Undertrays.....??

[Jono FD3]

Guys, I\'m looking at making some under trays (splitters or what ever you want to call them!!) Basicaly to reduce the flow of air through my rad (as I can\'t get the temps above 73 while driving!!) Has anyone got any images of front undertrayd on the FD\'s??

Also looking at making a rear defusor for the car as I\'m not realy keen on the ones that are on the market at the mo as they are eather not enough, or OTT for the styling on my car!!

Pics of both front & rear options would be apreciated!!

Found this on the front under trays & makes for some interesting reading.... what you guys think???

http://autospeed.com/cms/A_2456/article.html

Jono

[Nik da Greek]

Interestin link. I dunno if I\'m hopelessly wrong here (usually am) but I thought the undertray was an important aid to cooling on the FD :confused:? I thought it basically boxed in the front aperture to the radiator, creating a high pressure area in front of the radiator, and a low presure one behind, forcing more air in the front and sucking air out and away down the trans tunnel and under the car. If that\'s the case, wouldn\'t making an undertray make your car run even more cool than it does already? Can\'t help but be a good idea for aerodynamic efficiency, though :Thumbs-up

[AtomicRex]

Best thing you can do is to block part of the rad off
 
Are you sure your gauge is working fine?
Are you sure you havent got an air lock??  If you are using the standard pic up point they are crap....you need to put a sensor in the water as a lot of the time that is just in air.

[Hayward North]

Have a look at post 22 of mine on here http://www.mazdarotaryclub.com/forums/showthread.php?t=48807&highlight=undertray
This is what i did to mine

[Steve-Q]

I used to run a rotax max 125cc racing go kart and to get the rad temp right we used to used some extra special technical supa dupa duck tape and block a bit of it off, worked a treat. :rollinjust try that first, and its cheaper. if that makes nooooo difference then you know youve got a problem.  
 
Regards
 
Steve

[SiH]

Interestin link. I dunno if I\'m hopelessly wrong here (usually am) but I thought the undertray was an important aid to cooling on the FD :confused:? I thought it basically boxed in the front aperture to the radiator, creating a high pressure area in front of the radiator, and a low presure one behind, forcing more air in the front and sucking air out and away down the trans tunnel and under the car. If that\'s the case, wouldn\'t making an undertray make your car run even more cool than it does already? Can\'t help but be a good idea for aerodynamic efficiency, though :Thumbs-up

My understanding too

Low pressure under bonnet = good, air drawn into bay through path of least resistance. Make that the front bumper aperture, duct it all through th eIC and rad, and you\'re laughing

I\'ve got a MazdaSpeed Undertray and diffuser, I\'ll try to get piccies up at the weekend.
It runs noticeable cooler with the undertray on, and is also more stable at speed.

[RemarkLima]

I Jono, I take it you\'ve also replaced your thermostat? Or as said the sensor isn\'t out of voltage?

As with the correct thermostat even if you had Hurricane Ike coming through your radiator it wouldn\'t reduce the temps any further than the thermostat temp as it\'s not allowing any coolant to pass to the rad IYSWIM.

So seems a bit crazy to deflect air away from the rad, as you MAY need that air if it\'s a hot day and you\'re giving it some welly!

[Kevin]

I\'d just like to echo the fact that i\'d start looking into the fact of why your running at such a low temp before you do anything regarding airflow.

These cars run so hot that your temps dont really add up.  It almost sounds like you\'ve got a drilled thermostat, obviously you havent but definately check all the cooling system first.

Or as above check the sensors that they are giving the correct reading.  Would hate for you to block airflow off and result in cooking your car.

[Jono FD3]

LOL... There is a logical reason for it running so cool The car has a Vmount & a std bonnet lifted at the rear, also a deflector shield behind the rad, so the rad is going to be getting 80 - 90% of the air flow! My thought was by putting a front defusor on her and making a sliding pannel so I can ajust the amount of air flow through the rad, that would solve my problems.
The temps are taken from the PFC commander & not an aux gauge!! infact when I had a second gauge in, it read lower than it should!!

Jono

[ttpower]

Hi Mate,

Im currently at late prototype stages of both undertrays and rear diffusers and other bits and bobs! Just waiting for the final wind tunnel results from Japan before we can go ahead in full production. Will keep you all posted :Thumbs-up

[RemarkLima]

LOL... There is a logical reason for it running so cool The car has a Vmount & a std bonnet lifted at the rear, also a deflector shield behind the rad, so the rad is going to be getting 80 - 90% of the air flow! My thought was by putting a front defusor on her and making a sliding pannel so I can ajust the amount of air flow through the rad, that would solve my problems.
The temps are taken from the PFC commander & not an aux gauge!! infact when I had a second gauge in, it read lower than it should!!

Jono

I hear what your saying dude, but as said, if the thermostat is in good order (you may have a lower temp one, or as said it\'s been drilled out) then no matter how much air is going through the rad the temps will remain at the thermostat temp.

If the water in the engine block is 70C and the thermostat doesn\'t open until 80C then no water at all is going to the rad so it wouldn\'t make any odds how much or little air is passing through it, if that makes sense?

[nikp]

I hear what your saying dude, but as said, if the thermostat is in good order (you may have a lower temp one, or as said it\'s been drilled out) then no matter how much air is going through the rad the temps will remain at the thermostat temp.

If the water in the engine block is 70C and the thermostat doesn\'t open until 80C then no water at all is going to the rad so it wouldn\'t make any odds how much or little air is passing through it, if that makes sense?

Agreed. Doesn\'t matter (in theory) if it is in a blizzard in -20: the thermostat will just shut to allow the coolant to warm up, then open when warm, and shut to warm it back up again: it\'s a regulater. It doesn\'t start to open till about 81 degrees.

[Kevin]

LOL... There is a logical reason for it running so cool The car has a Vmount & a std bonnet lifted at the rear, also a deflector shield behind the rad, so the rad is going to be getting 80 - 90% of the air flow! My thought was by putting a front defusor on her and making a sliding pannel so I can ajust the amount of air flow through the rad, that would solve my problems.
The temps are taken from the PFC commander & not an aux gauge!! infact when I had a second gauge in, it read lower than it should!!

Jono

On one of my FD\'s I have an RE-amemiya D1 spec vmount with 3 core rad and intercooler, sheet metal ducting and a mazdaspeed vented bonnet.  I can never get my temps lower than 81 when doing general driving.

There\'s definately something not quite right for you to be getting those readings.

Just as a matter of interest when your stuck in traffic what are the temps?  Or if you leave it idling for a minute or two after driving?  Are they in the 80/90\'s or still at the 70 mark?  Or does the temps drop as soon as you start driving?

[nikp]

Just as a matter of interest when your stuck in traffic what are the temps?  Or if you leave it idling for a minute or two after driving?  Are they in the 80/90\'s or still at the 70 mark?  Or does the temps drop as soon as you start driving?

Some good Q\'s there.

[Jono FD3]

Sat in traffic the water temps get up to late 80\'s (don\'t get much traffic down here to be honest...... 4 cars is a traffic jam ) but then with in half a mile to a mile the temps are right down again!! water is up to the mark on both the filler neck & expansion bottle!! what temp do the cold thermostats run at?? just wondering as when I was driving it at 6am the other day, it didn\'t drop below 69c but didn\'t go above 72c on a 40 mile run

I\'m confused!!

Jono