Favorite CF Splitter for Daily/Track Use

[CRRobert]

Cool, anyone do the APR Performance? Looks like they have a splitter for stock bumper, one for the MP lip and then their own lip and splitter.

[stevehifi]

Hi Guys,

I'm kind of in the same boat, I had an OEM CS lip that got destroyed recently (ran over a container of some sort on a local street - unavoidable). I paid $900 over a year ago.. now its double the cost from the dealer.. ridiculous.

After I looked at the damage I can tell you that all these fancy carbon fiber lips (even the OEM stuff) is nothing but garbage and definitely not strong CF .. more cosmetic grade.

I had this lip with the matching rear CS spoiler and i personally feel that it doesn't really contribute much to downforce.. I've driven on the track at 140mph+ and I didn't really a difference when I ran last time without it. I think BMW did this honestly just for cosmetic appeal.

I think you really need something substantial like something from APR (wing+adjustable front splitter) but that's more for a full on race car.

Personally I'm thinking at this point of not running anything, I think like the other members on this post stated, you will get alot more bang for your buck with suspension upgrades.

BTW don't worry too much about EDC, you can run a delete kit (I use KW) and it works great.

However I must warn you that to run a delete kit the acceleration sensors need to be mounted on the shocks in the same orientation as stock.
The only shocks that have the same mounting points are: KW, Bilstein and Ohlins.
MCS, Moton, AST don't have these mounts, so in that case you have to 'code out' the EDC and remove the sensors and tape/seal everything up. You also have to unplug the module in the truck. All of this is kind of a hack.

I run Bilstein clubsport 575/800# and is a great set.. double adjustable monotube with camber plates in front and clevis mounts in rear. Just as good as those fancy MCS and much less cost.

I would also recommend KW 3way clubsport, but a bit more hardcore.

Steve

[CanAutM3]

Originally Posted by stevehifi

Hi Guys,

I'm kind of in the same boat, I had an OEM CS lip that got destroyed recently (ran over a container of some sort on a local street - unavoidable). I paid $900 over a year ago.. now its double the cost from the dealer.. ridiculous.

After I looked at the damage I can tell you that all these fancy carbon fiber lips (even the OEM stuff) is nothing but garbage and definitely not strong CF .. more cosmetic grade.

I had this lip with the matching rear CS spoiler and i personally feel that it doesn't really contribute much to downforce.. I've driven on the track at 140mph+ and I didn't really a difference when I ran last time without it. I think BMW did this honestly just for cosmetic appeal.

I think you really need something substantial like something from APR (wing+adjustable front splitter) but that's more for a full on race car.

Personally I'm thinking at this point of not running anything, I think like the other members on this post stated, you will get alot more bang for your buck with suspension upgrades.

BTW don't worry too much about EDC, you can run a delete kit (I use KW) and it works great.

However I must warn you that to run a delete kit the acceleration sensors need to be mounted on the shocks in the same orientation as stock.
The only shocks that have the same mounting points are: KW, Bilstein and Ohlins.
MCS, Moton, AST don't have these mounts, so in that case you have to 'code out' the EDC and remove the sensors and tape/seal everything up. You also have to unplug the module in the truck. All of this is kind of a hack.

I run Bilstein clubsport 575/800# and is a great set.. double adjustable monotube with camber plates in front and clevis mounts in rear. Just as good as those fancy MCS and much less cost.

I would also recommend KW 3way clubsport, but a bit more hardcore.

Steve

The aero on the CS is functional. The front lip works in conjunction with the vented hood to reduce front axle lift by 20kg at 200km/h, as wind tunnel tested by AM&S in their supertest. The front lip, vented hood and rear Gurney flap give the CS net downforce as opposed to the non-CS that have net lift at speed. It not by a huge amount, equivalent to the GTS in “street setting”, but it does make a small difference.

[Equilibrandt]

Originally Posted by CRRobert

Cool, anyone do the APR Performance? Looks like they have a splitter for stock bumper, one for the MP lip and then their own lip and splitter.

