After Market Air filters and Cold air feed - ummmm

Not specifically supra owners but anyone with a turbo'd car.

I hear people talking about their after market air filters and how they are looking at gaining nice cold air from having a pipe leading from outside of the engine bay on their turbo'd vehicle. And I’m thinking, what’s the point? As soon as this colder air is sucked up, its going to be forced through the turbo which can get up to temps around 700 Celsius. So no matter what you do its pointless to try and get cool air before it goes past the turbo, hence why we have intercoolers after the turbo.

Which brings me to my point, apart from the noise and looks of a nice aftermarket filter, is there any real point in them? So the filters are supposed to be less restrictive, but surely you can only flow as much air as the turbo can push through, and unless you have a larger single or twin set up I cant see it being that useful.

Don’t get me wrong though, I would'nt get rid of my blitz filter, it sounds good and looks good, but in reality, and the reason why I’m writing all this, there sold as a performance mod aren’t they?

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So your car feels the same to drive on a hot day compared to a cold evening?

So your car feels the same to drive on a hot day compared to a cold evening?

Considering overall temps of every aspect of the car will be hotter on a warmer day. Air at any point along the route will be warmer naturally, the intercooler can only cool to the temps of the outside air (to a maximum), which means you running on hotter charge temps, im talking about the differeance a cold a feed will make like for like on any given day.

Not specifically supra owners but anyone with a turbo'd car.

 

I hear people talking about their after market air filters and how they are looking at gaining nice cold air from having a pipe leading from outside of the engine bay on their turbo'd vehicle. And I’m thinking, what’s the point? As soon as this colder air is sucked up, its going to be forced through the turbo which can get up to temps around 700 Celsius. So no matter what you do its pointless to try and get cool air before it goes past the turbo, hence why we have intercoolers after the turbo.

 

Which brings me to my point, apart from the noise and looks of a nice aftermarket filter, is there any real point in them? So the filters are supposed to be less restrictive, but surely you can only flow as much air as the turbo can push through, and unless you have a larger single or twin set up I cant see it being that useful.

 

Don’t get me wrong though, I would'nt get rid of my blitz filter, it sounds good and looks good, but in reality, and the reason why I’m writing all this, there sold as a performance mod aren’t they?

 

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I must agree and have thought about this myself. On a turbo car it shouldnt matter what temperature air is going through the open cone filter as it gets heated up by the turbos and then goes through the intercooler, I think on hot days it doesnt have much to do with the hot air going through the filter but more to do with the air not being as cold to cool the intercooler, different story on a n/a I would think

Once I have installed my modded headlight I can datalog intake temp on the AEM and compare it without the headlight mod.

If it does not help why are most race cars, drag and touring included ducting from outside. Check the toms supra, HKS drag cars, RK drag car etc, they all have cold air ducts.

Some supra owners remove a headlight at the strip to help with cold air.

I must agree and have thought about this myself. On a turbo car it shouldnt matter what temperature air is going through the open cone filter as it gets heated up by the turbos and then goes through the intercooler, I think on hot days it doesnt have much to do with the hot air going through the filter but more to do with the air not being as cold to cool the intercooler, different story on a n/a I would think

I couldnt have said it better myself! Wez take note

I thought it was to do with colder air being denser, therefore more 'air' for the same volume compared to warmer air. more 'air' = more fuel, therefore more power.

Unless I have completely misunderstood, and seriously over simplified this, if so please feel free to ridicule me and or remove the post.

Mike

I must agree and have thought about this myself. On a turbo car it shouldnt matter what temperature air is going through the open cone filter as it gets heated up by the turbos and then goes through the intercooler, I think on hot days it doesnt have much to do with the hot air going through the filter but more to do with the air not being as cold to cool the intercooler, different story on a n/a I would think

If you have warm air fed into the turbo and the turbo then adds more heat the intercooler has alot more work to do to bring it down, therefore the resulting intake temp will be higher surely.

If the intake air is colder and the turbo adds some heat the intercooler has less work to do and should therefore result in a lower intake temp.

I thought it was to do with colder air being denser, therefore more 'air' for the same volume compared to warmer air. more 'air' = more fuel, therefore more power.

 

Unless I have completely misunderstood, and seriously over simplified this, if so please feel free to ridicule me and or remove the post.

 

Mike

You are correct, the end aim is to achieve more power and that requires cooler denser air.

Check the toms supra, HKS drag cars, RK drag car etc, they all have cold air ducts.

