Fourth in the "Let's Talk" series, this thread will cover the cooling needs of your G. This will be of significant interest to those with 5AT, but there should be something for everyone.

Let's Talk Cooling:
======================
Auto Tranny's, racing, FI, or just stop and go traffic can take its toll on your prized ride. So let's look at what products are out there, hear from those that have taken the plunge, and perhaps even come up with the best system(s) for our modded G's.

Items in this discussion will include:
* Tranny Coolers
* Oil Coolers
* Power Steering Coolers
* Oil Catch Cans
* Increased Capacity Oil Pans or Spacers
* Intercoolers / Aftercoolers
* Heat Shielding
* Air flow (not intakes/CAIs, that's been covered elsewhere ad nauseum)
* Better Radiator
* Crank driven to E-fan conversion (5ATs)
* Gauges & Senders



Please make sure to be concise in your discussion, descriptions and include pixes & links where possible.

======================



'03.5 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS - www.teamtransport.org/forums

 

I have flex-a-lite 210 dual 12" fans. I HATE THEM. The switch on and off sporatically even though it's thermo controlled. And they vibrate the crap out of the car. Some one told me it's because the harmonics and I should run one at 10 volts and one at 12 volts. Anyone know what size/wattage resistor I would need to take a 12volt 19amp down to 10 volt 19 amp. I also have a NISMO 170 degree thermostat. On a hot day with a/c and somewhat spirited driving if I hit stop and go traffic my temp gauge hits 3 ticks above the middle/normal operating temps. I'm considering a tranny cooler and oil cooler as well as a N-tercooler for NOS spray. What does an oil catch can do?

Thanks Ted for starting this thread. It's been over due for me.

 

craig: you will need an 105.2631 milli ohm resistor with a wattage rating higher than 38 watts. if my math is right. you want your Vout to be 10V and your Vin is 12V. You also need your current to be 19 Amps. so to find the resistance you take (Vin - Vout) divide it by R (your resistance) and set it equal to I (your current). when you do this you get 2/R=19, which results in 2/19=R. R is then equal to .1052631579 Amps or 105.2631578 mA.

now for the wattage. Power = I*V = I^2 * R = V^2/R you can choose which way you want to do it anyway you do will give you a rating of 38 Watts. so you will need a resister that can handle that kinda of power. i would find one with at rating of 40 Watts

Daniel

screw the GTC's. Maya RT5's now!!!

 

tranny coolers will be need if you change your TC cause it will now create much more heat, and could lead to failures and also steal your horsepower.

how does an oil catch can help with cooling? i thought it was for you intake?

power steering coolers i dont think will be need unless you track you car really hard. then you can runt he risk of cooking your power steering fluid.

oil spacers i would definately go for if i had an FI setup.

radiators: my friend just got the koyo raditor and it is very nice. put together very well. but has some slight fitment issues. it is also about twice the size of the stock one.

some please correct me if i am wrong on any of this. i am here to learn and learning i need.

Daniel

screw the GTC's. Maya RT5's now!!!

 

First off, how big is this fan??????????? 19A? Thats outragious for a car. Thats a 273 watt fan! Although it is possible to have a fan that big, I can't see how it is possible to mount it in the G? A 1.9A fan sounds more reasonable.

However, say it is a 19A fan. You would NOT want to use a resistor to drop the voltage to it. If your fan itself is pulling 19A to run, and you put a resistor in line to drop the voltage to it, you would have to put the resistor in series with the fan. This would allow them to operate at different voltages, however, both components would draw the same current. So, now instead of a 19A fan you have a 38A load.

I also can't see the point in running the fans at different speeds, unless you are trying to get them to resonate at different frequencies. Are the fans securely mounted to the bumper? I would make sure they are completely solid. After that, it would only be harmonics left to contend with. I would imagine you would want both fans running slower, instead of just one, but that is something you would want to play around with.

As far as changing the voltage to them your best bed would be to use a 10VDC voltage regulator (check www.digikey.com - I'm not sure they even exist) and then drive the output with some high powered MOSfets if the load really is 19A. If it is a lower load you can run the fans directly off of the voltage regulator, but make sure your voltage regulator is rated to twice the expected normal load (ie if your fans are 2a get a 4a regulator). With that high of a load it might still be a good idea to throw a transistorized output (two transistors working together) on the circuit.


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

I agree... 19 amps sounds high. You must have some fat jumper cables running to your fan motor. =P

Putting a series resistor won't increase the current though. Current remains constant through all parts of a series circuit. Adding a resistor can only reduce the current. That's why resistors are sometimes called current limiters.

I would say for a quick and easy way to drop voltage in clearly defined increments is with diodes. You can buy 20amp diodes at radio shack for cheap. Unless you get a specialty diode, diodes almost always drop exactly 0.7 V. Hook two or three of these puppies in series with your fan and you will be ready to rock.

2004 G35 6MT Blk/Blk Sedan Stillen Air, Stillen Exhaust

 

yeh kevin knows that now. we talked for a while about it after we made those posts. we looked up the fans and the total draw is 19A so each fan draws 9.75A. also Vin is not 12V it would be more like 14.4V because the car is running not sitting stilll turned off. with those numbers then you would want a 450.1282 mA resistor with a 42.9 W rating.

diodes would be another way to drop some voltage, also you can do it with transistors.

Daniel

screw the GTC's. Maya RT5's now!!!

 

Let's Talk Cooling... because you're a great guy, Ted!

