N52 Swap Discussion

[Cdmef]

I’ve had my eye on the Russian drlavr supersprint replica headers, real ones are a hard sell on value for me. They look to at least be very close to equal length, has anyone run them or genuine supersprints? The 3rd bends out quite far which makes me a bit worried about tower clearance

*actually now I think about it that bend is probably not an issue

[hoveringuy]

It simulates the CAN signals which would be missing because of the swap. The emulator helps remove several unnecessary engine codes that would show up and put it in limp mode. It allows the engine to actually run normally.

yeah, I don't have one and I'm not in limp mode. My only codes are benign ones like EWS not present. I think I have 2 or 3 background error codes that are meaningless but don't effect anything.

[LukeJ]

It simulates the CAN signals which would be missing because of the swap. The emulator helps remove several unnecessary engine codes that would show up and put it in limp mode. It allows the engine to actually run normally.

Do you sell the emulator alone?

Would it help with the A/C issue, with regards to the DME not picking up the rpms at idle when the A/C compressor is activated?

I'm curious about what codes would be thrown that would put it in limp mode? The only time my engine 'went limp' was when my fuel pressure was not enough. I forget which code that was.

[MWC]

When compensating for the DCT the difference is more like 35-40 whp and there are a few other things I need to optimize like the fuel injector tuning and vanos tuning.

I picked up another N52 this past weekend that I'm going to build up out of the car and swap in before spring. On this one I'm going to definitely switch to S54 headers and try and get the merge correct as well.

LukeJ is right about the AA headers, they aren't even close to equal length and my current merge is a horrendous hackjob we threw together with the existing S52 exhaust to get the car working.

[digger]

i don't know the dynos in question but there probably isn't 50whp peak in an exhaust unless its plugged. Can be huge differences in low end and midrange but usually not top end. There is also the different dynos being like a different measuring stick

[sweet3]

I'm happy to see you offering this! What's the Can bus emulator?

It simulates the CAN signals which would be missing because of the swap. The emulator helps remove several unnecessary engine codes that would show up and put it in limp mode. It allows the engine to actually run normally.

[hoveringuy]

I have forwarded the PipeMax calcs that digger ran for me and I followed the primary/secondary diameters and lengths perfectly, plus a Burns merge and mandrel bent turns.
It seems to work, but I also think more dyno time to optimize valve timing, ignition timing and A/F would pick-up power for you
LukeJ and I have the same tunes

[hubcapboy]

(blows dust off keyboard)

I don't know much of anything, and I've never dyno'd anything. My only goal is to beat the ~90hp coming out of my old eta. The only guess I might have about power levels goes back to the write-up that got me interested in this engine in the first place (too big to attach to this forum, but still available where I found it here: https://www.bimmerfest.com/attachmen...c-pdf.1046925/

BMW did a ton of optimization on this engine that might be getting left behind when you treat it as bare metal. How to reproduce it all as a starting point and build from there? No idea. Cue Nando to cut in and tell me that he knows everything it does and there's no magic and I just believe in witchcraft.

[LukeJ]

I would suspect those headers aren't measuring up to the S54 headers.

First off, not equal length. Secondly, the tube diameter is smaller, so more restriction.

Another thing you mentioned the E36 mid pipe. Are the pipes larger than 2"? Bigger pipes may actually be robbing power if the exhaust is losing too much velocity.

My swap dynoed at 248whp at 6700rpm or so. I built equal length headers, but my tube diameter is slightly bigger than the "optimized" S54 diameter. So my exhaust gasses are moving a little slower, everything else being equal. Also, my exhaust is a true dual exhaust until after the twin cats where they join the resonator. Not sure if not having a crossover pre-cat is hurting or helping.

Hoveringuy's N52'd E30 (268whp) is using the S54 headers, and his exhaust comes together after a couple feet to a single pipe with no catalytic convertors. So very unrestrictive.

EDIT: I just went out and took some measurements of the Ebay AA headers and the S54 headers. The S54 header runner tube inside diameter is 1.48". The Ebay AA headers, 1.38" ID. And as mentioned before, the tube lengths of the 1st and 3rd runners are way off, with the 1st being almost twice as long as the 3rd. So you're not getting the extra boost of having somewhat equal exhaust pulses.

[MWC]

I finished my build and it's running. I took the car to the dyno and had some disappointing results. The car made 220 whp on a Dynojet reving out to 7700 rpm.

I am trying to understand how the E30 is making almost 270. The only difference is I have the Active Alibabawerks headers into an adapted E36 midpipe and catback instead of S54 headers. I don't see how that could be worth 50whp though.

I am running a DCT which consumes around 5-10 whp, and I do have a few issues to work out, but I'm wondering what else could be going on here. My S52 made 220 whp too...

Is this E30 somehow a unicorn? I have not been able to find another N52 dyno with bolt-ons anywhere else that comes close to 268 whp. I am by no means suggesting it's fraudulent etc. I am trying to figure out what I may be missing. I'm trying to get as much as I can out of this thing.

[DEV0 E30]

Very nice.

[hoveringuy]

Posting this as a data point.... a Tesla brake booster will fit with full intake when the motor is on the E85 arms. This photo shows the booster with the integrated fluid reservoir, the cool kids are using the one from the CRV that is remote mounted and has oodles of room around the throttle body.

The closest point of contact is the DISA transfer tube thing where there's about 1/4". Slotting the booster outboard another 1/4" would help but not really necessary.

I'm not going to run this, I got Lee's dual MC boosterless.

[DEV0 E30]

Welcome to the fold. I thought the same, but quickly changed my mind too.

Tom had actually PM'd me right after I acquired my touring. Part of me wanted to get that one because I'm a hoarder? But it didn't make any sense to.

I sorted kicked myself knowing I'd eventually swap and that one was the perfect price for that. Looking forward to your progress.

Things add up, but hopefully you can get a ride. It seals the deal.

[iansane]

For some reason I thought I could keep the stock engine in my new e30 for awhile. With the bang-for-buck nature of the n52 and the path you all have forged, this is a nobrainer. I'm checking out car-part.com right now. Thanks fellas. What's the situation on oilpan "weld-kits" now? That coolant crossover?

Also, being in Tacoma, I wonder if I could finagle a look-see or ridealong at some of your swaps.

[Cdmef]

Awesome, thanks. I forgot you used one too. When I get the time I’ll be going over all the info again. My wiring experience comes from wiring 90’s Hondas lol! Now that’s easy.