After experiencing a myriad of problems with the induction side of my poorly 2.2 as can be seen from some of my threads, I had to replace the EGR as it causing problems and sticking partly open and I broke the coolant outlet pipe while trying to take it off! So with EGR off why not look at blanking it I thought.
I have a good mechanical background and have spent some time reading the various threads on EGR blanking, bypass and mapping out on the CDTI’s. As my entire induction system was out of the car being de-coked and cleaned I decided to fabricate a replacement bottom throttle body to manifold gasket from 0.4mm mild steel to PARTIALLY blank the EGR output. I only wanted to partially blank the EGR flow as complete blanking will cause problems with raised exhaust temp charge and increased fuelling.
The blanking plate is a simple rectangle with a small lip made of 0.4mm mild steel. The lip is there just to push down onto the manifold as a positioning guide. You need to use some semi hardening gasket paste to make a good seal on all surfaces to stop the very hot high pressure gases forcing their way out of the step caused by having the extra metal. I used Loctite 5922 but Red Hermitite or similar can be used.
Clean original metal gasket and manifold surface with GUNK or similar degreaser and then put a thin smear of Loctite around the manifold and place original gasket back into place. Then put a good smear of Loctite around the EGR manifold outlet and place the new EGR blank plate in place. Use a good smear of Loctite all round especially around the new gasket area and then leave for 5 minutes to semi harden. Once it has gone off, reassemble the throttle body back into place and that’s it! Once you have driven it though, it’s good practice to just nip up the studs a little as the metal will have expanded slightly and gaps could form in the gasket area causing gasses to leak out and possible LHM due lack of boost pressure..
On the performance and economy side then, I noticed no decrease or increase in MPG at all over the first full week of driving which was multiple trips of 60 miles at a time totalling 300 miles and 140 mile single trip. Performance did not increase either, but what I have achieved is a smoother running engine overall and much better idle speed and noise reduction during idle.
So was it worth doing and what did I actually achieve?
To be dead honest it was worth doing even though I didn’t get the results I was hoping for which was better performance. The Y22DTR is a bit of a lumpy noisy old thing when over 100k on the clock and with the EGR flow reduced is now a much smoother engine and better to drive which is quite surprising J
Ok, so as this is a partial blank of the EGR, the exhaust gas still comes through and some is held back under pressure. This will inevitably cause the EGR valve to carbonise quicker as hot oily gasses are now restricted around the valve. This means that 6 monthly strip cleans will need to be done unless I decide to make a new lower manifold gasket to restrict the exhaust flow into the EGR instead of the exhaust out flow. This will be better for the valve without doubt and you won’t need to clean it every 6 months, but the lower gasket will need to be stronger and more difficult to seal against the manifold. There is also the risk that the restrictor gasket could split and tear under the pressure of the exhaust gas. Something for me think on and If I do it, I'll post it up.
Would I do it again and would I recommend it to others? Yes I would, but do it at your own risk for obvious reasons.
I’ll upload the pictures tonight as I have them on USB key which is not with me today.