Functional Z3M side vents

[BimmerBreaker]

What is there to gain by lowering underhood temps a few degrees? The car has a true CAI anyways, more heat around the engine wont change much. The engine is still going to be operating at the same coolant and oil temps, iat may drop 1 degree - maybe - assuming massive heatsoak before venting and proper ventilation after. Fresh cool air is already rushing through the intake system cooling it whether the underhood heat is vented or not, there just isnt a big gain to be had there.

Not trying to be a wet blanket here... its cool to do, and just for that I hope someone does it. I just dont think it will make a big change to anything

[gmushial]

One of the benefits I see, and have seen on other cars: is simply everything else that's under the hood not having to operate at (as) high temps: hoses last longer; connectors last longer; insulation lasts longer; most things plastic last longer; and quite a bit of the electronics which are spec'd to operate at up to 110C isn't pushed as close to that limit. ... but yes: only bleeding off a couple hundred CFM isn't going to make a huge difference... but it would provide at least a first data point in terms of just how much pass through air is needed to really bring temps down significantly.

[gmushial]

Just changed the oil on the Z [it's springtime, ie, it's that time - dirty AMS oil out, pretty clean AMS oil in]... so had plenty of time to look at where one might route hot air out from under the hood... and it really looks like venting the strut towers is the only real choice if one wants to move any significant amount of air [other than maybe louvering the front to mid-part of the hood :-( ].... will have to put an air pressure gage under the hood and in the wheel well, do some freeway driving, and see if there would be a downhill pressure gradient from the engine bay to the wheel well.

[MC28REPSOL]

Hamman already has you covered for functional side vents.

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[gmushial]

Hamman already has you covered for functional side vents.

Any data available w/re the degree of effectiveness - they seem to have a rather small cross-section - especially given the amount of air that's being rammed into the engine bay through the front grill... wondering if they aren't more cosmetic? ... but I'll let the data speak for itself.. :-)

[BimmerBreaker]

Behind the gills is solid sheet metal... And even if you modified the hood there is more metal between the engine bay and the hood. Those Hamann gills are just as useless as OEM

[MC28REPSOL]

Behind the gills is solid sheet metal... And even if you modified the hood there is more metal between the engine bay and the hood. Those Hamann gills are just as useless as OEM

well, I can say that while not the best solution they are better then OEM.

I did indeed modify my hood and opened up the area behind the grills and yes there is a significant step between the hood and engine bay but there is space between the two allowing some air flow ... you can feel heat coming from the opening in the grill. but is it a sizable amount of air flow ... NO. but is that the question here? I don't think so. it was about a functional grill and these for all arguments, are functional. but if your looking to cool your engine bay this isn't your answer and that is why I choose to go another route.

[deni2s]

well, I can say that while not the best solution they are better then OEM.

I did indeed modify my hood and opened up the area behind the grills and yes there is a significant step between the hood and engine bay but there is space between the two allowing some air flow ... you can feel heat coming from the opening in the grill. but is it a sizable amount of air flow ... NO. but is that the question here? I don't think so. it was about a functional grill and these for all arguments, are functional. but if your looking to cool your engine bay this isn't your answer and that is why I choose to go another route.

Do you have any pics of hood modification under Hamann side gills? I could consider doing the same...

[gmushial]

well, I can say that while not the best solution they are better then OEM.

I did indeed modify my hood and opened up the area behind the grills and yes there is a significant step between the hood and engine bay but there is space between the two allowing some air flow ... you can feel heat coming from the opening in the grill. but is it a sizable amount of air flow ... NO. but is that the question here? I don't think so. it was about a functional grill and these for all arguments, are functional. but if your looking to cool your engine bay this isn't your answer and that is why I choose to go another route.

You say there is some heat coming out of the side vents - is that even with the large outlets in the hood? Or was that before you did such?

[Remotion]

I will put new weather strip back at the end of the summer and drive like this for now.
Partial removal causes buffeting noises.


