California SMOG, S52 swap visual inspection

[2mAn]

I would keep two ECUs and plug in the stock one when smog time rolls around. Being an OBD car I’m sure they will want to plug it in

[MuhTorks]

I've got a question that's not strictly related to the original post but the thread title still applies:


I've got an E30 with an OBD1 S52 which has already passed BAR as the engine from a "1995 M3" and only need to worry about normal smog tests now. Does anyone know for sure if CA smog tests for a '95 M3 would involve plugging into the ECU or not?

My understanding is that since it's a '95 they will only be performing a visual test, sniffer test, evap, and failing me if my CEL ever comes on. I plan to stick an aftermarket ECU in the case of a 1995 M3 DME and keep everything else looking fairly kosher, with all the goodies that I needed for BAR. I just want to verify that in a normal smog test they won't be trying to pull codes from it or anything.

[Motheye99]

Wasnt someone making custom under hood stickers. I really wish i saved the link

[2mAn]

You should do more research rather than asking these questions. Check the sub-forums for both of those motors. a High Comp M20 can make over 200whp if done right and thats plenty quick for an E30

[RyanTheHill]

Yeah I’m not sure if an m50 is worth swapping just because it doesn’t add a ton of power and like you said keeping the stock engine is probably preferable to a swap. I guess if I was going to go the BAR way then I would go for the s50 but the rarity and price for those is going up considerably right? Anyone know how much a stroker or higher comp m20 would make? Thanks again

[mtech325]

If you want to do a 24v swap and get it BAR'd, an m50 or s50 is probably the most straight forward approach. The m52 and s52 are obd2 from the factory, which is more involved to make BAR legal. Yes you can convert the obd2 motors to look and run like an obd1 engine, but could cause some serious headaches if the referee notices, so I would suggest sticking with the obd1 engines to be safe.

Like Simon mentioned, building an m20 is another option, especially with the 24v engines 20+ years old and likely in need of a rebuild. Something else to consider is if you decide to sell the car down the line, an m20 car tends to have wider appeal nowadays vs. a swap car which may require waiting for the right buyer.

[2mAn]

Making it BAR legal isnt that hard if you do it properly from the start. Just know that you will need everything from the donor car and you cannot modify anything between the MAF and the CAT, and if its OBD2 you will need all of those OBD components on and functioning.

[RyanTheHill]

Damn, I could make it a stroker but obviously the m20 is not the easiest engine to try and make fast without forced induction. I’m assuming a turbo would fail to because it is much more obvious than a well done engine swap. I just find it hard to believe that there’s really not much I can do to add a substantial amount of power. How hard is it to swap an s52 and have it BAR legal? I could put a turbo kit on and take it off to SMOG but the exhaust system would be a big challenge. Lots of questions but I’m trying to figure out what I want to do with the car modification wise. Thanks

[2mAn]

Best way to make power with a M20 without adding forced induction: Add Compression. Stock is ~8.5:1 get it closer to 10:1 or more and you will make more power. You could also add a stroker crank and still have a stock looking M20 with a beast internally.

[Rev Run D]

ITBs would fail. No easy way to add power. I guess you could build yourself a stroker, but that ain't easy.

[RyanTheHill]

Ok, I thought I could just sneak it through. Is there any easy way to add power without having to go through legal loopholes or no? Would ITBs still fail visual inspection?

[e30devo]

They look quite a bit different, and are usually compared to the underhood Federal Emissions Sticker which has a small illustration of the engine. The intake manifold really gives it away.

[Rev Run D]

Yes people notice and that’s why they get them bar’ed Sent from my iPhone using Tapatalk

[RyanTheHill]

Just curious if I were going to swap the old m20 out for an s52 or even m50, would the SMOG inspector know from a visual test? I know that you have to get a referee and BAR certified to be legal but since the valve covers say BMW on the 24v motors do you think anybody would notice?