EGR blanking - more info?

JayJay · Post by **JayJay** » Fri Feb 10, 2012 1:56 pm

I've never really looked in to blanking the EGR port. Could anyone add a bit of info regarding the pros and cons of it? Why do it?

Post by **NafemanNathan** » Fri Feb 10, 2012 2:01 pm

The EGR valve allows an amount of exhaust gases back through to the inlet runners to basically be reburnt. This helps lower emissions, as there will be a small amount of unburnt fuel in the gases still.

So the pros of removing EGR is all the air/fuel mix that makes its way into the cylinders will be fresh and also at a lower temperature (Obviously the recycled gases will be hot already and therefore raise the temperature of the air/fuel mix, which we all know loses a few BHPs for every degree).

The cons of removing it are higher emissions and possibly lower MPGs. Also if you remove the EGR you need to ground the connection else it will throw a cel.

JayJay · Post by **JayJay** » Fri Feb 10, 2012 2:19 pm

The thing is, I read that the re-circulation of the gas can *lower* combustion chamber temperatures

I do like the idea of the mix being fresh though. Although blanking it off would kind of defeat the purpose of having my EGR ports drilled and capped

the EGR valve meters a readily available inert gas (actually exhaust gas which contains a lot of very inert Carbon Dioxide) into the combustion chamber to effectively reduce the volume. Smaller effective displacement means less fire, and less heat and thus lower temperatures, thereby controlling NOx emissions.

Although at WOT it's disabled anyway.

Supercharged 無限MUGEN BB1 Profile · Post by **nucleustylzlude** » Fri Feb 10, 2012 2:32 pm

It's used as a dampener in reality it's like adding more fuel when tuners need to dampen down the heat for risk of detonation. However, the fact it's exhaust heat - it's going to be hot! So how well it works for intake temps is negative I would argue. In terms of unburnt fuel it's certainly going to help emissions and mpg, but I think as a result of poorer performance.

I got rid of mine a while ago and having taken off the intake manifold and seen the crap it cokes it up with - I'm glad to get rid to be honest. Appreciate some of the crap is oil vapour from the PCV system too - all nasty stuff you don't want to throw into the intake IMO.

Post by **NafemanNathan** » Fri Feb 10, 2012 2:33 pm

JayJay wrote:
the EGR valve meters a readily available inert gas (actually exhaust gas which contains a lot of very inert Carbon Dioxide) into the combustion chamber to effectively reduce the volume. Smaller effective displacement means less fire, and less heat and thus lower temperatures, thereby controlling NOx emissions.

Yeah, read that again...

It's basically saying it fills part of the combustion chamber up with inert gas, which means less room for your new air/fuel mix, which therefore means there is less "fire", which then obviously means less heat. But this is referring to less heat in the combustion chamber after detonation, it's not lowering the temperature of the fuel/air mix before detonation which would mean you could squeeze more into the chamber which would then give you more power.

JayJay · Post by **JayJay** » Fri Feb 10, 2012 2:38 pm

Ah gotcha.

nucleus - I know. When I took my old intake off (just the chamber and the EGR port etc) it was FULL of desposits and oil. I've since had the EGR ports drilled and capped so I can clean it when I need to (maybe once a year or whatever) but it's the oil coming back in as well that I'd like to stop.

I may actually blank the EGR port off, see how she goes. I can always put the valve back on and plug it in! I do really need to get an oil catch can as well

JayJay · Post by **JayJay** » Fri Feb 10, 2012 4:09 pm

I read this:

CAUTION: When you run EGR you advance the ignition due to the burn rates being slower, therefore if you blank the valve, i.e. no EGR flowing but leave it plugged in so the ECU thinks its flowing, you could run into detonation problems.

Any work arounds? I'll most likely leave mine plugged in and just clean it up occasionally, but if anyone else comes looking

stk prelude · Post by **stk prelude** » Fri Feb 10, 2012 4:13 pm

best bet is to speak to Rich at PAW mate

Post by **NafemanNathan** » Fri Feb 10, 2012 4:15 pm

... So if you blank it and unplug it the ECU will no there's no EGR valve and compensate accordingly. Probably best Rich giving a definitive answer on this, but that's how I always understood it.

Where are you getting your quotes from incidentally?

Post by **NafemanNathan** » Fri Feb 10, 2012 4:16 pm

stk prelude wrote:best bet is to speak to Rich at PAW mate

Great minds ay?

EDIT: ... Suggest speaking to the greatest