RX8Performance Under Tray Review
05-21-2012, 12:06 PM
#26
yall are forgetting one major thing. The coolant that this set up uses is NOT coolant that goes through the oem radiator. It is coolant that is supplied by the heater hose which bypass's ever going through the oem radiator. Its it fed back into the coolant system at the thermostat housing. That means if your coolant is for example 200F at the top radiator hose--it goes through the radiator and is cooled to for example 180F--right? BUT, then it mixes right before the water pump with hotter coolant for the heater supply( 200F unless the heater is on) which adds heat back into the coolant that is being circulated through the engine. So ANY cooling of that heater curcuit coolant is of big help.
05-21-2012, 03:42 PM
#28
My tranny temps were very nice. Last year when I ran stock, my tranny got so hot that the car was put into limp mode. This year, this never happened. My tranny temps, when being pushed really hard up hill with me paddle shifting and keeping the gear in 2nd for the climb and through turns, the tranny temps ranged from 205-230. Only once did it go above that, not by much at all, and that is because I was up the butt of another car, uphill, in 2nd gear about 6KRPM's and pushing it hard.
The temps on the car in all were a lot lower this year and not once had to back off or slow down or anything else to prevent overheating. I am VERY impressed with this tray and the cooling it provided. Would buy it a second time if ever needed
The temps on the car in all were a lot lower this year and not once had to back off or slow down or anything else to prevent overheating. I am VERY impressed with this tray and the cooling it provided. Would buy it a second time if ever needed
05-21-2012, 04:08 PM
#29
05-21-2012, 04:36 PM
#30
I am hammering it to the floor and running through the heat, up hill, in second gear the whole time...yeah those temps are good. Now yes, anything on the water temps over 220-230 is bad...but we are not talking about coolant levels, this was tranny temps and on the auto, anything above 250 is bad. For my coolant temps, The highest I saw was 223 and that was only once...the rest of the time they were in the low 200's
Last year when I ran it, my car shut down in limp mode due to excessive heat in both coolant and tranny temps. This year, she ran strong the whole time and did great
Last year when I ran it, my car shut down in limp mode due to excessive heat in both coolant and tranny temps. This year, she ran strong the whole time and did great
05-21-2012, 04:39 PM
#32
SARX Legend
iTrader: (46)
Where are you getting your data from as far as what is good or bad for tranny temps? Just because you were not going into limp mode doesn't mean everything is ok. In the towing world on much more robust transmissions anything above 220-225F is damage territory. But if it ran good then that is freakin' awesome.
05-21-2012, 08:05 PM
#34
Good to know the system shows positive results.
For what it's worth, I think the fans are blowing in the right direction. Here's a thought process of why.
a) First, the only reason air will move through the main (or any other) radiator, is because of a higher air pressure on the inlet side than the exhaust side. (Fans help this airflow because they reduce pressure on the exit side.)
b) The stock undertray helps cooling by preventing the higher pressure air from getting to exit side of the radiator without going through it.
c) Removing the stock undertray reduces cooling at speed by lowering the pressure difference across the main radiator.
d) Suppose the rx8perf tray were installed with the holes, but without the fans or aux radiators. Net cooling loss as in (c).
e) Now suppose the fans are installed (without aux radiators), but with the speeds set to exactly counteract the air pressure from the plenum above, to the lower pressure air under the car. Net effect = zero.
f) Speed up the fans. The pressure in front of the main radiator increases, flow through it increases. Net effect = plus.
g) Now insert the aux radiators. The pressure in front of the main radiator remains the same. The air is somewhat warmer. Where is that heat coming from? The main radiator! The hotter the aux rads (and and consequently their exhaust air), the cooler the main radiator is. Net effect = plus (still).
h) Additionally, the aux radiators are mounted to a large piece of aluminum exposed to fresh air, which adds both convective and radiative cooling not present in the stock system.
Would the low pressure under the car be enough to counter the "suction" of the upward blowing fans? Eventually, but I suspect at speeds higher than reasonably achieved. However, cooling problems usually don't happen at high speed but rather at a stop or in tight twisties or steep inclines where power output is high and (air) speed, low.
Finally, I'd propose, rather than do an install w/o the fans, do one w/o the radiators and just the fans. I suspect that there'd be a noticable improvement in cooling from both the added air pressure in front of the main radiator and the added 'help' the airstream gets in turning the corner around the bumper to reach rather shielded upper part of the radiator.
