Find the right ignition table SBC 350

[martin2day]

Hello,

i am using a modified TBI (MSD Atomic) with MS2Extra in my Cobra Replika.
It is a 350 SBC Gen.1.
I have rebuild the engine last year.
Now i am looking for a good ignition timing table for my parts.
- 350
- CR 10,5:1
- Trickflow 195cc aluminium heads
- camshaft: 225/235 @.050 .465in .488ex LSA112°
- AFR Titon komposit manifold
- hypereutectic pisten
- scat rods 6,0"
- scat crankshaft for the 6,0" rods
- MSD ignition box

Can somebody tell me please what is the right timing for my light "race" car?
This is how my table looks today.

Bildschirmfoto 2017-04-29 um 18.51.16.png

Regrads Martin

[billr]

I think the final WOT timing advance is a bit low, but not sure. The BBC seems to like 36+ from 3000 rpm on, and I expect an SBC would be about the the same.

[Yves]

numbers are fairly conservative. The numbers at WOT can be correct, but do seem low.

[kjones6039]

I am pretty much in agreement with the above.

On my somewhat similar 383 stroker I am running 16-18 deg. at idle (~1000 rpm) and I am all in (36 deg) at 3000.

Works very well for me!

Ken

[krisr]

400" Pontiac, 10.5:1 Edelbrock RPM heads (older bathtub chamber, not heart shape CNC), 242/248 @ 0.050 on 110LSA. This map works VERY well for me everywhere. My timing is aggressive in my opinion but only being 10.5:1 it's not "on the edge" plus I keep my AFR's under control.

[slow_hemi6]

But on the other hand krisr's map would ping like hell in my 11:1 iron headed SBM. Spark maps follow trends but are as individual as the cars/engines they go on. I have a 9:1 318 engine that goes quickest with 32 degrees. I can add timing but all it does is go slower, doesn't ping @ 38 but the MPH is down.

[martin2day]

Hello,

thank u very much.
I found a very good post... http://bangshift.com/general-news/tech- ... ike-a-pro/
Here you can see what happens wenn you remove 6° off ignition... to about 5000rpm nothing change in power and torque.
Then they remove 14° and power loose, but alos not very much.
So i decide also to begin very conservative...

Ok over 3000rpm i can check my timing performance test bench... but whats about the low end off idle...?
How can i find the timing from 1000-2000 rpm?

I have begin with 10° initial an a little bitt AE... The trottle response were not good.
Than i add up tu 8° and with the same AE throttle response were better...

Is 18° initial with my cam a good starting point?

Regards Martin

[Yves]

Like is said above, small differences from one engine to another make a world of difference as far as ignition is concerned.

I have asked a similar question and got a standard ignition map of an LT1 SBC. Do a search on my name and you'll find it somewhere. It's an engine with alu heads and something like 10/1 CR. The cam is more conservative though, so in essence it would detonate faster all things being equal.
I was amazed at how much initial timing the standard oem map had. My engine liked it as well.
However that map had a 38° timing in some areas around the top end. My engine didn't like that. Also on cruise and decel I'm not able to run 38°. Also on some areas below WOT at high RPM I had to reduce timing as well as it seemed to want to detonate.

A well characterized knock sensor goes a long way, but given the investment in equipment the OEM's have done to figure out ignition maps and characterize the knock sensor this is not something that a lot of us will ever be able to do.

[BigBlockMopar]

About 1.5 month ago I started using and tuning the ignition on my MS3x.
My car being a daily driver I was able to make daily adjustments and improve drivabillity greatly.

I would advise to focus on one certain area of the map, for instance;
- light, off-idle acceleration (below 50 kPa),
- mid-power acceleration (50-70 kPa),
- firm/full power acceleration (70+ kPa)

and also try similar startingpoints but from a higher rpm-range.

When I'm driving around, sometimes I will find the engine feels a bit soft in certain situations. I then take note of the vacuum gauge and RPM tach, and remember the numbers to alter that area in the timing map later on.
Trial and error finds out what your engine likes.

My car's engine runs on Propane... try finding a 'tuned' map for that online... ;)

[kaeman]

I have a 383 sbc and trick flow heads, trick flow recommends 36 to 38 degrees total advance for best power. At least my instructions recommended that. I build my engine and ran very conservative timing 32 degrees at max.....I was talking to a friend that builds race cars and he was telling me that running that low a timing on the sbc was actually hard on the engine. After changing the timing to include the recommended advance the engine made way more power, gets better mileage, runs cooler, had less heat issues under hood, no more glowing headers at low engine speeds, my conservative timing was actually cooking everything... the fuel charge was finishing the burn outside the cylinder in the headers.
my engine is similar to yours, except I have 11.7 to 1 compression and my camshaft is pretty aggressive 257 and 262 duration at .050, .588 lift. I would skip all the Pontiac timing, they always like more timing than the sbc. But I would recommend as pointed out earlier in this thread, concentrate on one area at a time, whether its the cruising area of the table or the acceleraton area, I would start with the low load cruising area and change the timing to the recommended advance for the trick flow 195's and the then you will have to tune your fuel again, but there is lots of power to be found giving yourself the timing the engine wants. Good luck.

[martin2day]

Thank u for your help,

i finde another stock map from a 1995 LT1 350.
This camshaft is 205/207... very mild. But i see the points you say.
Only the point in my sheet of the pistons say:

NOTE: Hypereutec c piston engines will require 2-4 degrees less total igni on ming. One key to top performance is to have all cylinders longing for the same ming numbers. Equal air ow, fuel mix, quench, chamber temperature, swirl, and compression at each cylinder work to this end.

Regards Martin

1995 Stock 350.jpg