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Wastegate worries - Induction/Turbo/Chargecooler/Manifold/Exhaust - The Lotus Forums Jump to content
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Dave Freeman

Wastegate worries

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Hi guys, you may have seen my previous thread on Hesitation / misfire. Having cured this I wanted to ensure that the wastegate was operating properly. I bought a pressure gauge and set the test kit up, plumbed in and ready to go. The adjusting nut was easy to undo, so to it then, apply pressure of 8.5 psi the actuating rod moved a massive 20 mm or so, definately something wrong. Although instructions in the manual and on various web sites are clear the actual doing posed some questions.

In order to get the required movement circa 0.4mm I had to pull the rod hard to get it onto the pin, this means that the internal spring must be compressed quite a bit, to get the required movement I had to put a little over 8.5 psi in order to get it to move, but slighly less to hold it at 0.4mm. So I am unsure if its accurate, question is how accurate hould it be.

On a test run the gauge in the car reads a healthy 0.65 - 0.7 boost. Might be a bit much but how accurate is the boost gauge, and whats the danger to the engine if it boosts at say 0.8, thinking that the EMU will cut in at 1.o bar.

Car is very quick, the waste gate was a mile out, but I am concerned that I may be over boosting.

Dave

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Dave,

I have been doing a similar thing to mine. I adjusted the older wastegate actuator using an external pressure gauge. The spring in the old one was obviously weaker than it had been originally, and I needed to screw in the adjuster to match spec., as you describe, so the spring was more compressed. Worked great for a while, instrument panel gauge finally went up to exactly 0.5 bar when cold and 0.6-0.8 bar when warmed up under acceleration. Previously, I never got it above 0.5 bar. Thought I'd solved the problem, but after only a month or 6 weeks, I was back to the original low settings. I assumed the old spring was not going to cut it, so installed a new actuator from Forge Motorsports.

This has a different behavior, much more abrupt switch on with, immediate, comparatively large travel. I've found I need to set it to about 9.5-10 psi (rather than 8.5) for the 0.4 mm deflection in order to have the car behave as I think it should. I'd like to install another gauge I can read while driving to see if the instrument panel one is accurate and will probably rig up temporary thing at the weekend by running a length of pressure tube to the cabin.

Hope these observations are useful.

Cheers,

Trevor

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Thanks mate, it is a problem, perhaps mine will only last a short while, best start saving for new one. This makes you wonder why there is both mechanical cut off and electrical via the ECU, never had understood this.

Best regards and thanks for your note

Dave

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^ Superdavelotus and forge^

You know it makes sense!!

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^ Superdavelotus and forge^

You know it makes sense!!

Not sure what this means, can you clarify

Dave

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Sorry,

sometimes my enthusiasm overflows and I speak gibberish!!!

The rest of the time its nonsense.

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"In order to get the required movement circa 0.4mm I had to pull the rod hard to get it onto the pin,"

Yikes! I've been told that doing this kind of thing will damage the internals of the wastegate actuator.

Is your car fitted with lumbar support adjustment? There are small hand pumps with built in one way valves at the base of the seats. You can remove one of these and attach it to the wastegate capsule line to move the rod into place with ease. Prior to this, I was using a large medical syringe (very inefficient).

Hope this helps

Cheers.

Ian.

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What Ian said with the damage - does sound knackered as well.

The ECU will flag a warning if the MAP (manifold pressure) sensor goes over a certain voltage but it will not flag a light - you need to use freescan to check your MAP values under boost.

The wastegate actuator is quite misleading however, it actaully holds the wastegate shut - in the even of a failure the wastegate will actually flap open - the correct terminoligy for it is a wastegate inhibitor, as it HOLDs the wastegate shut (to build boost) as opposed to open it up. Therefore a freely moving actualtor is less dangerous than a sticking one.

With the wastegate set wrong I would hope the ECU would cut the fuel on massive overboost - more likely it is working within parameters but it is far from ideal. I would go safe, get one of the sexy actuators from Dave and re-set the unit - always keep in mind if you run/risk the car outside it's safe parameters you can be looking at a

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