BLOCKING EGR

[Anonymous]

HI, IN A PREVIOUS POST I TOLD OF DIFFICULTIES WITH IDLE BECAUSE OF A (SUSPECTED) FAULTY EGR VALVE ON A XF EFI/4.1. I WAS WONDERING IF I BLOCKED OF THE EGR PIPE WITH A PLATE OFF SOME SORT (SO IT LOOKS LEGAL FROM OUTSIDE) WOULD THIS MEAN THAT TIMING / THROTTLE SETTINGS WOULD HAVE TO BE RESET???? THANKS

 

[yeah right]

Ok - I've just done this - on exactly that vehicle. Didn't make much difference but I could notice it - seemed to be better low to mid range. I just got some manifold gasket material (paper won't cut it cos of the temperatures) from Repco & cut a blank in the shape of the gasket but without the actual holes (only as a test).

My research into this reveals there may unfortunately be a downside to this - potentially higher combustion tempertures - maybe high enough to burn exhaust valves.

Before you do it bear in mind my experience may be a bit unique - my engie has other issues which I am yet to resolve - but give it a go & let me know how you get on.

 

[addo]

That bizzo about burning valves seems to be one of the old wives' tales. Run a dump from the extractors: "You'll burn your valves". Block the EGR "You'll burn your valves". Eat too much spicy food...

I'm not saying it doesn't happen, but haven't actually heard of it occurring myself. The burned valves I have seen are on the most crudded-up, horribly neglected engines and probably got sticky first.

Just my 2.2¢ worth, anyway.

Adam.

 

[yeah right]

You would say that... you're the one who told me to do it lol.

But seriously that's just what I've heard. It doesn't ring totally true with me either - I mean by recirculating already hot exhaust gases through the combustion chamber again can only cause an increase in temperature in the chamber. But we know how these myths start - and once they do they propogate rapidly (cos of people like me I guess...)

 

[xctasy]

Just my 2.2¢ worth, anyway.

Look at that, Addo answered so nicely we didn't see he ripped off an extra 10% for GST!

Slick, dude :roll:

 

[Anonymous]

Guys,
Adding an inert gas into the combustion process does actually lower the temperature of the flame front due to the lack of oxygen to burn with the fuel added.
This was and still is used to lower the oxides of nitrogen emissions.
Noel.

 

[addo]

But... You'd have to agree if it's not working as planned (as in totally crudded up), it's actually hindering performance. Even when it's working, the exhaust is taking the place of some fuel and air.

People retrofit water injection, for example. Nobody retrofits EGR.

Adam.

 

[Anonymous]

EGR hinders performance, full stop.
It is designed to operate at part throttle cruise and works against fuel economy.
EGR does not operate at full throttle and would not effect full throttle performance but will lower mid range performance.
Water injection to operate as intended should only operate at full throttle.
It is used as a performance enhancer. EGR is an exhaust emmision reduction system that works against both fuel economy and part throttle engine operation.
Noel.

 

[xctasy]

Perhaps they should. Water injection can hurt emissions too!

EGR is a good thing on a 1979-1986 Rover 3500. You loose 12.5% of the HP, 9% torque and increase fuel consupmtion

doesn't have the same ring as

My 250 runs on 91, has a 11:1 compression ratio and gets 30 to the gallon.

I havent asked Mudder Earth if its worse to make an engine more efficient, or reduce photo chemical smog. The debate rages.

 

[addo]

Out of curiosity, what are the intended operating parameters of the EGR? Is it s'posed to stay on until the engine is fully unchoked, or close before that, or after this point?

Adam.

 

[xctasy]

It's similar to the closed loop arangement. At wide open throttle its off, but on light off at a morning start, it's on. The mechanism for operation is a reed valve on the intake, which then channels the exhast heat and gas to the base of the carb.

Engine trouble shooting isn't my main bag, and no-one has to use EGR stuff in dirty old New Zealand.

Boy Backlash, your repleate with info tonight. Don't get OOS or RSI.

 

[Anonymous]

EGR is supposed to stay off until the engine has reached normal operating temperature.
Then once warm, the valve should only direct exhaust gas into the engine at light to mid throttle operation.
Just when you want the best from your engine to achieve the best fuel economy.
LUV NOEL.