How should timing advance be in a turbo car?

dburone · Mar 4th, 2005, 10:17 PM

I know timing is different for each engine, but im trying to see how the advance curve is on other engines to see what i can do on mine.
I still couldnt get the advance curve of my one engine.

**chimmike** · Mar 4th, 2005, 10:22 PM

you don't advance timing wih turbo at all....................you retard it.

Crazy-Mart · Mar 5th, 2005, 12:36 AM

wath he mean would be : wath kind of ignition tuning is used on turbo car compared to n/a one.

well you still advance it (tuning wise) but way less and the advance goes down in the higher boost/high load (if im right)... the best way to do it would be on the dyno with the proper equipment/getting a mallory unit for the E16 (unsure if its still avail.) changing it on an vacuum unit would be to change the spring and related vacuum arm mechanism with lower movement and getting a higher initial advance... you would want to get a little higher than stock initial to compassate for lower compression and as the boost comes on/vacuum lowers you would get it to retard from the oem specs...

(someone correct me if im wrong)

velardejose · Mar 5th, 2005, 08:24 AM

Thats the idea, but problem is to find a starting point for a blow through carb config
My turbo e16 will be ready next week, I am currenty running a fixed advance dist + carbs
The folks at http://autos.groups.yahoo.com/group/e15et/ posted some ignition parameters for ecus, I am starting from there on
Til yesterday I had 20 deg fixed advance, the car run great til 4000 rpm (90 oct gas), then its power curve fell like a rock
Last night I tried 15 deg fixed advance, now the car runs strongly til 5500 with a lil less quick response down
I will use this advance with the turbo, and keep an eye on my narrow band o2 sensor (too poor at the moment for a broad band unit) and my amplified mic to listen for pingin

velardejose · Mar 5th, 2005, 08:28 AM

I am thinking to install a working vacuum advance to get some part throttle fuel economy
Good thing is the oem unit has a scre w to regulate how much vacuum advance you want/need before pingin occurs, and at boost there will be no vacuum advance at all

I am trying to oversimplify things to make this reliable, hope to get a turbo ecu, sensors, dist and wiring harness in a few months...

lshadoff · Mar 5th, 2005, 08:57 AM

Supercharger kits for some US cars come with a modified vacuum advance which retards the spark under boost. See, for example, the description of the Vortech Supercharging Systems.

Perhaps you can get just that part from a supplier like them and adapt it to your carb.

Lew

dburone · Mar 5th, 2005, 11:10 PM

Quote:

Originally Posted by velardejose

Thats the idea, but problem is to find a starting point for a blow through carb config
My turbo e16 will be ready next week, I am currenty running a fixed advance dist + carbs
The folks at http://autos.groups.yahoo.com/group/e15et/ posted some ignition parameters for ecus, I am starting from there on
Til yesterday I had 20 deg fixed advance, the car run great til 4000 rpm (90 oct gas), then its power curve fell like a rock
Last night I tried 15 deg fixed advance, now the car runs strongly til 5500 with a lil less quick response down
I will use this advance with the turbo, and keep an eye on my narrow band o2 sensor (too poor at the moment for a broad band unit) and my amplified mic to listen for pingin

With "20 deg fixed advance" do you meen that the advance doesnt change and it stays at 20?
I was thinking about making some device with the vacuum advance taht will also retard when boost starts.

velardejose · Mar 7th, 2005, 07:01 AM

Exactly
The weights inside the dist are assembled blocked/fixed in the 'open' position, without springs, as if it were at maximum advance
Dual diafragms systems seem too complicated and non reliable to me
A failure, some heavy pinging at 5000 rpm (7 psi) and say good bye to your turbo e16...
Regards

lshadoff · Mar 7th, 2005, 08:28 AM

Here is a vacuum advance modification for a turbocharged Nissan L16 engine. It's pretty clever.

Lew

velardejose · Mar 7th, 2005, 09:19 AM

Interesting, I forgot about that page
In case of vacuum failure the spark simply retards...
Thanks Lew

dburone · Mar 7th, 2005, 06:13 PM

Thanks for the info!!