I bought the turbo-swapped RX-7 and I am in the process of gathering up parts needed to upgrade the cooling system. Part of the plan is to include a Lincoln Mark VIII electric radiator fan. This is what I found out about the fan:
Estimates of CFM are between 4300-5500... it is a 2-speed fan. 1100 rpm in slow, 1850 rpm in fast... The Lincoln Mark VIII fan will draw continuous currents of 33A@12.0V & 42A@14.4V, and has a starting current in excess of 100A!
CFM sounds perfect for a heat-machine like a turbo rotary but the amp draw is huge. The stock alternator has an output of 80amps. I have a 95amp alternator from a '94 Mercury Topaz that will fit with little modification, but needs rebuilding.
Will the extra 15amps be enough or am I going to need a heavier-duty alternator? The next cheapest higher-output alternator would be a 130amp unit from a Ford Taurus, but it requires fabricating a bracket, which I can't since I don't have a welder or fabrication experience. I have seen rebuilt Topaz alternators online that can put out 170amps but they are expensive.
33A and 42A? Where did you get that figure?
What are the phisical dimensions for the fan?
A quick look here http://www.flex-a-lite.com/auto/html/electric-fans.html might get you a similar CFM in a smaller, lighter package with a lower amp draw. Not to mention weight savings for monster sized wires to run it.
different alternators are usually easy to swap in- personally, i'd skip the Ford parts and get one of the CS series alternators from a later model GM car and swap one of them in. even the small ones put out something like 105 amps, with the big ones being 140 amps.
they come in a few different mounting configurations, and pulleys are generally easily swapped from one alternator to another.
An FD alt puts out 100A and is an easy swap...just need to change the pulley if it already has an S5 alt connector. There are about eleventy-billion FD alt write-ups on RX7club that you can reference.
On the fan, are you sure you need that much? Taurus e-fans have been used by many with good results. Again...write-ups on this are all over RX7club.
In reply to novaderrik:
The Topaz alternator fits as long as you bore out a double-sheaved alternator pulley (i.e. from Racing Beat) to fit the shaft. You also need a ton of washers on the mounting pin since the mounting bung on the RX-7 is smaller than on the Topaz. The Taurus alternator requires a bracket to fit and position it correctly.
porksboy wrote:
33A and 42A? Where did you get that figure?
What are the phisical dimensions for the fan?
A quick look here http://www.flex-a-lite.com/auto/html/electric-fans.html might get you a similar CFM in a smaller, lighter package with a lower amp draw. Not to mention weight savings for monster sized wires to run it.
I found the post here (post #15):
http://forums.corvetteforum.com/c3-tech-performance/1441606-mark-viii-fan.html
The info came from a dead website but most of the muscle car forums say the info is accurate.
Three reasons I'm going for the Lincoln fan:
1) It's cheap ($50).
2) They're easier to find in the local junkyard than Taurus fans.
3) I'm worried that a Flex-A-Lite fan will not have enough CFMs or last long enough to be effective, even on the Koyorad Aluminum N-Pass radiator I'm planning on buying. Turbo rotaries generate a ton of heat and I plan on doing autocross and track days in the car in hot and humid New England summers. Many of the aftermarket fans move less air than even the stock RX-7 clutch fan. And I've heard that FAL fans crap out more quickly than OEM stuff. Since the Ford Taurus fan also has a high amp draw (starting current over 90amp, 33amp continuous), I will start looking at RX7Club for Taurus fan installs to see if I can adapt it to the Lincoln fan. If not, then I can always sell the Lincoln fan. They are in-demand with muscle car guys.
