High compression timing map

[Kenyon]

This is the timing map from my N/A 1600 VW. Compression is 11.5:1, stock displacement, and fuel is 110 octane.

The car is running a Motec m4 ECU for ignition, but still uses the stock carburator, as the series rules require it.

Just wanted to get any thoughts or opinions you might have. Thanks!

[miniman82]

Shouldn't it be able to take a lot more timing at 100 kpa with that fuel?

[Kenyon]

That could be. The engine actually seems happy at full load at 34 degrees. Everyone else in this series is using distributors with compufires, and they say they run a max advance of 30 with the same fuel, so, I don't know, it made me nervous to push that.

I've been trying to get things fairly close by road tunes using EGT/Wideband, before forking out the cash for dyno time.

FYI, I'm also debating switching to E85. I think I'd save money and maybe even reduce some temperature. Would that be a huge power loss from the 110, even though I could increase the timing?

[TouringBubble]

If your not hitting the detonation threshold on E85, the power output should be very similar. And yeah, you can push a bit more timing. Its not bad though if you aren't monitoring for knock currently.

[Kenyon]

Thanks for the input. Really thinking about making the switchover to E85, I think the 110 is overkill and it makes the fuel budget hurt.

TouringBubble nice car! Are your windows glass or lexan?

[Kenyon]

If your not hitting the detonation threshold on E85, the power output should be very similar. And yeah, you can push a bit more timing. Its not bad though if you aren't monitoring for knock currently.

TimingBubble, are you monitoring for knock? If so, how? I don't know of any way to reasonably filter anything useful from a knock sensor if I mounted one.

The motec SKM runs about $1k...http://www.motec.com/skm/skmoverview/

[TouringBubble]

I monitor with det cans ... or, something close that I built at home. Basically I use headphones and an amp to listen to the tone of the engine.

The windows are all lexan aside from the front.

[Kenyon]

Do you think that I could I get away with more timing at higher RPM's under vacuum? I've read the SVDA's are around 42-44 degrees...

Would it even make a difference?

[TouringBubble]

Surely you could. You're just barely past what many engines run at peak tq.