Advice on cooling/voltage

[TuRBoTaLooN]

I just wanted to get some advice from some veteran dsmers here. I picked up my 95 TSi AWD a few months back and have a 06 cobalt ss s/c for my DD right now. However, I need to get rid of my Cobalt as the monthly payments are too much. So I'm trying to make my Talon more "driveable" on a daily basis. The only issues I am having is with my voltage and overheating when the a/c is on cruising. Let me explain a little more...

I have a FMIC (small core), long route piping, 16g (internal wg), and my jpipe goes to the driver side (right between exhaust mani and radiator), and a slimline fan for the a/c fan wired to a switch in the cockpit. My first issue I noticed was on the highway, the temps rose significantly while cruising at around 70 (probably due to lack of airflow to radiator). When I slowed down, the temps dropped significantly. The slim fan helps when it is on, but when cruising it doesn't help as much. I recently flushed out the rad and put in two bottles of watter wetter and the rest filled up with water. The car runs really cool right now, but I havn't tested it on the highway yet, just around town. I also plan on building some sort of ducting to bring air from under the bumper up to the radiator and possibly from the sides through the bumper.

Another issue I have is that my voltage seems to drop a little too low. When I first start up the car (when it's cold), the voltage jumps to around 14.0. At this point, I can drive around with music on (no subs, just stock speakers), lights on, wipers on, a/c on, a/c fan on, no problem. Voltage gets down to maybe 13.4 with everything on. However, after driving around for about 20 minutes and the engine bay gets warm, the voltage drops to 12.5 or below with a couple accessories on. With all accessories turned off (lights, a/c, radio, etc) the voltage goes to around 13.0, 13.1.

Here is my question. Would keeping the alternator cool (heat shield, air ducting, whatever) help keep the voltage up? If so, what would be the best method, and please share experiences. If not, would you suggest a new alternator? 75amp or 90amp? Also, any advice on ducting air to the radiator?

Any ideas are greatly appreciated guys. I did search a little and have some ideas, but I wanted to see what advice you guys gave on my specific situation. Thanks in advance.

 

[DGajre777]

Heat reduces alternator output, you can look into a vent in the hood. I wouldn't put a heat shield on an alternator, simply because it needs airflow to cool. If you put a shield on it, the heat that it puts out may be too much for the alternator since it won't have anywhere to do.

75 and 90 amp alternators are the same. The 90 amp alternators are Canadian amps rated to 90 amps, in the US they are rated at 75 amps. Why do you think the alternator has a 100 amp fuse instead of a 80 amp fuse?

Does the voltage drop to 12.5v at idle or at cruise?

As for radiator ducting, you can fabricate something. Check the tech guides, there are a few people who have made FMIC ducting.

As for suggestions, wire the slim line a/c fan to come on with the main fan.

 

[TuRBoTaLooN]

Does the voltage drop to 12.5v at idle or at cruise?

As for radiator ducting, you can fabricate something. Check the tech guides, there are a few people who have made FMIC ducting.

As for suggestions, wire the slim line a/c fan to come on with the main fan.

The voltage drops to 12.5v at idle.

As for the fan, I have no problem just switching it one when the motor gets hot, but when I do, the voltage drops 0.2-0.5volts. I guess I really just need to duct air to the alternator.

 

[DGajre777]

The voltage drops to 12.5v at idle.

As for the fan, I have no problem just switching it one when the motor gets hot, but when I do, the voltage drops 0.2-0.5volts. I guess I really just need to duct air to the alternator.

Check for corroded terminals and wires, especially on battery, battery to ground and battery to alternator.

Instead of making air duct for the alternator, look at doing the grey forest mod to allow hot air to escape the engine bay.

 

[TuRBoTaLooN]

Just put a new ground wire on the battery, and a new battery less than a month ago. I checked the wiring by the alternator and happen to come across a wire that got disconnected. I took the best pictures I could and they are below. Anyone know where they go?

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Sorry the pics aren't that great.

