Hey Mark, just curious the reason for using the Caddi fan and shroud instead of the Mark VIII fan I've heard so much about. Thanks Shawn

Looks like they make a nice radiator, Ill have to keep them in mind for future projects. Also nice that they are right here in Michigan.:thumbsup:

I have a DeWitts radiator on my TA and always recommended them to customers for their Corvettes. Great product and company. :thumbsup:

I'm wondering how available Mark VIII fans are now-a-days. That car hasn't been in production in a long time. I wonder how a C6 fan would compare? We should probably start a different thread so this doesn't get lost. It would be good to compile info on different factory fans especially since they are using Delta controllers now instead of own/off switches.

The Mark VIII fan is still a great part but it is a brushed motor and 1990s technology two speed fan. Not sure it’s flow rate but its power requirements on high speed is 25 amps or it’s a 300 W fan. The SRX fan is a brushless PWM (Pulse Width Modulated) fan that is rated at 850W (70 amps at full power). But, it is PWM so it only runs as hard as it needs to based on three inputs to the ECM – Engine Coolant Temp, A/C head pressure and Inlet Air Temp. So just cruising around the fan is very quiet only running as needed. The SRX fan is the biggest most powerful fan in production on a GM vehicle. (Don’t go buy one unless you can PWM it!) A couple manufacturers are working on a controller for it. Also it is huge so it is a very special application to use it. If you are not making over 700 HP and attempting to road race it don’t mess with it.

The other benefit to the large fan and shroud is I get a lot more face area and I can thin my heat exchangers up a bit. This engine rad had a thinner core but 20% more face area than Mayhem. I also uncovered the top 25% of the radiator to help cooling on the first pass of the double pass cooler. With a double pass radiator you can package the engine oil cooler and the other coolers in the driver’s side end tank. The C&R engine oil cooler is HUGE. A 7 lbs stainless steel deal. The guys at C&R are the real deal and helped me size the cooler for my application. They could have built my whole radiator but the Dewitt guys are in MI and can custom build cores. I like to drive over to a shop and work hands on. I’m very happy how it turned out.

Dewitt also made a custom core intercooler radiator to nest in front of the engine radiator. Because Dewitt custom made the cores the cores are the exact same width. Nested in front of the intercooler is Vintage Airs larger condensers. Again more face area to help reduce pressure drop.

With the Anvil lower valance all opened up I’m mounting the A/C and the intercooler low to pick up that air flow. I will also duct all the air though the coolers with close out.

Mark

[QUOTE= I wonder how a C6 fan would compare? We should probably start a different thread so this doesn't get lost. It would be good to compile info on different factory fans especially since they are using Delta controllers now instead of own/off switches.[/QUOTE]

Red Devil started with a 400W fan Corvette fan and it would not keep up. The SRX is 850 W and has a lot more power. When I swapped fans on Red Devil the temps were more under control.

Mark

Great source for thermostatically controlled oil bypass:

http://www.improvedracing.com/oil-co...ine-p-209.html

http://www.improvedracing.com/oil-co...gine-p-33.html

If cannot package (due to headers, frame, no LS engine...), can use this:

http://www.improvedracing.com/oil-th...stat-p-55.html

Having oil-to-water heat exchanger also helps warm up the oil after cold start, but still recommend having t-stat to control flow until desired temps are reached.

Nice feature on all these type bypasses is they never block flow to cooler, just open a 'bypass' to allow oil to return to engine prior to reaching temp set point. This allows some flow to always occur through cooler, so by time temp point reached and bypass is closed, not hitting engine with a slug of cold oil.

Dave

Since this discussion is already going here, does anyone have any thoughts on this. http://www.frsport.com/Greddy-124011...t_p_12814.html

Remote filter with built in thermostat, seems like it could solve some plumbing/packaging issues.

From the description is sounds like it's just a thermostat and not a bypass. So as Dave mentioned, you'll hit the engine with the cold oil that was in the cooler when the thermostat opens. Maybe I'm reading it wrong though.

Here's what a couple people I know are using and C&R says it should work good to help control oil temps with the bypass valve.

http://www.crracing.com/custom-built...r-bypass-valve

Do you feel that the fan power is needed for cooling on the road course ? I always kind of thought that 85+% of the cooling was done at speed and the fan was mostly for < 40 mph. I assume you overheating concerns aren't so much at idle since you keep mentioning the road course and HP.

Any thoughts on that ? IOW, at your average road course speeds do you feel that the fan is still doing significant work ?