Several setups use multitooth wheels with no missing tooth.

Some (mostly Japanese) engines like Nissan and Toyota's have

See [Fero's] config.txt and tables.txt (24+1 trigger used in a 6cyl supra with 1.1.12 firmware). Same trigger settings apply in later 1.1.xx firmware.

  • number of teeth: 24 (tooth_wheel=18)
  • tooth width is 30 deg (tooth_wheel_twidth1=78, tooth_wheel_twidth2=00)

The relevant part from Fero's 6cyl config:















h[1]=00 14 10 0C 08 04 00 00

Configlet available for theese settings at


A 4 cyl would be slightly different in the following:




h[1]=00 12 0C 06 00 00 00 00


Please note that N+1 where N<=11 requires 1.1.27 firmware (or newer). This is where tooth_width >=64 degrees, that is tooth_wheel_twidth2>0. Most notably relevant to

Pulse timing restriction

The campulse must always come between the exact same 2 crankpulse ("no race condition"). With HALL sensor, be careful to select the right edge (for both primary and secondary trigger) that satisfies this.

Since the cambelt sloppiness is usually well within +-12 crankdegrees, a 12 tooth crankwheel is practical (one tooth every 30 crankdegrees allows the sloppy campulse to be always between same two crankpulses).

How does this relate to auditrigger?

The InputTrigger/AudiTrigger (a.k.a. 270+1) is basically a very special case of multitooth-none-missing. The auditrigger hardware is special because of the 135 cranktooth, much more dense than 30 degrees (=12 cranktooth), so the crankhome-VR is needed, but a cam-HALL masking signal also needed.

The same software implementation (with appropriate config) could theoretically support either 24+1 and 270+1. But VEMS firmware uses slightly different, optimized implementation for each (that share some parts of course). Strangely the 270+1 was supported before the otherwise simpler 24+1 (10+1 and other related) trigger setup.

This N+1 style is supported in 1.0.x (since appr 1.0.36, early 2006), called InputTrigger/AudiTrigger setup, with 270+1 as the primary target (commonly found on 5 cylinder audi engines). 270+1 is when you have 135 tooth on crank. Unlike the 24+1, the 270+1 needs a hardware trick so the campulse always comes between same two crankpulses: it is a "pulse timed by crank, masked by cam" (nickname "cramhome"), that is the 3-input trigger system, see InputTrigger/AudiTrigger.

1.0.x Configuration example for 24+1

secondary_trigger=19 (rising edge, camsync without filtering) could work too. But secondary_trigger=09 cannot work
  • primary_trigger=FB # rising edge, coiltype (yes!), trigger filter disabled (bit2=0). Coiltype chosen. and primary trigger filter might work with 24+1 (but not with 270+1)

Note that in 1.0.x (only with auditrigger setup), trigger_tooth changes in the opposite direction than you got used to (with missing tooth wheel). That is, higher value will bring the spark earlier.


Please report your benchtest results with recent 1.0.x. There is some allowance for the campulse to come (eg. 1 pulse) ahead in some cases. This was desired for the original 270+1, and does not matter with a proper N+1, but with a bad camsync position (if the campulse sometimes comes slightly after crankpulse X, sometimes before), than 30 degrees retard you will feel for sure. The allowance should be configurable (like 0/1/2 tooth).

Beware: 1.1.x with auditrigger setup currently does not support N+1 if N < 270 (that is, below 135 tooth on crank)

Because with 135 or 142 tooth at appr 7000 RPM the engine lost power (retarded 1 tooth than cut spark, as a safety mechanism when firmware thought the input pulsecount was too low), there are some specializations in 1.1.x that currently do NOT allow arbitrary N+1, like 24+1. Work in progress, so 1.1.x will handle everything supported by 1.0.x (and more).