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Someone who wanted 1 bar of boost available from cold perhaps? :P

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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Maybe, Vanya.

 

Unfortunately, as the original turbo went back to the reconditioners, I will never know what the wastegate was set at. Part of me wishes I'd never spotted the blocked-off port!

Margate Exotics.

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I think the Esprit probably holds the world record for "number of botch jobs per vehicle" - the stuff I've found on my car and the tales told here beggar belief at times. 

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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Indeed Vanya, and unfortunately I suspect that the tradition is continuing unabated.

Anyway, following the replies I've had, and after reading the service notes once again, I do think that my solenoid is working as it should, although I cannot be 100% sure until the car is running again.

With no power, air can pass through the input port (from the compressor), straight through the bleed port. When the solenoid is powered up,the inlet port is blocked. But the two lower ports, become connected. This makes sense to me.

What doesn't make sense is the previously blocked bleed port!

Margate Exotics.

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  • 4 months later...

Resurrecting this thread, I've been driving the car a little while now, after having reinstated the waste gate solenoid as per the book. I have done some Freescan logs, which show the MAP sensor reading 2.23 when the TPS is at 100%. I'm assuming that 2.23 is measured on bar, however this is to be confirmed, as it occurs to me that it could be a reading that only the ECU understands.

Yesterday, during a 'spirited' drive, I glanced down and noticed the boost gauge was decidedly over the 1 bar maximum. I know these gauges are not the most accurate, however, and should not be replied upon. Whilst there is no doubt that the acceleration is pretty vivid, I'm now wondering if the boost is just too high, though.

I have no paperwork about any mods which might have previously been done, could the MAP sensor be telling lies? Or has someone messed about with the ECU, perhaps? It just seems odd to me, when the S4s boost should stop at 1 bar, according to what I've read. Whilst it's quite nice to have additional power, I don't want to damage the engine, and your views would be welcomed, if only to calm my fears!

Margate Exotics.

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From the Freescan Manual :

(Boost is approx. MAP-1.0, but it is not linear over the whole range, MAX value is 2.24 regardless of boost)

The OEM S4s chip will give a max of 1.0bar of boost but aftermarket chips give 1.25 bar. Have you looked at your chip, perhaps it's an aftermarket one?

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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Have you looked at your chip, perhaps it's an aftermarket one?

 

No, not yet.

I was more interested to know about the MAP sensor readings first, as to whether they appear too high or normal. If they're normal, then there's no need to pull the ECU.

Actually, how would I know whether the ECU has been chipped? Is it immediately obvious?

Margate Exotics.

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Chuck Freescan in the bin - it's unreliable when it comes to accurate MAP readings; use Espritmon or TunerPro instead.

The stock MAP sensor cannot read more than about 2.07 bar so any chip that's permitting boost above this is not going to work properly as the ecu will not be aware of the extra airflow.

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Chuck Freescan in the bin - it's unreliable when it comes to accurate MAP readings; use Espritmon or TunerPro instead.

The stock MAP sensor cannot read more than about 2.07 bar so any chip that's permitting boost above this is not going to work properly as the ecu will not be aware of the extra airflow.

If it's the case that it is chipped, I assume it would need a different MAP sensor for it to work correctly?

I shall have to do an Espritmon log, and report back.

Margate Exotics.

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Changing the MAP sensor alone will not permit the ecu to read more than about 2.07 bar. You would also need change quite a bit of the code for the ecu to know how the new MAP output voltage value relates to the pressure.

2.07 bar? Hmmm.  Is that a typo, Derek?

I did mention earlier that I wasn't sure what the MAP value as displayed by Freescan related to, because it clearly cannot be a direct boost pressure reading or the engine would not be lasting too long.

Also I don't know what those values relate to once they get into the ECU, whether they're linear, or how they're interpreted, which must be a part of the programming. Not that it matters, though.

Did I read somewhere that MAP values could be X minus 1? Or is that just so much twaddle?

 

Margate Exotics.

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You read it above in my post, taken from the Freescan Manual. 

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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