Overheating?

Hellmun · Postby **Hellmun** » Sun Dec 30, 2012 1:06 am

StuwieP wrote:Dan:1 Logic:0

for the sake of argument (i like a good debate, call me devil's advocate or at least interested the the answer) doesn't increasing the pressure differential on the front side of the radiator improve airflow velocity across the core of at least the IC? Air trying to reach equilibrium? Presumably the air hitting the rad is turbulent (maybe another reason Dave's cooling system is struggling? poor airflow over the radiator?) but isn't having higher pressure behind that turbulent air beneficial? Again ignoring aerodynamic drag negatives. That was a lot of question marks.

Cheers
Stu

Based on your other post I think the concept your not getting is that there is only a finite maximum amount of air that will flow through the combined radiators/surface area. So if you add up all the small passageways that the radiators provide for flow you only need a small front bumper inlet for the equivalent flow (the 1/3rd area Dan is talking about). Increasing the bumper inlet past that point simply creates a larger pressure area only increasing drag. Remember pressure is measured in PSI, pounds per square inch and increasing the inlet only adds area to the equation and doesn't increase the actual pressure exerted.

Davekmoore the mx5 gearbox gets very hot when on the track and if you don't wear gloves and have a metal shifter then I'd expect to get a very VERY warm hand, it's perfectly normal. Gloves are a good idea to get anyway as they also prevent sweat from taking away any grip on the wheel.

davekmoore · Postby **davekmoore** » Sun Dec 30, 2012 8:08 am

Thanks for the healthy debate everyone.

Yes, the bigger intercooler blocks the radiator so there's a double whammy of more power and less cooling.

Yes, I'll get the system flushed, correct amounts of coolant and Water Wetter put back in, and checked for airlocks.

Also need as many pics as anyone likes of any effective ducting using the existing radiator inlet. Extra points available for anyone who can point me at ready made ducting.

Hjt · Postby **Hjt** » Sun Dec 30, 2012 10:56 am

Sorry for the picture delay on my part.

I purchased some thin galvanised steel from bunnings, made a temp using a cardboard box then traced it over and cut once it worked sufficiently.

You can buy an expensive pretty version @ garagestar. Google it. Quality products, just a lot more than the cost to DIY would be.

StuwieP · Postby **StuwieP** » Sun Dec 30, 2012 2:06 pm

Hellmun wrote:
Based on your other post I think the concept your not getting is that there is only a finite maximum amount of air that will flow through the combined radiators/surface area.

Yeah I think I overlooked that :oops:

Is there any way to tell when you reach that upper airflow limit?

Stu

davekmoore · Postby **davekmoore** » Sun Dec 30, 2012 7:24 pm

Hjt wrote:Sorry for the picture delay on my part.

I purchased some thin galvanised steel from bunnings, made a temp using a cardboard box then traced it over and cut once it worked sufficiently.

You can buy an expensive pretty version @ garagestar. Google it. Quality products, just a lot more than the cost to DIY would be.

It'll be great to see some pics when you have time.

Do you mean this: http://garagestar.com/shop/radiator_plate_nb.html which looks good for someone with my lack of technical ability.

And is there anything for the sides and/or bottom of the air intake?

wazman · Postby **wazman** » Sun Dec 30, 2012 8:53 pm

The most recent addition to my cooling system was this header tank from
Justjap.

It dropped my temps 12 deg ! I was seeing 115deg easily after 4-5 laps of winton short(25-27deg amb temp)
I drift so airflow is terrible as the car is sideways most of the time and at far greater angle than a stock mx5 would be sideways at as I have far more lock than a standard 5.

My setup- BP 1.8 turboed. Built motor 220rwkw.
Cooling mods I have-
ASI 52mm alloy rad - modified to triple pass.
12 row oil cooler.
Coolant reroute
Main thermo replaced with SPAL 1250 cfm thermo fan.(straight blade)
Fans wired in series.
Motor bike thermo on oil cooler (this was another massive help, oil temp drops faster than water on cool down lap)

I can now do 8-9 laps at winton on a 32 deg day and never see more than 97deg!
And I still haven't got a vented bonnet yet.

Seriously I can't praise the header tank enough! Friends have put em on their Nissan drift cars and had the same results! 10-12 deg drop from normal load temps at the track.

vrmmmpshhh · Postby **vrmmmpshhh** » Mon Dec 31, 2012 9:42 am

Isn't the point of the header tank to get rid of bubbles in the cooling system? All the FD guys use that exact one for that reason.

gslender · Postby **gslender** » Mon Dec 31, 2012 9:57 am

vrmmmpshhh wrote:Isn't the point of the header tank to get rid of bubbles in the cooling system? All the FD guys use that exact one for that reason.

Yeah... I can't see how it helps other than to increase the water capacity? I would have thought it would still reach the latent cooling efficiency of the system.

G

davekmoore · Postby **davekmoore** » Mon Dec 31, 2012 10:50 am

gslender wrote:
vrmmmpshhh wrote:Isn't the point of the header tank to get rid of bubbles in the cooling system? All the FD guys use that exact one for that reason.

Yeah... I can't see how it helps other than to increase the water capacity? I would have thought it would still reach the latent cooling efficiency of the system.

G

Given what others have suggested I have no objection to it getting rid of bubbles in the cooling system. Nor do I mind it increasing the coolant capacity.

This pesky coolant reroute keeps coming back up.

93_Clubman · Postby **93_Clubman** » Mon Dec 31, 2012 3:02 pm

davekmoore wrote:This pesky coolant reroute keeps coming back up.

Dave, wazman's DIY coolant reroute on his NB8 might be of interest:
viewtopic.php?f=76&t=40239

wazman · Postby **wazman** » Tue Jan 01, 2013 2:25 am

one of the lines i have going into the header tank is "t" ed into the water return from the turbo.
It often has bubbles in it when i come back into the pits and the turbo is still glowing. So i figure its much better that this coolant gets mixed with cooler coolant in the header tank before it heads back into the motor. :roll:

I did replace the water/coolant line that came with the kit with reinforced hose from enzed.

Postby **NitroDann** » Tue Jan 01, 2013 11:40 am

The enthalpy of the system is only slightly increased by the factor of the amount of water that fits in that headers tank over the total water volume in the old system.

Its hard to believe that if your radiator couldnt remove all of the heat from the water before it can now due to slightly more water to heat soak.

Dann

Lokiel · Postby **Lokiel** » Tue Jan 01, 2013 2:42 pm

davekmoore wrote::
Also need as many pics as anyone likes of any effective ducting using the existing radiator inlet. Extra points available for anyone who can point me at ready made ducting.

This is what I plan on doing at some point: http://www.mazda-speed.com/forum2/index.php/topic,25844.0.html

It's DIY so you're going to get your hands cut up and there will be plenty of swearing involved getting the fit right, particularly as you approach the final straight.

Start with cardboard templates and try and get them as close to final-fit as possible, then trace them onto aluminium.

timk · Postby **timk** » Tue Jan 01, 2013 3:00 pm

What kind of oil cooler do you have and what oil temps are you seeing by the way?

davekmoore · Postby **davekmoore** » Tue Jan 01, 2013 7:47 pm

NitroDann wrote:The enthalpy of the system is only slightly increased by the factor of the amount of water that fits in that headers tank over the total water volume in the old system.

Its hard to believe that if your radiator couldnt remove all of the heat from the water before it can now due to slightly more water to heat soak.

Dann

That's what I thought, although I've never heard of the word "enthalpy". What about removing bubbles? If this is a way of removing air locks during use I'd be very happy with that.