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RE: Silly Season?
When looking at the ECU computer upgrades available for my TQC the questions
I would ask are:
What am I buying? Increased performance through a tweeked ECU or a
Does the seller of the modifications have horsepower and torque curve plots
of before and after stated modification so we know what we are getting? If
not how are the performance and power increases documented?
What is changed with the modification, max boost limit, timing curves, fuel
What level is the maximum boost limit changed to?
What method is used to increase boost pressure at the wastegate? Bleeder
valve, air pressure regulator, stiffer wastegate spring?
Doe the modification need to have the O2 sensor disconnected? Early Abt mods
How is the timing changed, and in what part of the rpm curve is it changed?
How are the fuel curves changed?
Is the redline rpm changed?
Is the modification CARB or EPA exempt? If not, is the modification easily
reversable, ie substitue PROM, so that I can do it once a year for the
What fuel MUST be used with the modification to keep from melting my
Can the modification be reversed so I can go back to the stock settings?
Are the modifications designed for US cars or for euro cars?
To try and keep us all informed comsumers, here are some of my notes when I
was talking to people about computer upgrades a few years ago, 91/92 time
frame. Again, this information only applies to TQC computers.
First a little information about what is in the TQC ECU. The ECU uses a
Motorola compatible 6802 microprocessor and a 2532 4096 byte ROM. There are
data tables and machine instruction code in the ROM. A list of the ICs in
the TQC ECU are shown below.
IC # Hitachi Part # Packaging Description
IC1 HD46802P DP-40 8 bit micro with internal
clock and ram
IC2 2332(A) DP-24 4096x8 ROM
IC3 S8873N DP-28 MC6840 programmable
IC4 HA17903PS DP-8 Dual Voltage Comparator
IC5 HA17904PS DP-8 Dual OP Amp
IC6 HD74LS00P Quad 2 input Pos NAND
IC7 HD14001BP Quad 2 input NOR gate
IC8 HA17902P DP-14 Quad OP Amp
IC9 HD46506 DP-52 Raised Board A/D
The stock TQC computer has a max boost limit of 0.9bar and goes down from
there depending on operating conditions.
Here are my personal notes fom TQC computer mods.
Ned Ritchey - runs Intended Acceleration
Old style mod(as described in european car Oct 91)- rewired computer, uses
stock prom, overboost fuel cutoff and rev limiter still enabled, does not
alter fuel delivery uses higher tension wastegate spring, boost limit
controlled by electronics at end of rj-45 connector, can go back to stock by
substituing in 'stock' connector, Optional external boost controller which
plugs into rj-45 connector. This mod no longer available.
New style mod- replaces prom with updated timing curves and ups max boost
pressure limit, does not use rj-45 connector anymore. Has CARB exemption
He advances timing about 8 degrees throughout the rpm range at max boost.
Does not reprogram fuel curves. Solders in new chip with some type of
scramble board. Also does two other slight electrical mods? Abt programs a
new chip with fuel and timing changes. New fuel curves cause the need for
the euro fuel pressure regulator. He has contact at Audi and Hitachi. He
says Al's computer is a tweaked copy of the DT chip.
Asked about Abt boxes, he has seen about 10, all different some use 3
resisitor changes, some 2, some 1, some have prom changes, some don't. His
stage II mod chips really advance timing, detonate when engine is cold, chip
ignors knock sensor input until engine temp reaches 58 degrees C. Always use
premium fuel and not recomended for cold weather applications.
His Stage I/II/III computer modifications have the timing and fuel maps
changed along with the increased boost pressure. He also has John Buffum's
racing computer maps available for anyone who wants a racing/off-road
computer. This computer works with some of the engine ancillary equipment
Hypertech(Al Solaroli) - runs Hypertech Engineering outside of Toronto,
builds 20V TQC engines, AL flywheels, etc
Mod1:10V- Replaces prom with updated prom which is similar in physical
dimensions to stock prom. Reprograms fuel and timing curves, less radicle
than 20V chip, (I think max boost pressure is around 12 psi here)
Mod2:20V- Remaps fueld and timing curves, ups max boost pressure to 14 psi.
Uses L shaped PROM chip?. Advances timing 12 degrees. Known to ping at lower
elevations and with bad gas.
He says DT only reprograms timing, no fuel.
Abt - Computer accepts increased boost pressures over stock about +3 psi.
Sold a complete 'euro' spec wastegate to increase boost level. Later
upgrades have a replacement PROM.
Detection Techniques(PJ Wales) - Superchips parent company in UK run by PJ
Wales. Replaces prom. Uses stiffer wastegate spring. Set up to run 18 psi of
Total Audi Perfromance(Ivor Wigam)- Has Audi rally involvement in the UK,
possibly with David Sutton Motorsports who ran the works teams. Have heard
his chip might be the BBR start chip, not confirmed?
Superchips USA(PJ Wales) - DT reps in the US
Says CIS injection is not chipable. Uses voltage divider circuit to scale
boost pressure voltage.(again sounds like our mod) Uses variable boost
A TQC owner in Texas - Owns 83 TQC with Abt stage 2 mods with lots of
personal mods. Has tried many different computers in his car. Abt computers
are modified by changing the resistors and caps which raises the max boost
level. Abt computer advances timing 8 degrees. Has put in 20V hypertech
computer and it pinged.
Hans Lehman- He worked on the factory rally cars, built engines, programmed
computers, etc. I have heard of TQCs with his computer in it, but have no
idea where you might get one.
Jo Hoppen - Ran US Audi pikes peak cars and TA/GTO cars. Not sure what is
available from him for the TQCs.
Dinan - Have recently seen ads in AutoWeek asking to use personal Audi cars
for chip development in retrun for a free chip. Not sure if they have
BBR Star Chip(UK) - ?
If any one has answers any of the questions at the start of this note for a
particular tuner modification, I would like to see them. Hope this was of
Dave Lawson firstname.lastname@example.org