Any heat exchanger will be an upgrade from the Roush unit. What size pulley are you planning on running, im guessing either a 82mm or 79mm. With either of those you are not really spinning the blower hard so you are not generating that much heat to begin with.
The only data I can provide you is from my VMP heat exchanger. I recently did a pull in third gear from 2k RPM all the way up to 7800. At the start of the pull my IATs were 113 according to my log. At the top when I let out they were at 89 degrees. They dropped throughout the entire pull until 6900 and then they leveled off at 89 degrees. This was with ambient temperature around 80 degrees. If I were to do a long extended pull the IATs would rise, I am just trying to provide you real world factual data.
Here is some data from a part throttle / idle log. I did a very slow pull in third gear from 1200 up to 5k and then the car sat and idled for about 4 minutes. Beginning of pull IATs were 118, after pull and idling my temps rose to 129. This is a great simulation of what you will see when driving around town. Once I am moving the temps drop very quickly which is what you want to look for. The faster your temps recover show how efficient your HE is.
There is a huge debate on fanned vs no fans. It all comes down to what you use your car for. If you are into road racing then do not go get fans. If you drive in stop and go traffic or are into drag racing, fans are great to have. I have my pump and fans wired to a switch so I control them, I am not a fan of the pump and fans running continously. The only time I use my fans is when I'm in traffic or after a 1/4 mile pass and I'm trying to cool the car off. What I have noticed through my datalogs is that while idling with the fans on the IATs still rise but at a much slower rate when I have fans running. I have not conducted any test with my fans off the car but I can tell you my temps drop fast when im moving.
Another item to consider for lowering IATs is an ice tank or bigger coolant reservoir. The more volume of liquid you have the longer it will take to heat up. I chose to go with the VMP underhood tank which holds quite a bit more fluid than the stocker and looks way better in the engine bay. You do not have to run ice to see the full benefit, the additional coolant in the tank will help keep your IATs lower.
Thanks, I've pretty much made my decision now (based mostly on information provided here). I'm going to contact Pro-Dyno and see if he has a pipeline to VMP for the fanless model. The price of the fans isn't justified for my use. It is a daily driver, but I don't see heavy stop/go traffic on a regular basis. Perhaps 5-6 times in a year. Most of my driving is over 40MPH. So I'll be installing the VMP unless the shop has some magic up their sleeves that would convince me otherwise.
Regarding the Pulley size. I don't know at all. Dan told me I'd be running about 10-11 psi.
If the shop has no pipelines, I'll find out and order myself.
Does VMP offer any discounts for disabled/retired veterans? Anything I can do to shave off a few bucks helps. If there is a coupon code, or a senior/disable/veteran discount of some sort, I'll apply that and make my order this week. I'm going to check in with the shop to let them know what I'm doing before placing the order.
You and handlebar Moustache have been a great deal of help. Thanks for that...
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