YMMV
For what it's worth, I think the fans are blowing in the right direction. Here's a thought process of why.
a) First, the only reason air will move through the main (or any other) radiator, is because of a higher air pressure on the inlet side than the exhaust side. (Fans help this airflow because they reduce pressure on the exit side.)
b) The stock undertray helps cooling by preventing the higher pressure air from getting to exit side of the radiator without going through it.
c) Removing the stock undertray reduces cooling at speed by lowering the pressure difference across the main radiator.
d) Suppose the rx8perf tray were installed with the holes, but without the fans or aux radiators. Net cooling loss as in (c).
e) Now suppose the fans are installed (without aux radiators), but with the speeds set to exactly counteract the air pressure from the plenum above, to the lower pressure air under the car. Net effect = zero.
f) Speed up the fans. The pressure in front of the main radiator increases, flow through it increases. Net effect = plus.
g) Now insert the aux radiators. The pressure in front of the main radiator remains the same. The air is somewhat warmer. Where is that heat coming from? The main radiator! The hotter the aux rads (and and consequently their exhaust air), the cooler the main radiator is. Net effect = plus (still).
h) Additionally, the aux radiators are mounted to a large piece of aluminum exposed to fresh air, which adds both convective and radiative cooling not present in the stock system.
Would the low pressure under the car be enough to counter the "suction" of the upward blowing fans? Eventually, but I suspect at speeds higher than reasonably achieved. However, cooling problems usually don't happen at high speed but rather at a stop or in tight twisties or steep inclines where power output is high and (air) speed, low.
Finally, I'd propose, rather than do an install w/o the fans, do one w/o the radiators and just the fans. I suspect that there'd be a noticable improvement in cooling from both the added air pressure in front of the main radiator and the added 'help' the airstream gets in turning the corner around the bumper to reach rather shielded upper part of the radiator.
YMMV
06-16-2012, 07:23 AM
#35
I recently installed Rx8 Performance's aluminum undertray also, but I was just replacing my factory one that had gotten all torn up and was providing NO airflow to my radiator.
The version I got has no fan and is just the aluminum sheet, weighs somewhere around 5 pounds (Way less than the GT spec) and I got it for a price that is less than the stock plastic one.
I was just curious on everyone thoughts? Do you think just the aluminum undertray by itself provides an noticeable gains over the plastic version? I have thoroughly enjoyed it so far though, definitely and upgrade from no undertray,
The version I got has no fan and is just the aluminum sheet, weighs somewhere around 5 pounds (Way less than the GT spec) and I got it for a price that is less than the stock plastic one.
I was just curious on everyone thoughts? Do you think just the aluminum undertray by itself provides an noticeable gains over the plastic version? I have thoroughly enjoyed it so far though, definitely and upgrade from no undertray,
06-16-2012, 07:55 AM
#36
Omfg! I'm starting to hate this forum. The amount of unresearched uniformed garbal. It's Fraken insain! Do any of you know s$@@, is this just a place to post what you think may sound educated to others beacuese someone who is cool said or did it,trying to get some street creed.
I joined this group and, really at first I thought a lot of people were d@&ks.
I now know this is not the case. Some are the same jackA$/ that rev at a light.
Was your last car an Acura.
I joined this group and, really at first I thought a lot of people were d@&ks.
I now know this is not the case. Some are the same jackA$/ that rev at a light.
Was your last car an Acura.
Last edited by cuadrillas; 06-16-2012 at 08:15 AM. Reason: iphones suck!
06-16-2012, 04:18 PM
#39
Ideally it would be tied to a speed sensor just like the radiator fans and only run them below some minimum speed when airflow is not sufficient on it's own.
For a rotary engine auto trans those temps are pretty decent You might be surprised how hot the manual trans and diff oils get in the same scenario if you ever took the time to measure them.
For a rotary engine auto trans those temps are pretty decent You might be surprised how hot the manual trans and diff oils get in the same scenario if you ever took the time to measure them.
06-16-2012, 10:33 PM
#40
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Omfg! I'm starting to hate this forum. The amount of unresearched uniformed garbal. It's Fraken insain! Do any of you know s$@@, is this just a place to post what you think may sound educated to others beacuese someone who is cool said or did it,trying to get some street creed.
I joined this group and, really at first I thought a lot of people were d@&ks.
I now know this is not the case. Some are the same jackA$/ that rev at a light.
Was your last car an Acura.
I joined this group and, really at first I thought a lot of people were d@&ks.
I now know this is not the case. Some are the same jackA$/ that rev at a light.
Was your last car an Acura.
06-17-2012, 10:59 PM
#41
Sometimes I think some people join this forum just so they have someone to bash on or talk trash too cause their life is pathetic. They try to be "hard" or acting like they are better than everyone else here to compensate.
Seph, glad you like the tray, its a great product. I have the tray with the coolers and fans and I am nothing but impressed and loving it. Good buy sir and thank you for posting up about it!
Seph, glad you like the tray, its a great product. I have the tray with the coolers and fans and I am nothing but impressed and loving it. Good buy sir and thank you for posting up about it!
