What is the maximum timing one can run on the evo @peak torque and all thru the RPMs - gas just would not knock (w/ water injection)?

 

depends on the vehicle, thats why cars are custom tuned, theres no one point for everybody.

 

I just want to get a feel of how much timing one can go before it heads the other direction and start to lose power. So far, i've seen....rraulston seems to have the most at about 11 degrees at peak TQ

 

I asked a question about maximum brake torque (MBT) timing on evom a few weeks back and havent got a conculsive answer........i'm sure this timing is "standard" on a stock bottom end....

 

With cams and ports being stock, there should be a general consensus on max timing at torque peak. One would need EGT's to help determine that, along with knock and a/f ratio. Generally speaking, timing is reduced slightly at peak torque and then increases again to redline.

 

it all depends on what octane, boost, ect. i am running about 9 degrees at peak TQ w/ 22psi ramping to 20 dgrees at redline on 93 octane, you really need to know your AFR's b/c sometimes your motor wont always knock when your runing lean. i was running 12.5 afr w/ NO knock, then i added a sh|t load of fuel.

 

Again, it depends.. I run about the same timing as Nez, but run my car at 11.5 or richer.. higher boost, better ignition, fuel quality, AFR, EGT's all these things will affect the timing you can run.. I have run 11 degrees in the past at peak torque, but was always concerned about causing problems but the car felt really good and had no knock in my setup.. I generally run a fairly tame tune most of the time, and have a *****-out tune that I can switch into if I need it (Glory run) But I'm an all-or-nothing kind of guy and will risk blowing my motor to win..

 

Keeping boost/AFR the same, advancing timing will lead to lower EGT due to combustion occuring in engine rather than out in the exhaust manifold......right..wrong?

 

No advancing timing ignites earlier which is the opposite of what you described.

 

oh ok....

dsm95hybrid:hey you run methanol right? whats your timing @peak torque?

 

This was pulled from a drag run so not sure how much good it would do since the rpms are so high.

2nd
5400 11
5800-14
6300-16
6700-20
7100-21

3rd
5400-8
5900-8
6020-11
6200-14
6500-17
6700-19
6900-20
8017-27

 

Timing numbers will also vary with your ignition system.. at very high RPM you see some cars with alot of timing, 27 degrees in some case, remember that if you upgrade your ignition that you'll have to back off the timing a few degrees and then slowly bring the timing back..

And EGT's depend alot on your timing and AFR, if your running very rich, you may still have burning fuel in your exhaust leading to high EGT's.. Too lean and you get very high EGT's due to complete burn in the combustion chamber, too much timing and you get high EGT's due to compressing expanding exhaust gases (detonation too) too little timing, and you get burning fuel out the exhaust.. the difference is the high EGT's due to late timing or rich condition is the fuel burning outside the combustion chamber.. but high EGT"s due to too much timing or too little fuel, result in conditions INSIDE the combustion chamber that can do damage..

 

Another very very important point.. YOUR AFR's have a direct impact on your timing.. Since the amount of fuel you use will directly affect the flame front and the point at which the gases begin expanding.. more fuel cools the combustion process and slows combustion allowing you to use more timing because it reduces the odds of detonation..

Octane additives (Race gas, methanol injection) do the same thing by slowing the combustion rate by cooling the combustion gases and slowing the combustion rate..

How does this produce more power? Because the more timing you use, the more combustion you get, the more combustion you get, the more expanding gases you get as a result of the process, the more expanding gases you get, the more downforce the piston gets, and that produces power.. Understand where this balance comes in? Too much timing and you can produce downforce or a shockwave against the piston as it approaches top of the stroke.. in theory perfect timing is when you trigger ignition so the burn process starts at the right momen, where the expanding gases are producing just after the piston reaches the very top of its bore.. if it happens before, at the least, you lose power because the piston has to work against it, at the worst you can melt, crack or break something because the piston, is pushing against all that energy..

 

This is detonation information.. Preignition due is something different, and that is due to hot spots from overly high combustion chamber temps that cause the gases to ignite before the plugs fire.. This is another reason why EGT's and combustion temps are important, this is the major reason why you run the car richer on pump gas and do what you can to keep temps down.. the extra fuel, or methanol, absorb heat and in doing that, remove heat from the combustion chamber that could otherwise cause preignition.

 

Good picture painted for all of those staring at their red valve covers wondering what magical mystery is going on inside that red topped thingy.