[youda]

Hey guys playing with the timing on my sierra sj50 g13a and the book says 10 degrees btdc. My question is has anyone played with the timing to get best results from premium or ultimate fuel. My aim is to get the best range utilizing the capacity of the fuel tank. my current range seems to be 290-300km on the highway with a few hills per tank.

[Jackson]

First off work out how much you get per litre rather then per tank (very scientific). I guess you could just fiddle around by adding a few degrees then getting it to work up some good hills to check for pinging and check your fuel economy at different settings. I guess this would probably be around 16 degrees? Maybe someone has run more.

[Proxy]

mine said it should of been 8, i know i moved it to something like 12 or more because it just bogged down at 8 and had no power rev's weren't smooth

[youda]

Im hoping that running premium unleaded and maybe 14-15deg btdc i could drag out another 50km per tank on the highway. i do alot of land based fishing and dont like having to make heaps of fuel stops. i figure with a full tank and two jerrys the benefits of this mod may well pay off.
Im aware that there are better motors for economy but i like the fact that nearly all the parts on the stock little motor are shelf items at supercheap.

[alien]

when i ran the 1.6 with a weber on it my timing was up around 12-14deg... in summer it'd ping a little still though (running 98ron).

didnt notice an economy difference cos i was using the extra power.. lol

[fordem]

I've run as much as 19* BTDC on my G13B - I can't comment on the improvement in fuel economy though.

[Rhinoman]

My Vit runs three or four degrees more advance in most parts of the timing curve, its stock at idle though to ensure that it passes the annual emissions tests. Our standard unleaded is 95 RON, we can get 98 RON or higher but its a lot more expensive.

[JrZook]

Rhinoman wrote:

My Vit runs three or four degrees more advance in most parts of the timing curve, its stock at idle though to ensure that it passes the annual emissions tests. Our standard unleaded is 95 RON, we can get 98 RON or higher but its a lot more expensive.

Hey James, have you had a chance to throw it on the dyno to look at the torque curves when altering the timing?

[youda]

i filled the tank up yesterday and have got a full jerry in the car now before i run the tank empty to see how far i get do i have to prime the pump in some way and will there be a negative affect on the motor running it empty....apart from the obvious coming to a stop, for all you smart ass's.lol.

once this is done ill run a tank with premium (95 octane) and 14deg btdc. and see how far i get.

[Proxy]

the bottom of the tank will be full of crud, which will block your filters, replace filters and repeat untill there's no more crud

[Rhinoman]

JrZook wrote:

Rhinoman wrote:

My Vit runs three or four degrees more advance in most parts of the timing curve, its stock at idle though to ensure that it passes the annual emissions tests. Our standard unleaded is 95 RON, we can get 98 RON or higher but its a lot more expensive.

Hey James, have you had a chance to throw it on the dyno to look at the torque curves when altering the timing?

No, I used to live on a big hill which was good for loading up the engine. In my previous job I used to design knock sensors and the electronics for them - which was handy . One day I will get it on the dyno, where I live now there is one not too far away.

[youda]

well time to post up result.
standard unleaded stock timing 310km per tank
standard unleaded 12 btdc 317km per tank small performance gain
premium unleaded 12btdc 348km per tank small gain
premium unleaded 18btdc 349km per tank big gain in performance
the last test was not my normal city driving/low k highway driving. however it was a long distance highway drive carrying 40l of extra fuel, 60kg worth of camping gear. a nearly full 41litre ezky and a 80kg passanger. was also still able to sit on 105km per hour on the highway on 235/75's. however i have notched it back to 16btdc. im gonna stick with premium for now but i have marked the dizzy cap so i can switch between 10 and 16btdc without a light.
also note that changing the timing gave a much better performance gain than milage gain.

[Rhinoman]

Thats good info. What plugs are you running? any sign of them running too hot?

[2stroker]

Proxy wrote:

the bottom of the tank will be full of crud, which will block your filters, replace filters and repeat untill there's no more crud

Why do people keep saying this, stop and think for a minute. The fuel pick up is in the lowest part of the tank therefore no matter how much fuel is in the tank you are always drawing the fuel from the very bottom. If you have rubbish in your tank it will get sucked up regardless of what your fuel level is.

[shandy92]

youda, well done mate. whats standard timing? 5*?

when you say premium, do you mean 95 or 98?

cheers

[alien]

2stroker wrote:

Proxy wrote:

the bottom of the tank will be full of crud, which will block your filters, replace filters and repeat untill there's no more crud

Why do people keep saying this, stop and think for a minute. The fuel pick up is in the lowest part of the tank therefore no matter how much fuel is in the tank you are always drawing the fuel from the very bottom. If you have rubbish in your tank it will get sucked up regardless of what your fuel level is.

the biggest issue is anything floating on top of the fuel... which is pretty unlikely =)

[youda]

shandy92 wrote:

youda, well done mate. whats standard timing? 5*?

when you say premium, do you mean 95 or 98?

cheers

stock timing was 8-10btdc. i was using 10.
by premium i mean 95oct. i havent used 98 oct yet as i dont believe the cost will match the gain. i may give it a trial though just in case.
plugs looked fine, though it was a cool day (for fnq) at 27deg.
i would knock 1 or two degrees off thoose times if im in an area that fuel quality is debious.

[shandy92]

ok mate, thinking about doing this on my g16b. stock timing is 5deg btdc.

sorry to hijack the thread, but does any one know if i need to bridge the plug? some people do and some dont.

cheers

[Drova]

Yeah man bridge the plug, when I first timed
My 1.6 I didn't (I didnt know) but when I bridged
The plug and checked it was a few deg difference.
Re timed and it ran better man. I found I got
A better L/100km (but don't forget to unbridge
It when you go for a test drive because the dissy
Won't advance)

[youda]

in my opinion best safest results are increase 2degrees from stock then another 2degrees for each type of fuel.
ie plus 2 degrees 91 ron normal unleaded
plus 2 more for 95 ron premium
plus 2 more for 98 ron ultimate/vortex.
this is usually pretty safe and will give a gain. experiment for best results but keep in mind if its pinging it can do serious damage to the motor.

[shandy92]

well i just bought i timing gun ($55 from repco) so ill have a play on the w.e, i hope i can find the plug!