SC400TT
Active Member
Good luck mate, the culmination of some major effort
Thanks Justen...
Ryan
Good luck mate, the culmination of some major effort
Ryan, as you know I'm not a fan of the Zirgo's. I think their ratings are overly optimistic, and you've already experienced their poor QC. FWIW, my 550 Ferrari came with SPAL's as the OEM setup, and they're 11 years old now and still working fine.....
I hope the Flex-a-Lites will help sort the problem, but be sure to build them a proper shroud. A good shroud is the only way to assure you're pulling air through the entire radiator core. I would also include the rubber blow out flaps as we talked about, and program your ECU to turn the fans off above 50mph.
FWIW, you may not have gotten the whole story on Dusty's pusher fan. All TT Supras came stock with an aux fan in front of the condenser so that it (the condenser) would get sufficient air passing through it all the time. It's especially critical when running electric fans that cycle on/off, as without enough air, the condenser will overheat, and the pressure in the A/C system will spike and cause the high pressure switch to open and cut out the compressor. It'll start acting like it's low on freon, when in reality, it's just the condenser overheating. Then some moron may decide to top up the freon in the system, overcharging it, and you can wind up with much bigger problems (AMHIK).
I'll have a close look at the Ferrari fan/shroud setup when I get home and see how they handled the air management.
Ok, first of all the original "shroud" was no such thing. The fans protruded to the core and the "shroud" surrounded them and was actually a air BLOCKER. The only flow you had was through the fan holes so you only had two 12" round holes for flow. The new setup without a shroud is much better as air can now flow through the entire radiator.
The new 14" fans should work better especially without the previous blockage. They also have back curved blades which should be quieter even though they are bigger.
A shroud will only help if you can create a plenum space for the fans to create a vacuum in. With the fans directly attached to the core a shroud will just block flow. Flaps on a shroud allow air to push through the core and not be restricted to the area left by a shroud. If you have no room for a shroud you have no need for shroud flaps.
As we discussed the DUCTING from the front of the car to the core is NEEDED to ram the air through the core as the vehicle speed increases. At low speeds and low to no load on the engine the fans work to keep things reasonable. At higher speed and load the engine creates more heat to deal with. This is where the ram air effect will flow more air than fans can IF you have proper ducting. This is why Mr. Cribb suggests turning off the fans above 50mph.
Proper ducting takes the air that enters the front of the car and SEALS it into a focused flow through the rad core. With a intercooler and air con condenser rad to deal with you need to SEAL the air flow from escaping around the radiator. So, from the car front build WALLS around the cores creating a tunnel for the air to be forced through. If your intercooler blocks and or heats the air too much you may need auxillary radiator capacity. Your initial highway runs are promising but this is an engineering exercise... some trial and error should be expected.
If you decide to get real fancy you can engineer some under car aero aids that could pull air out of the engine compartment reducing underhood heat and improving the air flow through the rad cores. Fancy and tricky are good words here.
The hot air is blocked within the engine and causing heat soak. Venting it out isn't enough. If you can push it out, it'll help big time. On my setup, I had thought about install a small e-fan at the bottom and between the radiator and the engine. This fan will suck in the air from the ground and blow the air up. It'll work similar like panel ducting......
Second, the main underside panel mates form the edge of the first panel and continues to cover the whole engine compartment form the bottom. This would force air rushing in to flow through the whole engine bay, and out the back. I figure this is playing a large role in overheating because the air is currently not flowing in the correct direction. In fact, the air is probably not flowing into the engine bay other than what the fans blow. I will see how this helps next.
Keep in mind that I have vented my hood...I will just remove the machine guns form the Aston vents, as they are probably blocking the air flowing out...LOL...
Ryan
Interesting discussion on shrouds. I have been running dual 14" pullers w/o any kind of shroud and on 100 degree days sitting in traffic, I never see the needl rise above the half way mark.
SC400TT, im sure your DB hood vents will help facilitate flow through the rad, acting like a drop vent hood.
Believe it or not this was covered in Corky Bells book...
Yep some seem to get away with cooling issues ..
Like I preach to my Mrs & kids...
Overheating is far far worse than running out of petrol !!!
The hot air is blocked within the engine and causing heat soak. Venting it out isn't enough. If you can push it out, it'll help big time. On my setup, I had thought about install a small e-fan at the bottom and between the radiator and the engine. This fan will suck in the air from the ground and blow the air up. It'll work similar like panel ducting.
what kind of radiaor are you using and how old? When i bought my 92 sc, it idled cool but at freeway speeds, it would overheat. Turns out the stock rad was plugged up with scale.
Believe it or not this was covered in Corky Bells book...
Yep some seem to get away with cooling issues ..
Like I preach to my Mrs & kids...
Overheating is far far worse than running out of petrol !!!