My S2 coupe
Hello, I own 1991 Audi S2 coupe with 2,2L 5syl 3B engine, and my main goal is to make it run on VEMS and get power between 350-400BHP. Right now my best ET at 1/4 mile is 12,82 seconds.
Engine
- big intercooler with opposite direction air flow, by-pass in new location and drilled intake manifold.
- Intake: AEM 4" air filter
- original K24 7000 turbo
- I recommend some uptodate turbo design (garret ?) not K26/27 like MembersPage/MarcellGal/PowerAndTraction where turbo wakes up a bit late (above 4200 RPM in gear 2) for the power (406 Hp)
- Exaust: RS2 manifold, wastegate wiht stronger spring (old 10VT audi one), stock downpipe, straight through pipe to last original silencer.
- Fuel: stock fuel pump but modified elecrical system, mallory FPR.
- Gauges: VEMS Round WBO2 and EGT (2mm EGT sensor, RPM input (signal from ECU wire, setting 5 and 229), analog input for boost (settings below), analog output for stock ECU NB lamda), autogauge boost.
VemsAudiAan shows a straightforward wiring recipe for this engine, wether
- using motronic ECU
- still needs some wiring, eg. WBO2
- using v3harness
- or building custom harness
- best fit, but most work and likely the most costly as well
for ignition upgrade, you can either go distributerless, eg.:
- apply a 2x2 wasted spark module to drive ign2,5 and ign3,4 like MembersPage/MarcellGal/PowerAndTraction (ign1 driven by factory ign transformer)
- apply AAN-type ignition: power output stages + transformers
- or without power output stages, just the transformers (driven with power "IGBT" output, of course)
- use 5 logiclevel COPs (not recommended, these COPs don't live long in high performance engines)
- or use 1 channel CDI and keep the distributer (make sure it is positioned well, especially if using ALS - not recommended though)
The most appropriate ECU:
- assembled v3.x
- 6 IGBTs + 2 logiclevels
- write in the order note: "255 Ohm logiclevel output" to allow even for the (otherwise not recommended logiclevel COPs)
- with the 4 stepper channels, this allows up to 6 logiclevel and 6 power outputs
- no 1 wire
- 30V flyback
- primary trigger=VR
- secondary trigger=auditrigger
- 300 kPa internal MAP sensor
- or 400 kPa, but without serious internal engine upgrade higher than 1.8 bar boost is not feasible anyway
- no screws (easier to mount in the audis without screws)
Chassis
Brakes: 4x zimmerman discs, ferodo brake pads, Motul RBF600 brake fluid. Front brakes are waiton for upgrade, alredy buyed wilwood 4 piston calipers and audi A8 320mm discs.
Suspension: 4x kony yellow shocks, original springs are wating for lowering ones.
Body: The car got new paint a year ago, for better cooling it has modified RS2 replica front bumper, a little wider rear bumper, loesed lower door covers, tinted windows.
Other: 034 short shifter
Plans:
- Need to change the 2mm EGT sensor with 6mm one.
- especially if the sensor is before the turbo (although I guess it is after the turbo, in the manifold in the factory place)
- Bigger MAP sensor for boost logging.
- Change the ingniton system and eventually VEMS ecu (this takes for some time).
Turbo update is already in my plans, garret GT3071r i think, but all this comes with VEMS ECU.
The EGT sensor replacement is becase it is now in manifold, wiht old manifold it was after the turbo.
Setting up analog in to read it from gauge and log it:
First you need little simple schematic between cable from MAP to gauge because otherwise, connecting it directly, it will probably affect MAP reading.
VEMS 300kPa MAP sensor
I connected my compressor variable output (with gauge: 0 to 2,5BAR) directly to MAP input.
Settings where: calibration 64, offset 0
First I needed to get 100 reading at atmosphere pressure, I changed numbers at analog in curve to get it.
Now raised compressor output to 0,5BAR and played with numbers in analog in curve to get reading 150, then output to 1BAR and played to get 200, then 1,5BAR to get 250 and then 2BAR to get 300. After that tested other readings, 0,1BAR - 110, 0,2BAR - 120, 0,3 - 130 etc. I din't have to change any more numbers at analog in curve because it was enough measure these 5 points (0BAR - 0,5BAR - 1BAR - 1.5BAR - 2BAR).
These are numbers from analog in curve:
0 - 0
1 - 0
2 - 0
3 - 0
4 - 0
5 - 0
6 - 0
7 - 0
8 - 0
9 - 3
10 - 38
11 - 73
12 - 107
13 - 136
14 - 169
15 - 225
16 - 240
First 8 rows are 0 becase they din't change the reading, also are 15 and 16 set to linear in because they din't cange nothing also.
Log file (RPM spikes are things what I can't get rid of):
It shows also that original turbo is small :P boost rises to 1,6BAR and then drops down again, also the A/F is not wery good (soft is for RS2 injectors, I'll try them later).