question on egr!

[InvisiBill]

Also, the EGR dumping exhaust into your intake gets crap all over, which can increase knock. You should run some Top End Cleaner through it once you disable/remove the EGR to clean it out good. There's a howto up, at SyTyArchives.com I think.

If you have the stock chip, you will get the Check Engine light sometimes. The EGR test works by turning on EGR and watching for a reduction in fueling (due to the reduction in volume of oxygen). It actually watches for the results from opening the valve, so the only way for the test to not fail is for EGR to be working (i.e. you can't block off the EGR passages but leave the valve hooked up or something to fool it). I've had my EGR disabled for a year and a half or so on the stock chip, and I've seen the CEL maybe half a dozen times. While the CEL is on, it does limit boost.

If you want a quick test, just unplug the vac line from the EGR valve and plug it. It's obviously not as good as blocking the passage at the head and the valve could still leak, but at least you're not specifically dumping exhaust into your intake. Like others, I saw at least a 60 degree drop in IAT just by unplugging the EGR vac line.

 

[Beavis]

ok let me see if I understnad this some, the EGR pumps hot gases into the cylinders while criusing, so this is why I see 150-165 on datamaster for intake temps. But when I increase throttle, my temps go way down, (110-140 depending on how long I hold the throttle for). So is this why?

 

[InvisiBill]

ok let me see if I understnad this some, the EGR pumps hot gases into the cylinders while criusing, so this is why I see 150-165 on datamaster for intake temps. But when I increase throttle, my temps go way down, (110-140 depending on how long I hold the throttle for). So is this why?

Yes, the EGR pumps exhaust into the intake. This creates "dead space" in the cylinder (basically making it a smaller engine) and burns anything left over in the exhaust. The exhaust going into the intake heats it up. The increase in throttle probably also flows more air through your IC also, which will help lower IATs...

 

[white92tyincalli]

Ok guys, it's really just this simple. The purpose of an EGR is as follows: The intake manifolds are calibrated to accept 10% of the entire volume of air/fuel moving through it to have the inert exhaust gas in it. By doing this it reduces cumbustion flame temperature, to prevent the formation of complex oxides of nitrogen (NOX). Higher burn temeratures and pressure create NOX. With the EGR system disabled or malfunctioning detonation becomes a huge issue and can eventually burn holes through pistons. Normal EGR stradegy is closed at full throttle and at idle. There will also be no EGR operation until the engine reaches normal operating temp.

 

[little black psycho]

So is it worth the gain in power?

 

[Matthew Little]

egr

egr

Is putting a cold air intake worth the power? Yes, a turbo is a heat pump ,why would you not want to lower the intake temps any way you can. Thats why turbo cars fells so much better on cool nights and like crap on a hot day.

 

[white92tyincalli]

it is worth the gain if you have a chip to compiensate for the egr not being there

 

[sy112]

egr=bad

not that hard of a concept. pumps hot air, thus heatsoaking the intake and increasing IAT's while cruising around looking for a race. So when you do race you IC now not only has to cool the air charge from the turbo but also play catchup with all the heatsoak going on.

Does it make a difference, yes. Just go to the track and get some ice and cool everything down. Make a pass, then do a hot lap. You WILL see a slower time due to the heat, guaranteed. Might not be drastic but you will see a difference. And that is with you just heating it up after a pass, not 30 mins of cruising.

If it wasn't that big of a deal you wouldn't see 5 bags of ice sitting on top of the trucks waiting in the lanes at the finals of the Nats :wink:

If you have emissions, you might want to leave it operational, just chip it out to make sure you pass emissions with ease. Some have talked about having trouble getting through the sniffer without EGR.

 

[little black psycho]

I just asked that cause I would rather have reliability than a tenth of a second.

 

[InvisiBill]

With the EGR system disabled or malfunctioning detonation becomes a huge issue and can eventually burn holes through pistons.

With EGR enabled, our intakes get really hot (simply unplugging the vac line to the EGR valve will cut intake temps down to 1/2 to 2/3 of what they were) which leads to lots of detonation. In our application, intake temps are a bigger issue than the EGR.

The stock chip is also calibrated for a 195° thermostat. Most people switch to a 180 or even a 160. This will help keep things cooler even without the EGR cooling down the combustion chamber.