3.0 litre EGR/Butterfly/Swirl Mod

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stubbsy351

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hey guys whats this egr/butterfly mod? ive seen a few people have it listed in there signature?
 

Laith

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EGR is exhaust gas return. A system that that distributes exhaust direct from the exhaust manifold to the inlet manifold to help reduce emissions ect.

It chokes the engine with carbon and affects engine performance in a negitive way.

The mod involves blocking the EGR pipe with a blanking plate and re-aranging the vacum hoses that control a butterfly in the inlet manifold. The butterfly closes the inlet manifold off (partialy I believe) to force the engine to ingest the exhaust from the egr.
 

stubbsy351

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so i suppose it would make a differance to eng performance? any pics of the hoses to be moved?
 

tweak'e

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i'll se if i ccan find the other pics

you can disable swirl control valve but only if egr is blocked off.

i've had one person say their fuel ecomonmy went worse after blocking egr. however he also had intercoler and other mods which may have been the cause.
 
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Shonky

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Hi Tweak

I remember you talking about disabling the swirl control on another forum, how did you go with it, and what was the reasoning for disabling it?
 

tweak'e

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it improves low down response. with no egr it simply chokes the motor a bit so its not really needed and has been running fine with it disabled for the last 20,000km or so.

i think its there to increase egr by blocking off half the air and running on one intake will help mix the egr with the air as it goes into the cylinder. it only operates when engine is hot (which is when egr is on) and up to 1700 rpm (i think). main butterfly operates up to 3000rpm.
 

Shonky

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Do you think it solves the flooding problem, I know with mine when taking off from an intersection for example if I let the revs die too much, down to 500rpm say, it doesn't really want to accelerate, it does eventually but it puffs smoke out the exhaust when it does it which leads me to think it's over fuelling, could this be the swirl control causing this?
 

tweak'e

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i think thats EGR doing that. used to have that problem when i had the egr working. it used to bog down and blow big clouds of smoke.
the other ute (with no mods) that we have still does that where as mine doesn't.

if you have egr blocked i would disable swirl valve. with your chip it may make quite a bit of difference.
 

Dave

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The puff of smoke is unburnt fuel. At 500rpm the engine would be developing fark all torque.

Dont forget these engines are low compresion engines and rely on boost to make the power. A TD series engine would easily pull from 500rpm but there compression ratios are 22 to 1. A QD32 would do the same aswell.

EGR stands for Exhaust Gas Recirculation.

Dave.
 

Shonky

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Yeah I understand that Dave, I know I'm expecting too much from the ZD30 to rev that low, I just tend to let the clutch out most of the time before I even touch the accelerator, probably explains why my clutches last forever. :18:

tweak'e said:
if you have egr blocked i would disable swirl valve. with your chip it may make quite a bit of difference.
I've just had a read of the service manual for the ZD30 and I'm unsure opening the swirl control valve will improve things, according to the manual it is only ever closed when the coolant temp is above 50 degrees C, and engine speed is below 1250 rpm. Opening the valve below this engine speed to my thinking could actually be detrimental due to the lower intake velocity, while there is more air with the valve open, the lower intake velocity means less swirl in the bore, and therefore a less efficient burn.

Here's what the manual says regarding the swirl control system.
While idling and during low engine speed operation, the swirl control valve closes. Thus the velocity of the air in the intake passages increases, promoting the vaporization of the fuel and producing a swirl in the combustion chamber.
Because of this operation, this system tends to increase the burning speed of the gas mixture, improve fuel consumption, and increase the stability in running conditions.
Also, except when idling and during low engine speed operation, this system opens the swirl control valve. In this condition, this system tends to increase power by improving intake efficiency via reduction of intake flow resistance.
I'll try it out anyway to see whether it improves things or not since it's super easy to try, all that is needed is to unplug the solenoid that controls the vacuum to the actuator.
 

tweak'e

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The puff of smoke is unburnt fuel. At 500rpm the engine would be developing fark all torque.

Dont forget these engines are low compresion engines and rely on boost to make the power. A TD series engine would easily pull from 500rpm but there compression ratios are 22 to 1. A QD32 would do the same aswell.

EGR stands for Exhaust Gas Recirculation.

