[BILTIT]

Are they all on seperate relays?

[george kujanski]

I checked out the Spal website, their 16" fan is rated 2800 CFM and 22 Amps.
Their 9" fan is 740 CFM and about 10 amps. That's running current, keep in mind that the starting current for these fans can be 3-5 times the running current.

George

[65gto69]

George,

Would I be better going with 2 smaller fans, than using the one big fan?

Would it pull less current to run 2 smaller fans?

Would I get the same cooling power with 2 smaller fans than one big fan?

Biltit,

I am not sure what you guys mean by relays? Each one is on its own toggle switch on/off that is it. I kind of know what a relay is, what advantage would it do for me rather than just having them on on/off switches?

Mark

[george kujanski]

65: at least with 2 smaller fans, you can "stage them" i.e turn on one at a time, relaxing the initial electrical load. You can also turn on only one if it'll do the job of cooling.

Mechanically 2 fans may cover more of the total area of the radiator rather than one large one.

A relay is a electrical device where a small current in the relay coil controls a large current to a device like a fan.

Typically you can run a shorter heavy wire from the battery to the relay and then to the device (fan), and a smaller wire from the relay coil to a toggle switch. The toggle switch only needs to carry the small relay coil current.

Using the fan as an example, the main advantage is you don't need to run a large gauge wire from the battery to the toggle inside the cabin and then back out to the fan, You can have the relay under the hood, kind of how a horn relay is typically used.

George

[BILTIT]

http://forums.maxperformanceinc.com/...d.php?t=454036

Some good reading on relays. You DO need relays if they are not already installed!!!!

[lust4speed]

Originally Posted by 65gto69

LPete,

I am running mechanical advance, no vacuum advance. (From Post #30)

Mark

What LPete said still applies to mechanical advance. A small increase on the load of an engine can decrease the idle enough to decrease the mechanical advance, which in turn drops the idle more. Solution to this, if it is part of your problem, is to have the mechanical advance come in above the critical RPM range. For instance, if you have a constant 12 degrees advance from 0 to 1,600 RPM, your engine won't be subject to any additional RPM reduction from timing when it drops a bit.

The alternative that you might be experiencing is having 12 degrees total advance at say 1,600 RPM and the RPM drops off a little and the engine drops back to its baseline 6 degrees initial advance - engine drops off a cliff and RPM drastically drops.

[lust4speed]

Also, I don't believe this was mentioned above, sorry if it has been. Rather than run a large fuse I simply came off the main power feed with a short 6" section of 14 gauge fusible link attached to the 8-gauge to the relay and 8-gauge to the fan motor. I'm running the Mark-VIII fan and while it does draw big current the system has worked excellent. The fusible link will take the high initial amp loads with ease, but still protect the fan circuit. I also run two relays in parallel for each fan speed. The electric fan is on the drag car where I don't turn it on until after the finish line. I still much prefer the stock fan with HD fan clutch for my street rides.