[tetsuo111]

UPDATE

I made this post to save others from going down the same dead-end I did. After posting, I found a solution, described below.

Also, here are the details and part numbers in case others are interested:


Part diagram:

http://www.realoem.com/bmw/enUS/show...diagId=51_6738

Part number and part:

https://www.ecstuning.com/Search/Sit...00763/ES74958/

Note - I purchased my bumper bar from a salvage yard at significantly less cost than a new part.




I learn my hardest lessons from failing. So in that spirit, thought I would share a mod / project that went off the rails today to save others the trouble.

This car is tracked. Weight management is an obsession for me. Since taking delivery of this car, I've dropped over 300 lbs without affecting comfort and daily practicality. RFTs? Gone. Lightweight rims? M3 aluminum control links? Rear seat delete? Replace the OEM exhaust with a lightweight version? Replace front seats with lightweight shells? All done.

Today's project was replacing the US-spec steel bumper bar with the M3 carbon fiber / kevlar bar, to save around 9 lbs at the front-end. I also have a Euro non-M rear bumper bar in transit, to save 12 lbs in the back. I "assumed" everything might fit because I'm running OE Performance Aero bumpers, which are larger than stock. The project was mostly straightforward, except for having to relocate the two horns.

Spent the day doing what needs to be done. When the time came to finally wrap it up and attach the outer front bumper skin, it was obvious the parts are incompatible. The M3 bumper bar extends too far forward for the non-M bumper shell to fit.

So for anyone else considering this, save your time and money and don't bother.

[Jozy]

thanks for sharing. Hope this will help other enthusiasts looking to shave weight

[tetsuo111]

Ok, it pays not to give in too soon. I found that removing the closed cell foam bump stops that press-fit in the CF/kevlar bumper bar provides enough room to fit the bumper cover.

Pro: Drop almost 10 lbs from the front-most part of the car.

Con: No foam bump stops to cushion and mitigate damage in a fender bender. There is no less crash protection because the bar is the stress member. The E9x non-M (steel) and E46 M3 (CF) bars also have no foam, so I don't see leaving the foam off now as being a problem, and certainly not a safety issue.

[Ruddigger]

Ha, you finally did it. Hardcore, man.

[justpete]

That's a really cool idea! Never thought there might be alternative part to stock, usually the whole bumper assembly is removed in a track car. BTW, the foam inserts might be to mitigate damage to the CF under very low speed impact.

How much did it cost?

[justpete]

What part numbers did you order?

And the tow hook inserts still match up with the openings, right?

[tetsuo111]

Originally Posted by justpete

What part numbers did you order?

I edited the OP with parts information.

Originally Posted by justpete

And the tow hook inserts still match up with the openings, right?

Very good question!

The Perf Aero front bumper tow access cover doesn't align perfectly with the threaded barrel in the carrier, even on the stock non-M carrier and using the stock alum tow eye.

This is no different. The barrel cylinder stands proud of the bar and extends almost to the cover. I "think" that a strap or wire could still work. If not than I'll test a motorsport-style non-threaded tow strap wrapped around the carrier or chassis rail.

Bottom line: The holes line up. The alignment is imperfect. If a strap fits it will be tight. Need to test fit to confirm.

[tetsuo111]

Project complete.

I replaced the rear US-spec bumper bar with the equivalent Euro-spec 330i bumper bar, BMW part 51127058467.

US bumper carrier - 10.40 kg / 22.9 lbs

Euro bumper carrier - 4.89 kb / 10.7 lbs

Weight loss - 12.2 lbs

I paid around $150 for a new bar shipped from the UK.

$12.29 / lb

This is a no-brainer. Most lightweight parts cost around $60 / lb plus or minus.

I expect skepticism from readers who haven't done this, but the resulting lower moment of inertia is noticeable and welcome.

[mad1stgen]

Was the rear bar from an E90 and installed on e91 ? Seeing this gives me hope, as I am looking to swap the rear bar to 335i one with correct exhaust hangers to facilitate exhaust conversion. Thanks !

Oh, and if you're selling your original front impact bar, I might be interested.

[tetsuo111]

Originally Posted by mad1stgen

Was the rear bar from an E90 and installed on e91 ? Seeing this gives me hope, as I am looking to swap the rear bar to 335i one with correct exhaust hangers to facilitate exhaust conversion. Thanks !

Oh, and if you're selling your original front impact bar, I might be interested.

Hi, you want to use a Euro 335i specific bumper carrier, part 51127157117. It's around 1 lb heavier than the 330i carrier, but includes hangers for a dual exhaust. You still drop around 11 lbs compared with our North American-spec bumpers. Here's a pic:

[Asonchadwick]

Sorry to bring this thread back but would this rear crash bar work on a 335d?

[tetsuo111]

Originally Posted by Asonchadwick

Sorry to bring this thread back but would this rear crash bar work on a 335d?

Yes, I believe so.

Suggest confirming first via RealOEM.

The rear bumper is extremely simple to swap.

[Raimund]

Originally Posted by tetsuo111

Yes, I believe so.

Suggest confirming first via RealOEM.

The rear bumper is extremely simple to swap.

Hey where did you order the euro bar? I keep trying on eBay but they keep cancelling my orders and saying the shipping is too much lol

[autoart]

Did you look into using a M3 rear crash bar?

[Prolix-2]

Discovering this thread myself, now with a front and rear M3 crash bar on hand, I would also like to discover if that will work without issue in my e91

[Serf27]

Originally Posted by Prolix-2

Discovering this thread myself, now with a front and rear M3 crash bar on hand, I would also like to discover if that will work without issue in my e91

The rear should work.
The front is questionable.
The m sport bumper on e90/1 dips in in the center.
The bumper in the OP is the performance bumper.