[stilesg57]

I'm doing the 3SIM conversion on my 328i and the DISA situation is driving me nuts.

First I bought Rein DISAs thinking those were OEM, but they're made in China. Sent them back; don't want to drop $350 in labor just to have to replace these again in a couple months and/or risk major engine damage. Notably, both large and small valves had metal shafts.

Ponied up the add'l $200 for true OEM valves that just showed up. Large valve looks great, but the small one looks like it has a plastic shaft. WTF?!? Part number is the newer -538 though?

What's the deal here? I'm bumping up against a deadline (and have already wasted $30 in shipping and return shipping) so I've gotta make a call fast and I'm pretty frustrated. Should I put in the OEM small one even if it's a plastic shaft? Or am I asking for trouble and I need to return it and either demand a metal shaft OEM one or -- gasp -- get the Rein small valve that definitely had a metal shaft?

Any thoughts?

This is so frustrating: N54 manifold conversion looks better and better every damn day.

[stilesg57]

Just confirmed it via the magnet test: the small valve (11617560538) has a *plastic* shaft while the large valve (11617579114) has a metal one. Both genuine Made in Germany OEM.

What should I do with the small one?

[cheerio]

I wouldn't overthink it. Haven't heard of the small DISA flap breaking; it's under much less load than the big flap. Would trust the OEM valves more than the Rein ones, regardless of what material the shaft is made from.

[e90yyc]

Good thing you went for the Genuine valves because everything else is a piece of shit. It’s the strangest thing too because you’d think a non-OE manufacturer (someone other than Mahle) would be able to make a flap that works reliably. The thing has only two positions for christ’s sake: open and closed. But from everything I’ve read these don’t exist.

Don’t worry. This is the latest revision and there’s nothing to worry about. I recently bought two new BMW valves and was surprised to see this too. There’s some info out there that seems to indicate the latest revisions of both the large and small valves have metal shafts, but that isn’t the case—just the large.

[stilesg57]

OK thanks so much for confirming, I know I'm probably just panicking and overthinking it I just don't have enough leash from my wife to have to do this again or to lose the motor over it.

100% agreed on the situation with these parts; can't believe this is the case but here we are. If I had to do it over again I'd have gone with the N54 manifold and saved the better part of a grand; oh well, maybe I'll feel differently when I'm basking in the (hopefully reliable) surge of mid-range torque.

I'll go ahead and have these installed, thanks again!

[e90yyc]

Happy to help!

Issues and cost aside, I think the 3IM is a better choice for a good majority of people..

The N54 manifold is amazing and I have nothing but respect for those who’ve championed it, but the need to wind out the engine to really see it shine reduces its appeal to me. I’d rather have more low-end torque for city driving. If this was a track car or perhaps under different circumstances, I’d absolutely go with the N54 manifold.

To further assuage your concerns about not having gone with the N54 manifold, there is the added cost of a tune. With the 3IM you have great free software from Bimmerlabs, but with the N54 manifold you’re forced to pay for a tune. Correct me if I’m mistaken though!

Sure you could probably eek out some extra power with your 3IM and a third-party tune, but chances are you’ll be more than happy with the Bimmerlabs no-MAF software.

Curious to hear your post-install thoughts!

[stilesg57]

Thanks again man, will do! I pick the car up on 3/28, get it aligned 3/29, then plan a big rundown thread on going from bone stock to all new underpinnings and a 3SIM & 3.73 rear diff within a week or so of that. Fingers crossed it feels worth it!

Actually I already spent $400 on a Kassel DME tune so it's in place before the manifold goes on next week -- I know it's a step up from a stock 330i tune but it's still another $400 this swap has cost me that would be a wash going to the N54. Deep down I'm sure you're right though and it's better for what I'm going to be doing with the car 99.8% of the time: driving around town.

[e90yyc]

Yeah keep us posted man!

I'm sure you're going to love it.