Hey guys,

I have an 05 Evo VIII the only mods it has is K&N drop in for stock air box, Test Pipe to eliminate Catalytic converter, Evo IX Metal BOV and a Grimmspeed 3-port boost controller Other than that the car is stock. Stock exhaust, down pipe, turbo and all. On Pump 93oct. This is my daily so this is pretty much where I want to keep it mods wise in terms of bolt ons. I'm having some friends help me tune the car since I'm new to this ECU flash but not new to tuning and my current issue is my boost continues to fluctuate. I want it to hold around 25lbs but itll go from 25-20-27-23-25-21... Ive tried different setting on the boost by gear table with no luck... anyone else have this issue? I'm about to go to a manual boost controller.

AFRs are 11.8 timing is conservative.

Here's a vid for reference...

 

Are you tuning it with all the boost error correction factors set to zero? Max total upward correction set to zero?

It seems to me that is not the case and the car keeps over correcting.

 

Yeah post your boost tuning tables.

Also the mrfred how-to would help in this case. (Post #3, tuning)
It's written for a single boost, you have gear based boost control but other than that this is the same tuning procedure.
Just adapt the boost for each gear. (Good example at post #10, custom boost by gear example)

 

Thanks I'll review this into further depth when I get off of work. But I noticed alot of individuals have an OMNI map sensor or JDM 3 bar. I'm still running the stock USDM sensor so I don't think some of the information provided would help me.

 

This will help you:
Stock USDM sensor won't work for controlling boost.
The main reason is that his 0-5V signal is maxed at 14,7 psi absolute. It tells the ECU if it's out of boost or not. Stock boost control system is open loop/no pressure feedback.

Advice: Buy the omni 4 bar. It's the most popular here and many V7 roms and patches are setup for it.

 

If you're hell bent on tunning the boost while waiting for a map sensor, use load based. Aim for a flat 250 load curve, that will yeild you an average 23psi across the board.

 

I'd be happy with a consistent average of 23psi... Honestly dont plan on getting a Map Sensor. So Load based? Whats the name of the table specifically, I had tuned it on ECU flash prior and didnt have so many tables as tephra so I need a bit of guidance as of right now I'm using the Waste gate duty boost by gear.

 

When I get home from work I can help walk you through it, unless someone chimes in before me. We are actually in the process of creating a how to for implimenting Tephra roms. I am not sure of the boost control section has been finished yet.

 

I'm working on it now. Coming along quite well. I hope to have it done within the next week.

OP, just disable all corrections for now and start by figuring out your WGDC table. Once that's done you can look into used load-based correction if you want to.

 

Ill try that here soon. I looked at my maps and under Boost desired by load I tried inputting 250 and it maxes out at 159.5 or something like that... I look forward to reading the guide you guys are creating. Tephra has many options and there isnt enough easy to find information out there to use it to its full potential.

 

Sorry wasn't able to walk you through it. I will try to post here and there to give you a hand. Search for Merlin's Guide on here. There should be a link in the Important ECU Threads sticky. You use Boost Desired Engine Load + Load Adder to set your target load. BDEL maxes at 159, so use BDEL 140 + Load Adder 110 = Target load of 250. Then you use your Waste Gate Duty Cycle to get you there, and your Boost Error Correction to monitor and make adjustments if you overshoot/undershoot your target load. Help that helps a bit.

 

Your fine. Let me try Zeroing out the correction tables first and go from there and if not Ill try load.
SO I would be Zeroing out:
Under Main Map Boost Control Settings - Boost Desired Engine Load, Boost Desired Engine PSI, Boost Adder Load, Boost Adder PSI.

Under Global Boost Control Settings - Boost Error Correction Load, Boost Error Correction PSI.

I Also lowered WGDC=100% under this load to 100

Am I missing something? I'm gonna try this tomorrow after work.


If that doesnt help do I just zero out Main Map Wastegate Duty and change Boost Desired Engine Load to 140 and Boost Adder Load to 110 and go from there? thats what I'm understanding.

 

Before you do anything, you need to read the guides that are available for boost control under the important ecu thread links sticky.

The tables you zero out are as follows:
Boost Error Correction and Max Upwards Correction under the global boost settings header

Boost Desired Engine Load + Boost Adder Load = Target Load. This is the target that the ecu looks for when determining whether or not to make corrections. If it sees your load is above target it will correct your WGDC curve down the specified percent and check again and again to maintain the load curver, and vice versa.

Your Waste Gate Duty Cycle is what you tune to get you close to your desired load curve.

So in short.... You tune your WGDC to get the desired load curve (with corrections disabled), your target load curve (BDEL + BAL) is the load path your wanting the ecu to monitor and maintain, the correction tables determine how drastic that correction is when the ecu needs to make one.

 

I've read several, but I noticed the majority of them are more towards the original ECUFlash and not Tephra V7... I really appreciate the information being provided. I have a better understanding of what tables are the ones I should be messing with.

So Essentially I should set
Boost Desired Engine Load + Boost Adder Load = Target Load to equal 250 Load like we had talked about earlier and make adjustments with WGDC with corrections zeroed out... Overall I have a better understanding what the tables do. Hopefully you guys can come out with that guide explaining what each table is for. Similar to Merlins ECUFlash guide. I printed that whole thing out but alot of it is different from Tephra... Again thank you. I will update with results.

 

So it worked! Thanks everyone. It hold 22-25 pretty steady. No more Oscillation...

Here's how my WDC map. I did it on the street so I need to put it on the Dyno and clean it up to get the boost closer to 24-25...