Re: 89-90 200Q performance

[STEADIRIC@aol.com]

>Ahh..Even though, talons/eclipse 4 cyl. manage ~190 HP with 91. ?
>It would seem, with an extra cyl. and extra displacement, you could burn 
>more fuel and air without knocking, therefor have more torque and HP.

I used to race for Eagle (Rossi Racing) in IMSA.  The talon/eclipse 
motor's are grenades you'd be lucky to get 150K out of one with stock 
boost.  I have several friends who upgraded their cars ECU's to 16psi and 
each of their cars have gone BOOM less than 45K after the brain swap.  
The Mits motor is more on the ragged edge.  the Audi on the other hand is 
a much more robust motor that can go forever, my '81 coupe has almost 
400K and it's never had the head off. 

Back to your knocking question.  The Audi motor's ECU figures timing and 
boost according to several inputs; Ext Temp, Coolant Temp, Charge air 
temp, RPM, Barometric pressure, crank position, Knock sensor and O2 
content (BTW That's why you don't want to add NO2) From those inputs the 
ECU figures the Max boost and the Max timing, there interelated, If the 
engine hears Knock it dials back, The kicker is though it can only dial 
back 8 degrees (Crank) of timing to try to calm the knock down.  91 Oct 
and more than 1.8 Bar = Big knock.  That's why Ned Ritchie will not sell 
you the 2.0 bar (Stage II) or 2.5 Bar (Stage III) ECU Mod without Turbos, 
Headers, bigger Intercoolers etc. Even then you HAVE to run 93. 

PDQSHIP and myself have been playing with big boost and power and anytime 
we run 92 Oct, gas with MBTE (I thinks that's what it's called) or Gas 
with plant based additives (Alky) we get big knock and we have to back 
off for that tank.  In the winter it's annoying.... in the summer it can 
do really bad things to the engine.

Later!

Eric Fletcher
'87 5KCSTQIA2RSR2B