M3 cowl conversion

[AndyW]

So, FCPeuro has a kit (https://www.fcpeuro.com/products/bmw...-64316958817kt) but it says only for the 3 series...but I know people have done this for the 1er. I even asked them and they said it won't fit. Can anyone who has done this clear it up - will it fit? Thx!

[TM9030]

Let me see if I can find the thread where someone did a detailed explanation on doing the swap.


In the mean time..here is one FS on the e9X forums:

M3 Cowl https://www.e90post.com/forums/showthread.php?t=1796267

Same thing and might save you a few $$

[TM9030]

Found it! Here you go:

m3 cowl and strut braces https://www.1addicts.com/forums/show....php?t=1156251

They have part #s listed too.

Hope it helps

[AndyW]

Originally Posted by TM9030

Found it! Here you go:

m3 cowl and strut braces https://www.1addicts.com/forums/show....php?t=1156251

They have part #s listed too.

Hope it helps

Thx much!

And I shouldn't have the windshield sprayer issues as I have a Siebon hood.

[AndyW]

So I got all the parts, including the wire harness support, but the wire harnesses are too short? Did the 1M have different wire harness lengths from the 135?

[Suprgnat]

Originally Posted by AndyW

So I got all the parts, including the wire harness support, but the wire harnesses are too short? Did the 1M have different wire harness lengths from the 135?

The 1M didn't use the M3 cowl.

[AndyW]

Originally Posted by Suprgnat

The 1M didn't use the M3 cowl.

Ah. Guess I'll have to mod the wire carriage so the wires can fit.

[AndyW]

Originally Posted by AndyW

Ah. Guess I'll have to mod the wire carriage so the wires can fit.

Ended up using the wire carriage as a zip tie location so I could hang the wire harnesses below it. Worked well.

[StevieJ2]

Why would you not just rip everything out and use these? Cheaper, less hassle, and removes a few pounds off the front end.

[drwillb]

Just my .02 on this one: I used the BMS filters and no cowling for a few months but my car is a DD and I was concerned about water intrusion and snow covering the filters. I also looked at the M3 bits but saw that required a lot of adapting and the washer jets created interference.

What I settled on was just modifying the stock 135 parts. Basically, I cut a section out of the middle of the hard tray in order to allow underhood air to escape. I then cut out notches to allow the tray to seat over the 1M strut bars. Just took a little time and a cutoff wheel. 5" wheel for starters then Dremel for finish work.

[AndyW]

Originally Posted by StevieJ2

Why would you not just rip everything out and use these? Cheaper, less hassle, and removes a few pounds off the front end.

I have a set of those I use when testing. Why this vs that?

1. There is a high pressure region at the back of the hood. The hood needs to be sealed back there to prevent opposing flow. As I track this car, this is important.

2. Aesthetics.

[AndyW]

Originally Posted by drwillb

Just my .02 on this one: I used the BMS filters and not cowling for a few months but my car is a DD and I was concerned about water intrusion and snow covering the filters. I also looked at the M3 bits but saw that required a lot of adapting and the washer jets created interference.

I wouldn't have done it if I hadn't had a Seibon CF hood which I knew wouldn't need adaption for the washers.

Originally Posted by drwillb

What I settle on was just modifying the stock 135 parts. Basically, I cut a section out of the middle of the hard tray in order to allow underhood air to escape. I then cut out notches to allow the tray to seat over the 1M strut bars. Just took a little time and a cutoff wheel. 5" wheel for starters then Dremel for finish work.

Actually, air is *entering* your hood via that section.

[Bullitt]

Andy, is your new M3 cowl actually sealing against air entering from behind the hood? If you look at the underside of the hood (at least the stock one, not sure about the Seibon one), there is countouring that protrudes to seal against the cowl gasket. This countouring is shaped to seal with the 135i cowl and not any other - from the looks of it. This is my only hesitation against the M3 cowl, otherwise I'd get it in a heartbeat.

[AndyW]

Originally Posted by Bullitt

Andy, is your new M3 cowl actually sealing against air entering from behind the hood? If you look at the underside of the hood (at least the stock one, not sure about the Seibon one), there is countouring that protrudes to seal against the cowl gasket. This countouring is shaped to seal with the 135i cowl and not any other - from the looks of it. This is my only hesitation against the M3 cowl, otherwise I'd get it in a heartbeat.

It definitely will not seal without modification on the Seibon hood. I added rubber sealing strips to fix that.

[StevieJ2]

Originally Posted by AndyW

I have a set of those I use when testing. Why this vs that?

1. There is a high pressure region at the back of the hood. The hood needs to be sealed back there to prevent opposing flow. As I track this car, this is important.

2. Aesthetics.

Not going to argue with this observation, as generally that is the rule. but, have you measured it with a magnehelic gauge to see the variation? I have one here and could measure what it is dead center, say 6" from the rear of the hood if there was any way you could measure it with your car's configuration.

Would be interesting to compare the numbers.

[AndyW]

Originally Posted by StevieJ2

Not going to argue with this observation, as generally that is the rule. but, have you measured it with a magnehelic gauge to see the variation? I have one here and could measure what it is dead center, say 6" from the rear of the hood if there was any way you could measure it with your car's configuration.

Would be interesting to compare the numbers.

No, I have not. I don't have one but I'll ask in my circle if someone does.

[StevieJ2]

Originally Posted by AndyW

No, I have not. I don't have one but I'll ask in my circle if someone does.

I'll be busy most of the weekend, but will get some numbers from on top of the hood and below the hood. Need to do this anyways because I'm running with
the belly pan off and I wasn't sure how much it affects these cars at speed.

[AndyW]

Originally Posted by StevieJ2

I'll be busy most of the weekend, but will get some numbers from on top of the hood and below the hood. Need to do this anyways because I'm running with
the belly pan off and I wasn't sure how much it affects these cars at speed.

Good...cause that will help me know what range meter to get...

[Bullitt]

Originally Posted by StevieJ2

Not going to argue with this observation, as generally that is the rule. but, have you measured it with a magnehelic gauge to see the variation? I have one here and could measure what it is dead center, say 6" from the rear of the hood if there was any way you could measure it with your car's configuration.

Would be interesting to compare the numbers.

The back of the hood is a high pressure zone with a ram air effect - this is actually the second best place to put a cold air intake after the front of the vehicle. Therefore it is important to seal this area off for the engine bay to efficiently ventilate heat at speed.

Shirtpants_ on e90post.com performed testing with a magnehelic gauge to find the best place to vent heat from the hood, and his results verify the observation that applies to almost every hood. Pressure on the hood increases as you approach the windshield. The worst place is at the back of the hood where pressure is highest. Ref: https://www.e90post.com/forums/showthread.php?t=1306425

Attached below is an image of pressures variations on the hood of a Miata. It’s best to avoid placing any heat vents in the positive pressure zones where air wants to go into the engine bay and trap its heat. Negative pressure is where engine heat can escape when the vehicle is moving.

[drwillb]

Thanks for all the good info and links. If my car ever makes it to track car status I'll go ahead and replace the tray. For now, I like the extra underhood noise.