alky turn on point and weather

[turboaddict2]

Its gonna get warm here in NJ. Well its already spring so thats a start. Is it better to have the alky turn on earlier or later in warmer weather?

 

[blackbuick87]

A little later, maybe 1-2#

 

[turboaddict2]

thanks for the reply!

 

[lrover2]

A little later, maybe 1-2#

With the thought of earlier and easier detonation because of heat wouldnt you want to go the other way and have it spray a bit earlier? The whole idea is to cool things off not wait until they are hotter to cool.

 

[blackbuick87]

Re: A little later, maybe 1-2#

Originally posted by lrover2
With the thought of earlier and easier detonation because of heat wouldnt you want to go the other way and have it spray a bit earlier? The whole idea is to cool things off not wait until they are hotter to cool.

When the air is cooler it is more dense, cylinder pressure is higher and the turbo is more efficient. Therefore the turn on point comes down. This is the same reason some guys get more boost at the same wastegate setting when it is cold out.

When the air is warm it is less dense, and if you turn on the alky earlier it will bog the engine.

We are not talking about changing the t/o point by 5#, I am talking very minor adjustments. Some cars dont need to be adjusted at all.

 

[turboaddict2]

so warm air turn it on later and with cold air turn it on earlier?

 

[Turbo__Tim]

Right, blackbuick87 has it dead on.

 

[Steve Hill]

if you think about it, turn-on points have nothing to do with total w-a flow, which is really what you want to look at.

As you guys point out, colder air is denser (more of it in a given volume) so you need a bit more fuel to keep a/f ratio from going too lean.

You have a couple other ways to better solve this.
You can increase your injector p/w's, or crank in a pound or two FP, or increase the w-a flow, or, as a last resort (hee hee), remove a pound or two of boost.
A peak hold EGT meter really helps sort this out.