ANTAV

[SimonUK]

I know what ANTAV actually is, but what do the initials actually mean as i can't find anything on it.

The crank sensor on our engine is 7.5degrees after TDC for number one. I am right to Set the ANTAV as -7.5deg?

Thanks
Si

[SimonUK]

I know what ANTAV actually is, but what do the initials actually mean as i can't find anything on it.

The crank sensor on our engine is 7.5degrees after TDC for number one. I am right to Set the ANTAV as -7.5deg?

Thanks
Si

[Dan Deussen @ Weber Motor]

Simon,

I believe you said you were using and EFI ECU which is Italian made.
I don't know for sure but let me take a wild guess here:

ANT = Anticipo = (Spark) Advance

and the rest probably stands for offset from TDC. So you are probably right to set the variable to -7.5 degree.

Just out of curiosity, what type of trigger wheel are you using (number of teeth and layout)?

Look at this thread (http://fsae.com/eve/forums?a=tpc&s=763607348&f=125607348&m=7786020025&r=8816063125#8816063125) for instructions to verify if your timing is correct.

[SimonUK]

Again thanks Dan, you're too helpful http://fsae.com/groupee_common/emoticons/icon_smile.gif

Indeed we are using an EFI ecu, everything is in english just it doesnt explain the ANTAV term.

We are using a 4+1 timing wheel setup, this was the easiest to setup as the engine used a 24-2 layout on the standard flywheel so we machined off the teeth leaving 4 teeth at 90deg spaces and a 5th 15degrees after.

The Crank sensor sits between the TDC 1+4 tooth and the extra 5th tooth when cylinder 1+4 are at TDC.

We haven't been able to check the ANTAC (criP) as the engine is all covered and the if we were to run it without a cover on then oil would go everywhere.

Thanks again Daniel

Simon

[Dan Deussen @ Weber Motor]

Simon,

Do I understand it correctly that the EFI ECU will not let you use the 24-2 layout and requires you to run the 1+4 setup? I have seen these low looth trigger wheels before and I am convinced that they don't work well for FSAE applications because the crankshaft accelleration rates are so high (up to 4000revs/sec^2). The more teeth you have on the crank trigger wheel the easier the ECU can determine the actual rpm under transient conditions. Bosch has been using a 60-2 setup on their automotive applications for many years for a good reason.

I have actually seen a BMW V8 race engine (http://cs.svsu.edu/~dsdeusse/armaroli/armaroli.htm) with destroyed pistons due to detonation problems caused by improper spark advance during transients with the same trigger setup and ECU manufacurer you are using.

[B Lewis @ PE Engine Management]

Hi Guys,

The accuracy of the spark depends not only on the number of teeth, but also the algorithem used to determine position. We use a standard 12-1 tooth pattern (as does the stock Honda) and see little deviation (<0.2 degrees) from the set timing during huge transients. Also, the stock Yamaha and Suzuki crank wheels are only 4+1 style wheels.

[SimonUK]

Daniel,

Yes you are correct, we cannot use 24-2 on the EFI ecu. 36-4, 60-2 along with the 4+1.

We choose 4+1 as whilst it may not be the best for transient engine speeds it was possible to use the existing timing system and therefore not suffer from reliability problems of self made timing wheels as we have had in the past.
Previous teams have also tried a 60-2 setup but had problems with it making a wheel to provide an accurate signal at high engine speeds.

Thanks again

Simon