Anyone have real data on the typical performance gains possible when removing some timing? and the F.I. system it is on.

Particularly interested in Vortech which seems to be very conservative in the S.S. box timing.

 

on my vortech every 1 degree i added netted 10 hp on a dyno jet, but thats only at the peak

 

If you are asking how much power you will GAIN by REMOVING timing, then the answer is none. Running less time creates less power but allows you to run boost/more boost. It comes down to your particular engine and setup.

Hope this helps,

-George
GT Motorsports

 

Is there not an optimal time during the combustion cycle (14-15deg After TDC) which will achieve max cylinder pressure to occur, and for this to happen,when should the spark plug fire. My question is is there an optimal (safe) timing that will yield the greatest amount of power the engine can develop.?.If you can develop more boost from timing does that not equal more power? Help me out here.

 

the optimal time depends on the load and the rpm. you can't just set the timing to 1 setting and leave it there.

think of it this way,......it takes a certain amount of time for the air/fuel mixture to ignite and burn. generally speaking, the higher the rpm, the earlier (more degrees BTDC) you need to light off the mixture. that is very general, though.

 

i think what he's trying to say is that basically it comes down to your particular setup on how much timing you can safely/optimally run. I don't think its a set number type of thing like Air Fuel would be

 

What George is explaining, is that best timing is not a fixed number, so your question cannot be answered. MBT is a function of countless variables, including engine RPM, load (boost pressure), coolant temp, the engine's VE..etc..etc.

 

I appreciate all that has been said however I'm not looking at a # to dial into my car I am asking what have others found on their car when they changed timing... What is the (safe) potential for timing on engine output..
TIA

 

i was wondering the same thing, i asked the same question only you asked it a little better. so for example can a FI z stock motor handle 18 degrees timing in full boost from 4500-6500 rpm?? or is that too much for regular gas? how far can you push this car with timing in full boost safely isnt there a certain number that you wouldnt go over?

 

There is no clear cut answer. The best timing for one car is often different than the next, even with similar mods. 18degrees at peak torque may work for one setup, and grenade another - there are many variables involved. To dial in timing you need something to listen for knock and a dyno (load bearing such as dyno dynamics is preferred).

There is no default 'safe' value, and an overly 'safe' (retarded) ignition map is not that great either as you will be giving up power and driving up temps.

 

not to get to OT but on a rear mount setup would it be beneficial to retard timing early in the rpm range to drive up EGT's to help spool the turbo?