EGR blocking - any performance change?

[Graham]

Hi all,

I searched through the forums as much as possible, but couldn't find what I was after, so here's another thread on EGRs.

I've just blocked off my EGR at the exhaust manifold using solid aluminium plate. From a quick drive around the block I didn't notice any difference, so will need to go for a longer drive.

What I want to know is:

• Is there any difference between blocking the EGRs at the intake versus the exhaust manifold?
  
• If blocked at both manifolds, is it safe to remove the valves & pipe completely? (I'm sure someone has already said that it is)

I'm intending to block both anyway, it's just the intake side is taking me longer.

Oh yeah, I am still trying to sell the MU. No harm in improving it while I'm waiting for a buyer.

Cheers! Graham.

[James W]

I blocked off both ends and got rid of the "up and over" pipe.
If you block one end only I would think you would have lag or air moving up and down the pipe,

[justin]

Graham I just recently did mine the same way as Dragan did his, which is inserting a thin plate between the vertical face of the valves and the top manifold.

As I said in an earlier post, this is the one modification which has noticeably improved performance and reduced the visible emissions at night. I think the next improvement from here will be a 2.5" exhaust. J

P.S. That pic is 640 x 480 at 48kb. Hows that download to all you dialup people?

[Graham]

I wish I'd seen that pic before I started playing with my EGR system - I didn't realise how involved it was to remove until I tried to work out what I was looking at!

So for the next ppl who try to block their EGR valves, here's a quick run down on how I removed mine, but first, an early warning
** Be careful not to lose the metal gaskets from between the EGR valves and EGR pipe, and between the pipe and the exhaust manifold.**

---

• Grab a 12mm socket on a 12" extension. You'll need the 12mm for all these nuts & bolts.
  
• Place a chair or step ladder at your drivers side front wheel to stand on and undo the 2 bolts that hold the drivers side EGR pipe to the exhaust manifold.
  
• On the passenger side & using the 12mm socket, undo the 2 bolts holding the fuel pump to its bracket. It should drop slightly to be out of the way. (The FP is the brassy coloured cylinder on the bottom right of Justin's photo above)
  
• Loosen the 4 nuts holding the EGR valves to the intake manifold, but don't remove them yet.
  
• Undo the 4 bolts holding the EGR pipe to the valves. These are under the valves/pipe and go in vertically to the valves.
  
• Now remove the 2 pressure lines to the top of the EGR valves and remove the 4 nuts holding the valves to the intake manifold. Slide the EGR valves off, directly away from the manifold.
  
• Now the pipe can be removed by 'delicately' lifting, swivelling, rotating and sliding it between the manifold and the dipstick tube until the exhaust manifold end can be extracted.

---

I'll be doing the inlet side as soon as I can because I imagine that if the valves are open incorrectly, that positive boost pressure running down the EGR pipe might not give an optimum result in engine performance. I don't think it would make much difference, but hey, a 1% improvement is going to save me that much money at the diesel pump!

Ciao! Graham.

[Graham]

Well, I've been able to drive the MU a few times now and aside from the freezing cold midnight run, it's going well after the EGR block on the exhaust side. Still haven't blocked the inlet side yet.

More power? Maybe, but definitely less than 10% (IMO 10% increase is noticeable at the seat of the pants
Free revving? I think so - it smoothly revs to 3500 now, whereas it struggled a little before. It even goes past 3500 and shifts smoothly and willingly.
Better fuel economy? TBA, I've only done about 75Kms so far!

Realistically, I can't say that there is a difference after blocking the EGRs as the changes I have noticed could be explained simply by colder weather meaning more oxygen into the engine.

I'm watching the fuel gauge now for a measureable change
Graham.

[James W]

I don't think these EGR mods actually give you any or much net power increase as may be perceved amoung these discussions. However if the EGR system is faulty or not functioning the mod should bring you back to orignal power, but no net increase..... Well my thoughts anyway.

[wayne]

I had a small gain in the zone between idle and turbo cutting in.
If it was a mod you had to pay for I wouldn't bother.

W.

