gmendoza Posted July 16, 2009 Report Share Posted July 16, 2009 As some of you may remember my thread about testing the system for boost leaks. Well everything was good up to 4psi with my hand pump. Well after my last dyno numbers being a little lower than I expected, I decided to test the system using a compressor @ 15psi. Well that didn't go well. I noticed I was losing alot of pressure out of the EGR pipe. So I pull the plenum and checked the EGR valve. The EGR valve is fine but the design is LAME!!!!!!!!!!!!!11111111111111111111. The piston on the EGR valve is on the pressure side so any positive pressure blows the piston open and lose pressure into the exhaust manifold. So all V8s leak. No wonder the stock turbos are so overworked. I also found my EGR pipe cracked but I guess thats "common" too!!! Quote '03.5 Final Edition Esprit ~ 5.7lbs/hp mildly modded - 430rwhp, 353rwtq Link to comment Share on other sites More sharing options...
gixxer Posted July 23, 2009 Report Share Posted July 23, 2009 At what pressure did you detect leakage this time? Have you tried blocking off the EGR altogether---does it ping? Cheers, Brian Quote Link to comment Share on other sites More sharing options...
fastdave92649 Posted July 27, 2009 Report Share Posted July 27, 2009 Hey Gonzo, Where are you at with this? I would love to block the EGR off like the european spec ones. I know it will most likely cause a CEL/MIL but is there a work around for it? Has anyone in a US Spec car ever blocked this and done emmissions testing? Quote Link to comment Share on other sites More sharing options...
gmendoza Posted July 27, 2009 Author Report Share Posted July 27, 2009 (edited) Hi Dave. I ended up installing a block off plate between the EGR valve and the plenum and another plate at the exhaust manifold. I have no CEL and the car runs great but best of all, no boost leak. Later, I scanned the car to see what the emission readiness monitors were doing. Turns out, Johan's ECU does NOT support EGR. So it was useless in my car anyways. As for the EGR valve, it begins to leak at a pressure difference of anything over 5psi. A few days ago, I tested a 98 V8 with the High Tq ECU and it leaked also; no surprize there. My 5gal compressor could not pressurize the system more than 5psi (same as mine). The more the compressor would supply, the more it would leak. Now, we may block it on this car to see if we get any CEL's because the High Tq ECU DOES support EGR unlike my ECU. Edited July 27, 2009 by gmendoza Quote '03.5 Final Edition Esprit ~ 5.7lbs/hp mildly modded - 430rwhp, 353rwtq Link to comment Share on other sites More sharing options...
WEllison Posted July 28, 2009 Report Share Posted July 28, 2009 Hi Ganzalo, A most interseting test result! Lets give Lotus credit for good engineering for a moment. That means in Lotus's testing they always saw less that 5 PSI deferential acrossed the EGR valve. Since the spec for any stock ECU is .75 bar or 10.8 PSI relative, that means there would be 10.8 - 5.0 = 5.8 PSI minimum of pressure allowed in the EGR pipe from the exhaust manifold at maximum boost. Seems high, but maybe. With higher boost you would need higher back pressure to keep the EGR closed. Lets see with a 2 bar absolute map semsor, a hole in the EGR pipe and a one channel Innovate recorder, we would know. A spacer plate between.... ah never mind. Anybody ever measured or have a sense of this?? Wayne Quote The Older I get the Faster I was Link to comment Share on other sites More sharing options...
gmendoza Posted July 28, 2009 Author Report Share Posted July 28, 2009 I'll give you that Wayne. Lotus designed it to be just enough for the stock application. Although you lost me with your idea for a test. Are you suggesting a video of actual EGR operation and/or measuring back pressure? Quote '03.5 Final Edition Esprit ~ 5.7lbs/hp mildly modded - 430rwhp, 353rwtq Link to comment Share on other sites More sharing options...
