I recently Been adjusting my cam gears. I know that when you advance the intake cam, your suppose to adjust your ignition timing. Now here is the question. If I am running +3 on the intake car, and since the intake car and distributor are connected to each other, would it make sense that a +3 advance on the intake cam gear would correlate with a +3 degree advance in ignition timing? Also do I have to jump the ECU, not service connector, but the ECU fuse to clear its memory everytime I adjust ignition timing. Thanks!

 

1° of cam timing is supposed to equal 2° of ignition timing, but I can't remember if it worked out this way for me or not. So advancing your intake cam 3°, should yield a 6° advance in ignition timing.

You have to jump the service connector for a proper timing adjustment, (I can't think of any circumstance where you would want to [b/]jump[/b] the ECU fuse). But after the timing is set, you should pull the back-up fuse to reset the computer... every time.


[Modified by 94gsr, 5:01 PM 1/26/2002]

 

Thats what i meant the ECU fuse in under the hood. What do you think about this. With Cam Gears set at 0,0 I bough the engine running close to 18 ATDC, basicaly at it. This is how it has been set since I swap this motor in and today was the first time I have ever checked the timing. Anyway so in advancing my cam gear and setting my ignition by your method, would you think a 19 or 20 degree advance is better, I have digital timing light that i love dearly! It can not read in .5 degree increments. Oh yeah, how do you type the little degree mark! One more thing, does adjusting fuel pressure effect ignition timing at all? Thanks again.



[Modified by Zynentech, 11:08 PM 1/26/2002]

 

I think you mean BTDC. I'm not sure that the car would even run firing 18° ATDC.

Unless you're very familiar with your engine & it's demeanor, don't go any higher than 19°BTDC on 92 octane. And depending on your particular engine & other mods, you might not want to even go there. You'll just have to do some tuning, (or have someone else tune it), to find out where you want to be.

If you're referring to your timing light, I have no idea. If you're talking about something else, you'll need to elaborate.

No.

 

Yea i meant BTDC ...still learning, and what I meant about the degree mark is like when your typing here in the post. Instead of typing "18 Degrees" , How did you type the little degree symbol


[Modified by Zynentech, 11:34 PM 1/26/2002]

 

If for example your igntion timing was set at 16 btdc and intake cam at 0, and you moved the intake cam to +3 degrees your ignition timing would go to 22 degrees btdc. Every degree of cam timing will move your igntion timing 2 degrees. Make sure short the service connector when you adjust the timing.

 

Oops, had to fix that - I typed it backwards.

 

Yeaup, for every degree you advance the intake cam, you advance the ignition 2 degrees.

For those of you with low compression pistons, you can run more timing than those with high compression.

 

THanks for all your guys responses! It has helped alot. I have my intake cam set at +2 degrees right now. I tried advancing it to 20BTDC but it just didnt seem like it was running that great in the midrange. I turned it down to 19 BTDC, and turned and bumped up the fuel pressure. Car is runnning awesome. Stil would like to take it to a dyno soon as time allows. What do you guys think is the max saftest to advance ignition timing with , 89 Octane gas, and 93 octane? Thanks again

 

AFter advancing the intake cam, wouldnt the ECU automatically retard the ignition back to factory settings? 16*(+/-2) If it doesnt then i can adjust with the distributor correct?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1SlowSi &raquo;</TD></TR><TR><TD CLASS="quote">AFter advancing the intake cam, wouldnt the ECU automatically retard the ignition back to factory settings? 16*(+/-2) If it doesnt then i can adjust with the distributor correct?</TD></TR></TABLE>

You should jump the connector, then adjust your base timing back to 16° (or where ever you want it) using the distributor.

 

I guess ill do that, but if the ECU would do it automatically then shouldnt i just let it?

 

It won't.

 

OKay sweet. If the motor does sense knock/detonation, what will it do then?

 

If the knock sensor detects knock, the ECU will indeed pull timing, but that isn't something you want happening. The ECU won't "automatically adjust" your base timing back to 16° BTDC, but it will pull timing if it detects detonation. However, you don't want to depend on your knock sensor to retard timing (for a number of reasons), and you obviously don't want detonation, so you need to set the base timing to an appropriate value.


Modified by Padawan at 6:08 PM 5/1/2004