Title says it...

if the point of the underdrive pulley is to reduce parasitic losses, is it a beter option than an electric water pump? I figure it is cheaper, difficulty to install is probably a wash but the pumphas the advantage of alowing the alternator to turn at full speed.

Can anyone help me out with advie on which is a better option and why? Does one free up more HP than the other? How durable are the meziere pumps?

For maximum power u do both. The Meziere pump has a 2500 hour life in most cases. I had 1 for my 03 Mach 1. Usual gain on a V-8 is around 12-15 hp. For the average enthusiast this is not the bolt-on to do solely do to the electric part. If it fails and u dont catch it in time, 1 motor coming up. On non daily drivers more then worth it.

If you do an electric water pump, doesn't that create a draw on the alt...creating more drag on the alt....?

No. The minimal draw from the electric motor is less then the parasitic
draw of the mechanical pump in terms of HP loss. Not to mention if you have UD pulley then it is even more efficient. Charlie

Usually people will do the ud pulley and then put a smaller pulley on the alternator to get it back up for proper voltage.

The electric water pump is not worth the potential headaches. A fuse blows, the motor craps out, wire disconnects, whatever, you are going to wish that mechanical pump was back. Keep your stocker in the trunk if you are out of AAA free towing range.

I guess it depends on the skill level of the installer. I had put 1 on and 3yrs later the same fuse, wiring etc. We had it rebuilt due to Meziere recommendations and the same wiring, fuse etc is still going. A lot of times components get a bad name due to the experience of the installer. At the same time I think it is better to have a mechanical pump on an everyday driver. Charlie

I agree a lot of the negativity is because of the install and not the pump itself. The 2500 hours is based on correct voltage, and whenever a crimp connector is used there is always a possibility of a voltage drop. Not to trash crimp connectors, I use them all the time.

Maybe someone can put together a harness setup that is more or less plug and play with weatherpack connectors, and also a light that lights up in the event of the pump going out. Basically, making it an idiot proof mod that everyone can enjoy without worrying.

A factory type harness could be made with ease. My professional opinion is save this type of mod for a non-daily driver.

Usually people will do the ud pulley and then put a smaller pulley on the alternator to get it back up for proper voltage.

The electric water pump is not worth the potential headaches. A fuse blows, the motor craps out, wire disconnects, whatever, you are going to wish that mechanical pump was back. Keep your stocker in the trunk if you are out of AAA free towing range.

Or just keep a spare fuse in the glove :)