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Boost roll-off above 140mph? (Serious question!!)

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Old May 15, 2003 | 05:54 PM
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Hi all,

I think Mike Wood at Prodrive once said that the boost is rolled off a bit above 140mph... I have a Prodrive car (MY00 PPP) and it pulls like an absolute train up to about this speed then seems to quite quickly ease off.

Now before you all fall about laughing, this is just a curiosity of mine to find out . I have no intention of staying at this speed for any period of time! It was just a memory of someone Prodrive-related once saying this...

Before I get the anti-speeding brigade on my back, I'd like to point out that I live in Germany and can therefore legally sit at >140mph if I want...

Cheers
Richard

[Edited by Re-Bitten Hero - 5/15/2003 6:02:03 PM]
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Old May 15, 2003 | 06:08 PM
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Isn't it more to do with the revs that the engine is running at that speed, rather than the actual speed itself?

Oh yeah, forgot to say - it's outrageously irresponsible to drive at those kind of speeds, don't you realise you're an accident waiting to happen, blah, blah, blah

[Edited by Mungo - 5/15/2003 6:10:15 PM]
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Old May 15, 2003 | 06:37 PM
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Becarefull m8, scoob engines dont like alot of that, bigend bearings welded to the crank ect.
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Old May 15, 2003 | 08:00 PM
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Not to do with revs, rolling road graph shows it pulls straight 255bhp from 5500-6800rpm, and that backs up what I felt before I even put it on the RR.

Totally agree about not doing it long term! This was just a quick run to prove a point against a Merc

Any ideas?

R
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Old May 15, 2003 | 08:19 PM
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It does, yes. Don't have any details myself - think it's set to run off at 140-144? JB would know, if he ever comes along...
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Old May 15, 2003 | 09:13 PM
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From: Zed Ess Won Hay Tee
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doest the ecu back off boost over them speeds?
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Old May 15, 2003 | 10:07 PM
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As far as I know the ECU reduces the boost to keep the maximum speed just over 140MPH.

Ecutek can adjust the speed the ECU starts reducing boost to increase the maximum speed (probably not a good idea!).

E.
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Old May 15, 2003 | 11:19 PM
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From: 32 cylinders and many cats
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I removed my boost roll off, but I have a large turbo and FMIC

Between 137 and 147 mph the ECU gradually withdraws the boost in smooth stages to slow you down. Where the exact equilibrium is may well be the official top speed
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Old May 16, 2003 | 08:37 AM
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From: STi8 G spec (400+hp)
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John,

Can you tell if STi7&8 share same values, I was expecting something like 155mph ?
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Old May 16, 2003 | 10:00 AM
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From: 32 cylinders and many cats
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I'll dig out my laptop and have a look. If I forget remind me with a polite email
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Old May 18, 2003 | 03:39 PM
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Ah, that does explain it then! I thought it wasn't just me

I'll settle for that as a top speed then Though in fact I don't normally go much about 100-120 anyway.

Cheers
Richard


ps John - I'd still be interested to hear what you find!
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Old May 18, 2003 | 04:04 PM
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Sorry I did actually forget

240-245 km/h is the control range (hysteresis) on the UK/Euro STi.
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Old May 19, 2003 | 06:33 PM
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Thanks John! Backs up what I felt on the road.

Another one for the Scoobynet FAQ .

Cheers
Richard
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