Passive/Active Cooling for Hotside Inlets

cityazndan

Specialist
Jan 17, 2017
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Anyone have ideas beyond the classic 335d snorkel for passive airflow for hotside inlets? Don't say stock location inlets because that's not helpful or I don't need your snarky-ass comment.

Mine thus far:
-Run ducting from the foglight/brake duct area to upwards to cool filters from underneath (don't know how substantial this will be)
-Hood duct/venting/louvering above inlets with a boot funneling the air downwards
-Some sort of heat shielding like RB Evo style inlets

-Some sort of active cooling system (stop and go or stuck in traffic is notoriously bad for "hotside", seen IATs climb up to 150*F) involving an intake fan within the 335d snorkel that pushes air through but then stops when moving past a certain mph (either RPM based or manual button actuation)
 

dyezak

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May 4, 2017
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Best would be a sealed intake box fed from the top by the 335d snorkel that then had outlets on the bottom to the turbo's. Probably a panel filter of some sort doing the filtering.
 

JBacon335

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is there anything stopping someone from running the inlets to the front like by where the fog light sits? I don't have an oil cooler so don't know if that's in the way for people that do have one
 
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Bmwfixerguy1

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Jun 5, 2017
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This has been something I've stared at for hours thinking and thinking.

I've thought about louvering the fender liner. I feel like a hood vent or scoop would be best

Not a full on new hood just an add on vent
 

dyezak

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Once I switch over to a single I'll be building an intake box from aluminum and powder coating it. I'll use the 335d snorkle to feed the box on the top and have the output to the single turbo on the bottom (bottom mount turbo).

This is totally possible with twins and a relocated hotside intake setup.
 
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R.G.

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Nov 17, 2016
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I'm with fixer. I've stared at it for longer then I'll admit looking for a viable option. Fog light area is a no go if oil cooler is in passenger fender.
Zak has the ideal solution IMO. Isolate the intake from heat. Same thing as OEM. Or...

24424


 
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JBacon335

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Guess this is one time not having an oil cooler helps me out, I may try some custom routing when I finally do my inlets.
 
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The Convert

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Jun 4, 2017
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I bought a 335d intake filter box to see how they would fit in the space...they do not fit. Mounting points are all there, but it ends up too close to the motor to route any piping to get the air down to the turbo on my motiv kit. Right now I'm working on freeing up some space by redoing the turbo outlet pipe and will be working on the intake routing next.
 

Torgus

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Nov 6, 2016
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Personally I don't think it is worth the time and hassle. The air is going to go through a glowing red turbine. Even if you could get air that is say 10-20 degrees cooler, I don't think you would see a real life performance change worth noting.

I would focus on the air after the turbine and not before. Better IC, Meth/Water, use E85 etc.

If just for 1/4m racing remove the headlight. I would be surprised if there was a change in your 1/4 mph. Or chop up your hood but it will look ugly imo even with a naca duct, scoop, etc.
 
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dyezak

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Personally I don't think it is worth the time and hassle. The air is going to go through a glowing red turbine. Even if you could get air that is say 10-20 degrees cooler, I don't think you would see a real life performance change worth noting.

I'm not sure if you are trolling or being serious. Are you serious? If so I'll take the time to reply seriously.
 
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doublespaces

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Oct 18, 2016
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The compressor wheel is going to be hot because its proximity and the fact its connected by the shaft to the turbine side, but any time you can start with a lower ambient air temperature that is going to help. I have a 'hot side' intake as well, so I'm always interested in ideas to reduce some of that heat. I'm just not convinced there is a cost effective solution, which is what he may be referring to. I also like my engine bay to look not stock, but like it came from the factory that way. So things like zip ties and tape are out of the question for me, this is not a race car.
 

Aaron

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Sadly, I think he was being serious. But he skipped thermodynamics class one too many times.

I'm not sure if you are trolling or being serious. Are you serious? If so I'll take the time to reply seriously.

Lowering pre-compressor temperatures is the best way to lower IAT's. You should always prefer having 0* ambient, heated to 100* by the turbo and going into the motor with no intercooler, as opposed to 100* ambient, heated to 150*, brought back down to 100* by the intercooler. Cooling IAT's any other way than reducing initial temp costs energy.
 

langsbr

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I'm not sure if you are trolling or being serious. Are you serious? If so I'll take the time to reply seriously.

I don't see that as trolling. I agree - it's much more effective to have a better intercooler or use meth. I know my IATs have easily hit 140+ while idling in traffic. Once I start moving and ingesting fresh air, they drop down to 100 - 110, even on a 95 degree day.
 

Torgus

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I'm not sure if you are trolling or being serious. Are you serious? If so I'll take the time to reply seriously.

Please show me a real life example that negates what I stated on the N54 engine.



Cooling IAT's any other way than reducing initial temp costs energy.

Injecting water/meth in my cp costs me energy? What energy? I'll taking losing 'energy' with my meth kit over a fugly attempt to get ambient temperature air to my intakes. I guarantee meth, water, or meth + water will produce more power than reducing initial intake temps to ambient in this example.

Once you start moving all of this is really not an issue worth discussing. Let me know at 80mph what a thermal probe on your filter reads vs. ambient.



