Members Page/Istvan Audi - VEMS wiki www.vems.hu

2.3L audi 5cyl 20VT audi for drag racing

Engine is built to >800 Hp specs. A similar engine measured on engine dyno reached: 976 Hp at 375kPa @ 8000 RPM.

We'll see.

Trigger

10+1 trigger, that is

primary trigger: HALL 5 pulses on crank
- trigger_tooth=01 is appr 72 deg BTDC (trigger_tooth=00 would be at about TDC prev cyl, not good)
secondary trigger: HALL 1 pulse on cam

Engine is running with firmware 1.1.27

V3GUI_ ... firm1.1.27
- but firmware and temp tables are uploaded already, should NOT be needed
VemsMT1.1.27 prebta0
- use to tune maps (12x12 highboost). Don't tweak trigger settings with it.

Injectors

First running was with small injectors (from some Opel Monsa).

Now running 1600cc/min low-impedance injectors, with 6.8 Ohm (50W) series resistors. Currently 36V flyback (30V transient + powerflyback).

I think the 1600 cc Bosch LowZ injectors do not work with 1.5 .. 1.8 bar fuel pressure:

we spent hours debugging why the sparkplugs are so different: some sparkplugs were DRY
ECU did well on the bench
I just got to know in the end they lowered the FP to get longer PW and better injection
- => Jorgen1_: I would expect them to have a bad spray pattern, what problems is seen.
- Jorgen1_ The usual big injector tuning is done? Never leaner then lambda 0.85-0.90 or so => no, it does not run well at 0.85, some sparkplugs are dry (and apparnetly not always the same??)
Isn't it the 4,9ohm injectors?
- I don't know, but series res = 6.8 Ohm 50W
We run them without series resistors.
Jorgen1_ Check if they are the normal 4.9ohm type and rip the resistors in that case. They will never work otherwise.
- we'll also have to apply proper fuel pressure

Ignition

Now running with inductive ignition. (idles at 77kPa, around 800 RPM, big cams)

It sounds like not all 5 cyls run at idle. (gets better at rev)

Finally it will use CDI ignition.