WEllison Posted July 29, 2009 Report Share Posted July 29, 2009 Use a 2 bar GM map sensor, build a spacer plate (1/4") with a port on it, to go between the EGR pipe and the exhaust manifold. attach a line between the new port and the map sensor, supply the map sensor with regulated 5.0 Volts from the ECU and use a one channel innovate data logger to record the voltage. It would provide a direct read of the pressure in the exhaust manifold. Compare time stamps to the OBD-2 scanner stamps to track rpm & boost and you have it. No sure how long the map sensor would last with hot gases going into it, long enough for 1 or 2 runs, their cheap! Wayne Quote The Older I get the Faster I was Link to comment Share on other sites More sharing options...
t70 Posted August 25, 2009 Report Share Posted August 25, 2009 This would also lead to an improper afr reading from the o2 sensor.. it would read lean.. which would make the car run even richer than the already ridiculous afr... wow.. Gonna go block egr now Quote Modifying esprit's.. now that's fun..PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician. Link to comment Share on other sites More sharing options...
fastdave92649 Posted September 8, 2009 Report Share Posted September 8, 2009 I blocked off my EGR when I had the plenum off to do wires/injectors/and IAC... On first start I got the standard EGR CEL's.. I cleared everything and restarted, been running now for about 4 weeks and have never seen the CEL's come back. This is on a stock US spec ECU. Quote Link to comment Share on other sites More sharing options...
97-Esprit V8 Posted October 4, 2009 Report Share Posted October 4, 2009 (edited) Did this actually improve your power? Leaking into the manifold shouldn't be an issue on a running engine as the pressure in the exhaust manifold should far exceed the boost pressure. I'm going to have a close look at my EGR as I have the engine out for repair and modification. Edited October 4, 2009 by 97-Esprit V8 Quote Link to comment Share on other sites More sharing options...
gmendoza Posted October 4, 2009 Author Report Share Posted October 4, 2009 I haven't scheduled a dyno yet because I was rebuilding the gearbox but the car does feel good. Although I don't believe there is more pressure in the exhaust than the intake. If there was, then the stock 5psi wastegates would get blow open way before the car achieved 11psi of boost. Dave, any update on your CEL? Quote '03.5 Final Edition Esprit ~ 5.7lbs/hp mildly modded - 430rwhp, 353rwtq Link to comment Share on other sites More sharing options...
fastdave92649 Posted October 8, 2009 Report Share Posted October 8, 2009 I have not seen any noticeable performance gains from it. I did it more to allow for easier fab of my intercooler piping. Still no CEL's since blocking it off. Quote Link to comment Share on other sites More sharing options...
Rgardner01 Posted October 8, 2009 Report Share Posted October 8, 2009 (edited) When you guys are blocking off the EGR valve are you: Are you blocking the EGR off and leaving it off the car completely and disconnected from the computer? Also are you removing the air injection lines and the little vacuum combi valve on the back of the LH cylinder head? Edited October 8, 2009 by Rgardner01 Quote Link to comment Share on other sites More sharing options...
97-Esprit V8 Posted October 9, 2009 Report Share Posted October 9, 2009 (edited) I haven't scheduled a dyno yet because I was rebuilding the gearbox but the car does feel good. Although I don't believe there is more pressure in the exhaust than the intake. If there was, then the stock 5psi wastegates would get blow open way before the car achieved 11psi of boost. Dave, any update on your CEL? The exhaust pressure should be near twice what your intake pressure, this is pretty standard (2:1 ratio), obviously it will vary design to design. Certainly the EGR will have more pressure on the exhaust side so the test you did doesn't replicate running conditions. This about how the turbo works, kind of hard to have less pressure on the side that drives the compressor. Edited October 9, 2009 by 97-Esprit V8 Quote Link to comment Share on other sites More sharing options...
fastdave92649 Posted October 11, 2009 Report Share Posted October 11, 2009 Rey, When I blocked mine off all I did was pull the pipe running from the turbo housing to the valve under the plenum and put in blocking plates on those 2 locations. I did not pull the valve or any other wires or lines. I saw no real need to pull the rest and it will make it easier to cobble something together if I ever have an emission issue when testing. Quote Link to comment Share on other sites More sharing options...
gmendoza Posted October 11, 2009 Author Report Share Posted October 11, 2009 When you guys are blocking off the EGR valve are you: Are you blocking the EGR off and leaving it off the car completely and disconnected from the computer? Also are you removing the air injection lines and the little vacuum combi valve on the back of the LH cylinder head? All I did was installed a blocking plate at the exhaust manifold and another between the EGR valve and plenum. I left everything else connected. Quote '03.5 Final Edition Esprit ~ 5.7lbs/hp mildly modded - 430rwhp, 353rwtq Link to comment Share on other sites More sharing options...
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