This is the one I've been hoping someone would bring up. It's not a super low lip (though it does stick out a fair bit toward that parking curb you're trying to avoid) but the included aluminum skid-plates seem to be more motorsport oriented. APR does some great CF for standard splitters that need tie rods - though those are just simple flat planes of CF. At $1100-ish, it's a nice middle ground between the CS/Vorsteiner and some other reproduction $400-600 CF models. Would still be heartbreaking to crack on an apex though.

[SYT_Shadow]

Originally Posted by CRRobert

Cool, anyone do the APR Performance? Looks like they have a splitter for stock bumper, one for the MP lip and then their own lip and splitter.

Link?

[NYG]

Originally Posted by SYT_Shadow

Link?

https://shop.aprperformance.com/inde...product_id=587

http://shop.aprperformance.com/index...product_id=495

http://shop.aprperformance.com/index...product_id=506

[NYG]

Unless you guys mean this one: https://shop.aprperformance.com/inde...product_id=446

But without an undertray, this is more of an aesthetic thing. Value is not there for aerodynamic performance.

[NYG]

Originally Posted by CanAutM3

The aero on the CS is functional. The front lip works in conjunction with the vented hood to reduce front axle lift by 20kg at 200km/h, as wind tunnel tested by AM&S in their supertest. The front lip, vented hood and rear Gurney flap give the CS net downforce as opposed to the non-CS that have net lift at speed. It not by a huge amount, equivalent to the GTS in “street setting”, but it does make a small difference.

Functional is a pretty loose term though. The stock front lip is too short, not deep enough, and the vents + reverse rake on the F8X has some negative effects on the airflow under the car. The spoiler does offer downforce but minimal and unlike the GTS wing with 0AOA, there's a significant drag penalty for getting it.

I had my CS setup with front rake and a minimum of 150 mph on the backstraight of the Glen was guaranteed. One of the guys I always track with has a 1LE camaro with full aero (canards, splitter + undertray, wing @ 0 AOA for Glen + endplates) on a diet - he couldn't break 146 mph. IMO, I think you might be giving the stock aero too much credit.

[Equilibrandt]

You don't think this splitter would do much? I understand it isn't a flat plane splitter tray (the first 3 APR ones listed) like a time attack car, but the protrusion does seem to be substantial as long as the angle of attack is downforce-favorable. The fact that the splitter itself is only and inch and some tall is pretty appealing.

https://f80.bimmerpost.com/forums/sh....php?t=1088053

[NYG]

Originally Posted by bspaulsen

You don't think this splitter would do much? I understand it isn't a flat plane splitter tray (the first 3 APR ones listed) like a time attack car, but the protrusion does seem to be substantial as long as the angle of attack is downforce-favorable. The fact that the splitter itself is only and inch and some tall is pretty appealing.

https://f80.bimmerpost.com/forums/sh....php?t=1088053

It would but you need to adjust the car's rake for a flat splitter or you'd want to get something like the CS splitter.

[Equilibrandt]

Originally Posted by NYG

It would but you need to adjust the car's rake for a flat splitter or you'd want to get something like the CS splitter.

Getting closer and closer to your coil-over recommendation if I'm going to be getting into rake and +/- the nose and tail heights. Really appreciate your help!

[CRRobert]

This is the lip that can be paired with the splitter above you also linked.

Thanks for adding the links.

Originally Posted by NYG

Unless you guys mean this one: https://shop.aprperformance.com/inde...product_id=446

But without an undertray, this is more of an aesthetic thing. Value is not there for aerodynamic performance.

[CanAutM3]

Originally Posted by NYG

Functional is a pretty loose term though. The stock front lip is too short, not deep enough, and the vents + reverse rake on the F8X has some negative effects on the airflow under the car. The spoiler does offer downforce but minimal and unlike the GTS wing with 0AOA, there's a significant drag penalty for getting it.

I had my CS setup with front rake and a minimum of 150 mph on the backstraight of the Glen was guaranteed. One of the guys I always track with has a 1LE camaro with full aero (canards, splitter + undertray, wing @ 0 AOA for Glen + endplates) on a diet - he couldn't break 146 mph. IMO, I think you might be giving the stock aero too much credit.

