I have a 1998 td5. Do i get rid of the egr valve or am i better off keeping it. If i'm better off skipping it how do i go about this and best place to get parts and cost involved? Also i've been advised to get a stage one piggy back chip and a new exhaust to get rid of the cat and sconed box, any advice again on cost involved and best place to get parts involved.
As my names been mentioned.....
I personally would get rid of the EGR.
The science bit (taken from my website - so still in draft)
What is the EGR and what does it do??EGR or Exhaust Gas Recirculation.
As its name suggests, the Exhaust Gas Recirculation (EGR) system allows a controlled amount of spent exhaust gas back into the air intake of the engine. On both Td5 and 300Tdi this is controlled by the vehicle ECU (Tdi has a standalone ECU for the EGR).
The purpose of recirculating a percentage of the exhaust gas is to reduce nitrous oxide emissions and combustion noise, recirculating a percentage of exhaust gas reduces the combustion temperature and slows down the fuel burn rate - which leads to reduced emissions, but also reduces performance. Although the EGR only works at certain part load conditions, removing it completely should make a difference in performance, and will possibly also lead to an improved mpg.
Why should I remove it??As mentioned above, removing the EGR system completely will often make a difference to performance, and can lead to improved mpg - however that is only part of the story.
When the EGR system works correctly, then it should only operate at part load, part throttle conditions - i.e. the times when you, as the driver, shouldn't notice its operation. But this isn't always the case. On both 300Tdi and Td5's it is very common for the solenoid valve to become clogged internally, which prevents it from sealing correctly. When this happens, performance and MPG will be substantially impaired... it is also very bad for the engine. If the percentage of EGR is too high, rapid engine wear (bore wear) will occur.
The EGR gas will also soot/clog up the inlet manifold. On Td5's this can cause problems with the MAP (Manifold Absolute Pressure) sensor.
Looking at it from another point of view, removing the EGR basically means there is one less thing to go wrong!!
You should also remove the EGR if you regularly use high Sulpher diesel (in the UK, all diesel is low Sulpher)
Does it cause any problems at MOT time??The current 2008 MOT system for Diesel (i.e. compression ignition) vehicles only requires an Opacity test, (i.e. smoke) and not an actual emissions test as per petrol (spark ignition engine).
The EGR system (and the catalytic converter for that matter) does not actively affect smoke…. This differs from a diesel particulate filter (which is also exempt from testing at the current time). The only requirement is that the max smoke value for a turbo charged diesel is a mean (of the last 3 smoke tests) not exceeding 3.00m-1. For an initial 'fast pass' the smoke value must be below 1.50m-1.
In simple terms.... the only reason a modern diesel have CATs and EGR (along with other things) is to enable a manufacturer to meet the current EU legislation (for example EU4/5), but once a vehicle model has been type approved, and sold to the customer... the customer is technically free to do what they like regarding emissions, as long as they meet the requirements of their country, which in the UK is just the MOT test.
This can be confirmed by reading the MOT manual.
P.s . If you want a 'proper' EGR removal kit then I do one, with a discount for forum members.
Again, my point of view... stay away from plug in boxes, and have a proper remap instead!
Contrary to what people will try and convince you, a plug in box is still a bodge method of tuning!!
Some boxes are a bit more sophisticated than others, but on a Td5 all they do is add a delay to the fuel injector so it adds more fuel, with no actual regard to what the engine is doing. This means, if for example the engine went into limp home mode, then the box would still try to shove in extra fuel!!
Some people will also try to convince you that you can't remap your ECU as it is a pre flash version... well you can!!! - is slightly more involved than a later flash type ECU as you physically have to change a chip on the ECU, but not a problem to do.
Exhaust wise… being pre 2002 your 90 will not have a CAT, so you can save yourself some money. A centre silencer replacement pipe is £50.
I would also recommend an ITG filter (about £50).
On from that… the next upgrade would be a bigger intercooler and a stage 2 remap.
Ian
