[Andy M]

Another idea I had for testing which would be more realistic is having some sort of tire pressure sensor that will output data in real-time (and must take a reading every second or faster).

I'll run a simple track circuit using cruise control and then again with the diffuser. This will test both the straight away downforce and the downforce on a turn (which is where diffusers are supposed to shine). Run several laps with the diffuser and several times without the diffuser. The change in tire pressure should be a direct correlation to the downforce generated. (based on the law of conservation)

So...now I need to find a wireless pressure gauge that will send data to a laptop at a 1 sec or better frequency...(found some that do it ever 5 mins........that's not going to help me much)

[Andy M]

Just an update on this one.

CF drawings were completed a whikle ago and sent to the factory for mould fabrication and production. First CF part should be completed mid-October and shipped to Toronto.

Redesigned the prototype and I'm getting the CAD drawings out for production now. I've made allowances so that it can be mounted on all E9X models regardless of model year and will allow for fabrication tolerances so fitment can be ensured. Mounting requires stock bolts.

Design is now a single flat plate on the back of the vehicle spanning from the rear bumper over the rear wheel well area where there's the most aerodynamic loss. Design features three venturi tunnels, one center tunnel and two outer tunnels. (Design is inspired by F1 designs).

Main diffuser fins remain aluminum powder-coated (black, pewter grey, or a custom color or finish), PET tunnels, aluminum base plate to protect the PET from the exhaust heat, and PET side skirts to prevent loss from the sides of the undercarriage. Two main fin options will be available: the fin designed for use with the CF deflector and the fin designed for use without the CF deflector (for those who have M-tech).

Can be bought as a package (diffuser, CF for non-mtech, and PET side skirts) or parted out (e.g. CF piece only, side skirts only, etc). Reason for part-out options is because since this is an underbody design, it'll inadvertantly take damage and require replacement once in a while. Obviously some parts will take less damage than others (e.g. aluminum base plate and CF deflector will likely never need replacing whereas the PET side skirts will probably require replacing if you drive over a curb) and that's why I chose the materials that I did to lower the cost of future replacement of damaged parts.

I'm thinking November 1 I will receive the first shipment in Toronto and I probably get orders in for mid-November or early December for the first shipment in time for Christmas.

[dzenno]

cool man, keep up the good work!

[E90MCF]

Can't wait!

[SupremePower3335]

[MrSkinny]

any photos or sketches to see what they will look like?

[Andy M]

Edited.

[Protruck]

I am an authorized distributor for Racepak Data Systems and located in Oakville. We should be able to come with a solution to test the diffuser and can actually sample up to 100 times per second for that type of sensor. One option would be an infra-red ride height sensor and it would be easy to calculate the change in ride height with the rear spring rate to give you a direct downforce reading. Give me a call to discuss it.
905 467-5148

Ian

[Andy M]

Thanks to everyone interested. And thanks Ian for your offering to help too!

Just an update, the drawings have been sent to the factory and the first version should be here early November. I'm actually away out of town for the rest of the month for business so an early November arrival date for the first production version is good timing.

I'll take the first few weeks of November just to check the fitment and post updates on here on confirmed fitments. I can start ordering for E90's as soon as I receive it (since I'll confirm the fitment that day on my own car) and then as I test the fitment on other cars, I'll make ordering available for those.

Thanks all for your interest!

[turugara]

bump. Anything new?

[Andy M]

Actually the whole thing is sitting in the closet behind me right now. I had to redesign one part because the factory decided to use tack welds for a key structural piece and that created many structurally weak points. Basically I wasn't happy with what was done so I redesigned the piece so it'll work. Will need to use new bolts likely for mounting as opposed to the existing bolts.

I'm also creating a "lite" version of this so it'll be just to simulate the look of it but will cost a lot less to produce (and therefore be cheaper on the consumer end). Won't be as effective as the full venturi tunnels under the car but at least it'll still channel air through and probably be half or even a third of the cost.

I'm hoping to get something soon...shipping starts to get slower around this time of the year because of Christmas so I don't think I'll be able to handle any sort of volume shipment until January.

[Andy M]

Updating this...

So the thing's been sitting in my closet for months now but the final pieces are coming in in about 2 weeks time. I redid the CF piece by adding an aluminum mesh piece where that slot is just to make it look a little more sporty and aggressive.

Also, I'm finding the price of this thing will be quite high due to the fact that it's MASSIVE in size. The thing is 5' in length and about 2' in width since it's meant to cover from the rear bumper all the way to the doors (essentially spanning over the large wheel gap). Because of that, shipping is really expensive so I would imagine that for someone who's just looking for the look but not looking to go completely hardcore, probably won't make it so attractive.

So my design for the "lite" version is in but my factory in China is on holidays now for Chinese New Year. I'll probably have the lite version (the one that most people will be interested in) sometime mid-February to early March.

I'll post pictures in a couple of weeks when the first full-size production model is installed.

[turugara]

Interesting. I'd be interested in the full version if shown that it actually works. Toronto is but a road trip away from Philly.

[Andy M]

Well if there's enough interest in Toronto for the full version, I can probably do a really good price on it since the majority of the cost is shipping (and size not weight). So I'd ship it to Toronto, assemble it, and deliver and install it on the weekend for everyone in Toronto. I'd probably need a group buy of at least 10 though.

[Chris@codemybimmer]

cant wait for this to be pictured!

[Andy M]

Updates: not good news. The above design doesn't fit. Looks like I can't go with the full 1/3 body length design. It'll lose a lot of function so I'm not sure if I should continue with it or not. I might just might make it a lot simpler and just call it a cosmetic design?

[Chris@codemybimmer]

thats not good...
still looks amazing as a cosmetic though
if you can get a functional one that'd be fantasic!

[Revision2]

Sorry to hear that it doesn't seem to be working out as you've clearly spent a fair bit of time and money on this already. I think turning it into a cosmetic piece wouldn't be too bad especially since you've already put in a fair bit of R&D and there are very limited options right now for non-Mtechs. Or perhaps you may consider switching to doing something for the front of the car?

[Andy M]

Well, after reevaluating, I just made it too complex. I'm sure the original idea will work if I had the substantial cash behind it to develop it but it'd be priced so far out there no one will buy it...may end up doing it as a custom project just for my own car.

Going to go back to the drawing board and go back to the original design which I know has a good chance of working. Better to stick with something that I know will work.

[Chris@codemybimmer]

any updates?

[Andy M]

Redesigned it from scratch, this time almost all CF. The biggest issue was weight and size (for shipping). Also I have to worry about high temps if I'm using CF. Had to redesign it to keep the cost of CF down .

The factory that I get my CF done is off for Chinese New Year so I won't be able to get a response in terms of production until mid-February. Going to see if I can work on some renders and post them up if possible.

Decided to basically simplify it and make it work with non-mtech and m-tech. It'll have to sit below the lip of the rear bumper instead of coming up like the previous renders.

[Chris@codemybimmer]

Originally Posted by Andy M

Redesigned it from scratch, this time almost all CF. The biggest issue was weight and size (for shipping). Also I have to worry about high temps if I'm using CF. Had to redesign it to keep the cost of CF down .

The factory that I get my CF done is off for Chinese New Year so I won't be able to get a response in terms of production until mid-February. Going to see if I can work on some renders and post them up if possible.

Decided to basically simplify it and make it work with non-mtech and m-tech. It'll have to sit below the lip of the rear bumper instead of coming up like the previous renders.

thanks for the update! i look forward to it
when you get a prototype may i come see it?