Re: 89.5 10vt [200]

[QSHIPQ@aol.com]

In a message dated 97-03-09 12:22:06 EST, you write:

<< 	QSHIPQ reports that "from a computer upgrade, really nothing 
 available for the 89.5> 10vt cars".  If by that it is meant there is no 
 turbo mod available for this motor, that is incorrect.
 
 	If you have one of these cars [IMHO, best cam profile on any 
 10vt], and you want a computer upgrade, call ......

	Bruce
  >>
BE VERY VERY CAREFUL on this folks, see Dave L Kaboom post of Feb....  10vt
dual knock sensor turbo cars are much more prone to kaboom than a single
knock car due to it's higher static compression ratio.  Given the
"definition" of computer mod (I presume you were referencing that in both
paragraphs bruce), the ice is much thinner here than on an earlier MC car....
 

Specifically, the increase in static compression ratio is from 7.8:1 pre 89.5
to 8.4:1 89.5>....  2 bar at sea level on the earlier cars (7.8:1) gives an
Effective Compression Ratio of ~15.75:1.  2 bar at seal level on the 89.5>
cars (8.4:1) give an Effective Compression Ratio of ~17.0:1...  Equalizing
that would mean that the later cars should only max at 13psi or 1.8xxbar....
 Doesn't sound too bad

Except that with the current "box" mods, 2 bar boxes exceed 2 bar with a 2
bar (max) pressure transducer attached, with proper outside temps, I have
measured in excess of 21psi ....  I would find hard to believe that any
"real" changes apply to the 89.5> mods....  So the "boost" pressure
transducer accuracy is within the same parameter as the earlier cars...
 Kinda makes you think a little....  Combine this with the fact that the k24
turbo has higher potential for heat soak, I would be very careful on this
mod...  I wouldn't do it at all without at least a 2.5 PT attached, high end
boost levels are more critical on higher static compression motors....  

Bruce and I had the discussion on this upgrade some time ago.  Knowing how
the current mods are being executed, higher compression motors carry a higher
risk...  Understand YOU are assuming that risk.  

On the "cam" profile, that was a running change and it's based on chassis
numbers.  Are you sure you have it Bruce?  Do you know what the difference is
between that and the earlier one?...  If you post me your 44 chassis numbers
(the numbers after ...44... in your VIN, I can give you a definite, and
anyone else for that matter.  The performance gains on this cam are minimal
unless you are tweeking the valvetrain.  My understanding of the profile is
that is was designed more to control HC (reduced unburnt fuel) on the higher
compression motor than "add" perfomance, though by definition, did the
latter.   My research indicates that this cam is expensive and hard to find,
some hard core measures of cams can help you make your choice on a better
cam...  Back to turbo and exhaust theory.

Computers:
EPROM, EPROM, EPROM....  Hardware mods are simpler, but MUCH higher risk....

For the money being charged for "hardware" mods, the demand should be higher
than the current commercially available stuff....  Please take the time to
ask the hard questions, blowing up turbochargers and motors is risky
business, and hardly necessary, there are some on this list already
addressing "better" ways to the same end, safer too.  

My .02 arbitraged thru the peso

Scott