does any mod...(drastically snipped to preserve B/W)

[Efraim]

Hi Ameer,
I really enjoy your comprehensive posts.  Recently I "hacked" my 5KTQ by
installing adjustable WG cap, resistor, zener and auxiliary boost gauge.
After reading your reply to Konstantin, I wonder if you could clarify few
points for me:

<snip> The R-Z mod just fools the ECU into thinking the pressure never goes
> beyond 1.4 bar. This is dangerous in itself, b/c you could easily get the
> turbo to overspin or raise the boost to dangerous levels beyond 2.0 bar.

When using adjustable wastegate cap, the boost level can be preset at any
reasonable value up to 2.2Bar (1.8Bar in my case) so under normal
circumstances it should not fluctuate.

<snip> Although the actual pressure could be 1.6, 1.8 or even 2.2 bar, the
ECU
> will never know. It will only see a constant 1.4 bar, until you go under
> 1.4 bar. It's nice to have some sort of limit on boost thru the ECU and
> it's also nice to see the right boost on the stock gauge.

Stock gauge is not accurate at the best of times, so by installing a good
quality auxiliary gauge this problem could be easily solved (I use 0-1Bar
2-1/2"dia gauge). There is always a blow-off valve option for those who are
safety cautious and can't be bothered watching the gauge.

<snip>Timing will then be retarded by any increase in
> intake temp or knock. It's not as nice to rely on those factors to retard
> boost as changes can be drastic, causing poor performance, especially
since
> knock retards all cylinders. Also there is some delay here and some limit
> to how much the timing can be retarded by knock sensor. By setting a
timing
> entry in a mod'd ECU for 1.5, 1.6, etc. bar, you can preset a certain
> amount of retard avoiding any issues above.

I use 94 octane gas and I experience no knocking at all. Considering that
95% of my driving is in the city and I can't  use full boost for longer than
couple of seconds because when I reach 1.8Bar my speed is around 60mph
(multi demerit points territory),  what is the real advantage for me to
properly chip ECU as opposed to R/Z modding? I am going to strap IC (already
bought two S/S hose clamps) and so far I immensely enjoy the results of my
"hack".
It significally improved the low RPM performance and this is a real plus.
The only concern I have is an increased fuel consumption, it is now about
16MPG and I pay about US$2 per gallon of 94 octane. Would properly "chipped"
car have a better fuel consumption? OTOH, the pleasure of driving is well
worth the few extra bucks.
Thanks,
Efraim
'88 5KCDTQ  324K km (201K mi) , 1.8 Bar
'90 90 100K km (62K mi)
Vancouver, Canada