Assuming AFR has been adjusted to be constant at 11.5 at peak torque, does timing have to be reduced as we run higher boost? Let's say I am knock free running 7* at peak torque with 21PSI...do I have to run maybe 5* at peak torque with 25PSI or even 1* with 30PSI? Is there a tuning principle specific to Evo IXs governing timing with boost?

 

Yes you need to lower timing as the load increases from higher boost but there is no specific curve to the timing map. You just need to tune until the presence of knock and then back off a hair.

 

Are you running the same octane for all those different pressures; for example if 21 psi on 93 oct., 25 psi only on 100 oct., and 30 psi is only on c-16?

 

typically yes, you'll need lower timing for higher boost

 

well, assuming if someone will run 30psi, they will be either on race gas or meth. when u have higher octane fuel, you can run more timing.

 

generally speaking you're probably right, I'm running 30psi on 93 octane though

 

well when i go to the track and raise my boost i just increase fuel on those load cells to cover knock....

but what im doing is just temporary for the track........

 

For the sake of a fair comparison, let's take it that I intend to run all the different boost pressure on 100 oct. So both fuel and AFR curve remain the same with the only difference being the boost pressure.

 

You didn't alter the timing map when you increased boost but just dump fuel? Won't that still knock?

 

So basically I have to tune for the highest load with the max timing I can run before the onset of any knocks to be safe? There's no specific timing that I can take as the reference being the optimum timing for each loadcell or boost pressure?

 

Exactly.

 

Aim for scattered counts of 1-2 counts and no more than 5 counts rolling into boost (assuming you have a stock sized turbo) or less. Keep in mind that most people that run 30psi arent going to be able to reach it until higher in the RPM range and are using a goodly sized turbo, so they dont have to spend as much time keeping low rpm tuned as well. When I first started messing with 30psi on pump with my Green, I wasnt worried about starting a pull at 3k because I couldnt make 30psi until 4k. Switching around some parts though I realised I needed to be able to start the pull from lower RPM if need be.

 

When I build my maps, I start with stock boost and adjust those cells for that load range. Then I increase boost for the next load range. I do this up til my peak boost levels I prefer. Once I'm done, I basically have a universally safe set of maps. As most will agree, this isn't the "best" way to set up a map for one specific boost level since there are many variances as you spool up thru the load cells. I would just use Tephra's dual map switching patch and tune for your HIGH boost setup and one for your DAILY boost setup.

 

I'm running a GT35R

 

what is this "low boost" setting you speak up. Mine is on kill mode 24/7