what part would you like to see made for the z4?

[Rsipad]

Personally, I quite like the look and performance gain of the RPI Scoop. Not sure if that was the intake piece you were referring to.

A brake cooling duct would be pretty neat. I know pre-LCI E85s can delete their fog light and run a duct, but, to my knowledge, the post-LCI non-M doesn't really have any options at the moment.

Yeah the RPI looks effective, do you have to reposition the cross brace for it? for me its hard to justify paying $130 for such a simple metal apparatus :roll:

Nope; it just slots in. It does have a few mounting screws, but I couldn't reach the ones in the back so mine is just held in by the bottom screw and 3M tape. Hasn't gone anywhere in the year I've had it installed which is a good sign :lol:

It does look like a simple piece of metal, but it seems a lot of thought has been put into it. The scoop is the biggest size possible without blocking air from the radiator and it fits as close as possible to the left grille and silver brace underneath it without touching either.

 

[solo_the_lad]

Personally, I quite like the look and performance gain of the RPI Scoop. Not sure if that was the intake piece you were referring to.

A brake cooling duct would be pretty neat. I know pre-LCI E85s can delete their fog light and run a duct, but, to my knowledge, the post-LCI non-M doesn't really have any options at the moment.

Yeah the RPI looks effective, do you have to reposition the cross brace for it? for me its hard to justify paying $130 for such a simple metal apparatus :roll:

Nope; it just slots in. It does have a few mounting screws, but I couldn't reach the ones in the back so mine is just held in by the bottom screw and 3M tape. Hasn't gone anywhere in the year I've had it installed which is a good sign :lol:

It does look like a simple piece of metal, but it seems a lot of thought has been put into it. The scoop is the biggest size possible without blocking air from the radiator and it fits as close as possible to the left grille and silver brace underneath it without touching either.

well I might have to reconsider it then... still however a bit tempting to just try and make my own out of carbon though

 

[coldel]

An open air filter unit, with heat shield, that isn't silly money

When I had the 350z they did these for about £85, obviously no performance enhancement but looked good in the engine bay and made a great sound!

like the AFE but less $$ is that what you're getting at

Yep. Ultimately its just a metal box with a 10 quid ebay cone filter in it

 

[SOhioZ4]

An expansion tank redo , those things are terrible .

 

[brillomaster]

i think you'd be surprised at the effectiveness of some front brake ducting, even if it does just blow air into the wheel well. it'll only hit the tyre if you're on full lock, but most trackday applications you're rarely turning the wheel more than a quarter turn, miles away from full lock like you'd need to do a three point turn. and that blanking panel is ripe for a trumpet of some kind, slight turn on it and then blast it straight at the caliper would be great.

e85 z4s have zero front brake cooling as standard, and pulling through air from a high pressure point like in front of the bumper would be very effective IMO. no need to protrude into the wheel well, just an angled vent would be blasting 80mph air at the brakes. at the very least it would stop the air in the wheel well becoming hot and stagnant - as i say, zero brake ducting as standard!

 

[DaveP]

so here's the model I have in mind for the ducting @DaveP
83FDC5B8-3805-4C9D-8A0D-D98D831466EC_1_201_a.jpegE82123F3-8E2A-41B4-A1F7-F09CC516AE43_1_201_a.jpeg

0596C9EB-648A-4043-964F-6D4046E2E8E2.jpeg

with my pretty standard sized aftermarket wheels, we've only got a few cm or so of spare room for the duct to pass by, and my wheel could've still been turned inwards a tad more. Keep in mind too I have stretched tires, so if you had proper track tire fitment, this would leave just about no room between the liner and the tire. What people on the forum have done previously is run some ducting under the car and completely avoided the wheel well, but this isn't a good option for lowered cars, which most people who track their cars will likely be relatively lower... :?

this leaves us with one option as far as I see,
which is to pass an oval shape tube between the CV shaft and the sway bar as shown in the next pic. I don't know if this is a good idea though as I assume the CV shaft travels upwards a decent ways in congruence with the suspension
IMG_7870.jpg

of course there is the option of just having it dump where the yellow circle is ...
0F014962-F66E-4D7D-9A78-F3FF42FF4467.jpeg
however this won't do much good if you are turning right in this case as it will just be blowing air at the tire

Some real brainpower going into this.

I'd be interested to know about the performance benefits of 'on disc/caliper' ducts, vs those which are just generating airflow in the general vicinity. Gut feel is that, for Joe Average like me, the difference is probably not that great.

 

[enuff_zed]

i think you'd be surprised at the effectiveness of some front brake ducting, even if it does just blow air into the wheel well. it'll only hit the tyre if you're on full lock, but most trackday applications you're rarely turning the wheel more than a quarter turn, miles away from full lock like you'd need to do a three point turn. and that blanking panel is ripe for a trumpet of some kind, slight turn on it and then blast it straight at the caliper would be great.

e85 z4s have zero front brake cooling as standard, and pulling through air from a high pressure point like in front of the bumper would be very effective IMO. no need to protrude into the wheel well, just an angled vent would be blasting 80mph air at the brakes. at the very least it would stop the air in the wheel well becoming hot and stagnant - as i say, zero brake ducting as standard!

Don't forget that there is also a cooling gain to be had by extracting the air from the wheelarch, allowing cooler air to come in from outside, even if that is from around the wheel. Of course, this would ideally require a vent of some kind. For a trackday car you could cut slots in the rear of the wheelarch liner, perhaps covered with gauze mesh to reduce the crud build up behind the liner. Then look at a vent that could replace the side indicator. They are very easy to remove/refit, so you could even pop them back in for a legal trip to and from the track.