 

[Black 95 TSI]

That looks like the wire that goed to the PS pump, You will notice on the PS pump there is a termial by the mount bracket. The wire if for the ecu to see the pressure on the pump when you turn the wheels

 

[fourreGsixty3]

OK, for 1 you want some anti-freeze in your cooling system as it provides lubrication for such things as your tstat. You may want to check your rad. cap for corrosion/dry rot on the seal, if either of these are present replace the cap. You can also remove the rubber piece that goes along the back side of the hood( between the hood, and the firewall, and just infront of the wiper galley), then you can take a few thick washers, and remove the bolts that hold the hinge to the body for the hood, then slip the washer's under that(so the bolts go through the washer's), then bolt the hood back down. That will allow hot air to also escape from the engine bay. Also someone on here used a street sign( or any piece of metal thats roughly 20"L x 6"W x 3/8"T. Then you can attach this to the body between the radiator, and FMIC. This will act as a scoop, and throw more air at the radiator.
Here is the link to how he did it with pic's... http://www.dsmtuners.com/forums/showthread.php?t=224201

Sorry I can't really help with the wires.

 

[TuRBoTaLooN]

Thanks...I'm actually not running a thermostat for the summer. There is a little antifreeze in there, but very little. Also the two bottles of water wetter work as an anti-corrosion/lubrication agent.

If that wire goes to the PS pump, I checked all the other wires and they seem fine. They were all tucked away in that plastic wire tube. I peeked inside and they all look 100% fine. Could this low voltage just be the alternator going bad? It looks pretty old and worn. As I said, I bought the car a few months back and never changed the alternator myself, and I don't know when the previous owner changed it. Also, it only seems to have low voltage after the car has warmed up for about 20 minutes or so of driving.

 

[fourreGsixty3]

No tstat? Ummm...it doesn't get THAT hot in Jerz. You could always drip 3-4 holes in the outter ring of the tstat (roughly 1/16"-1/8" in dia.) this will allow constant flow of your coolant. By the way do you have heat sheild's on your o2, and exhaust manifold? If not throw both of them back on, they are proven to help lower temp's in the engine bay, and keep the dangerous heat away from your plastic fan blades.

 

[TuRBoTaLooN]

First, the wire did go to the PS pump and I plugged it back in.

Second, I do have the heat shield on the exhaust mani, but not on the o2 housing. I don't have one. But i'll pick one up asap.

 

[Dr3wStx]

Don't worry about that voltage it's fine. The alt loses efficiency as the heat builds up.
If you're getting these readings from your TT, or a digital gauge they are not 100% accurate since they are usually tapped into a switched 12V source under the dash. If you want to really know how your charging system is doing, put a voltmeter across the battery posts when the car is running. That will give you a true idle voltage.

I have the same overheating problem... I'm running a 40/60 mix of antifreeze/water with a bottle of water wetter. I wired my fans together, that fixed my normal cruse/highway driving. The car still overheats in traffic hot days with the AC on (ac off is no problem). I created a shroud between the fmic and the rad that doesn't allow air to flow around. I also picked up 2 12" slim fans that I'm going to replace the stockers with.

I'm fairly sure thats going to solve my overheat issues once I get the fans in.

 

[TuRBoTaLooN]

After flushing my rad and adding 2 bottles of water wetter it runs fairly cool now.

I just built a heat shield yesterday for the o2housing and some of the dp to block that excess heat from getting to the alternator. However, my alternator pretty much just took a dump on me as the car's idle voltage dropped to around 12.0. Just going to replace it tomorrow and see what happens.

 

[TuRBoTaLooN]

I feel like an idiot.....

Happen to just check the alternator fuse and it's completely blown. Going to replace the alternator anyway as it looks old, along with the fuse.

 

[Defiant]

I recently flushed out the rad and put in two bottles of watter wetter and the rest filled up with water.

Put in 30% Prestone immediately. You now have too little protection against corrosion, electrolysis, and water pump seal failure.

Never run a modern engine without a thermostat.

 

[TuRBoTaLooN]

there's a small amount of antifreeze in there. i just need to test what the mixture is.