Flash tuning results on a stock 99 VR4

[Greg E]

You guys don't understand. Jason car has been a tough cookie to flash. For some reason ECUFlash and EVOScan don't like his car. Connections are intermittent, flashing stops mid way randomly, CE codes don't even show up... Finally got it Saturday after the car show.

[Greg E]

One final attempt with the car before I start upgrades!!

After weeks of staring at code, I finally located and disassembled the entire stock boost control system. Got lucky because the EVO BCS system is similar (although there are a few key differences) so figuring out how it all worked was a piece of cake!

The Boost control signal is a constant 16 HZ with varying duty cycle dependent on RPM. Boost solenoid is energized when the ECU pulls the white lead of the solenoid to ground. Logging this Waste Gate Duty Cycle (WGDC) from MUT request 86 shows:

RPM - WGDC
2000 - 100% Constantly energized = BCS shut
3000 - 80%
4000 - 70%
5000 - 55%
6000 - 46%
7000 - 44%

Here's a prequisite log of my car just before I started tweaking the tables.



The highlighted column in yellow is boost, the orange is WGDC. BTW you are seeing that correct. My stock car is boosting almost 14psi stock and it tapers to 7 by the redline. This has been verified on 2 other 99 VR4s. The service manual claims 2G cars only boost 10psi stock and as you can clearly see, that's understated!

Anyway, the results of modifying the stock boost tables weren't as grand as I was hoping. The stock solinoid with the restrictor pill only allows 16psi spike and 10psi by redline. Poor little 9Bs can't even push air on a stock car. I was amazed the stock fuel system was able to keep up. The wideband stayed perfectly flat at 11.5 so still quite conservative on AFR and timing.

HP wise was a bit of a disappointment though. My ignition system is 126K miles old and was nothing but blow out at anything above 14psi, it was 97 degrees outside and it seems 9B's flow nothing more than hot lava from satans asshole at 10psi because you can see the knock above 6Krpms in that log. It's not a fuel issue either.




By the time I got a half way decent tune, these were the results:



I was really really hoping for 300whp and maybe I could get there with new wires and coils but this looks to be the end of this adventure.

After the last pull my crank pulley separated and that was just the excuse I needed to rip my car apart and begin the upgrades. Called Matt Monnett earlier and placed an order for a set of billet DR650's and I can finally install this closet full of parts I've been collecting.

So stay tuned!

[Jesters Deadd]

One final attempt with the car before I start upgrades!!

After weeks of staring at code, I finally located and disassembled the entire stock boost control system. Got lucky because the EVO BCS system is similar (although there are a few key differences) so figuring out how it all worked was a piece of cake!

The Boost control signal is a constant 16 HZ with varying duty cycle dependent on RPM. Boost solenoid is energized when the ECU pulls the white lead of the solenoid to ground. Logging this Waste Gate Duty Cycle (WGDC) from MUT request 86 shows:

RPM - WGDC
2000 - 100% Constantly energized = BCS shut
3000 - 80%
4000 - 70%
5000 - 55%
6000 - 46%
7000 - 44%

Here's a prequisite log of my car just before I started tweaking the tables.



The highlighted column in yellow is boost, the orange is WGDC. BTW you are seeing that correct. My stock car is boosting almost 14psi stock and it tapers to 7 by the redline. This has been verified on 2 other 99 VR4s. The service manual claims 2G cars only boost 10psi stock and as you can clearly see, that's understated!

Anyway, the results of modifying the stock boost tables weren't as grand as I was hoping. The stock solinoid with the restrictor pill only allows 16psi spike and 10psi by redline. Poor little 9Bs can't even push air on a stock car. I was amazed the stock fuel system was able to keep up. The wideband stayed perfectly flat at 11.5 so still quite conservative on AFR and timing.

HP wise was a bit of a disappointment though. My ignition system is 126K miles old and was nothing but blow out at anything above 14psi, it was 97 degrees outside and it seems 9B's flow nothing more than hot lava from satans asshole at 10psi because you can see the knock above 6Krpms in that log. It's not a fuel issue either.




By the time I got a half way decent tune, these were the results:



I was really really hoping for 300whp and maybe I could get there with new wires and coils but this looks to be the end of this adventure.

After the last pull my crank pulley separated and that was just the excuse I needed to rip my car apart and begin the upgrades. Called Matt Monnett earlier and placed an order for a set of billet DR650's and I can finally install this closet full of parts I've been collecting.

So stay tuned!

That is great, you found the boost solenoid control table! Are you using the stock boost solenoid for your testing or an AEM type?
Also just a thought, humor me here. If a person had a boost controller already and wanted... say a shift light, couldn't this table be modified a little to make a simple shift light to replace the boost control control? Or couldn't it be used for a simple MiVEC control if you put Mivec heads on?

