My S52 swap into an '86 325. Pulling from a 1998.5 89k M3

[rcfanatic]

Hi everyone. I'm going to begin an S52 swap in a few weeks so I'm trying to get everything in order. I've done a lot of reading, but most of the solutions on here involve starting with only an S52 and possibly ZF trans.

I'll be parting from a complete M3 and I have a limited time frame for this build, so I'm trying to reuse as many parts from the M3 as possible.

Does this make sense for the quickest swap:

1. Keep OBD2. Only need to flash the EWS out of the DME if exhaust and tank sensors can be kept.
2. Have harness/adapter fabricated by 3rd party
3. Exhaust, can a muffler shop make the M3 exhaust fit the E30 underbody? If not, my current exhaust is dual all the way from headers to muffler. Would splicing the two systems together be effective?
4. Keep the fuel system as-is. (Not sure about M3 in-tank sensor)
5. Keep ZF trans and acquire 3.25 or 3.15 diff.
6. Relocate booster 1/2". Fabricate new clevis
7. Everything else the same as other swaps.. oil pan/dip stick, fan, etc.


Any input appreciated! I'm sure I forgot something

[ParsedOut]

As for the exhaust, here's how mine is set up and it's good.

Stock M52 manifolds -> M50 (correction!) mid section w/ stock cat (not the same as OBDII M3 stuff) -> ebay E36 catback with stock E30 muffler clamp hangers.

With this you need to upgrade to the Treehouse racing control arm eyeballs, or you can use Bimmerworld's version or even cheaper (what I did) on ebay there is a brand Top Speed, they are powdercoated orange but exactly the same as the previously mentioned.

Here are some links to exactly what I have. BTW, the ebay catback sound is perfect, extremely quiet and mellow at part throttle but growls nicely at WOT, no rasp. Exhaust hangs a little low, could use some custom "adjustments" to bring it up but it's a great start and pretty cheap. Also worth mentioning, I painted the muffler high temp flat black to get rid of some of the bling.

http://www.ebay.com/itm/BMW-E30-3-Series-84-91-Performance-Front-Forged-Control-Arm-Bushing-Bushings-/390688815497?pt=Motors_Car_Truck_Parts_Accessories&hash=item5af6de3989&vxp=mtr

http://www.ebay.com/itm/Alex-Catback-Exhaust-fit-95-98-Alex-Back-E36-328i-95-98-Alex-Back-E36-M3-/231109675297?pt=Motors_Car_Truck_Parts_Accessories&hash=item35cf35c921&vxp=mtr

[rcfanatic]

OK, looking at underbody pics of E36's, M52 and S52 exhausts appear to be almost identical. So if you're able to fit the M52, then S52 should fit back to the cats as well.

This hopefully means I can keep the M3 midsection with cats and O2 sensors. If need be I can splice my current cat back/muffler, which is only a couple of years old, to the M3 exhaust.

Can anyone chime in to confirm?

[nokincy]

As for the exhaust, here's how mine is set up and it's good.

Stock M52 manifolds -> M52 mid section w/ stock cat (can't speak to if this is the same as OBDII M3 stuff) -> ebay catback with stock E30 muffler clamp hangers.

With this you need to upgrade to the Treehouse racing control arm eyeballs, or you can use Bimmerworld's version or even cheaper (what I did) on ebay there is a brand Top Speed, they are powdercoated orange but exactly the same as the previously mentioned.

Here are some links to exactly what I have. BTW, the ebay catback sound is perfect, extremely quiet and mellow at part throttle but growls nicely at WOT, no rasp. Exhaust hangs a little low, could use some custom "adjustments" to bring it up but it's a great start and pretty cheap. Also worth mentioning, I painted the muffler high temp flat black to get rid of some of the bling.

http://www.ebay.com/itm/BMW-E30-3-Series-84-91-Performance-Front-Forged-Control-Arm-Bushing-Bushings-/390688815497?pt=Motors_Car_Truck_Parts_Accessories&hash=item5af6de3989&vxp=mtr

http://www.ebay.com/itm/Alex-Catback...35c921&vxp=mtr

Do you have some more pictures of your set up?

[ParsedOut]

Do you have some more pictures of your set up?

What specifically do you want to see? The engine bay looks like any other 24v E30 in need of some post-swap clean up. Nothing special.

[rcfanatic]

What specifically do you want to see? The engine bay looks like any other 24v E30 in need of some post-swap clean up. Nothing special.

I think he's referring to your exhaust setup. The underside of the car

[ParsedOut]

I think he's referring to your exhaust setup. The underside of the car

I don't have any pics under the car. Nothing custom though, pretty straight forward. Although I guess I should clarify, the ebay catback needs to be for an E36. The muffler on the stock E36 rear section is way too large to fit and I don't think an E30 exhaust will work without some hacking, hence the need for an aftermarket part here. Also will mention that you need to jack up p-side of the motor when installing or removing the exhaust so it'll clear. It's a tight fit, but nothing too crazy.

[rcfanatic]

What is the deal with the in-tank sensor. Is there any reason not to flash it out? Would it be easy to swap from the M3 I have now?

Being that I have a complete car to pull from, is there anything else I should flash from the DME aside from EWS?

[rcfanatic]

Can anyone provide information about whether or not the flash the fuel tank pressure sensor. Does the fuel pressure control valve need data from this sensor to operate?

Would I just remove the control valve all together and flash the sensor out, since the the E30 tank already has a vent tube?

[drulle]

I'm in the same boat, not sure what to do with fuel tank pressure sensor/spare tire tank vent valve.

[ParsedOut]

Had the car up on a lift today so I snapped some pics of the exhaust for you guys.

Correction to my original post, the mid section is from an M50/OBDI E36. Rear section is an ebay part for E36. Needs treehouse/bimmerworld/top speed control arm eyeballs and the downpipe needs to be "massaged" to clear the sway bar. Also the cross member needs to be notched for the O2 sensor to fit.

[rcfanatic]

Had the car up on a lift today so I snapped some pics of the exhaust for you guys.

Correction to my original post, the mid section is from an M50/OBDI E36. Rear section is an ebay part for E36. Needs treehouse/bimmerworld/top speed control arm eyeballs and the downpipe needs to be "massaged" to clear the sway bar. Also the cross member needs to be notched for the O2 sensor to fit.

Can you repost the images their links are broken

[ParsedOut]

Fixed, sorry I reorganized my photobucket last week.