97 Suburban Electric Fans ?

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L31MaxExpress

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Perhaps study up on what PCM managed EGR valves actually do. To improve cylinder fill ,cool off cylinder heads ,reduce/eliminate detonation ,and the list goes on.
I am up on it and know exactly how it works. EGR sucks on these engines. Gunks up the lower intake, the intake ports, the valves and recirculates carbon back into the cylinder bores. Not exactly what I call productive to engine life. Cylinder fill is REDUCED with EGR due to the inert volume of the exhaust gases as well as the intake charge heating. The stock spark table does not cause detonation without EGR provided the EGR is disabled in the tune. EGR causes a slower burn and less torque. The amount of heat into the heads is negligable at most. Better to run lean cruise and no EGR for both MPG and engine life.
 

L31MaxExpress

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EGR allows more timing to be used at light throttle cruise without detonation which leads to better MPG.
EGR allows more timing because it REQUIRES more timing to properly burn the mixture with extra inert exhaust in the mixture. More timing is not necessarily a good thing as the more you advance BTDC the more negative work you do on the crank as the cylinder pressure builds before the piston hits TDC.

Regardless the EGR opening is minimal at light throttle cruise on a Vortec. The valve opens nearly wide open at slow speeds and under load, but closes nearly entirely at highway cruising speed. The result is less torque at part throttle around town, requiring a heavier throttle foot and near zero difference at highway speeds.
 

GoToGuy

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Hey mr big talk, some of us live in states where we don't have the luxury of ripping all the emissions controls off. Comparing your built-up engine with stock vortec are apple's and oranges.
I own 86 k35, 95 k25, 93 k15, 98 K Tahoe, 90 stepside. 07 mini for wife. Eat rocks.
 

Erik the Awful

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You do realize that both of you have valid points, right?

EGR is designed to reduce oxides of nitrogen in the exhaust. That's it. Anything else is just a benefit.

Removing your EGR is illegal. If you can make it work, leave it in place and deal with it, especially if you live in a place with higher population density.

Prepare to take a hit on gas mileage deleting EGR as well as throttle response as cylinder temps go sky high. No tune can compensate for loss of EGR.
This is a gross overstatement, so overstated that it's bad info.
 

L31MaxExpress

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Hey mr big talk, some of us live in states where we don't have the luxury of ripping all the emissions controls off. Comparing your built-up engine with stock vortec are apple's and oranges.
I own 86 k35, 95 k25, 93 k15, 98 K Tahoe, 90 stepside. 07 mini for wife. Eat rocks.
I did not rip any of it off except had it off when I ran the marine intakes. Although when I built the 383 I went back to the truck manifold. The egr port inside the manifold is plugged off and it is turned off in the tune. Mine still went through a smog check, its all there to this day on the 383 even. If I need to I can always remove the threaded plug I installed and turn it back on.

Mine was stock and tuned stock when I compared having it operating vs disabled.

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stutaeng

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So how was it possible to remove the EGR systems altogether on the early 2000s engines? Better or more precise tuning/timing? ECUs with a bit more power and/or processing speed?

I'm not even sure if the Gen V engines have EGR systems anymore, do they? It was probably something that at the time worked, but they found a better way to achieve the same without the valve? I think diesels still use EGR (?), but that's another subject.
 

SAATR

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So how was it possible to remove the EGR systems altogether on the early 2000s engines? Better or more precise tuning/timing? ECUs with a bit more power and/or processing speed?

I'm not even sure if the Gen V engines have EGR systems anymore, do they? It was probably something that at the time worked, but they found a better way to achieve the same without the valve? I think diesels still use EGR (?), but that's another subject.

It was briefly mentioned earlier, but to use F-bodies as an example, the camshaft profile changed on the later 4th gens (and the tune, I'm sure) to reduce lift and duration and increase overlap very, VERY slightly. It had the same effect on NOx as the EGR system, so GM removed it.

Can the same be accomplished on the L31? Absolutely. I just doubt anybody is going to spend the time, effort, and money to run these trucks with different cams and tunes on a dyno with a sniffer to back that up. Even if that were done, it would still be illegal, as nobody is going to go to the further expense of emissions certifying a mod for one of our obsolete engines.

I also find it HILARIOUS that there are so many feathers being rustled over this conversation. I don't see nearly this much interest in the plethora of carburetor/header/full exhaust installation threads that pepper the forums, especially on the environmental tack. If we're going to harass folks for defeating emissions, let's do it with an even hand.
 

El Tigre

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Oh ,I'm sure if one scratches the surface one can find plenty that believe carburetors are vastly superior to fuel injection. HEI distributors are better than PCM controlled ignition. Etc ,etc... Opinions masquerading as fact regardless of published research contradicting it. Don't really care what people do with their own vehicles ,but when they pass along their bad advice to folks who don't know any better? Guess they get to learn the hard way huh....
 

Frank Enstein

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Im installing electric fans to get rid of the giant fan shroud and have a ton of space in front of the accessories for easy maintenance. Also will be deleting the egr, carbon canister and anything else that isn't necessary that's clogging up space.
Plus up here in Michigan it's freezing and i would like to get heat much quicker than i am with the mechanical fan running from start up on!
This is my go to controller. https://www.summitracing.com/parts/der-16789
 
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