Finally got my JDM MAP sensor working with EvoScan and have solid proof that the majority of the boost taper can be eliminated with proper wastegate control. Yes, the boost is a bit wavy, but there is no taper out to 6500 rpm. There's going to be a bit of taper by 7000 rpm, but probably no more than 1-2 psi, and I can eliminate that if I want.

 

Mrfred,

I'm impressed by your flat 220 load out to 7k rpms. In 3rd gear and high boost my load tapers TO 200 load by 7krpms (from 260 or more). Can you hold the load flat at say 260 load in 3rd gear?

Also...anyone with an ebc just raise the solenoid duty cycle at higher rpms in order address boost taper? Right now im using the aem truboost emc and it only allows you to set a constant solenoid duty cycle. With this feature I see extreme boost taper in 3rd gear.

I'm thinking of upgrading my ebc to one that will allow mappable and gear dependent solenoid duty cycles so that I can just dial out the boost taper.

 

Yup, if the EBC does DC by rpm/gear you can do that. The Apexi AVC-R is one of those type of EBC's.

You can also do it with the factory ECU in conjunction with either a different restrictor pill size or a different solenoid.

 

Yeah, I'm pretty happy with boost and load curves. With better gas or alky (and a 3" TBE), I could probably hold higher boost across the rpm range (say 23-24 psi), but from my experience so far, I doubt the load would go past 240.

 

Thanks Mrfred. Can explain how you eliminated the boost taper? Using ecuflash?

What maps and how did you adjust them? You are using stock solenoid? Removed restrictor pill?


I'm trying to get a 100 octane tune but the boost taper in 3rd gear is crushing me. This is on a IX turbo in an 03 evo.

 

jesus why don't people search. All evo 9 will taper more than the 8. it's normal. it's a stock turbo. don't tell me you want to hold 23 psi om pump gas. or you can get 18psi spring wastegate

 

that graph don't do nothing. I mean you cut the run off right when the turbo tapers anyways. Try holding that amount about of boost to 7600rpms.

 

I don't go out to 7600 rpm. My car signs off at 7000 rpm. Here is another log that I took this morning that goes out a bit past 7000 rpm. Yes, there is a bit of taper out past 6000 rpm. That is done purposefully by me. I have the waste gate duty cycle pulled back a little bit because the motor can't tolerate any more boost out there without knocking.

 

Will you post your duty map / error correction map / offset and any physical modifications to the stock BCS?

 

looking at your plots, you took the injector duty cycle and divided it by 4 to fit the scale correct? if so, your running 100% duty cycle at 6500rpm and up.... what do your A/F ratios look like? that may be why you can't tolerate any more boost at the higher RPMs... just not enough fuel flow up there.

 

Sorry, can't give the maps out because its a vendor flash. Its easy enough to see on the Vishnu website how Shiv modifies the boost control system. I guess if you like what you see, you can get a Vishnu mail-in (what this is), or try to duplicate his boost control mod, and then build your own maps.

Yeah, you noticed the duty cycle. I don't have a wideband installed, so I couldn't say if its going lean, but its a possibility. There is some debate as to whether 100% IDC as measured from EvoScan/Mitsulogger data really is 100% IDC. Some people report routinely exceeding 100% without going lean. Might be just tuned a bit lean too. Shiv is known for tuning on the lean side. Another possibility is that I'm choking the motor with my essentially stock exhaust system (with the exception of the Random Tech HFC).

 

I am now peaking at 26 psi @ 3600 and holding 19.5 psi @ 7K...I would post my boost graphs if I could figure out how to do a screen capture of my ZT log , but basically I have 24.5 psi until 5600...

Sorry Alt + Print Screen does not work...

 

ALT + Print Screen

 

Also remember that for the ECU and calculations.... you are using 513 when in reality the INJ are 560 cc.

 

isnt it just printscreen, no alt?? least that works for me.