Steven6282

Hello all,
There isn't a lot of summer left at this point, but all summer it has bothered me how hot my car gets compared to how it was last winter when I first installed my 350. In the winter it would max out around 185 degrees which is within specs for the engine, but now in the summer it is sometimes reaching 240 which is way above engine spec. And yes I've checked everything out to make sure everything is good, the radiator is in perfect condition and the water pump is working, thermostat is opening etc. It's just the heat when I'm sitting still. As long as I'm moving and collecting some air in the air dam it stays around 180.

So I've been thinking about converting to an aftermarket aluminum radiator. But I have no clue what makes a good radiator. I see people taking about multiple core radiators all the time, is that the number of rows a radiator has? Like this one on summit for example: http://www.summitracing.com/parts/SUM-380455/ It says it's 2 rows doesn't say anything about more than one core. And I also saw the sticky post about a 3 core aluminum radiator on ebay, but checking that ebay store I see some radiators listed as 3 rows and some listed as 4 rows, nothing about multiple cores though. If more rows means more cores and more cores are better then one similar to the one in that sticky except with 4 rows is not priced to badly in that ebay store.

And this brings me to the second part of my question, I have a stock single electric fan on my radiator. I saw in the FAQ stick about a dual fan conversion. Does converting to dual fans really make that big of a difference? I always figured it was a minor difference since the dual fans are smaller than a single fan and it just had something to do with using less power when only one fan needed to run or something. But if dual fans do make a difference that is something else I may consider doing. One of those 4 row radiators on ebay even comes with two 12 inc fans and a mounting kit, so I might would go with that one if a dual fan conversion seemed like a good idea.

If I do a dual fan conversion I will probably do some custom wiring for it. I dabble in electronics on the side and rigging up a small Arduino chip to have modifiable temperatures for each fan to turn on and having override switches should be a fairly simple process (I've deleted my ECM in my system and have been toying with the idea of building an Arduino ECM replacement as a project anyway hehe).

Thanks for the info!

EDIT: Oh also I forgot to ask, if I have a manual transmission, and the radiator has the transmission cooler included, do I just plug those holes? I think my radiator now has them plugged but I'd have to look to double check.

grd_radar

yes, the more cores/ rows the more cooling. Most all air conditioned cars used a 4 row rad. duel fans can help also, as the primary turns on say at 195 and the sec. at say 210.

Steven6282

Hrm, if thats the case I'm wondering if an aftermarket radiator would even help my cooling any. I'm pretty sure the radiator in mine now is aluminum from the factory, and if it's already 4 cores since it is an AC equipped car, would there really be any improvement with another aluminum 4 core radiator?

This is the one I was looking at on ebay, if I did the dual fan conversion too:
http://www.ebay.com/itm/12-Dual-Fans...item1c2987ef13

TallTim

iTrader: (2)

re: do dual fans make a diff: when my 2nd stock fan motor was bad at idle in drive w/ AC it would get over 220 and it would stumble and stall. Would not start again until cooled down some. This is with new low end Autozone rad. and new water pump. Replaced 2nd fan motor all is well.

Steven6282

Yes but that is on a dual fan system. I'm questioning whether the smaller dual fans will make a large difference cooling compared to a single larger fan. I'm not sure on the diameter of mine off hand but just from memory I'd guess it's 16 or 18" Dual fans like the ones that come with the radiator I linked are much smaller (12" in this case) so each fan individually moves less air than the large fan (most of the time).

So I'm just questioning if two 12" fans will cool a lot better than a single 16" fan (or 18" whatever it is).

one92rs

iTrader: (5)

it will come down to surface area. 1 16" fan covers 16" surface area. two 12" fans cover 24" surface area. when i had the stock rs fan it did a good job. when i went to the 4th gen fans ( stock rad ) it cools much quicker.

Steven6282

Can anyone confirm this about air conditioned cars used a 4 row radiator? All the stock oe replacement units I can find for my car are either 1 row or 2 row.

Yeah, I did the actual math on it. A 16" fan covers ~201 square inches, dual 12" fans covers ~226 square inches. So they do cover ~12.5% more surface area, but they also move less air. So I don't know which way is better. I guess if no one can tell me for sure I'll have to decide if I want to spend the extra 60 dollars to get the radiator with the fans + the money on some relays and such to set them up, in order to test for myself which is better.

Edwardgp

Boy this is a hard one.

BlackenedBird

iTrader: (5)

Look for the threads talking about the Taurus fan mod. Apparently the single Taurus fan cools way better than the 3rd gen dual fans.