[namic69]

Blocking off the valves is mostly better for your engine, All engines prefer cold fresh air to preform at their best. Their will be slightly more power but not that much.

[justin]

My increase was significant, the emmisions at night were greatly reduced, and the fuel economy has improved by an extra 50ks a tank. Based on the general feed back from others I would agree with James, and my EGR's were probably stuffed. I have since blocked mine at the exhaust manifold too as the statement Graham made earlier seemed logical. J

[namic69]

I blocked off my ERG and did a 2.5" exhaust from turbo and installeda K&N air filter at the same time. noticed about 10% more power

[Roger]

All I did was remove the 2 vacuum hoses and inserted a screw in each- lazy style!

[Graham]

Well, I'm convinced now that there is more power available. There's a large hill on the way to work and I'm always stopped by the lights at the bottom, so acceleration test up it is my standard comparison.

Before, it often sat in high revs in 2nd and third but wouldn't shift up, nor could it accelerate.
Now it accelerates all the way and shifts smoothly. Hasn't once gone back to 3rd from top since blocking the EGR either. Now it could be because its colder now, but it was doing it the week before I blocked the EGR.

Fuel consumption might not show any difference for me as the engine revs better and drives smoother, even with the accelerator to the firewall. I think the extra power available is being made use of frequently.

One thing though, I think my turbo boost is down slightly. I used to see it frequently at 0.9bar, but now that's only up very steep hills with 100% throttle and it tops out at 0.8bar under normal road levels.

After looking at the carbon build up in the EGR valves, I'm concerned that mine aren't closing properly. They operate smoothly, but it seems like there's a 2mm deep carbon layer in places!

Ciao! Graham.

[Pissy]

I recently blocked mine and noticed a slight power gain, the MU accelerates smoother and quicker.
But thats about it, I would guess no more than 5% power gain? I already have a 2.5" exhaust and performance filter, so I did not expect too much from the EGR blocking. Now wondering if Hilcones would help?

Cheers
Chris

[Jimmu]

I am considering Hiclones as well.

Fit them after the intercooler is fitted and the exhaust before it is dyno tuned and the fuel pump wound up.

Jimmy.

[DavidM]

I'm interested in this mod and have got some .040 stainless steel sheet to make a blanking plate for the exhaust manifold and some .060 2024 T3 aluminium for the inlet manifold. I favour removing the valves and pipe completely. But before I do can someone please explain just what is the purpose of this system and the theory behind it? For the life of me I can't see how squirting hot exhaust gas even in small quantities into the inlet manifold can have any beneficial effect on anything to do with engine performance or fuel economy in an engine running at normal operating temperature. However this is my first diesel car and I am quite prepared to admit that there may be very much I need to learn.

David.

[MattMU]

David, quick answer, find more on a google search but here goes. EGR Exhaust Gas Recirculation. It is meant to introduce small amounts of inert (non-combustable gas) into the combustion process, this gas will absorb heat and lower combustion temperatures and improve emissions. Hence why we are not SUPPOSED ot remove it!
If you want to, the pipe can have an end cut off and welded up as a cap and then it bolts back on neat as a pin. The valves can be removed, much neater (looks like a Rodeo manifold then) and a few plates made up to seal them up using the gasket already provided!
Easy!

Goodluck
Matt.

[Len]

Does anyone know if this can be done on the 4JX1 engine? Always looking to get more power.........

[geeves]

I would be very carfull about modifying anything on that engine. The manual for that engine warns against useing non standard exhausts even as these can affect the readings on the exhaust temp and oxygen sensors.Remember every bit of that engines life is controled by a computer.

[DavidM]

matt said:

David, quick answer, find more on a google search but here goes.

Thanks Matt. Had a look at Google and as a result I see the logic behind the system now and have decided to leave well alone.

David.

[maletimaru]

I think i did it the lazy man's way too - i just took off the two pipes (as pictured above) and popped 2 adequately sized screws in them - do i need to block off the 2 pipes coming out o fthe egr thing attached to the manifold or not? i have this taped over with electrical tape for now!!