I also opened the side wents. They dont get much airflow, but propably some because they are mildly warm after driving.
Because they are 90% boxed shut, they mostly get (propably some) airpressure from wheelwell if (like my car) your inner fenders are cut slightly.
And hopefully they release highpressure from there. They also get some air from engine bay from frontside over that innerfender.


It would need to drill two circular holes into structural box section behind it and weld air directing tube into opening...

On ECU side that sealed compartment is way too big for only ecu to reside. It would be decently easy to modify, and make new smaller airtight enclosure for ecu and there would be room in front of it to make similar opening into that sides wents.

[deni2s]

On ECU side that sealed compartment is way too big for only ecu to reside.

I think that doesn't applies to US market cars - they have secondary air pump here too, if I am not mistaken.

[BimmerBreaker]

On some engines yes that is correct

I'd be curious to see pictures of how you guys are modifying these things to vent air. If you want to try to add some more functionality to it, I wonder if some sort of duct could be developed to, if nothing else, at least cleanly route the air from the engine bay towards these gills.
As far as aerodynamics, for the nobody that cares, the hamann gills or OEM M would be best as they have a flared edge just forward of where the vented air would be exiting... so laminar flow attached to the body of the car would not be so much of an issue with those (would be much more noticeable on the moulded non-M style or aerodynamic gills).

[ZoO]

any chance you can drill 1 or a couple of well placed holes behind the strut tower, leading to more well placed holes drilled into the hood, eventually venting out side vents?

[MC28REPSOL]

You say there is some heat coming out of the side vents - is that even with the large outlets in the hood? Or was that before you did such?

that was before I installed the hood vents

any chance you can drill 1 or a couple of well placed holes behind the strut tower, leading to more well placed holes drilled into the hood, eventually venting out side vents?

I think people that want to do this, fail to understand that if they want effective ventilation of the engine compartment this isn't the way to go. there is very little air flow in that area and there wouldn't be any REAL benefits that would equal the work involved to make it effective. take it from someone who did it. I didn't do it for venting (installing Hamann Grills) I did it for looks. but since the Hamann Grills had venting I said what the hell and cut an opening in my hood to match the grill opening. after use I did notice some heat coming out of the vent after a drive. but definitely not worth the effort unless you already had a set of haman grills and definitely not worth cutting up part of the engine bay to gain more air flow. if you're looking for air flow ... just add vents to your hood like I did.

[MrBlonde]

What is there to gain by lowering underhood temps a few degrees? The car has a true CAI anyways, more heat around the engine wont change much. The engine is still going to be operating at the same coolant and oil temps, iat may drop 1 degree - maybe - assuming massive heatsoak before venting and proper ventilation after. Fresh cool air is already rushing through the intake system cooling it whether the underhood heat is vented or not, there just isnt a big gain to be had there.

Not trying to be a wet blanket here... its cool to do, and just for that I hope someone does it. I just dont think it will make a big change to anything

For me it was the giant turbo coking the absolute bejeezus out of everything underhood. For an NA car I don't think I'd be too worried unless I circuit raced the car and it was an issue.

[BimmerBreaker]

For me it was the giant turbo coking the absolute bejeezus out of everything underhood. For an NA car I don't think I'd be too worried unless I circuit raced the car and it was an issue.

Yes on F/I heat management is much more critical both for performance and reliability so for that I see the purpose. But I just cant imagine it ever making a difference on a bone stock car

[Dakar Ole]

Hood scoops are Qool!

[MC28REPSOL]

For me it was the giant turbo coking the absolute bejeezus out of everything underhood. For an NA car I don't think I'd be too worried unless I circuit raced the car and it was an issue.

He Lives!!! Blonde!!! Hey, howz your car? do you still have it? if so any up-dates?
break bread!

[zellamay]

I'm making my Z3M side gills functional. I'm having trouble taking them apart. I took out the little black clips, and the chrome pieces start to move out, but stop cold. I don't want to keep pressing or pushing and break something. What is the trick to separating the chrome piece from the grill?