Edwardgp

The Taurus fan does the trick.

one92rs

iTrader: (5)

even though they may move a little less air they are covering more of the radiator. moving a little less air over more of the radiator is better than moving more over less.

grd_radar

I would have to agree with the dual fan setup. The manufacturers went to duals for a reason. More surfise area covered. Also check for cold spots on your rad when it is heated up. You might have a couple blocked cores.

Steven6282

That is true to a point. There is a balance to it. I know a bit about cooling in general from working on computers and overclocking CPUs and the like. More surface area at less air movement is not always better. If this were the case, you car should cool just as well with a cool breeze accross the radiator and no fans as it does when driving 60 mph down the road.

However in this case I think the dual fans move enough air that the increased surface area makes them the better choice over my stock fan. If I had a 14" single fan it wouldn't even be close and the dual fans would be the obvious choice.

But also now that some others have mentioned the single taurus fan, I have to take that into consideration.

I took some of my coolant to a shop I use sometimes yesterday and had them test it, apparently when I changed out my intake I screwed up the antifreeze - water mixture when refilling it enough that they think that might be causing some of my heat issues. So I've got them doing a cooling system flush on it today. Will see this weekend how it does and then decide if I'm going to go ahead and get a new radiator next week or not. I'm just worried based on the temperatures it ran at last year, a 4 row radiator that cools really well might cool it to much when driving at highway speeds in the winter and not let the oil get to 165 degrees operating temperature. Last winter it never broke 185 degrees, but that was the water temp, I don't have an oil temp gauge atm. Although I might have to get one of them.

one92rs

iTrader: (5)

1 gallon antifreeze with the rest distilled water and one bottle water wetter is all i use in all my vehicles and a number of industrial pieces of equipment. 2 14 inch fans should move more air than a single 16 inch fan. i have dual fans that are a set of 4th gen fans. i believe they are around13 or 14 inch fans. cool in half the time.

TreeFiddy

For me, fully shrouded dual fans made the difference over the factory single partially shrouded fan. As noted above it came down to engagement of more of the core area with sufficient airflow.

An Arduindo based fan controller is a bit overkill; I made a simple discreet circuit with op-amps using the factory temp sender as a reference, trimpot adjustment, override switch and dash leds. Works great.

abray1

one92rs is right about the antifreeze, distilled water and water wetter except I use two bottles. The surface area of two fans does cover more area but the name of the game is air flow (CFM). I have tried so many combos I should write a book. The taurus fan I have recently installed is easily twice the fan of anything I have worked with and brings my needle down quicker than dual fans. At one time I had 5 fans on mine and it didn't cool nearly as well as my current set-up. Most fans lose there effeciency by the air going around the side of the fans. I put a bead of gasket maker on my taurus fan and mounted directly on the core. This insures no air leakage. I have let mine idle in 105 degree heat and it never got above about 195-200 or halfway between 180 line and 220 line. This is with straight water.

Steven6282

Overkill yes, but a lot of fun Besides I've been thinking about adding an arduino to my car for other things. For example detecting the RPM and beeping with a piezo buzzer, as I get close to a preset RPM limit.

And the coolant flush has made a difference. Today running it fairly hard at an autocross it got up to about 200 once but quickly cooled back off to around 180 / 185 and stayed around that for the rest of the day. Guessing that one time it got a little high was just the fan not cutting on immediately or something for some reason. I'm still going to look into getting a better radiator at some point, but it's not as pressing of an issue now and I have some other things that will take priority. Thanks for the advice everyone, I'll be sure to take it all into consideration when I do work on it and play with the fans.

Where I messed up at with my coolant before was I just pulled the intake and didn't completely drain the system. So when I filled it back up mixing with what was already in there I didn't do it right.

TreeFiddy

You may have had an air bubble in the system, which you managed to burp out with the flush. Now that your problem is solved, I'll hijack your thread and go a little off topic

I would have been all over the Arduino or Stamp type microcontrollers 20 yrs ago, when I was heavily into hobby electronics and programming, and had wayyyy more time on my hands (rather than keeping an ancient needy V8 on the healthy list ). I am sketchily aware of the Arduino, you sound like you might be pretty well-versed. I too have wondered about using one for auto applications, like running a set of digital gauges.

Hardware-wise, do you know if can it handle multiple analog inputs, with little or even no signal conditioning? Eg temp, oil pressure, fuel senders etc.

biglano

what exactly is "water wetter"

abray1

Water Wetter is like purple ice. It is made by Redline. They make oil and other products like that. Doug Rippie uses there products and swears by them. Water Wetter is good for a 10-15 degree temp drop. Purple ice works about as well but you need to use two bottles of the stuff. They help the water lose temp by helping water adhere to metal better or something. I made a C in Chemistry so I lightly understand how it works.

