Timing advance-how much is too much?

Stevehose

Stevehose

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For my recent triple weber install I have been fiddling with the all-in timing advance at and above 3k rpm - the car seems to like more advance above the 32 degrees or so I have read is the suggested max for a stock coupe M30. Currently it is set around 34 but would take more. Have read on other car forums that some people advance timing until it pings under load then back it off until it doesn't.

Also, is there any issue with having higher than stock advance at idle?

I don't want to blow it up on the highway or sitting in traffic.

Engine is stock USA with pertronix, I run ethanol free 93 octane gas.

What say the gruppe? thanks in "advance." :)
 
I have found that running much more than stock timing gives better low rpm performance but has a negative effect on high rpm performance. Maybe it is due to the way my engine is set up. I don't see any problem with advanced timing at idle but too much timing can make it hard to start unless you have a really good battery.

If it is not pinging under load, you should be OK.
 
Which distributer

do you have? There were several. The early 2800 distributer could put up to 16 degrees at 1000 rpm where the subsequent distributers were emissions oriented towards 8-12 degrees; same rpm.

So given stacking or wear there is a tendency for the mark to be all over. So do your best to triple check balancer, flywheel, mark, etc. Not to mention an M30 has quite a bit of overlap at TDC.

So dialing in 2-4 degress isn't going to hurt anything. 6-4 degrees and you need to start listening. The second thing is the car's torque will become more smooth- kinda like a B35 on injection with more advance.( Say 8.)

Now in the case of triples, they like more advance down low. That's the number one reason to go mechanical and recurve the distributer. Because they can move air faster, your vacuum is all over; hence vac advance is not optimum but rpm is.
 
Can you translate this into noob-speak for me :D

I think the 34 all in I have is about 14 at idle. It wants 36 or more - will this hurt?

Thanks.


61porsche said:
do you have? There were several. The early 2800 distributer could put up to 16 degrees at 1000 rpm where the subsequent distributers were emissions oriented towards 8-12 degrees; same rpm.

So given stacking or wear there is a tendency for the mark to be all over. So do your best to triple check balancer, flywheel, mark, etc. Not to mention an M30 has quite a bit of overlap at TDC.

So dialing in 2-4 degress isn't going to hurt anything. 6-4 degrees and you need to start listening. The second thing is the car's torque will become more smooth- kinda like a B35 on injection with more advance.( Say 8.)

Now in the case of triples, they like more advance down low. That's the number one reason to go mechanical and recurve the distributer. Because they can move air faster, your vacuum is all over; hence vac advance is not optimum but rpm is.
Click to expand...
 
Timing advance and compression ratios go hand in hand. What is acceptable at 9 to 1 is dancing with the devil when you have 10 to 1. I tend to think 37 degrees is max for a 9 to 1 and 31 degrees for 10 to 1 when you start tuning
When you go to forced induction you need to think minus 1 degree for every psi of boost.
If you would like timing maps for the m30 b35 which is 9 to 1 - or a map for the 10 to 1 euro spec send me a pm.
 
Instead of backing off on the timing you can also bump the fuel octane. This will be more effective in producing hp. If you want to stick with pump gas, then you are suck with backing off on the timing.
 
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