[Randy Forbes]

Keep pushing.

[z3forlife]

I've taken mine apart to replace the chrome and it can be tight but work it slowly. Put a squeeze slightly on the tabs and try getting front or back loose first

- - - Updated - - -

Damn. Randy beat me with a better explanation before I could finish typing

Black zip tys will work if your black wedges break during removal/install

[zellamay]

Z3M functional side vents work! I disassembled vents, cutout the dished part of the vents, reassembled. It's hardly noticeable unless you really look you can see the hood shocks. I cut the hood in the same area: I left 4 of the vent mounting points, removed the 2 middle lower ones, remounted vents with nut clips and screws. I put foam (I'll use something more permanent when I get time) between the fenders and hood, in front of the vents, to block fresh air from the vents, hoping to get more of the hot engine air out. It's been 115 plus here in Phoenix lately. At 80 mph, my temp needle would creep up, so I'd slow down to let it drop. It doesn't do that anymore. Not a scientific test, but after a couple of days, I'm becoming confident that it helps. Sitting still with the fan on, I can feel hot air coming out the vents. I'm thinking that the effect is greater at highway speeds.

[rf900rkw]

Z3M functional side vents work! I disassembled vents, cutout the dished part of the vents, reassembled. It's hardly noticeable unless you really look you can see the hood shocks. I cut the hood in the same area: I left 4 of the vent mounting points, removed the 2 middle lower ones, remounted vents with nut clips and screws. I put foam (I'll use something more permanent when I get time) between the fenders and hood, in front of the vents, to block fresh air from the vents, hoping to get more of the hot engine air out. It's been 115 plus here in Phoenix lately. At 80 mph, my temp needle would creep up, so I'd slow down to let it drop. It doesn't do that anymore. Not a scientific test, but after a couple of days, I'm becoming confident that it helps. Sitting still with the fan on, I can feel hot air coming out the vents. I'm thinking that the effect is greater at highway speeds.

This. in spades. I've been testing and tweaking for several summers now. What I have learned is the M bumper is NOT adequate for air flow in extreme conditions. This isn't about sitting in traffic, or looking hip in the parkinglot. It's about getting air in and out (and getting max use out it) at speed. Fan or not doesn't matter, this is not a low speed issue. It's the 70-80mph highway runs tucked in a Talladega draft.

I have to assign most of the blame to the M front bumper. The 6cyl Z3 do not suffer the same issues. I'd love to see pics of what you did. I have a few ideas in the works, just ZERO time to implement then.

[BimmerBreaker]

Z3M functional side vents work! I disassembled vents, cutout the dished part of the vents, reassembled. It's hardly noticeable unless you really look you can see the hood shocks. I cut the hood in the same area: I left 4 of the vent mounting points, removed the 2 middle lower ones, remounted vents with nut clips and screws. I put foam (I'll use something more permanent when I get time) between the fenders and hood, in front of the vents, to block fresh air from the vents, hoping to get more of the hot engine air out. It's been 115 plus here in Phoenix lately. At 80 mph, my temp needle would creep up, so I'd slow down to let it drop. It doesn't do that anymore. Not a scientific test, but after a couple of days, I'm becoming confident that it helps. Sitting still with the fan on, I can feel hot air coming out the vents. I'm thinking that the effect is greater at highway speeds.

I'd be curious to see how you did this. It sounds like you gutted a decent chunk out of the metal behind the gill.

Also curious if you have your underpanel in place. The only times Ive seen temps creep up like you describe was when I first put on an aluminum underpanel that wasn't ducting air through the radiator properly.

[zellamay]

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The site says I can only load 5 pictures on a post, so I'll have 2 posts. Pictures here show inside and outside, and foam to block fresh air from vents. (If anyone has a good idea for something nice that will fill that space, please let me know. I'm thinking rubber that will fit top and bottom when hood is closed)