I just wanted to know the exact reason why timing should be retarded for a Turbo Car.

 

Because of the increased density of the air/fuel mixture.

The higher the density in the chamber, the less timing that is needed for the flame to travel in the bore.


Modified by Bryson at 10:30 AM 8/27/2004

 

timing is normally under N/A motors around 35 degrees before top dead center (full advance) by the time the combustion takes place, when the force starts to push the piston down, is already when the pistons is 0-few degrees pass TDC, wich will make the optimal power


on a boosted motor, u cram so much air and fuel into the motor that it becomes a very powerful and fast reaction under compression and spark present....
because it reacts so fast, u cant combust it at normal 35 degrees BTC.. because it will start pushing the pistons down when they arent yet TDC, and basically the combustion will push down, while pistons are still going up
BAD BAD thing

so u have to time it close to TDC , so u get all the power to push the pistons down,


Modified by USDM 4G VTEC at 6:11 PM 8/26/2004

 

Thanks, that helped alot.
There is more stuff than I thought, when tuning the ignition, and cam.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bryson &raquo;</TD></TR><TR><TD CLASS="quote">Because of the increased density of the air/fuel mixture.

The higher the density in the chamber, the less time that is needed for the flame to travel in the bore. </TD></TR></TABLE>



This is kind of a rough example. Imagine a balloon filled with pure hydrogen. When you ignite it, it explodes slowly and semi-powerful compared to a balloon filled with 1/2 hydrogen and 1/2 oxygen...... the explosion is more powerful and MUCH quicker. This is because the balloon filled with pure hydrogen has to take time to react with the oxygen outside the balloon, while the one filled with 1/2 oxygen can react inside the balloon. This creates a quicker more powerful reaction.

It's sorta the same thing is a car engine. This quicker flame front is countered with a retard in timing.

That's how I think of it.

BTW: if i've mis-interpreted any of this lmk so everyone will know what's right, but this is the general idea

 

Just out of cuiosity, this has nothing to do with the topic; Racinskittle but what kind of Spark Plugs were you running when you did the 14.3 Run??

 

Bkr7Es gapped to .028" on a sunday perhaps?

 

Oh wow, .28, Damn.
I guess i'll try .30 instead of .35. Even though I have All MDS Ignition Setup.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by {StatuS ChecK} &raquo;</TD></TR><TR><TD CLASS="quote">Just out of cuiosity, this has nothing to do with the topic; Racinskittle but what kind of Spark Plugs were you running when you did the 14.3 Run??</TD></TR></TABLE>

ZFR7es-11 or ZFJ7es-11 can't remember which. I got the 7 heat range from advanced auto. I also ran 14.1@102 with the plugs Just never updated the sig