The stock AT Sedans (up to June, July, August 2004) are equiped with two different fans. An engine driven, 7 blade, 16" diameter "mechanical" puller fan with 5" blades and an electric auxiliary "pusher" fan.

All other G35s have two electric driven 10"-12" puller fans. One of these fans has 4 blades, the other 5.

While all G35s have three fan control relays, the earlier AT Sedan's IPDM E/R, Engine Room Wiring Harness and lower fan shroud mounting locations are a "stand alone" design.

Now for my two cents on Electrical Fans / Circuits.

Think direct current, as well as control and operating circuits.

Flex-a-lite's # 210 twin (2500 CFM - 12" - 10 blade / 21 degree) puller fans. Each fan draws up to 9.4 running amps or a total of 19.5 amps at 13.5 VDC. The fans' starting or in-rush current can be higher.

After much R&D, I finally selected the following major components. (Note: I decided to leave the stock aux fan in place.)

1) Flex-a-lite's "Syclone" S-Blade # 394 (1505CFM - 14" - 8 blade / variable pitch) puller fan. This fan can draw up to 9.2 running amps at 13.5 VDC. The starting or in-rush current can be higher. The fan motor leads are 12 AWG wire. All control wire is 18 AWG except for the thermister's (temp probe's) leads which are very small in diameter. (I tested this fan in the "across-the-line" starting mode and it does indeed inpact the engine's rpms at idle.)

2) Flex-a-lite's VSC (Variable Speed Controller) was selected because it provides a 60% speed "soft start" as well as speed regulation in response to the thermister's input.

With the battery cover in place the installation is very stealthy. Several folks have commented that it looks stock.
And, in over 10 months of real world summer and winter desert climate operation, there's been zero problems . No overheating, no vibration, no noticable drag when the fan's start.

By the way, I found the people at Flex-a-lite to be very helpful during the R&D process. Here's a good link --- http://www.flex-a-lite.com/auto/html/electric-fans.html ---


DaveO
03 G35 AT Sedan / DP / Willow / Premium / Sport / Aero / Mods / 262 & 260.8

365335-394 E-Fan VSC.JPG

 

The Electric Fan and stealth wiring.


DaveO
03 G35 AT Sedan / DP / Willow / Premium / Sport / Aero / Mods / 262 & 260.8

365336-394 E-Fan.JPG

 

After researching everything last night while talking to Dan I redid everything today. If at 13.4 volts the fan draws 9.75A then at 10VDC it will draw aprrox. 7.25A. Therefore, the inline resistor would have to draw 4.4 Volts at 7.25A (assuming the motor is not fully regulated to allow it to constantly spin at a preset RPM). In a series circuit the sum of each loads impedance is equal to total circuit impedance = R1 + R2 = Rt. Since R can be rewritten as V/I we can say that (V/I)1 + (V/I)2 = Rt.

10/7.25 + 4.4/7.25 = R

1.38 + 0.61 = R
R = 1.99 ohms

Now, subtract the resistance of the fan (1.38) to get the necesarry value of the resistor - .61 ohms @ a min of 32 watts.

The diode idea, while not necesarry designed to be used as voltage droppers isn't that bad of an idea, except youi can't get 20A diodes from Radioshack. In fact, the biggest barrel type diode I could find was 7A. To get a 20A diode you would have to move into a 220 footprint - 3 legs with a heatsink. The diodes at Radioshack are rated at 20/30A surges, but typically 3A constant. To drop the voltage from 14.4 - 10 you would need 6 diodes in series! Also, in order for the diodes to be riliable you would want the current capacity to be twice as high as the needed value, so 20A would be perfect for our 9.75A fan.

Still, the best route would be to buy an adjustable voltage regulator, tune it to 10VDC, and put two high current transistors on the output.

And, just think, I got paid time an a half today to figure this all out and post it!

Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

What did I start????

I'll have to read this again and again and get back to you guys with results. Right now I only have one fan running and the car seems to be running fine, and the vibrations have ceased.

 

Its all Dans fault, he started it. If you want a 10VDC controller for your fan PM me. I'm sure KPtechnologies could produce something fairly cheap and easy using the method I mentioned above.


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

i didnt start it you did. also kevin you could come up wit hit here while you are in tampa, and work on the car itself.

side note: when do you get here tomorrow?

Daniel

screw the GTC's. Maya RT5's now!!!

 

One of the things I've been looking at for the G (notice I didn't saw Z or VQ35DE) is an aftermarket radiator. Something with a little more capacity, aluminum and with two rows.

Guess what? There's nothing out there for the G. I come up with at least four a/m radiators for the 350Z's

like the Blitz LM @ around $696:


Or the Koyo at $399 providing somewhere in the range of 20 to 30% more cooling than OEM radiators.


Power Enterprise comes in at around $565 and is a double row.

Stillen at $649 (6MT only)

So..... I wonder who we can get to build us a radiator? Anybody got any ideas?

Let me know... -Ted


'03.5 Sedan 5a: BS/G, Prem, Aero/Body, Sport, Nav
Click for MODS - www.teamtransport.org/forums

 

I'd love to see a radiator for us.....

Here is an idea (sorry if it's already been offered above, haven't read all of the posts)...

What if we find a shop to make the double row core for our radiators and still use our top and bottom tanks. There are several advantages to this, incl. better/oem look, retention of the at cooler in the bottom tank of the at models, lower potential cost...

Gurgen