SWAP Thread: '91 325i Sedan - S50b30us

[phreshkid]

Good job OP, I'm in the same boat. I'm heavily considering buying new injectors and putting in new plugs as well. My HC are too high as well but only minimally like your initial problem.

I will see what I can find out.

Thanks for the inspiration!

What plugs did you end up using? What injectors? Links?

[hwy84]

Good job OP, I'm in the same boat. I'm heavily considering buying new injectors and putting in new plugs as well. My HC are too high as well but only minimally like your initial problem.

I will see what I can find out.

Thanks for the inspiration!

What plugs did you end up using? What injectors? Links?

You can do it! :mrgreen:

Start with plugs for sure - cause they be so cheeep. I used Autolite Copper "Resistor" plugs - 3924. Old school tech for old school motor, I guess. Not sure if this really made any difference, but what the hell - 12 bucks for all of 'em.

I went with the stock green top injectors, rebuilt from OK Injectors in Oklahoma. Search for 'em on ebay - 132 bucks for the set of 6 rebuilt, flow-matched, guaranteed for 1 year injectors. Can't beat it.

[treff-7]

OBD1 s52 with OBD2 cat. Yay or nay?

I'm finishing up my s52 swap in a week or two. It will be OBD1 but planning on using the OBD2 exhaust that came with the engine. Welded ports and plugged O2 sensor holes of course. Do you think it will be fine or they really pay attention to the cat?
Thanks!

[hwy84]

I'm finishing up my s52 swap in a week or two. It will be OBD1 but planning on using the OBD2 exhaust that came with the engine. Welded ports and plugged O2 sensor holes of course. Do you think it will be fine or they really pay attention to the cat?
Thanks!

I used OBDII manifolds with bungs on my OBDI motor, and they didn't bat an eye.

They did look over the cat pretty closely - but mine is OBDI, so I had no issue. Like I said - I think you can go a million times, and it is free if you fail (and only $8.25 if you pass) so I say give it a shot.

[M3PO]

Are the aftermarket cats approved (with an EO number) for the engine you are running? They will ask.

Pretty sure ebay headers won't fly. But the good news (I guess) is that I am living proof that you can go back again and again and again without issue - so you might as well try. The worst the can do is fail you, and you have to go back again with the changes made.

The car still has the original M20 in it for the time being. I failed smog a few months back and had to put in a new cat. It's a California approved cat. I'm wondering if I can reuse it when I drop in the S50 that I just picked up.

[treff-7]

The car still has the original M20 in it for the time being. I failed smog a few months back and had to put in a new cat. It's a California approved cat. I'm wondering if I can reuse it when I drop in the S50 that I just picked up.

The aftermarket cats are good for a long list of cars. schröe30er just bought a magnaflow one and it is good for like 2 dozen different cars varying from 1.6l to 6l so chances are yours will work for the s50 but you should look it up. On the other hand it might not be the best flowing cat for that engine but if it works for a 6 liter engine it should work for a 3 liter as well.

[treff-7]

I used OBDII manifolds with bungs on my OBDI motor, and they didn't bat an eye.

They did look over the cat pretty closely - but mine is OBDI, so I had no issue. Like I said - I think you can go a million times, and it is free if you fail (and only $8.25 if you pass) so I say give it a shot.

Wow! It's really odd that it's that cheap! I thought it would cost $100-$150 at least! I will give it a shot and report back.