L98 Spark timing and E38 knock sensitivity

Hers one of my tables with a cammed SSVE we did recently....some knock tables need no changing wheras some need quite a bit of work to eliminate false knock....

Attachment 5731
varies from engine to engine.......

Attachment 5732

Heres a standard cammed SS VE map for you to compare what you're doing to. See how the timing at peak torque ,4400 rpm, pulls out then increases again as rpm climbs to the limiter. The Blue area is unused or not accessed with standard engine.
On our 95 octane aim for 22 to 23 deg between 3200rpm to 3600rpm, 18 deg by 4400 at full load and about 24 degs by 6200rpm. :secret:
See how you go.
Cheers,
Mike

Quote:

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Originally Posted by The Alchemist

Hers one of my tables with a cammed SSVE we did recently....some knock tables need no changing wheras some need quite a bit of work to eliminate false knock....

Heres a standard cammed SS VE map for you to compare what you're doing to. See how the timing at peak torque ,4400 rpm, pulls out then increases again as rpm climbs to the limiter. The Blue area is unused or not accessed with standard engine.

On our 95 octane aim for 22 to 23 deg between 3200rpm to 3600rpm, 18 deg by 4400 at full load and about 24 degs by 6200rpm. :secret:
See how you go.
Cheers,
Mike

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How are you differentiating false knock from real knock?

Best torque with lowest timing on a dyno and knock phones :)

I found most e38s have different sensitivity from car to car, When I tune I have them relaxed and if i here detonation on the dyno it also shows on the KR map. It is how i find knock but also determining at what load point it occurs. And MBT occurs a fair bit b4 knock sets in, I generally see 5hp loss after MBT b4 detonation shows up and at that time the knock retard is pulling timing but not soon enough. I then pull timing back until power drops off then bump up two degrees, then put a slightly more aggressive KR map in that will show its ugly head on the dyno if knock is a problem, once u find MBT u can leave the knock settings sensitive as u are 2-4 degrees from knock anyway.

For eg a cammed VE I did today I put up to 32 deg timing in it and it still refused to knock on 98 pump fuel.Pulled retard of 0.1 deg with relaxed settings then and could here onset of detonation but not bad. Quite typical, But hp dropped by 5 at 32 degrees, go back to 30 increases by 2, back to 28 increases by a further 3. Keep going back and then move up I ended up with 22 peak torque 28 full power, Which gave consistent results at 12.8:1 afr. With even sensitive settings in the car it still didnt knock on street or dyno and I new I was 4 deg away from knock and with sensitive settings it would never be an issue.

I big thing I found was that on certain settings I have in KR I can actually find MBT, and still be well clear of real knock, one i find it i relax them a little. a good track tuning trick.

Quote:

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Originally Posted by The Alchemist

On our 95 octane aim for 22 to 23 deg between 3200rpm to 3600rpm, 18 deg by 4400 at full load and about 24 degs by 6200rpm. :secret:

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Thanks for the top secret tip :cheers:

Quote:

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Originally Posted by The Alchemist

Best torque with lowest timing on a dyno and knock phones :)

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Dirka dirka! Ta!

2 days ago we did 2007 lumina SS "similar to VEss" cammed 588/588 228/228 114, long sureflo headers, and air intake only, I do 25 deg with 95 RON octane, no knocks showed up. We got around 420 hp and 400 tq on my dyno (dynomite). Little bit conservative.

Some facts:

I do admit “these cars love richer fuel and advance timing as well!!!!!”
These engines make 4 deg retard while they are stock with stock tune!!!!!
Their knock sensors give fault readings and they are too sensitive.

Thought it was about time i reported back on this topic.

I pulled a lot if timing from most of the high spark map and still had to do a lot of work on the knock threshold tables to eliminate the false knock retard recorded in the logs.

On the road the car feels much stronger everywhere.

On Dyno Dynamics stock made 220rwkw.
With shielded pod filter, x-force twin 2.5" exhaust, x-force stepped headers with cats and of course the modified tune made 260rwkw.

I've attached my current modified tune and the original tune for comparison, comments welcome.

cheers