3.8 VP

[v6bucket]

I'm not sure I'm going to have time to fiddle with this tune as my son is going back home tomorrow, & have had to fix a few other things for rego, plus a crook sensor or bad connection as the fuel consumption was a little high, not sure which one it was, but it appears to be going ok now.

[v6bucket]

Whilst checking out some bin files, I've noticed that the timing curves seem to reduce in the higher rpm range. As most of my tuning has been with distributors, the timing always stayed at the max once it got to a certain rpm. Is this to reduce emissions or is there some other reason for it?

[Holden202T]

depends on the motor i guess .....

i know in the case of the ecotec, it have been running it on 98 octane and winding the timing up to see what it can handle, at high rpms (about 3500 onwards) it hasn't been able to handle alot more however in the lower rpm areas it has taken alot more!

the other thing that can change it is the cam .... generally in the cams power range you'll see less timing but out of its power range it'll have more timing.

[v6bucket]

The bins that I refer to are std GMH for a series 1& 2 3.8. Just trying to understand why the ign. timing retards at higher rpm.

[Holden202T]

it might also be changes in compression ratios also developments in tunes, i know from looking at memcals.com some of the information in tunes, like one says its been superceeded by another tune to fix pinging etc .... these may explain why some tunes have different timing to others.

dizzys were always a compromise with timing because they are limited to what they can do with the advance mechanisms on them, efi motors don't have this issue, they can have whatever timing wherever you want it and can have an up and down timing curve throughout the rev range to get the most from every load point.