Does ANYONE have high-flow cats for Silverado?

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Apr 29, 2005 | 09:01 PM

#21

budhayes3

PT's Slowest Truck

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Joined: Apr 2004

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From: Hackensack, NJ

Quote:

Originally Posted by buktseat

Through what mechanizm does the computer let the fan relays know that it's time to kick in? I mean, I'm assuming it all works on the existing temperature sensing circuit that feeds the computer, and that's fine. But is there an open plug somewhere underhood that this relay harness plugs into?

Also, what do you folks have to say about the flexalite fans that end up being a bit cheaper? Any thoughts? And where might one get hold of the LS-1 fans you mentioned that don't require a radiator upgrade? Is there any reason to think that these would be inadequate?

I really appreciate all the info! Thanks!

From what I understand, the harness comes with a wire that you install into pin 42 of one of the PCM connectors, then you wire power and ground to the relays, and plug in the fans. So basically the PCM gets it's temp signal, and internally sends a signal (ground?) to pin 42...I'm not sure how the tuning guru's do it though (although I do plan on learining someday)

As far as the LS1fans go, I've seen them for sale in the classified section here, on ebay, want-ads, etc. Alot of folks here have used them with great results, I can't think of any reason why they'd be inadequate. I'm going with the 05's because I wanted the bigger radiator with the extra cooling capacity to begin with, and I like the fact that it's a clean swap that'll look factory original.

Apr 29, 2005 | 09:24 PM

#22

1slow01Z71

Tin Foil Hat Wearin' Fool

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Joined: Oct 2004

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From: Austin, TX

The flexaites and ls1 electric fans will let your engine get hot if you are towing. If you plan on towing and want the electric fans then you need to upgrade to the 34" radiator and the 05 electric fans then you will be able to tow safely with electric fans. And the fans are controlled by the pin on the computer thats down by the radiator on the drivers side.