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What Boost Readings are SE Owners Getting "Stock"? - Induction/Turbo/Chargecooler/Manifold/Exhaust - The Lotus Forums Jump to content
Chris89turbo

What Boost Readings are SE Owners Getting "Stock"?

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I have some deep running issues with my SE right now (running rich), but there is an obvious issue with my turbocharging. I am getting little to no boost at all. I had a 1989 turbo, and it had an obvious sound from the turbocharger and you could feel it kick in, but my 1990 SE is a turd and my gauge doesnt even read 0.25 of a bar (4-5 psi) when I get on it and run the RPM up... I realize its adjustable, but just wondering what the average SE out of the box is reading in the factory gauge so I have a bench mark.... thanks ... 

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Edited by Chris89turbo

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P.S. On a side note; one of my friends thinks that my lack of boost may be the cause of my "running rich" problem. Although it makes sense that my turbocharger not boosting would starve the intake of air (causing the car to run rich in fuel). However; I would think the MAP sensor would compensate?.. Unlike a newer EFI system where a Mass Air Meter is used, I would not think this would be relevant... hmmmmm,,,,, Just thinking out loud

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assuming your boost transducer is functioning properly:

check your wastegate actuator for proper operation

check wastegate for proper seating

check for leaks in intake system

check for leaks in exhaust manifold

lastly, turbo may be malfunctioning

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Well, there is indeed a leak in the exhaust. I can see where it is and I can hear it (even in the cabin while driving).. Its right next to the turbocharger.. However, I did not realize that a leaking gasket would possible cause that much loss in boost?.. interesting.. I will get that fixed then to start...

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Is the engine water tempreture coming up to 80

On the gauge.

You won't get full boost until then. If that's ok you need to look at waste gate or turbo malfunction as mentioned. A small exhaust gas leak shouldn't be that much of an issue in my option. Although it should be dealt with ASAP.

Regards

Wayne

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Does the CEL illuminate when you turn the ignition on?

If the bulb has gone or been removed then the boost will be restricted, if so you need to replace it & read the codes in the ECM :o

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Mine boosts at 0.5 all day long then when he's feeling in a good mood (oil temp right) it goes upto 0.8 and really shifts for a 25 year old motor

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Water temp Andy. The ECU pays attention to that, not oil temp.

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To sum up what some others have said, and maybe add a bit.

 

The boost should get to .65Bar regardless of the ECU, that is based on the mechanical wastegate adjustment.  If it isn't getting to .65 bar, then you have an issue with the wastegate, the boost hoses, the turbo, or a restriction in the exhaust (or intake possibly).

 

If the boost goes to .65Bar, but not higher, then you might have an issue where the ECU is limiting boost to protect the engine.  That could be anything from the coolant temperature is too low <~77C, in which case you need to replace the thermostat.  Or it could be the ECU protecting the engine from a lean condition.

 

In your case I would look into an exhaust restriction like the EBPV (exhaust back pressure valve), or a blocked CAT, but then you probably wouldn't be able to get any rpms either.  But do look first.

 

Next I would verify the wastegate settings with a small vacuum hand pump per the EMH manual.

 

If you are hearing a high pitched turbine sound, then I would say you have a boost leak at the rubber hoses between the turbo and the intake manifold plenum.

 

Oh and the maximum boost you see on the gauge depends on your altitude.  At my 5300ft altitude (I drive up to 14,000ft though) the boost gauge is always pegged with full boost.

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Ah right, ive always thought it was the oil temperature? You need to poodle around for half an hour to get the oil warm anyway. Vulcan Grey - i wish you lived on my street id be round every day for info ha ha

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Andy,

It's a good thing we have the internet :)  I only bought my car because the was a local community (and internet community) to help me be able to learn and work on it.  Now I just try to help others the same way.

 

Joining a local club and organizing club days to work on the car or at least stand around and learn (Similar to what Sparky has done) is a good idea too.

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Well, there is indeed a leak in the exhaust. I can see where it is and I can hear it (even in the cabin while driving).. Its right next to the turbocharger..

 

 

Perhaps the leak is affecting your O2 sensor readings? (02 sensor is just after the turbo). Or would the pressure of the exhaust not allow air in from the outside?

 

I've had (really) low boost problems caused by:

1) a loose (orange) pipe on the turbo exit, but that is audible (whooshing sound, which is probably much different from an exhaust leak sound). Sometimes the clamps appear tight, but aren't.

2) wastegate flapper not seating properly (spindle displaced sideways due to the spindle bushing migrating.. no longer flush with the turbo housing)

 

Would the ECU limit the boost THAT low due to sensor or thermostat problems? (as shown in the photo) I wouldn't think the turbo cooling system would drop the boost down that low, too???  (It's easy to check the cooling, though)

 

Chris, do you know what modifications have been carried out on your car? Do you have an electric water pump for the chargecooler? Has the Exhaust Back Pressure Valve (EBPV) been disabled or removed? (Out of the factory, there is a valve between the Cat and the muffler with a vacuum hose on it). It can be disabled in a number of ways. The car's vacuum system opens the valve when the engine is up to temperature (and during starting/cranking). If the (black) vacuum hose has fallen off you will have a continuous restriction in your exhaust.

 

Cheers

Ian.

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