1/2 degree retarding per psi?

facko · Post by **facko** » April 12th, 2005, 3:34 pm

i was askin a friend about how much i should retard the timing on my car and he said it was like 1/2 degree per psi...is this about right or what? right now im running between 7-10 psi if u got any suggestions

JWMotorsports · Post by **JWMotorsports** » April 12th, 2005, 4:02 pm

Honestly it's only a guide line. It all depends on turbo size n flow, fuel system, efficiency, compression ratio...etc... and you'll have to adjust it at your own risk.

The way I tune timing is to keep advancing it till you hear it detonate, take your time advancing it (detination sounds like loose change rattling in the engine) IMMEDIATLY let off the throttle (to avoid engine damage). Pull over and retard the timing a little at a time untill it's gone. In order to change the timing properly you'll need to jumper the diagnostic box (4cyl SOHC wiring box was TEN pin jumped to GND pin) which will put the car in test engine mode. Once the timing is changed remove the jumper before driving. Make sure you test for detination in 5th gear WOT after testing the other gears. If any exists only slightly in 5th gear you can usually add a little more fuel with the S-AFC to get rid of it. Also be sure to occasionally check your spark plugs for signs of detination. Signs are usually little silverish speckels on the electrode and/or insulator (light amount of detination w/ high EGT's). Other signs are crackes or lines in the electrode insulator (bad detination). If you see ANY of these you need to either add more fuel and/or retard the timing untill it stops. You'll need to clean or replace the plugs each time. I recommend NGK V-Power Resistor plugs gapped at .030"-.032" in turbo cars. Remember....detination of ANY kind is the #1 engine killer!

Take your time, listen carefully, and watch those spark plugs!!! They will tell you whats going on. If all is tuned right, they'll burn pretty clean (in most cases). Watch your air/fuel gauge also, it should stay about 3 bars green under WOT in most street cars (this is for the Autometer gauges).

facko · Post by **facko** » April 12th, 2005, 9:23 pm

do you know which pin to jump on the dohc?

JWMotorsports · Post by **JWMotorsports** » April 13th, 2005, 5:47 am

I'm not possative about any of the others. Call Corksport or consult a repair manual for your specific year w/ DOHC. One of your local repair shops may look it up for you as well. The SOHC's have the Diagnostic box mounted on the driver side firewall with the pin out diagram on the inside of the cover. As for making a jumper you can either use a paper clip or use a piece of wire w/ spade terminals on each end.

jaydog5678 · Post by **jaydog5678** » April 13th, 2005, 1:56 pm

facko wrote:do you know which pin to jump on the dohc?

It's the same as the sohc. Jump the 10 and GRD.

facko · Post by **facko** » April 13th, 2005, 9:28 pm

thx alot guys

clay · Post by **clay** » April 14th, 2005, 10:06 am

is this needed when you trubo the motor or just preffered?

JWMotorsports · Post by **JWMotorsports** » April 14th, 2005, 8:28 pm

This is how you tune a car's timeing. It doesn't matter if it is turbo or not. Just use extreme caution and go slow. All hurring will get you is a blown up motor. Advancing the timing not only makes more power but it helps you burn off more fuel as well do to the power stroke being longer.