Bartman

Did you try disconnecting the alternator? I had one go bad and it constantly drained the battery.

Matt, With the testing you've done are you able to say that the ducting has actually succeeded in making your car run cooler? I've been playing with this for a while, and I'm not convinced I've been able to get it to run any cooler than it does without any ducting whatsoever.

So I got the Spal 4" fans I mentioned in my last post and went ahead and set one in place. I think I will fill in the couple of vent holes I made previously, but here's a couple of pic's showing what I'm planning. I also added a piece of wire mesh to the inside to prevent debris from getting kicked by the tire into the fan blade.

My cowl panel is fiberglass with a carbon fiber layer on top and I installed the fender vents myself. This Spal fan may just be the ticket since it is small, moves a good amount of air, and is waterproof: Spal 4" fan

I guess computer fans actually use 12V, so this may be a great solution. I've even found 250mm fans that move over 105 CFM! 250mm fan. I think your correct with the 120mm fans being easier to fit, so I'll probably give them a try.

Computer fans may work, in fact I seem to remember a post on some other site that did just that - but don't they need to be changed to run on 12V? Venting out the cowl may work, but my cowl panel isn't vented and my outer fender already is, so all I should need to do is add more venting and a fan to the inner fender to move lots of air. I won't be messing with my exterior at all.

Yes, I have and I've even posted my radiator ducting with pictures...but no reply. I'm looking for specific information regarding venting hot air out of the engine bay like what cygnusx1 posted (thanks cygnusx1). I'll probably just move forward with this experiment, it's just a matter of determining the best size fans to use.

I have an airbox to the radiator and it doesn't seem to make much difference. I seem to have plenty of air getting through the radiator, but not enough hot air leaving the engine bay. I've thought about inspection lid venting, but since I have fender vents already it seems to make sense to try and use them to rid the engine bay of heat.

So I've been having ongoing problems with cooling on my Z. I've made several changes over the years and it works fairly well until it gets really hot (over 90 degrees or so) and I use my A/C. The other day I test drove my car around my neighborhood on a hot day with the A/C on and sure enough it eventually starting running hot. I pulled into my driveway and kept it running with the A/C on and the hood opened. It started cooling down almost immediately and went back to normal operating temperature, so I figured that I need to find a way to get the air out of my engine compartment. I don't have a vented hood, but I do have vents in my fenders, so I'm thinking I should hook up fans and make them functional. So I pulled one of my fenders and am looking at a couple of fans I already have laying around. It would take considerable amount of work to make these fit, or maybe I can find some smaller ones. So I'm just throwing this idea out there to see if anyone has any input on. Here's a few pic's:

So based on the testing on my setup, it made my car run hotter. Has anyone actually decreased their operating temperatures using a very small inlet with steep angles? While I think that some ducting can be helpful, it can actually hurt if done incorrectly. I made shorter ducts with less of an angle to avoid unwanted turbulence, os I hope I get beter results with this setup.

So my car runs hot, and I've made some wholesale changes to try and help it run a little cooler. I'm running A/C, and before these changes it would run okay with the A/C off, but as soon as I'd turn it on it would run about 15 degrees hotter. So here's my mockup that I thought I'd share to see what you think.

Thanks for clearing up regarding your setup, but I think an insulated terminal block would be a better ground point than a bolt installed in a firewall. Regarding the positive side, I have several accessories that came with their own inline fuses and thought that a terminal block would be a good way to give it battery current without going through my fuse block which may not be suitable for the amount of draw these accessories require (such as driving lights, amp, HID lights, fuel pump, etc.). Obviously there are others that feel the same as I can find several sources for this type of product.