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The mkiv Supra Owners Club

map sensor only good for a bar


supratoy

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Ummmm I'm actually gonna have to disagree with Alex there - it's not OK for the first turbo to run over 1bar of boost, in fact 1 bar is too much for it's little legs... I ran 1bar on mine many moons ago and felt a noticeable power falloff. 0.8bar is the most you want to run I'd say, unless you've got dyno runs to show it actually makes more power at 1+bar :)

 

-Ian

 

I was talking about in parallel mode, post transition.

"When both turbo's are online"

 

But yeah before transition I'd stick to 0.8bar

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Got my car back today. em it hit 1.4 bar on the rolling road but on my profec b only seen 1.3 so far.

 

He has set the 1st turbo to hit 1bar before transition. Is this really bad idea because I dont really want to have to get mapped agian if Icould get away with it?

 

O only made 391whp is that about right or abit low because the previous owner of the hybirds hit a much higher figure than that?

 

 

(My supra has hybirds, full 3inch exhaust from turbo, fmic, 650cc,walbro,power fc, all other some parts)

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391RWHP through an Auto or a manual?

391 is probably about 450bhp at the fly and that's what I'd expect from a dyno that's setup correctly and not for pub bragging rights. That's more than a Porsche 911 Turbo...so it's not that bad!

 

If your dyno curve shows an improvement for running 1bar on just the first turbo with the PFC then stay with it, but it maybe hindering the transition to twin mode/raising your egt's for no gain.

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I'd be happy with that power output :thumbs: Sounds accurate rather than, er, "inflated" ;)

 

I still don't reckon 1bar on the first turbo only is good. If you could get it set to 0.8bar and run another dyno you'd probably see the same if not more power out of it. But that's £££'s and you'd strangle me if I was wrong :D

 

-Ian

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It's been dry today and had a few blast in it, running the first turbo on 1bar and about 0.8.

 

When running the 1 bar its feels alot smoother when the second turbo comes online and alot more responsive low down, but I like the 2nd turbo kick :D

 

I compared my graph to a standard uk spec and bottom end there is defin an improvement but around 3500ish rpm it was the same for a few hundred rpm then mine increases.

 

I'll just leave it the way it is at the moment because I'am skint:thumbdown:

 

O its a 6sp.

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problem with my blitz controller its goes 1.0, 1.5, 2.0. i cant even set it at 1.2 so abit annoying.

 

surj

 

I doubt that, the blitz controllers don't specify a boost level...they have a gain and set.

 

The set changes the % of boost increase

The gain changes how fast boost builds.

 

Which Blitz controller do you have? I'd start a new thread...

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  • 11 months later...
The stock map sensor runs out of range at 1.2bar. It can read up to 1.25 but it's erratic and nonlinear at that point so I wouldn't rely on it. If you think it reads up to 1.6bar then you are mistaken. With an AFC, your car may fuel OK if mapped for 1.6bar but it'll run progressively richer as boost drops off because the signal from the MAP sensor is still flat out at 4.9v so the load site remains the same. Apart from the fuel pressure dropping which will alleviate the overfuelling somewhat.

 

This happens until you get lower 1.2bar, whereupon the MAP sensor starts kicking out a lower voltage signal as it's back in range.

 

-Ian

 

Does anyone have the full voltage Vs pressure specs for the MAP Sensor?

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