[Greg E]

That is great, you found the boost solenoid control table! Are you using the stock boost solenoid for your testing or an AEM type?
Also just a thought, humor me here. If a person had a boost controller already and wanted... say a shift light, couldn't this table be modified a little to make a simple shift light to replace the boost control control? Or couldn't it be used for a simple MiVEC control if you put Mivec heads on?

No. Everything you mentioned requires custom code be added to the ROM. That's way beyond me at this point.

I'm using the stock BCS. I had planned on pulling the restrictor pill out and doing more testing but my crank pulley broke.

[Jesters Deadd]

No. Everything you mentioned requires custom code be added to the ROM. That's way beyond me at this point.

I'm using the stock BCS. I had planned on pulling the restrictor pill out and doing more testing but my crank pulley broke.

I have heard the stock Boost control solenoid is only good to about 14 psi. You may want to test with an AEm style solenoid.
Well what I was talking about was instead of using the BC circuit for Boost control... Change the circuit to a ground for a shift light, and change the table to
RPM - WGDC
2000 - 0% Constantly open = light off
3000 - 0%
4000 - 0%
5000 - 0%
6000 - 0%
7000 - 100% = light on

Then the shift light would come on at 7000 rpms and stay off below that.
Or do the same thing with say a Mivec controller.

RPM - WGDC
2000 - 0% Constantly open = Mivec off
3000 - 100%
4000 - 100%
5000 - 100%
6000 - 100%
7000 - 100%
Then the mivec would come on at 3000 rpms and stay off below that.

[Greg E]

I have heard the stock Boost control solenoid is only good to about 14 psi. You may want to test with an AEm style solenoid.
Well what I was talking about was instead of using the BC circuit for Boost control... Change the circuit to a ground for a shift light, and change the table to
RPM - WGDC
2000 - 0% Constantly open = light off
3000 - 0%
4000 - 0%
5000 - 0%
6000 - 0%
7000 - 100% = light on

Then the shift light would come on at 7000 rpms and stay off below that.
Or do the same thing with say a Mivec controller.

RPM - WGDC
2000 - 0% Constantly open = Mivec off
3000 - 100%
4000 - 100%
5000 - 100%
6000 - 100%
7000 - 100%
Then the mivec would come on at 3000 rpms and stay off below that.

Who ever told you that is very obviously wrong. I'll post logs if you'd like to see them. Since this has never been done before, I'm not sure where your source is getting their info.

In fact, with the restrictor pill removed the solenoid should be able to bleed off even more air from the wastegates so we can get even more boost. I have a GM 3-port on stand by for when I get my car going again but I'm still going to play with the stock solenoid some more.

I see what you're saying now with the shift light. I don't see any reason why that wouldn't work.

As for MIVEC, it would be much better to use a 3D table that's both RPM and load based for control over that solenoid. I bet one of the unused fuel tables would make a great candidate for that.

[Jesters Deadd]

Who ever told you that is very obviously wrong. I'll post logs if you'd like to see them. Since this has never been done before, I'm not sure where your source is getting their info.

In fact, with the restrictor pill removed the solenoid should be able to bleed off even more air from the wastegates so we can get even more boost. I have a GM 3-port on stand by for when I get my car going again but I'm still going to play with the stock solenoid some more.

My comment was complete hear-say not based on any test I saw. But now that you mention it afterwards he did sell me a new solenoid.

I see what you're saying now with the shift light. I don't see any reason why that wouldn't work.

As for MIVEC, it would be much better to use a 3D table that's both RPM and load based for control over that solenoid. I bet one of the unused fuel tables would make a great candidate for that.

Cool! Unused fuel tables? which one are you referring too? there is the high octane map and the low octane map... maybe I am not remembering some?

[Jesters Deadd]

Have the fuel solenoid map, egr solenoid map, charcoal canister solenoid map been found?

[bboyalan]

Who ever told you that is very obviously wrong. I'll post logs if you'd like to see them. Since this has never been done before, I'm not sure where your source is getting their info.

I have only read about one person actually attempting to push the factory BCS to any reasonable limit, and that was BlackStealth who had set up DC maps as well for a measly 12psi lol.

My GM 3-Port has been sitting for over half a year, so I cannot wait to finally use it hahaha. GrimmSpeed seems to be what is "in" nowadays though.

[Greg E]

My comment was complete hear-say not based on any test I saw. But now that you mention it afterwards he did sell me a new solenoid.


Cool! Unused fuel tables? which one are you referring too? there is the high octane map and the low octane map... maybe I am not remembering some?

Sucker!

Mitsubishi liked to recycle code for some reason. In the OBD1 days, there were separate maps for fed and california ecus. So you have a high and low octane map for each emission ecu. I have to double check the code again but I think there maybe 6 or 8 maps total. Gate or Brett could probably back me up on this.

Anyway, hardware wise the California and fed spec ecus have their differences but they all shared the same (almost) code. The only difference in the code was which set of tables that ecu used.

When OBD2 became standard and every car shared the same ecu, they never got rid of those extra tables in the code for some reason. Even the EVOs have 3 high and 3 low octane fuel maps even though only one is used.