Duke

Some might wonder how to tune for big power.
Here's a clip that explains it all. I picked up 150 rwhp just for watching this clip

http://www.youtube.com/watch?v=cIrA4iWkhbE

Voith

Great video

carlege

Dwell meter? I might as well ask for muffler bearings at the local autozone.

JohnKoaWood

Come in cheap and expensive models, and in my experience you get what you pay for...

http://www.google.com/#q=dwell+meter...7e51d4c9f90cac

Timing adjustments can also make amazing throtle response and low end torque response changes.... and yes, I did timing adjustments on my previous setup, and my new setup on my 951 will include individual coils and timing will be a factor when tuning the standalone... I am considering moving the old 951 setup to the N/A... just to have something to play with in coming weeks and months... I had more than one persone tell me my timing maps were "rather agressive" but I wasn't seeing on throtle knock so they must not have been too bad...

Chris White

I kept watching and waiting for the “Beep”….
Only ‘old’ people will know why.
And yes, I do own a dwell meter….

Ignition timing is a very critical item in tuning – its more critical than air fuel mixtures. Your AFR can be +/- 10% and it will still run OK, if your timing is off by a couple of degrees than you are either giving away 50hp or buying a new engine….

There are a lot of things going on to get ignition timing just right – like the speed of flame front propagation (here is an interesting article - http://engine.princeton.edu/download...ont-Ju-Lee.pdf )

And now Duke is finding the true joys of a 16v cylinder head….way better at sustaining a stable flame front without pressure spikes that could trigger detonaiotn….in other words – crank up the timing!

If you look at equation in the left column on page 2 about ¾ of the way down – you will see a term that represents “the thermal relaxation via transverse thermal diffusion”…..and it looks a lot like somebody mistyped “Duke” to me!!!!

Duke

Haha my new screen name - DthK2!
Good stuff Chris, but for turning my post into something technical and serious

I love those old productions, I mean just the voice on these clips!
VW has made several training films:
http://www.youtube.com/results?searc...ning+film&aq=f

Black51

Thanks Dan Aykroyd!

JDS968

To change the reel, of course

Fishey

I have to disagree/agree

Timing in itself isn't any more important then A/F ratio as they work in conjuntion with each other.

Flame front speed is significantly dependent on the Air Fuel Ratio (and compression) so it can play a significant role in your timing.

12:1 A/F is the ratio that will yeild you the fastest flame speed. Any movement to the rich side and flame speed starts to drop at a rapid pace but when moving towards lean it tends to drop less quickly. 12:1 however has such a high level of unburned fuel there is alot of wasted power. That is why we see max power in most engines lean towards being in the middle of 12:1 and stoichiometric. Usually, in most engines maximum power is made between 13:1 and 12.5:1 A/F.

Also, like you said propogation is a big part of tuning.

factoring into account is your ignition system. The simple fact is the better the ignition system the less timing your going to have to run because it helps promote a faster propagation of the flame front. The main thing we see though is that the better they system the more open the plug gap or design can be ran. However, with crappy stock ignition on a higher powered car you will see your gap size start to significantly decrease as blowout becomes an issue. As a result you will hinder your propogation and be forced to run more timing.

I have always tuned for TQ as it will tell you when you got all your ducks in a row but its kind of blind if you don't have information like Cam timing, Ignition timing, EGT and Air Fuel to look towards to make proper adjustments.

P.S.
Dwell is not something that many people are concerned with these days. lol