turbo sizes - was "kkk vs. garrett'

[Mihnea Cotet]

Javad,

Peak HP output won't increase because of overboost but
torque will, to a certain extent at least,
boost=torque IMHO/IME.
I can assure you that the feeling of a K24 at 1.9 Bar
overboost is superb, the feeling of the car is even
more brutal than an RS2 equipped AAN because of the
instantaneous response you get due to the HUGE (yeah,
huge is the word) WG spring and appropriate chip
programming of course. FWIW, on 98 octane (RON, thus
european) the ECU didn't even attempt to back off
timing during those overboost accelerations and we had
no knock at all either (that's for those who doubt
about my abilities to reprogram a chip, :-) )....

Mihnea


--- JShadzi at aol.com wrote:
> 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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>
>
>


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