Again I would focus on the other side of the turbo. If you want to focus on the inlet go for it. Just cut a hole in your hood and expose the filters to open air, hell remove the filters and pretend you can compress air by ramming it in at automotive speeds. Let me know your 1/4 mph gains not touching tuning.
 
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dyezak

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Thermodynamics is a well proven branch of physics, and this is a dead horse. I'll just say that as a general rule of thumb, on an NA engine reducing IAT by 10F generally yields a 1% improvement in power. On a FI engine it's generally 2%, without tuning. However with a consistent reduction in IAT you can feed more advance and realize an even larger gain. What would it be total? I don't know, 3% maybe? Is it worth it to you? Depends.
 

Aaron

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This seriously is not worth my time.

Please show me a real life example that negates what I stated on the N54 engine.

The fact that it's an N54 has no relevance, these are basic thermodynamic principles. Anytime you lower pre-heater temperatures, you're going to lower outlet temperatures as well. This is beneficial, and the most efficient way at lowering overall IAT's.

Injecting water/meth in my cp costs me energy? What energy? I'll taking losing 'energy' with my meth kit over a fugly attempt to get ambient temperature air to my intakes. I guarantee meth, water, or meth + water will produce more power than reducing initial intake temps to ambient in this example.

Once you start moving all of this is really not an issue worth discussing. Let me know at 80mph what a thermal probe on your filter reads vs. ambient.

Again I would focus on the other side of the turbo. If you want to focus on the inlet go for it. Just cut a hole in your hood and expose the filters to open air, hell remove the filters and pretend you can compress air by ramming it in at automotive speeds. Let me know your 1/4 mph gains not touching tuning.

This is just ridiculous, it's like arguing with a blind man over what color the sky is. You think injecting meth is more efficient, and a better overall way to lower IAT's, than having a good intake system in the first place?

Meth is dangerous. Meth is a band-aid. Meth DOES cost you energy to run.

You guarantee that injecting water/meth will make more power than negative 15* IAT's? Explain to me how that works. And be careful, science can hurt stupid people.
 

Torgus

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Nov 6, 2016
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Anytime you lower pre-heater temperatures, you're going to lower outlet temperatures as well. This is beneficial, and the most efficient way at lowering overall IAT's.

This is not what I said or was discussing. I said an upgrade IC and or Meth would be a better place to spend your money & time than trying to get ambient air temp air to your hotside inlets. Period. No shit cooler air coming in means cooler coming out. So way to quote me out of context and go on about something I was not discussing.

You think injecting meth is more efficient, and a better overall way to lower IAT's

Yes, Meth + water is a much more efficient, predictable, and better overall way to lower AITs + you get a great octane boost. It is better than putting a hole in your roof to duct in ambient air, a naca duct, or some brake ducting to attempt to get ambient air to your hotside intakes. It also does not look like shit.

I just looked at a log, started at 80 AIT and down to 60 at the end of the pull. I feel like your fancy ducting to get ambient air to your hotside inlets will not be able to do this. But I didn't take your thermodynamics class so maybe I am wrong...

Meth DOES cost you energy to run.
My pump draws very little, I think my alternator will be just fine keeping up. But thank you for the concern lol. Is this the energy you speak of? If not, I hope the energy you speak of matters in a real world scenario, I am sure you would not be discussing it if it was inconsequential.

Meth is inexpensive, even less expensive when you mix with water. Never met anyone who regretted running it.

You guarantee that injecting water/meth will make more power than negative 15* IAT's? Explain to me how that works. And be careful, science can hurt stupid people.

When did I say that? Honestly. Quote me where I said that. Oh wait, I did not. Now were are on to name calling eh? You can always tell when someone is starting to lose an argument by who starts calling names 1st.

I guarantee anyone will make more power on 93+ meth+water injection + hotside inlets vs. whatever contraption you make on 93 octane and hotside inlets after tuning. If your contraption nets you 15* less AITs I am happy for you. Let me see a dyno oh wait, that will not work, let me see a 1/4 mph increase with you fancy new ducting if you are so sure about it. My 1st post and all posts in this thread are about real word results and what is practical, not the math you read in your overpriced college text book which I am sure you are happy to dig out of your basement to quote me on.

What makes the most sense and is not going to look like SHIT? If you want your BMW to look like a honda trying to squeeze every little bit of speed out of it good for you. If you can make it look clean like stock even better, assuming the time and money spent is worthwhile vs. say spending that time and money on the other side of the turbo.

Personally I believe that meth is not a bandaid. This is my opinion, apparently your opinion is meth is a band-aid, to each their own. Plenty of people on this platform and others use it with no negative issues. I am happy with it and I guarantee a meth/water set up will make more power than your ducting ever will.

We all drive N54s bro. Go unbunch your panties and have a beer, smoke a joint, etc.
 
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JBacon335

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Nov 7, 2016
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Pretty sure if the intake air is cooler it'll make more power with meth too. It's not like it's not going to help just because you're injecting methanol now
 
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The Convert

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Jun 4, 2017
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Cooler air is more dense. Denser air has more stored energy. The more air you can feed into the system, the more power you can extract from it. Therefore, the cooler the air coming into the system, the more power you can produce.

This means that if you handicap yourself in the very beginning by sucking in hot air, and then cooling it with meth, you are hurting throttle response if you are making up for the initial loss of power. If you're not hurting throttle response, then you're losing power. Point being, you're losing something by being less efficient.
 
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