08-07-2012, 11:51 AM
There are gains to be had from disabling the EGR.
I haven't done extensive testing with a blanked EGR, but I would say to get the benefits you ideally want to also de-activate it by unplugging it.
EGR essentially scavenges exhaust energy at transient and low to mid engine loads to use that exhaust gas to make the combustion richer.
The problem is the system can never be intelligent enough to know what you are planning to do next, or what you want from the engine, so it is a compromise. The EGR basically takes away energy that you might want the turbo to have access to to spool up faster.
In all cases this means any part throttle to full throttle acceleration is started with a half second pause to the EGR closing, so for that first part of acceleration the turbo isn't getting as much energy as it could. This is basically artificial turbo lag and it is noticeable in blind testing, and imo it's quite significant.
I think with EGR blanking you may reduce this issue quite a lot, but technically the EGR system volume is still present and stopping that volume being accessible in the first place by just unplugging the EGR is a much better choice.
I'm not really sure what blanking does, I suppose it makes more sense on later cars (206/307 etc) where a visible warning is left on the dash if you unplug the EGR. In those cases removing the vacuum pass on feed to the EGR actuator is probably the next best fix.
Blanking plates are cheap and easy to fit so probably worth doing. It might improve the air flow pattern into the intake manifold, then again it might hurt it. I've not done any testing to know, but it's probably nothing to worry about.
So to sum up, stopping EGR working via unplugging or intercepting the vacuum feed to the actuator will get you 90%+ of the benefits. EGR blanking plates might not get you all the benefits due to the EGR volume still being fed to by the EGR valve, so you still need to de-activate to assure you get the actual gains that are available, those being throttle response and turbo lag improvements.
Thanks
Dave
I haven't done extensive testing with a blanked EGR, but I would say to get the benefits you ideally want to also de-activate it by unplugging it.
EGR essentially scavenges exhaust energy at transient and low to mid engine loads to use that exhaust gas to make the combustion richer.
The problem is the system can never be intelligent enough to know what you are planning to do next, or what you want from the engine, so it is a compromise. The EGR basically takes away energy that you might want the turbo to have access to to spool up faster.
In all cases this means any part throttle to full throttle acceleration is started with a half second pause to the EGR closing, so for that first part of acceleration the turbo isn't getting as much energy as it could. This is basically artificial turbo lag and it is noticeable in blind testing, and imo it's quite significant.
I think with EGR blanking you may reduce this issue quite a lot, but technically the EGR system volume is still present and stopping that volume being accessible in the first place by just unplugging the EGR is a much better choice.
I'm not really sure what blanking does, I suppose it makes more sense on later cars (206/307 etc) where a visible warning is left on the dash if you unplug the EGR. In those cases removing the vacuum pass on feed to the EGR actuator is probably the next best fix.
Blanking plates are cheap and easy to fit so probably worth doing. It might improve the air flow pattern into the intake manifold, then again it might hurt it. I've not done any testing to know, but it's probably nothing to worry about.
So to sum up, stopping EGR working via unplugging or intercepting the vacuum feed to the actuator will get you 90%+ of the benefits. EGR blanking plates might not get you all the benefits due to the EGR volume still being fed to by the EGR valve, so you still need to de-activate to assure you get the actual gains that are available, those being throttle response and turbo lag improvements.
Thanks
Dave