 

Some supra owners remove a headlight at the strip to help with cold air.

Good point, buts there really really highly tuned cars, so heat is a totally different ball game there i would presume. im no expert but the only advantage i can see is instead of the turbo heating up 15 degree air say, its starting off with a hotter air, but it the grand scheme of things?

I couldnt have said it better myself! Wez take note

I can see what you guys are saying and without proof from testing i can see you have a perfectly good argument.

If you have warm air fed into the turbo and the turbo then adds more heat the intercooler has alot more work to do to bring it down, therefore the resulting intake temp will be higher surely.

 

If the intake air is colder and the turbo adds some heat the intercooler has less work to do and should therefore result in a lower intake temp.

I agree, but like i said, where such extreme temps are involved when the air meets the turbo, is it going to make that much differance your going to even get one pony? i dont know, just seems a waste of time for the benifits - you know cost v gain

If the intake air is hotter / less dense, then less volume of air is compressed at a given turbine speed resulting in less boost ??

I can see what you guys are saying and without proof from testing i can see you have a perfectly good argument.

suppose the real test would be measuring temps after the intercooler using both a cold air fed set up like the hold in the headlight and the normal air filter in the engine bay. then again, if testing proved that the differance where very slight then the problem then would be assuring both test conditions where the same.

What would you expect to see Wez, temp differance wise on a typical 12 degree day on say a BPU under the above parameters?

If the intake air is hotter / less dense, then less volume of air is compressed at a given turbine speed resulting in less boost ??

argh yes that would make more sense.. the plot thickens

suppose the real test would be measuring temps after the intercooler using both a cold air fed set up like the hold in the headlight and the normal air filter in the engine bay. then again, if testing proved that the differance where very slight then the problem then would be assuring both test conditions where the same.

 

What would you expect to see Wez, temp differance wise on a typical 12 degree day on say a BPU under the above parameters?

I really dont know but I could measure easily on my car on the same stretch of road with and without the headlight mod on the same day.

Another one to think about is the standard airbox (fed with cool outside air) is regarded as better than aftermarket filters due to it not pulling in hot engine bay air.

If the intake air is hotter / less dense, then less volume of air is compressed at a given turbine speed resulting in less boost ??

I like that but would it not be for the same boost you have less oxygen due to the air being less dense, boost is regulated by the wastgate so should be the same with either setup.

but intake temps at the filter would only be 10 deg higher in the engine bay max I would think and if you think about how hot the tubbies run (above 700deg) whether the air is going in to them at 20deg or 30deg the turbos would be that hot the air coming out of them into the intercooler will pick up serious heat either way and its then down to the outside air temp to keep the intercooler cold. Just my opinion but I would think even a 10 deg difference in air temp going into the tubbies it wouldnt be 10deg higher when it came out. they would probably be the same.

I like that but would it not be for the same boost you have less oxygen due to the air being less dense, boost is regulated by the wastgate so should be the same with either setup.

The O2 percentage would be the same at whaterver boost (okay there's more 'polution' under the bonnet (Especially on singles!), but the O2 % will be the same for any air charge.

but intake temps at the filter would only be 10 deg higher in the engine bay max

Really? that low? suprised at that, but if thats the case then theres little argument really like you say, whats 10 degreeds when your playing with hundres of degrees

Its all to do with air density as already said, the colder the air entering the intake/turbo the denser it is, more air density will only help turbine speed and spool up, also it will take more heat energy to change the temperature, so efficiency wise the cooler the air passing into the intercooler,the easer i it can be cooled even further, so its all a knock on effect.

Why do you think its hundreds of degrees?

Are you saying the air ingested at the turbo at approx 30deg is heated to 700deg by the turbo and the intercooler cools it back to 35-40deg by the time it reaches the intake?

So whats providing the extra boost in winter / colder weather ?

The colder intake air or the colder ambient air through the IC hence colder charge-air ?

Or if both, which makes the most difference.

thats just a gues but how much hotter can the air get it cannot get that hot because when the cars moving there is 'fresh' air getting blown about the engine bay aswell, I guess it could get quite hot in the bay if you ragged the car about and let it sit but moving surly it couldnt get more than 10 deg difference. but I may be wrong

Its all to do with air density as already said, the colder the air entering the intake/turbo the denser it is, more air density will only help turbine speed and spool up, also it will take more heat energy to change the temperature, so efficiency wise the cooler the air passing into the intercooler,the easer i it can be cooled even further, so its all a knock on effect.

umm, take a look at post 18, not sure myself.