Steven6282

Honestly, I'm not sure. I've got a good grasp on it but I'm still learning a lot. A lot of projects I do / want to do are learning projects for me as well as just fun to do. My full time profession is computer programming, so the electronic stuff is a nice little side hobby for me.

I know that the chip I use for most of my projects (ATMega328P) has 6 analog pins with an internal ADC. But you can only put 5 volts on those pins. I'm guessing the signal lines for a lot of stuff can be up to 12 volts, so you would need some voltage dividers to get that down to a usable level.

Then you also need a stead analog reference, if you are using an actual arduino board like the arduino uno (uses the ATMega328P), it has a built in 5v analog reference. The stand alone chip like I use only has an internal 1.1v analog reference, to go any higher would need an external analog reference. Should be able to achieve a 5v external analog reference with a 7805 voltage regulator though (5v regulator that can accept up to 18v input).

The only other thing I would question is speed. The ATMega328p is capable of 16 Mhz with an external crystal (8Mhz with internal but I'd use an external for more precise timing in this case). I know some of the signal wires work off pulses, so as long as 16 Mhz is fast enough to read all the signals / do whatever you need to do with them and restart the loop before the next pulse then it should be ok. Looking up the T56 for example, it's 17 pulses per driveshaft revolution. I'm not sure exactly what that equates to, going by something I read that the GM factory stuff works off 4000 pulses per mile / 40 pulses per revolution I'd guess factory stuff is around 100 driveshaft revolutions per mile. At 60 miles per hour that would be 6000 revolutions, or 102,000 pulses. I'm just unsure of the time frame for this. If that is per mile, then that means it's 1700 pulses per minute, or 28.3 pulses a second. I guess that sounds about right, almost 2 drive shaft revolutions per second at 60 miles per hour. The arduino should be fast enough to pick up that many pulses per second pretty easily. There is also a arduino library function to monitor pulse modulation on something though. I just haven't messed with it much to know exactly how it works, but I'm guessing it would be the best solution for monitoring pulses. I believe it works off one of the digital PWM pins available (11 of them).

EDIT:
Sorry that last part is wrong. The PWM (Pulse Width Modulation) is for output only, to make digital pins act like analog output pins. To do PWM style input you'd use one of the interrupt pins (only 2 hardware interrupt pins on the atmega328p, but I believe you can emulate more using other digital pins through coding).

EDIT2:
I asked on the arduino forums (http://www.arduino.cc/forum) and at 16Mhz external crystal 60 pulses per seconds would be pretty slow hehe. So it should be capable of handling that and everything else with no problem. I think that would leave only the hurdle of cutting down the voltages to under 5 volts so you don't fry the chip. And that isn't really a hard task. Just do a little math to figure out the size of the resistor to use going to ground versus the size going to the pin and it should be good to go. If you needed to monitor more than 6 analog signals, the ATMega2560 has at least 16 analog pins, it's just a lot harder to solder into a custom project since it's surface mount only and the pin pitch is really small. The Arduino Mega 2560 comes with that chip though to avoid the soldering if you needed that many.

TreeFiddy

I figured some type of signal conditioning would be required to convert the 12v analog into a 0-5v deal, like an op-amp in some adjustable voltage follower config with a zener clamp or something. Been out of the electronics thing for a loooong time now, I'd really have to get back into it before I could assess it I guess.

As for the pulse input for a speedo, I was assuming a programmable interrupt would be the way to go, happy to hear it's got one. I actually built a car computer in 1983, and stuck it in my first car. It was based on a Motorola 6800 processor, betcha never heard of that dinosaur! It had a clock of 1 Mhz and 2k of RAM in full 8-bit glory iirc. Used a 12" b&w television for a monitor, which I mounted right below the dash. Yep - a 12" in-dash monitor in 1983 - no I never took a picture

Yep - I was a geeky kid

It did only a few functions - speedo, trip functions, and fuel consumption (and a real lo-res Space Invaders), all in awsome b&w with 64 x 32 pixel resolution iirc. No analog inputs tho. The speed sensor was a coil of wire wound on a bolt mounted next to a pair of magnets epoxied to the tailshaft. After squaring that up, it fed into an interrupt line, who's handler just incremented a register. Every second that count was just converted into speed and distance data. I assume this tactic would equally apply to the Arduino - if a 1 Mhz clock could handle it back then, 16 would certainly have no problem now.

This will undoubtedly stay on my long list of ideas/projects I'll never get around to, but the Arduino platform does sound like it would be a lot of fun to muck around with.