S52 headers + downpipe clearance with an M50?

[bimmerteck]

ObdII headers went on well here, I'll have to modify the downpipe/center section but I knew that going in.


This pic shows the spacer I used for the motor mount. (12mm) as well as the clearance to the subframe.

Photo by systemdelete, on Flickr


This is the only pic that really shows the headers under the heat shields.

Photo by systemdelete, on Flickr

[lolcantturn]

^awesome, that's exactly what I needed. How much welding did you need to do for the downpipe/center section?

[bimmerteck]

^awesome, that's exactly what I needed. How much welding did you need to do for the downpipe/center section?

zero welding sir. I slightly "smushed"(my wife's technical term) the forward pipe to give it a slightly oval shape with my bench vise, I then dented it 2x one to add clearance for the sway bar and one to clear the subframe. It currently has 4mm of clearance to the subframe and 1/32" to the swaybar but I plan to space the swaybar mounts down a few mm to improve that. With this method the midpipe pipe cannot be installed with the subframe in place it must be unbolted and dropped a few inches but once the midpipe is installed it mounts back up and clears. You also need to be wary of how much your modifying the pipes as if you get to heavy with the hammer you can change the angle of the end of the pipe making it very hard to get a good seal to the headers. It can be done. :) Keep in mind that I have a 12mm spacer helping in the clearance department and the OBDI mid pipes are easier to fit.


Photo by systemdelete, on Flickr


Photo by systemdelete, on Flickr

[MR E30 325is]

So what do you guys recommend? I really want to stick with the S52 headers since I can get them for pretty cheap. I want to save as much money as I can so I can get coilovers right after I install the M50 haha

You do realize that with S52 headers you are going to have to weld up the secondary air pump ports?

Not an easy job, nor is it very practical, in my opinion.

Ebay headers are the way to go.

[bimmerteck]

You do realize that with S52 headers you are going to have to weld up the secondary air pump ports?

Not an easy job, nor is it very practical, in my opinion.

Ebay headers are the way to go.

I guess I should have mentioned that part. You do have to modify the headers or leave a capped off OBDII secondary air pipe hanging out there. but once that's done you shouldn't have to modify the mid pipe much if it's OBDI.



The welding isn't too bad, my local speed shop did it for $20 including milling the flanges back flat.

Photo by systemdelete, on Flickr


Photo by systemdelete, on Flickr

[rbartongrimley]

I guess I should have mentioned that part. You do have to modify the headers or leave a capped off OBDII secondary air pipe hanging out there. but once that's done you shouldn't have to modify the mid pipe much if it's OBDI.



The welding isn't too bad, my local speed shop did it for $20 including milling the flanges back flat.

Photo by systemdelete, on Flickr


Photo by systemdelete, on Flickr

This is exactly what I had done. I haven't had them installed yet, but I am sure it will go fine. I don't really mind having to modify something to work. If you think about it, we are using something engineered by BMW whereas most people are using replicas with now engineering backing behind them. I know which one I would pick.

[2mAn]

bumping this back up for some more info.

Asked a CA resident what he did since I read he was using stock downpipes. This is his response

had to heat up and ding in the sub frame the smallest amount and ding in part of the down section of the midpipes (cats). there is swaybar clearance issue is why you have to do the dinging.