FD cool air ducting solutions to SMIC & Intakes?

[Aubec]

Right, trying to bring down my intake temps... £££ answer is to replace the standard SMIC, which I will do in due course, but I wondered what everyone else that\'s ditched the stock airbox has done about ducting?

I\'d kept the plastic air deflector thing installed as in the first picture below, but since its splitting the incoming air into two channels, one to the SMIC and one to the filters, I am wondering if I am as well removing it and just covering the hole from the SMIC intake (circled in yellow in the second picture) to ensure at least only clean cool air is blowing through the intercooler.  I figure that\'s better than any custom ducting will be for the SMIC?




The only problem then of course is that the only air to the Intakes is the hot air thats just blown through the radiator, so was thinking I could get a vented pop-up cover and use that to channel air to the intake filters?  If anyone has done that I\'d be curious to know if you\'ve actually put hosing from the pop-up to the intake, or if you just let the air gush in to the engine bay and hope it ends up in the intake?  Any other suggestions, ideally with pictures, for how to get cool air to the intake very welcome!

[CharlieP]

I\'m jumping on this as wanting to find out
Got my Trust SMIC on...but sure the air flow can be improved!

[CharlieP]

Oh by the way....you\'v got the same problem as me with the filters......they\'ll be sucking in warm air from the back of the rad....I\'m going to make up a box/shield of some sort soon though

[Aubec]

Oh by the way....you\'v got the same problem as me with the filters......they\'ll be sucking in warm air from the back of the rad....I\'m going to make up a box/shield of some sort soon though

Yeah, but you still need an air source if you are going to box in the intakes and block the air route from the intercoolers intake duct - which is really what the second part of my question is about.  Perhaps a NACA duct or a scoop in the front of the bonnet and a double walled metal airbox around the intakes?

[Aubec]

Hmm, found this VERY interesting article about undertrays, scoops and vents... if you\'re going down the fabrication route mate this is worth a read!

http://autospeed.com/cms/A_2162/article.html

[CharlieP]

Will have a read.....
 
EdRX7 put some direct airducts in his bonnet, just like your paint pic!
And when mapping, there was plenty of air available for fuelling! :burnout

[Timmy]

You\'re better off leaving it. It would be well worth putting a heat shield between the rad and the filters tho.

[CharlieP]

You\'re better off leaving it. It would be well worth putting a heat shield between the rad and the filters tho.

Not very ambitious are you!

[Timmy]

I\'ve already tried it, don\'t think it made any difference slightly worse if anything. The increased density of air going on is probably more important. Mazda surely would have done this for a reason.

[Nik da Greek]

I\'ve already tried it, don\'t think it made any difference slightly worse if anything. The increased density of air going on is probably more important. Mazda surely would have done this for a reason.

Well, Mazda designed it with an airbox, not cone filters anyway! :3Confused

All sorts of factors compromise what they might have liked to make as the optimum performance design, such as cost, practicality, ease of manufacture, ease of maintainence, noise suppression, etc.

....your right, though. I spent ages titting about with heat shields and ducts and all that and it\'s made no significant difference to temperature control. Heat soak\'s the real nemesis...in this congested country, you can never go too far before hitting traffic, and then all the ducting and venting in the world doesn\'t help at all :mad:

[Aubec]

I\'ve already tried it, don\'t think it made any difference slightly worse if anything. The increased density of air going on is probably more important. Mazda surely would have done this for a reason.

Mazda\'s own design is a compromise though, designed for a 250bhp car, driven on the road off boost most of the time, and where intake noise is to be minimized.

It\'s been demonstrated that under certain conditions, on boost the intake can suck air backwards through the intercooler, therefore heating the intake charge rather than cooling. Sealing off that opening would preven that possibility.

[CharlieP]

I read bits about the reverse pull of air....
 Can you explain that further...i.e. why/how it happens?

[neil_jdmr]

I blocked the hole in the factory ducting and using an arc smic with a vented cover i have found the temps drop much quicker than before. Being a smic set-up it still suffers from heatsoak but with the vented cover and factory ducting all sealed up im happy with the way the temps drop once moving again.

[SmbFD3S]

I read bits about the reverse pull of air....
Can you explain that further...i.e. why/how it happens?

Essentially this is what happens:-
 
If you have the standard setup with the airbox and the air duct which feeds from the intercooler duct when on WOT the amount of air the twins are taking is more than the duct can provide alone.  Due to this, the rest of the air comes from the engine bay essentially sucking air back through the intercooler from the engine bay...  
 
This has two effects.
 
1. there is no air going through the intercooler to cool it
2. the intake air is getting superheated air from the intercooler
 
You will see temps rise extremely quickly when on WOT and drop quickly when you let off as air makes it\'s way through the intercooler...

[Timmy]

I understand what you\'re saying, but i don\'t think that applies if you\'ve got an aftermarket induction kit as it pulls air from both the ducting and around the engine bay unlike the standard airbox that just pulls in from the air feed.
I know it made next to no difference on my set up which is arc smic and arc airbox, probably because the ducting is no longer the only source of air for induction.