 

[DaveP]

i think you'd be surprised at the effectiveness of some front brake ducting, even if it does just blow air into the wheel well. it'll only hit the tyre if you're on full lock, but most trackday applications you're rarely turning the wheel more than a quarter turn, miles away from full lock like you'd need to do a three point turn. and that blanking panel is ripe for a trumpet of some kind, slight turn on it and then blast it straight at the caliper would be great.

e85 z4s have zero front brake cooling as standard, and pulling through air from a high pressure point like in front of the bumper would be very effective IMO. no need to protrude into the wheel well, just an angled vent would be blasting 80mph air at the brakes. at the very least it would stop the air in the wheel well becoming hot and stagnant - as i say, zero brake ducting as standard!

Don't forget that there is also a cooling gain to be had by extracting the air from the wheelarch, allowing cooler air to come in from outside, even if that is from around the wheel. Of course, this would ideally require a vent of some kind. For a trackday car you could cut slots in the rear of the wheelarch liner, perhaps covered with gauze mesh to reduce the crud build up behind the liner. Then look at a vent that could replace the side indicator. They are very easy to remove/refit, so you could even pop them back in for a legal trip to and from the track.

Given the ride height of a road car, I suspect the air would take the path of least resistance and flow out under the car. Race cars are obviously a different story, where clearance is smaller and air is being more actively routed underneath.

 

[enuff_zed]

i think you'd be surprised at the effectiveness of some front brake ducting, even if it does just blow air into the wheel well. it'll only hit the tyre if you're on full lock, but most trackday applications you're rarely turning the wheel more than a quarter turn, miles away from full lock like you'd need to do a three point turn. and that blanking panel is ripe for a trumpet of some kind, slight turn on it and then blast it straight at the caliper would be great.

e85 z4s have zero front brake cooling as standard, and pulling through air from a high pressure point like in front of the bumper would be very effective IMO. no need to protrude into the wheel well, just an angled vent would be blasting 80mph air at the brakes. at the very least it would stop the air in the wheel well becoming hot and stagnant - as i say, zero brake ducting as standard!

Don't forget that there is also a cooling gain to be had by extracting the air from the wheelarch, allowing cooler air to come in from outside, even if that is from around the wheel. Of course, this would ideally require a vent of some kind. For a trackday car you could cut slots in the rear of the wheelarch liner, perhaps covered with gauze mesh to reduce the crud build up behind the liner. Then look at a vent that could replace the side indicator. They are very easy to remove/refit, so you could even pop them back in for a legal trip to and from the track.

Given the ride height of a road car, I suspect the air would take the path of least resistance and flow out under the car. Race cars are obviously a different story, where clearance is smaller and air is being more actively routed underneath.

Air will find every route it can. Given that the rear of the tyre is pushing upwards it may well direct more air out there than you think.

 

[Rsipad]

Yeah the RPI looks effective, do you have to reposition the cross brace for it? for me its hard to justify paying $130 for such a simple metal apparatus :roll:

Nope; it just slots in. It does have a few mounting screws, but I couldn't reach the ones in the back so mine is just held in by the bottom screw and 3M tape. Hasn't gone anywhere in the year I've had it installed which is a good sign :lol:

It does look like a simple piece of metal, but it seems a lot of thought has been put into it. The scoop is the biggest size possible without blocking air from the radiator and it fits as close as possible to the left grille and silver brace underneath it without touching either.

well I might have to reconsider it then... still however a bit tempting to just try and make my own out of carbon though

Go for it! It would definitely be cool to see and I'm guessing you'd still end up with similar performance gains.

 

[solo_the_lad]

i think you'd be surprised at the effectiveness of some front brake ducting, even if it does just blow air into the wheel well. it'll only hit the tyre if you're on full lock, but most trackday applications you're rarely turning the wheel more than a quarter turn, miles away from full lock like you'd need to do a three point turn. and that blanking panel is ripe for a trumpet of some kind, slight turn on it and then blast it straight at the caliper would be great.

e85 z4s have zero front brake cooling as standard, and pulling through air from a high pressure point like in front of the bumper would be very effective IMO. no need to protrude into the wheel well, just an angled vent would be blasting 80mph air at the brakes. at the very least it would stop the air in the wheel well becoming hot and stagnant - as i say, zero brake ducting as standard!

Don't forget that there is also a cooling gain to be had by extracting the air from the wheelarch, allowing cooler air to come in from outside, even if that is from around the wheel. Of course, this would ideally require a vent of some kind. For a trackday car you could cut slots in the rear of the wheelarch liner, perhaps covered with gauze mesh to reduce the crud build up behind the liner. Then look at a vent that could replace the side indicator. They are very easy to remove/refit, so you could even pop them back in for a legal trip to and from the track.

I like your idea of the rear vents, where do you think they'd exit though, just diagonally out of the side fender? Also would this be more effective than a top mounted vent in the fender like most people do I believe. Also side note, considered repurposing the side markers as well at one point, to be exhaust exits Figured it was too difficult to manufacture though, not to mention illegal

 

[enuff_zed]

I imagined them replacing the side indicators

 

[solo_the_lad]

Alright I may have come up with a much simpler idea for the brake ducts.

So this method would be a relatively simple design, except for the inlet component. The benefit of this design is it will avoid needing to remove the bumper/ cut holes in the side of the plastic wall behind the bumper, and it would have a more direct air path. It would however require a cutout of the plastic grill on the part where that middle fin is, which could possibly look a bit strange if that fin is broken into sections around the air ducts. I suppose we don't necessarily need to cut into the grill at all, and just mount the duct behind it (will not have cool looking ducts tho). And lastly I'll have to figure out a material to make it out of, which currently I am leaning towards 3D printing for simplicity, cost, and weight. We can also use flexible brake duct tubing in-between the inlet/ outlet components to save on weight as well. Let me know what you guys think!