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turbo in reverse gear?

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Old 28 October 2005, 09:16 AM
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mgcvk
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Default turbo in reverse gear?

Just curious really. If you gave car enough welly in reverse would turbo still spool up?
Old 28 October 2005, 09:19 AM
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R19KET
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Yes, unless, it also works in reverse, and sucks, instead of blows


Mark.
Old 28 October 2005, 09:23 AM
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Andy.F
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And if it was one of your then it may well do
Old 28 October 2005, 10:11 AM
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R19KET
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Andy,

Yep, but it would be the best suck job you'd ever had

So, fancy 210mph..............backwards

Mark.
Old 28 October 2005, 10:15 AM
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Yes, but you'll need to have your scoop to face the other way. Perhaps mount a second scoop on the boot lid and feed the IC with Safari style intake pipework?


Nick
Old 28 October 2005, 11:56 AM
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harvey
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It would spool backwards but you can cure this if it was important to get full boost in reverse.
Old 28 October 2005, 01:53 PM
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What if ?
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why wouldn't it ? what a strange question.........do you really think the engine runs backwards ????????????
Old 28 October 2005, 05:02 PM
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Originally Posted by harvey
It would spool backwards but you can cure this if it was important to get full boost in reverse.
Why would it spool backwards???

I'm no expert but i thought turbos worked off exhaust gases, which work exactly the same way no matter what direction the car is going.
Old 28 October 2005, 05:25 PM
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twybrow
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they do! i dont get it. Of course it would spool up if the exhaust flow is sufficient. Try it!
Old 28 October 2005, 06:03 PM
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Gearboxes love to be redlined in reverse, yes i think you should try it
Old 28 October 2005, 06:43 PM
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Yeh, go and try it and let us know what happens
Old 28 October 2005, 08:34 PM
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Which turbo do you have in mind because they all have different characteristics. My TD05-06 20 G witha ported W.G. is boosting Ok in reverse but it comes in pretty viscously and there is lots of tyre spin when it takes off.
Old 28 October 2005, 08:38 PM
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Originally Posted by cookstar
Why would it spool backwards???

I'm no expert but i thought turbos worked off exhaust gases, which work exactly the same way no matter what direction the car is going.
They do work off exhaust gas but think about it, if you go fast backwards then the pressure will build in the exhaust, this in conjunction with the reversed flow across the scoop and low pressure in the engine bay could result in a reverse spool surge event.
Old 28 October 2005, 08:48 PM
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SNIGGER.....
Old 28 October 2005, 08:58 PM
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Maybe a twin turbo arrangement using a flap engaged by the reverse gear sellector to control which turbo is used and an early EVO turbo for the oposite direction spool would do the trick?
Old 28 October 2005, 09:06 PM
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JamieMiller
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why don't you try a j-turn while your at it, i'm curious to see if that would work as well.
Old 28 October 2005, 09:10 PM
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It's a fact that evo's are quicker on left hand bends that scoobs due to the gyroscopic effects on the reverse spin turbo, of course the scoob makes the ground up again on the right hand bends.
Old 28 October 2005, 09:15 PM
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Is that why twin turbo's (supra's / skylines etc ) can't corner ?
Old 28 October 2005, 09:18 PM
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Originally Posted by Butty
Yes, but you'll need to have your scoop to face the other way. Perhaps mount a second scoop on the boot lid and feed the IC with Safari style intake pipework?


Nick
Forget an FMIC, you'll be in need of an RMIC
Old 28 October 2005, 09:49 PM
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cookstar
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Originally Posted by Andy.F
They do work off exhaust gas but think about it, if you go fast backwards then the pressure will build in the exhaust, this in conjunction with the reversed flow across the scoop and low pressure in the engine bay could result in a reverse spool surge event.
So are you saying it wouldnt spool then?

This is confusing me a bit.. I thought the air that came into the scoop was to cool the intercooler down and nothing else. Ie when people have frontmounts they sometimes loose the scoop altogether.

Not being funny, cos i know you know your stuff mate.

Just askin'
Old 28 October 2005, 10:16 PM
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Originally Posted by stevem2k
Is that why twin turbo's (supra's / skylines etc ) can't corner ?
Yep, if only they'd thought it through and put one turbo on each side of the engine, not both on one side, those Toyota boys eh..
Old 28 October 2005, 10:33 PM
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So dose that mean the dump valve would go "hsssssit" in sted of "tissssh
Old 29 October 2005, 12:08 AM
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Tim W
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It wouldn't dump, it would ingest...think of Cat's experience on Backwards World
Old 29 October 2005, 12:40 AM
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My college tutors celica makes a swoosh in reverse...




but we reckon he's just got a tape player with a "Tishhhhhh" sound on it after all, he has got a novelty horn!
Old 29 October 2005, 01:17 AM
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buzzard
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Exclamation

The reverse airflow through the radiator will create a negative vortex that equalises vertically at 20-22.5mm central to the jiggle pin in the oil pump. when this happens, the hydrodynamics of the oil under these conditions,through a sequence of thermal transposures, creates random 'hot-spots' in the catalyst honeycomb. as each implosion takes place a series of inverted vortices travel (7th Principle of harmonic gasflow) in the opposite direction to 'actual' exhaust gas flow. the knock-on effect of this is 'turbo-syphoning',where the turbine wheel literally tries to 'suck' itself off. the rapid sucking and blowing creates negative boost in the compressor housing resulting in reverse rotation. only right hand drive models of impreza my92 to my01 are affected.
oddly, this doesnt occur in the EVO.

Last edited by buzzard; 29 October 2005 at 01:37 AM.
Old 29 October 2005, 04:29 AM
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cookstar
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I am now hanging my head in abolute shame


Tis true what they say - a little bit of knowledge is a dangerous thing.
Old 29 October 2005, 12:07 PM
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Pedroskate
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Default Overpresure

Think about it?
(This is just a theory)
All that pressure running back up the exhaust, the turbo wastegate open but no where to go, pressure builds exponentially until……..
KABOOM!!
and your left sitting in the middle of the road wearing nothing but the charred remains of your skiddies.
Its witchcraft…don’t go there!
Old 29 October 2005, 02:34 PM
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ru'
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Originally Posted by buzzard
...literally tries to 'suck' itself off. ....
This thread's brilliant!
Old 29 October 2005, 02:40 PM
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Originally Posted by ru'
This thread's brilliant!
No it aint





Old 29 October 2005, 07:10 PM
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buzzard
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Originally Posted by cookstar
No it aint









......but its very informative


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