Need straight answers on LS1 fan install...

[Moze]

...and that's basically it. Do the LS1's bolt directly to where the current fan bolts on? If I could get a good summary of the install steps, I would sure appreciate it.

I'll be installing them on a 2003 Silverado 5.3.

Thanks guys...

[Slowprocess]

Originally Posted by Moze

...and that's basically it. Do the LS1's bolt directly to where the current fan bolts on? If I could get a good summary of the install steps, I would sure appreciate it.

I'll be installing them on a 2003 Silverado 5.3.

Thanks guys...

Moze....Here's a few pics that will show you one of the easiest ways to go about doing this install. These are not my fans installed(I made a different bracket setup out of stainless steel for eye candy), but it gives you an idea of what to expect on installing them.







Now, as far as making them fuctional. There are 3 main ways to do this. You can by a variable speed controller from your local parts store that is made to power the fans. This will have a probe that is placed in your radiator to determine temps and control the fans.
You can also build a 2 or 3 relay fan controller setup, which is explained in detail here...... http://www.cardomain.com/ride/766391/3
The third option is to purchase a fan harness made by Allen Nelson. It is extremely well made and looks completely factory. This is the option I took. Check Nelsonperformance for more info.

On a side note..if you choose one of the last two options, you are going to need either a custom tune or a tuning program such as ls1tech to turn on the fan control feature in the pcm. This will enable the fans to turn on at a certain temp determined by the pcm, as well as one coming on when the ac is on. Hope this helps you out some.

[Moze]

Awesome - exatly what I needed, thank you! Is it esentially the same situation for attaching the bottom?

Did you notice a significant increase in hp? If so, where (low end, mid, high)? From what I've read, switching to electric can give you around 20 additional hp...does that sound right?

Thanks again for the reply!

[jethro_3]

In the bottom rail there is a pin that you can rest the fans on or drill a hole in the bottom of the shroud to rest the shroud into. That is what i did, makes it real secure...

[Moze]

Cool - how about the 2nd part of the question...increase in hp...?

[Slowprocess]

There's definately horsepower to be made from the loss of the parsitic drag of the clutch fan, but its extremely noticeable when temps get to where the stock clutch fan would normally engage. I would say gains as much as 15-20 could be had in that situation. The truck always felt extremely weak when the clutch fan locked up(which was quite often). It's definately a worth while mod, and my fans cool the truck better than the clutch fan did. It really opens up the engine bay with the removal of the clutch fan and shroud as well.

[jethro_3]

Let's see.... clutch fan spinning at any speed -> loss of power appx 5+ hp. clutch fan spinning at full engage -> up to 18+ hp. electric fans not on at all -> no hp. electric fans on high draw on alt -> appx 1/2 hp. Simple math. Plus the engine already has a temperature sensor that the computer can use. The clutch fan uses a fluid that senses the temp of the air after the air has come through the radiator... a little too late in my opinion. As accurate as the gauges were in my truck the temps came down almost 10 degrees and would never go up once warmed up unlike the clutch fan.

I did the LS1 fans on my '01 and would do it again if I had to. Almost all Chevy and GMC trucks now have electric fans since the '05 year.

[Moze]

So do the electric fans out of the '05 or newer trucks work in the '03's?

[Moze]

OK, Pep Boys is listing an electric fan setup for an '03 Silvy...?!? I didn't think they came with electric fans?? Price is $89 which makes me wonder if I shouldn't try that option rahter that the LS1's?

[Moze]

And yet another follow up...

The fan at Pep Boys is a single fan. So no go there. I went to a local salvage yard and picked up an LS1 for $100. Next move is to get the wiring harness from Nelson.

Anyway, just wanted to thank everyone for their help up to this point. The only thing I'm not sure about is how to tune the PCM to turn Pin 42 on....Can that be done at any mechanics garage?