Ignition Timing for Spec S on Irish fuel.

[Kieran]

Hi folks,

Just baught a timing gun and checked my timing, it was at 15* advanced from TDC. I increased it a degree at a time taking it for a run and listining for detonation. Its at 18.5* now and makes a very noticable difference, the power comes in at lower RPM's and the delivery is far smoother. Theres defenatly a bit more power and it should help the milage. I highly recommend doing this but it only applys to non-turbo's on irish fuel which is 95 RON. Also anyone in a warmer country like Austrailia should not advance this far as its more likley to detonate if the air intake tempreture is high. I think the turbo's need to be more retarded than this.

 

[S15 SILVIA]

Do you know what the factory settings are?
Are they 15degrees?

 

[Kieran]

I think it is, i cant find the service manuel anywere online. But i was talking to a guy in california who said he has seen anything from 10 - 15degrees from the factory depending on market it was sold in, they retard it alot for saftey as things like humidity, tempreture, altitude, and local fuel octaine levels will effect the point were it starts to detonate. I did it cause a guy in the US said he advanced it to 17* and that was safe on there ****ty 89 octaine fuel so i pushed it to 18 but dont want to risk going futher. Definatly worth it but try and borrow a timing gun i paid 60euro for halfords cheapest one. I used online walk through but they were all for vacuum and they say you have to disconnect the TPS and rev it to 3000rpm. dont do this just time it at idle 900rpm.