;-0 :-)
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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Mr Whippy
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| posted on 1/3/18 at 08:33 AM |
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WTF take that for an SVA....
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AntonUK
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| posted on 1/3/18 at 04:17 PM |
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reminds meof this work of art
Build Photos Here
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craigdiver
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| posted on 1/3/18 at 05:23 PM |
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quote:
Originally posted by AntonUK
reminds meof this work of art
That is truly awesome
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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coyoteboy
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| posted on 1/3/18 at 11:50 PM |
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quote:
Originally posted by AntonUK
reminds meof this work of art
Oh my eyes! That hurts my eyes and my sensibilities!
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slingshot2000
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| posted on 2/3/18 at 12:05 AM |
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Is that the beast that was being built on an old London black cab chassis, with two Jag straight sixes in it ?
(I lost the link to it, was on Garage Journal)
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Angel Acevedo
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| posted on 2/3/18 at 12:39 AM |
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quote:
Originally posted by craigdiver
Want this look on my straight-6 BMW haynes roadster but need to accomodate 2x O2 sensors (one on each bank of 3 cylinders), any ideas?
Sorry to chime in late...
Could you not put the first three into a center pipe concentric with the other three on the annular space?
Put the first O2 sensor after the third cylinder merges with this.
put the second just before both exhaust streams merge together.
May be a b1tch to fabricate, but I think its doable.
HTH.
AA
Beware of what you wish.. for it may come true....
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AntonUK
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| posted on 5/3/18 at 01:22 PM |
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quote:
Originally posted by slingshot2000
Is that the beast that was being built on an old London black cab chassis, with two Jag straight sixes in it ?
(I lost the link to it, was on Garage Journal)
That’s the one
Build Photos Here
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CTLeeds
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| posted on 4/4/18 at 11:21 AM |
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Hi Craig, here's what my M52 exhaust ended up like... I wanted it to look like your original post but there are so many reasons why it
couldn't exit straight out of the block...
Regards,
Chris
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craigdiver
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| posted on 4/4/18 at 11:42 AM |
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quote:
Originally posted by CTLeeds
Hi Craig, here's what my M52 exhaust ended up like... I wanted it to look like your original post but there are so many reasons why it
couldn't exit straight out of the block...
Regards,
Chris
That looks great - massive help, thank you. how have you managed without lambda sensors (my ECU had 4 before it was reprogrammed to delete 2 after
cat). Was your emissions ok to pass IVA without cat?
cheers
Craig
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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CTLeeds
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| posted on 4/4/18 at 12:04 PM |
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Hi Craig, I do have the 2 x pre cat sensors fitted...
I haven't been through IVA yet, and at the moment it's running a bit rough. I'm hoping it's just a sticky ICV or similar
though.
Chris
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craigdiver
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| posted on 4/4/18 at 04:50 PM |
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quote:
Originally posted by CTLeeds
Hi Craig, I do have the 2 x pre cat sensors
I haven't been through IVA yet, and at the moment it's running a bit rough. I'm hoping it's just a sticky ICV or similar
though.
Chris
Ah - see them now. Your exhaust looks great, did you TIG it yourself? Do you have a cat in there somewhere?
[Edited on 4/4/18 by craigdiver]
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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CTLeeds
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| posted on 4/4/18 at 04:57 PM |
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I wish! No, I had to hand a large sum of money over to a professional.
Chris
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craigdiver
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| posted on 4/4/18 at 06:08 PM |
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Do you have a cat in there somewhere?
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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CTLeeds
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| posted on 4/4/18 at 06:11 PM |
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Yep. There's a 300 cell sports cat in the silencer.
Chris
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craigdiver
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| posted on 5/4/18 at 03:08 PM |
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quote:
Originally posted by CTLeeds
Yep. There's a 300 cell sports cat in the silencer.
Chris
Do you mind me asking how much it cost to have the exhaust fabricated including cat?
If it ain't broken, fix it anyway (just because).
Building - BMW powered Haynes Roadster/442E hybrid.
Volvo C30 T5 Polestar
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