turbo sizes - was "kkk vs. garrett'

[JShadzi at aol.com]

I don't doubt that chip tuning can cause a turbo to overboost and grenade, no need to get into that, pretty fundamental...really...

My beef is the idea that somehow while the turbo is overboosting that the output of the motor will be proportional to that overboost spike.

Power on an I5 isn't limited by boost pressure, 30psi doesn't instantly equate to "way over 300hp" for a few seconds....

Javad

>Javad,
>
>That's not totally false, a very bad chip as the ones
>being sold on Ebay provide with a very quick overboost
>"spike" to 1.9 Bar relative pressure but as the
>pressure drops very quickly afterwards to 0.8 Barg,
>this makes the turbo accelerate and decelerate very
>quickly and this deceleration kills its thrust
>bearings, BTBrokeThat on my own previous K24. Now if
>the chip is properly done and there is an appropriate
>MAP sensor in the ECU, it's possible to have an
>overboost to pretty high pressures but to have boost
>pressure drop slower, thus not putting so much strain
>on the turbo as with the "crappy" chips.
>
>I've tested this in a friend's UrS4 who wanted to use
>a WG spring that you could barely compress 5mm with
>both your hands (I mean it was stiff as a suspension
>spring :-) ) just for the fun of it, so I did him a
>chipset with which he could reach almost any pressure
>if the spring was stiff enough during overboost, then
>pressure would drop to programmed values. The result?
>1.9 Bar relative (2.9 absolute) at 2000 RPM, same
>pressure for 10 seconds in 4th through 6th gears, then
>it would drop to approximately 1.6 Bar until 5000 RPM
>and then 1.25 Bar at 6000 and 1 Bar at 7000. We don't
>have any actual figures but the engine response was
>instantaneous (and I used to think a K24 with a stock
>spring didn't have lag, yeah right, it has!) and
>torque was massive to the point that the clutch would
>slip even in 2nd and 3rd gears if we floored the car
>around 3000 RPM.
>
>I know such experiences are stupid with a K24 because
>they reduce reliability of the turbo but my friend
>tested this for 5 days and the turbo is still fine
>now, 3 months after whereas the ebay chips destroyed
>the turbo in my friend's 3B-ed 90q20v and mine (3B as
>well) in 1 day and about 5 hard accelerations.
>Anyway, don't try this at home unless you know how to
>reprogram a boost chip for such springs (I do) because
>otherwise kaboom might be the final word (and I don't
>even speak about fuel and ignition settings here).
>
>Just my 0.02,
>
>Mihnea
>
>--- JShadzi at aol.com wrote:
>> --
>> [ Picked text/plain from multipart/alternative ]
>> Hmm, maybe I should keep my mouth shut...but... that
>> last bit below sounds
>> like a BS at worst, marketing hype at best...
>>
>> Javad
>>
>> In a message dated 3/5/2003 7:59:40 PM Pacific
>> Standard Time,
>> conner at cfm.Ohio-State.edu writes:
>>
>> > >Oh! and one other thing regarding how tough the
>> turbos are:
>> > >I can supply a pair of chips that will blow up
>> your stock turbo in 3
>> > seconds
>> > >or less.  You'll have way over 300 hp for those
>> seconds though.
>> > >
>> > >Ned
>> > >http://www.IntendedAcceleration.com
>> >
>>
>>
>>
>>
>
>
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