Tuned With Cas Not Set To 15* ?

[Super Drager]

Hey guys, i've noticed on a few cars, mainly skylines that they are dyno tuned with the CAS set to either full advance or full retard. Why is this done? When doing minor adjustments on my own car the CAS is always at 15* and every adjustment is done via the map itself. Seen a few Jap imports with the CAS fully retarded and when the new owners get the cars and put it back to 15 the engine blows(pinged to death). Hell, my old mans R33 had the CAS set to full advance, no pinging at all with the knock light or kmon.

[hy_rpm]

Most jap cars are set that way cause the have aftermarket cams or gears when tuned

Also it's alway best to set the base timing to factory first before tuning as altering later will affect the whole map

[AngryRB]

ive tried advancing mine with stock computer and adding octane booster, went pretty hard down the quarter mile lol.. but not a good idea I know..

That skyline pictured must go hard by the way... side note: give me a link to your build thread for the 300zx, im not far behind lol

Edited October 22, 2013 by AngryRB

[89CAL]

If its been tuned with the CAS how it is, then best bet is to leave it. If the CAS is advanced this would have been compensated for in the timing map by the tuner. So if the CAS is advanced say 5 degrees, then you might find some points on your map where the timing looks retarded 5 degrees when you look at someone elses tune with similar specs.

There's no harm really in doing it this way,

[NYTSKY]

Mine is also done this way. Mostly because it is easier to pull the CAS off and on without worrying about where the timing is.

[89CAL]

Mine is right over, but thats just where I had to put it to get base timing at 15 degrees :S

Seemed a bit odd, was making me think I had a tooth out on the belt or something but when I pulled the engine out it was fine

[Missileman]

I've got a couple of R32GTST out font my place, one with a Mitsubishi branded cas, the other with something else? What I did notice when I swap the cas over, is that the engine that originally had the mitus cas, required full advance to achieve the correct static timing with the other brand cas attached.

[hy_rpm]

Sometimes the marks on the crank pulley can be off as the damper between the pulley is worn and cause it to give you false readings

but it's always best to get the base timing insync with what the ecu sees

So if the ecus saying its at 15 then make sure it's reading 15 at the crank otherwise you whole map will be off by what degree you set it off by

[Guilt-Toy]

with aftermarket ecu's the timing ofset is done in the software so it does not matter where the CAS is positioned.

if you have a power fc or a stock ecu remapped then it would matter, the tuner would have to know where the timing is and adjust the whole map to suit.

[Hanaldo]

with aftermarket ecu's the timing ofset is done in the software so it does not matter where the CAS is positioned. if you have a power fc or a stock ecu remapped then it would matter, the tuner would have to know where the timing is and adjust the whole map to suit.

This.

I know my tuner likes to set the CAS to full advanced on cars with a stand alone ecu, then tune from there. Means people can't then try to advance the timing (lookin' at you AngryRB, nawwwty!) or put it in the wrong spot if they have to remove it. Not a bad idea really.

[simpletool]

This.

I know my tuner likes to set the CAS to full advanced on cars with a stand alone ecu, then tune from there. Means people can't then try to advance the timing (lookin' at you AngryRB, nawwwty!) or put it in the wrong spot if they have to remove it. Not a bad idea really.

Yeah, not a bad idea. Although the tuner would need to remember that light load, and low RPM areas on the map would need to be compensated, not just areas under load/booooooost. As would any background timing tables such as idle, cold start, etc.

[Dose Pipe Sutututu]

Yeah, not a bad idea. Although the tuner would need to remember that light load, and low RPM areas on the map would need to be compensated, not just areas under load/booooooost. As would any background timing tables such as idle, cold start, etc.

If you offset it in the ECU then it will be in sync again like stock.

e.g. you dial in 25 BTDC and you offset it by 10 then it would be 15 again

[hy_rpm]

I remember when I first had my car tuned on road and the cas was too retarded so off the mark it would be very doughy but build boost fast .

I set the timing after to std 15 as it was 5 and made a massive difference drove and revved much easier

Took it to the dyno to see what power it made but it was pinging very badly so they retarded it back to stop it but it drove like before

So I took it back to the tuner to fix it end up driving better and made 182rwkw out of the old sr and t28 with smic but it was a remapped std ecu

So if you tuning with a std ecu or power FC having the base timing off before tuning will cause issues

[Rolls]

with aftermarket ecu's the timing ofset is done in the software so it does not matter where the CAS is positioned.

if you have a power fc or a stock ecu remapped then it would matter, the tuner would have to know where the timing is and adjust the whole map to suit.

Exactly, doesn't matter how it is set as long as the tuner uses this as their base. One reason though I wouldn't ever do it is it confuses people and a backyard mechanic might set it back to 15 degrees thinking he is doing the right thing and blow the motor up, if you set it full advance and tune it then this isn't so bad as you make setting base timing much easier and means if you get bad fuel it is easy to do a full retard and then put it back.

Yeah, not a bad idea. Although the tuner would need to remember that light load, and low RPM areas on the map would need to be compensated, not just areas under load/booooooost. As would any background timing tables such as idle, cold start, etc.

Does nistune etc have a "k factor" equivalent for igntion, eg you can shift the entire map (and all subsequent cold start maps) by +- X degrees?

Edited October 27, 2013 by Rolls

[GTSBoy]

nup.