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?
(http://www.aubec.com/Intake1.jpg)
(http://www.aubec.com/Intake2circle.jpg)
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!
I\'m jumping on this as wanting to find out
Got my Trust SMIC on...but sure the air flow can be improved!
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
Quote from: CharlieP;616322Oh 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?
(http://www.aubec.com/nacalocation1.jpg)
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
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
You\'re better off leaving it. It would be well worth putting a heat shield between the rad and the filters tho.
Quote from: Timmy;616343You\'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! :P
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.
Quote from: Timmy;616378I\'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:
Quote from: Timmy;616378I\'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.
I read bits about the reverse pull of air....
Can you explain that further...i.e. why/how it happens?
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.
Quote from: CharlieP;616394I 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...
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.
Quote from: Timmy;616495I 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.
Well at least in theory I would say having the hole open would lower pressure on the cold side of the SMIC as there is an easier route for air to travel into the bay than through the SMIC, so should be reducing flow through.
Only way to be sure is to test it. I\'ll go for a drive with/without it blocked and post back with my intake temps. Think I might buy some magnahelic gauges and measure the relative pressures for myself.
Definitely looking at putting a vent in the front of the bonnet to channel cool air to the intakes, and maybe a duct behind the SMIC to let the hot air out and reduce the overall pressure in the bay.
I think that last bit is what you want to concentrate on, a vented bonnet with the vent behind the IC will create a venturi effect through the \'cooler and literally suck air through because it\'s far lower pressure than in the front of the IC, especially with good ducting. The top of the curve on the bonnet is the lowest pressure point from the wind tunnel pics I\'ve seen, which is where good vented bonnets like the MazdaSpeed and Knightsports stylee ones put the vent.
Quote from: Nik da Greek;616860I think that last bit is what you want to concentrate on, a vented bonnet with the vent behind the IC will create a venturi effect through the \'cooler and literally suck air through because it\'s far lower pressure than in the front of the IC, especially with good ducting. The top of the curve on the bonnet is the lowest pressure point from the wind tunnel pics I\'ve seen, which is where good vented bonnets like the MazdaSpeed and Knightsports stylee ones put the vent.
Dremel time :)
Good feedback, thanks mate. I think I need to do that along with a cold air feed towards the intakes though, cos otherwise I\'ll end up with low pressure (good for intercooler) hot air (bad for the intakes) in the bay.
Well, my experiment in plastic and silicone has knocked average intake temps down from 55-65 degrees, to 35-45 degrees, with ambient air at 23 degrees or so. Thats conclusive enough for me, its staying blocked! :)
That\'s with the factory SMIC, HKS intakes and no other changes to the ducting other than blocking that rectangular hole in the cold air feed to the SMIC. Hoping it\'ll be even better when I get an uprated SMIC.
Heatsoak still an issue of course, doesn\'t take long in standing traffic for the temps to creep up into the 60\'s again, but they come right back down when I get moving quickly.
This might interest you Aubec??
Decided to try something out and it actually works rather well :D
Previously i had the standard top air duct (shared with intercooler) mounted to get some fresh air to the Trust Airinx filter i\'ve just put on but this to be honest was a bit crap, didn\'t work very well and also robbed air form the intercooler....
So, thinking about it i got some 2-1/4 inch flexible ali and had a play. Previously also when i had the standard airbox i opened up the side of the radiator as per Rob Robinette site. With this is mind and also slightly based on the Pettit Racing intake i\'ve come up with this:-
Flexible duct squashed to get between body and radiator for airflow to the filter. This at present is cable tied but i do plant to make some more solid duct at a later date but it will do for now to monitor things. Also sprayed it black so it don\'t look too out of place lol....
Comments welcome.
Oh and a while ago i installed a temperature probe (small digital 2.99 thing off ebay) and strapped this near the filters. So we\'ll see what the temperatures do :D Before the intake it was a fairly constant 33 degrees unless stuck in traffic or the fans came on in which it obv pushed the temps up but when moving came back down to the 33 ish mark.
So this is what we have:-
(http://i185.photobucket.com/albums/x125/smb2200/RX7%20Intake/DSC02886.jpg)
(http://i185.photobucket.com/albums/x125/smb2200/RX7%20Intake/DSC02891.jpg)
(http://i185.photobucket.com/albums/x125/smb2200/RX7%20Intake/DSC02892.jpg)
Cheers
Scott
I was thinking of something similar the other day when I was in halfrauds and saw the flexi hose - couple that with a box round the filters and you could get some reasonable results - let me know how you get on as it is!
Even better (but fugly) would be a small bonnet scoop above the filters (I\'ve come to the conclusion that my HKS filters are too far forward to put a NACA duct in to feed them), and a box around them to keep the cold air isolated. If I had a spare bonnet I would try it...
Yep SMBFD3S has the right idea, im going to be doing similar with my single setup, as theres no point sucking in the hot air, from what ive read a lot of it is down to how you duct the air :Thumbs-up Air will take the path of least resistance, so make sure there are no other routes other than where you want it to go.
Quote from: leon;626508Yep SMBFD3S has the right idea, im going to be doing similar with my single setup, as theres no point sucking in the hot air, from what ive read a lot of it is down to how you duct the air :Thumbs-up Air will take the path of least resistance, so make sure there are no other routes other than where you want it to go.
Well it Deffo makes and improvement, outside temperature was what 16 degrees last night and i was seeing 18 on the temp probe when moving which is located directly underneath the filter so they are deffo getting some nice colder air than before. Intake temps on the Commander where showing 26 (ARC SMIC) so yeah all good me thinks for a fiver lol....
Will let you know how it fairs in the daytime with ambient temps and keep you posted but it\'s all looking good to be honest.
Leon - yep how you duct it is important and if you want to go to the n\'th degree then you could insulate it aswell... You also have to consider where high and low air pressures are too if the air wont be "forced" as it could have the opposite effect and actually creating a vacuum
True, reading that website opend my eyes a little to how airflow really works, I was thinking of just giving the air the option of going via the intercooler/rad or going up the intake pipe. I was going to relocate the filter to down within the ducted area.
I\'m looking into getting some headlight covers with a slit similar to the Attain design (obviously not the same in case of copyright) made they will be for both sides not just the side with the air filters. depending on what they cost me I\'m hoping to have both plain and carbon fibre covers made up. I\'ve been messing around with my leaf blower to try and simulate flow and so far the mock up does allow a flow of air which after alterations to the plastic lips fixed to the bonnet are carried out improves this further.
keep us posted - sounds interesting :chat
Quote from: David Wiltshire;626639I\'m looking into getting some headlight covers with a slit similar to the Attain design (obviously not the same in case of copyright) made they will be for both sides not just the side with the air filters. depending on what they cost me I\'m hoping to have both plain and carbon fibre covers made up. I\'ve been messing around with my leaf blower to try and simulate flow and so far the mock up does allow a flow of air which after alterations to the plastic lips fixed to the bonnet are carried out improves this further.
Quote from: Aubec;616325Yeah, 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?
(http://www.aubec.com/nacalocation1.jpg)
This is something I have been working on a while ago on a spare bonnet to get cold air to my filter on my LS1 V8 conversion. The NACA duct works and fits really well with minimal dremeling required, but I may now look into an over the rad solution as I would prefer to keep the bonnet standard looking.
Yes I agree about the bonnet line remaining smooth I\'ve made a point of looking out for every aftermarket bonnet and don\'t like any of them, I\'m sure many of them do allow underbonnet heat to get away quickly but I just don\'t like the look of them. I have seen some subtle intakes around the number plate area which can look good but I\'m still trying the headlamp cover route