RB25DET Timing for Power

[rev210]

Was wondering what people out there are running as base timing?

I have played around with the timing a bit and done a few 'other' things to allow me to run about 5deg more advance than the very last marker on the crank.

[GTS-t VSPEC]

I'm not sure hwo useful this will be cause each car will support different amounts of timing depending on mods. When my car was tuned I think it ended up with 14deg of advance, anymore than that and it was pinging, this was at 14psi.

I think the only safe way to do it is have it dynoed, then they can change the timing while monitoring the pinging and do it safely.

See'ya:burnout:

[Doctor]

I think alot of timing issues have alot to do with plug heat range too. I moved to 7s and it pings at 11psi (17deg) I 'll be moving back to 6s to get rid if the pinging.

Of course there are alot of other issues as well but this is one that not many people think about in relation to timiing.

Doc

[rev210]

At present I have probably about 30degrees advance or so. I tuned my timing 'on the road', boost set to 10psi (spikes to 12 every now and then).

Doctor: I agree with the plug thing, going to 6's is a hotter plug, less suited to high revs and boost than a 7 or 8. But, its the range I am using with a gap of 0.75mm.

If you can be bothered an '8' range plug just for the races is a good idea if you can be stuffed changing them before you go home (i can't).

[GTS-t VSPEC]

30 degrees advance? shit that seems like alot.

I didn't realaise that plug heat range had so much affect, we just gapped mine real close, don't have any problems with misfires. We tuned mine for 14psi, therefore I think the timing has to go back to reduce the chance of detonation, the 2psi extra pumps alot more heat into the intake air and promotes pinging.

See'ya:burnout:

[macka]

My car doensnt go anywhere near 25 degrees let alone 30??

Paul your wolf does your timing anyway so your base timing should always be 15 and you set your advance up thru the rpm ranges hey..

I think its better tuned on the road the dyno cant reproduce all senarios but is good as a start

[GTS-t VSPEC]

Macka,

I'm just going by what Steve(SST) said, I have no idea what it is. The wolf totally controls the timing, we moved the CAS right back so it wouldn't affect anything then adjusted the timing from the computer. Still think 30 sounds high.

See'ya:burnout:

[Hicks]

Barry advanced mine, not sure how much by but I got quite a lot more power. Doesn't ping..........much.

[rev210]

The basic rule of thumb with ignition is:

Base timing --- advanced, more if you run a lumpy cam or have poor cumbustion down low.

Top end timing --- Retards as load increases and combustion mixtures become leaner or more prone to detonate easily.

As if my car wanted to prove a point I got a little bit of pinging today, I suspect it was the last lot of fuel I put in was a tad dodgy.

30deg advance means that when the ecu decides to penalise you for too much air flow you have beat it to the punch. Thats the therory I have worked on and it seams to be right. However I am open to what others have to say.

[GTS-t VSPEC]

The more advance you run the higher the potential power output, but it provides a narrow margin for error in tuning. The potential of pinging at high advancement is increased significantly, and therefore minor things like and increase in air temp or slightly dodgy fuel can lead to major problems.

I have mine tuned on the safe side, I'm after reliable power without the worry of detonation. When it was being tuned there was quite a bit more power to be had through advancement but it started to ping, so we backed the timing off a little.

See'ya:burnout:

[rev210]

You tend to find 'worked' cars run a larger amount of advance in the bottom rpm range and less advance in the top end. When I say less I mean less than a stockie motor, with more boost and and higher cylinder pressures there is less encouragement needed to start combustion at the right time for best power.