Dave.
yes/no. i'm told that many DI motors are 18:1 even with atmo motors across different manufactures. IDI NEEDS the higher compression because it looses so much heat in the flame port. ie its inefficient and requires the extra compression to get enough heat to ignite the fuel.

the smoke is unburnt fuel, but its unburnt because the EGR puts the flame out.

Yeah I understand that Dave, I know I'm expecting too much from the ZD30 to rev that low, I just tend to let the clutch out most of the time before I even touch the accelerator, probably explains why my clutches last forever. :18:



I've just had a read of the service manual for the ZD30 and I'm unsure opening the swirl control valve will improve things, according to the manual it is only ever closed when the coolant temp is above 50 degrees C, and engine speed is below 1250 rpm. Opening the valve below this engine speed to my thinking could actually be detrimental due to the lower intake velocity, while there is more air with the valve open, the lower intake velocity means less swirl in the bore, and therefore a less efficient burn.

Here's what the manual says regarding the swirl control system.


I'll try it out anyway to see whether it improves things or not since it's super easy to try, all that is needed is to unplug the solenoid that controls the vacuum to the actuator.
couple of things they don't tell you.... egr slows down the burn so they need to swirl it to raise it back up to normal. imho its more about how the egr gas mixes with air. if egr is mixed poorly with air you will get inconsistent burn ie good burn in one part of the chamber but lossy burn in another. that not good for emissions.

also that closing the swirl valve INCREASES egr. because egr is only on one runner you normally get 2 part air and 1 part egr. close the swirl valve (blocking one runner) you only get 1 part air and 1 part egr. effectively decreasing the amount of air (read nitrogen) as well as increasing the amount of egr.
this is done because at low rpm there is very little backpressure to push egr into the motor.

with egr blocked the swirl valve simply restricts the amount of air going in. which i why there is a bit more performance at low rpm with it disabled.
 
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Jon

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When blocking the egr what sort of plate did you use? I have some 2mm ally lying around that I could use would that do the trick or something a bit more substantial?
 

Shonky

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The thinner the better Jon, if you go too thick it could deform the shape of the EGR tube, if you were to do it on the EGR valve side, rather than at the exhaust manifold you could get away with cutting up a coke can in the shape of the gasket. If you go on the exhaust manifold side you will need to go to something heavier due to the amount of heat it will have to deal with there.
 

tweak'e

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The thinner the better Jon, if you go too thick it could deform the shape of the EGR tube, if you were to do it on the EGR valve side, rather than at the exhaust manifold you could get away with cutting up a coke can in the shape of the gasket. If you go on the exhaust manifold side you will need to go to something heavier due to the amount of heat it will have to deal with there.
i don't think so.

exhuat side a couple mm STEEL plate is fine. who cares about the shape of the egr tube, there won't be any gas in it to worry about.

inlet side thin alloy sheet is fine. coke can is NOT thick enough. something about the same thickness of the gasket or bigger is ok. stainless steel might be better.
2mm alloy should be fine.
 

maddogrc

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the pictures are a little bit confusing for me.

i'd like to do this mod on my new d22, but there doesnt seem to be hectic wiring like in the original pictures. also i'm running the stock air to air intercooler so i dont know if that will affect it or not.

anyone with a turbo/intercooled car done this mod yet?
 

tweak'e

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you have the 2.5 intercooled variable turbo D22 ??

if so...... blocking the EGR is a whole different ball game. its nothing like the old ZD30. the turbo plays a big role in EGR operation and you need to adjust the turbo to suit the blocked EGR.
not sure if anyone has a write up on doing it on the D40. otherwise have a look through Patrol 4x4 - Nissan Patrol Forum and about the dawes valve.
 

mike/kerry

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Hi tweak'e can i just unplug the red swirl solenoid plug?

as i cant get on the uk site and i can't remember what you told me last time

thanks i will see if this helps mine from bogging on take off

thanks mike
 

tweak'e

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Hi tweak'e can i just unplug the red swirl solenoid plug?
as i cant get on the uk site and i can't remember what you told me last time
thanks i will see if this helps mine from bogging on take off
thanks mike
yeah, i've been running mune upluged for the last 6 months or so.

don't forget you can ONLY do it if EGR is blocked off.
 

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