I am not giving it "too much credit", I am just stating empirical facts. Subjectively, I did say it makes a small deifference. The fact that it makes the car go from net lift to net downforce means it is functional. For sure, a setup on street car will be nowhere close to a more aggressive race setup.

As for the front lip and hood vents on the CS, their main pupose is to reduce the amount of air that travels under the car to reduce the positive pressure. A flat splitter (such as the one on the GTS) will further increase downforce by creating an area of positive static pressure above the splitter, the one the CS is not designed for that. The hood vents also reduce the positive pressure under the hood, further reducing lift. As for the rake, it will favor front end downforce balance resulting from the airflow progrssively slowing down as it travels towards the rear of the car.

I am not sure how comparing the top speed at a given track of two completely different cars leads to any conclusions .

[NYG]

Originally Posted by bspaulsen

Getting closer and closer to your coil-over recommendation if I'm going to be getting into rake and +/- the nose and tail heights. Really appreciate your help!

Any time man - I genuinely want you to get 100% out of the car and not have regrets. It was my biggest mistake and eventually cascaded with a bunch of other things which led me to getting rid of it. Some of the best times I ever had on track was with that car and it has so much potential.

Originally Posted by CanAutM3

I am not giving it "too much credit", I am just stating empirical facts. Subjectively, I did say it makes a small deifference. The fact that it makes the car go from net lift to net downforce means it is functional. For sure, a setup on street car will be nowhere close to a more aggressive race setup.

As for the front lip and hood vents on the CS, their main pupose is to reduce the amount of air that travels under the car to reduce the positive pressure. A flat splitter (such as the one on the GTS) will further increase downforce by creating an area of positive static pressure above the splitter, the one the CS is not designed for that. The hood vents also reduce the positive pressure under the hood, further reducing lift. As for the rake, it will favor front end downforce balance resulting from the airflow progrssively slowing down as it travels towards the rear of the car.

I am not sure how comparing the top speed at a given track of two completely different cars leads to any conclusions .

I should actually say my bad bro. I think I replied to your post after working an all nighter and it looks like a bunch of random babble.

[USSEnterprise]

Originally Posted by NYG

I should actually say my bad bro. I think I replied to your post after working an all nighter and it looks like a bunch of random babble.

Nothing kills an internet argument like an apology. I was hoping for fireworks between you and CanAutM3 but you just had to take the high road eh?

[NYG]

Originally Posted by xxaarraa

Nothing kills an internet argument like an apology. I was hoping for fireworks between you and CanAutM3 but you just had to take the high road eh?

Haha, I was just debating points he wasn't even implying. I read it twice like, ok well I get what I'm saying but why am I saying it.

Getting a new car so I'm in a solid mood.

[USSEnterprise]

Originally Posted by NYG

Haha, I was just debating points he wasn't even implying. I read it twice like, ok well I get what I'm saying but why am I saying it.

Getting a new car so I'm in a solid mood.

Congrats! What car?

[NYG]

Originally Posted by xxaarraa

Congrats! What car?

Thank you brotha, R8

[USSEnterprise]

Originally Posted by NYG

Thank you brotha, R8

Sick! Congrats. That’s the only Audi I would ever want.

[NYG]

Originally Posted by xxaarraa

Sick! Congrats. That’s the only Audi I would ever want.

Lmaoooo same. Thanks brotha, big step in my car game. Feelin' blessed.

[bimmerboyE92]

Originally Posted by NYG

https://shop.aprperformance.com/inde...product_id=587

http://shop.aprperformance.com/index...product_id=495

http://shop.aprperformance.com/index...product_id=506

Researching aero... Would adding the flat splitter on the stock bumper without a "lip" be enough to balance out a wing?

[F80Speed77]

I dont think those are going to provide a significant increase in front downforce. The GT4 front splitter from AP Motorsport looks legit and is the only "off the shelf" one I would expect a big improvement from.

Also if you have a wing I would suggest trying it at the lowest AoA possible to see how it helps stability.