[s-cars] Re: fuzzy logic et. al.

[QSHIPQ at aol.com]

Dwayne
Let's make sure we differentiate between software and hardware.  What you 
present below is a hardware problem (IMO), hence my urging for a better valve to 
control boost.  The biggest issue with the stock WGFV is it's slow and weak at 
the low and high ends of it's function.  To verify this, try adding a stiffer 
wastegate spring to the WG.  You will notice a significant increase in low 
end torque BTDT.  Why would this be on a bottom feeder that should be able to 
interrupt boost to the wastegate?  Confirming my point that certainly the stock 
WGFV have a usuable and ramping range that is far from ideal.  In this case a 
boost controller with a better solenoid or a stepper motor will show faster 
low end response and high end trim.  That's not at all to say the motronic 
computer/software isn't asking for ideal, it just has a less than ideal rover 
attached to the other end of the wire.

HTH

Scott Justusson
QSHIPQ Performance Tuning

In a message dated 1/23/2004 11:01:18 AM Central Standard Time, 
dccosby at hotmail.com writes:
Not that I want to throw myself into this discussion...

I do agree that you are giving up ECU control of boost and that could 
present a safety hazard. (I would hope that ECU will kill the timing if 
anything really messes up - that nasty bump would surely be enough for me to 
jog my foot off the loud pedal.)

That said I run the same Apexi controller as Hap on my IA stage 3 chipped 94 
S4. About 1 year after the install, the Apexi pressure sensor failed so I 
switched back to the stock MAP/WGFV setup while waiting for the replacement 
part. Now running only the IA chip with the EXACT same peak boost (and very 
similar boost boost drop off curve) as the chip, the car felt so slow that I 
thought something else was broken. I'm sure the peak power was likely the 
same in both scenarios, but with the chip alone, the car was extremely 
unresponsive (in comparison) and boost came on later. Understood that Ned's 
chip isn't as aggressive as MTM's but I've driven MTM chipped cars and they 
still feel a lot slower than my IA + Apexi car. Before anyone chaulks this 
up to a particular of my car (i.e. wastegate issues, etc.), I helped with 2 
other installs after mine and we all felt the same way.

I'm having a local tuner do a custom dyno tuned chip for my RS2 goodies, big 
TO4e/50, and custom mapped chip in about a month when I get all the parts 
together. I'll do some back to back comparisons with and without the 
controller (takes 15-20 minutes to change) - but I'd be suprised if my 
feelings change.

Cheers.
Dwayne
94 S4

p.s. I also run water injection (at the track) and I know how controversal 
that is too...