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Well my experience from the Xede is that dropping boost by 1% doesn't even drop the boost. I was overboosting with my stock map also. I would change those percentages to about 92%, then take all the 100's and change those to about 96%. I would think that would drop you about 2 lbs of boost allong the spectrum. Thats what I did atleast and I am not overboosting again.

 

I agree A 1% change in duty cycle is pretty small. My recommedation is to make changes to boost in 5% increments first. Then make fine adjustments when you're close to where you want to be.

Cheers,
shiv

 

Another call for datalogging, it seems.

If you are at 5000RPMs and then floor it, does the boost spike?

I don't see how adjusting that table could possibly get rid of a boost spike. In order to get rid of a spike, a boost controller needs to keep track of boost as it rises, plot the slope, and then react to the increasing boost BEFORE boost hits its max level. This should be done at any RPM, and any load cell.

Actually, are those load cells in the vertical axis, or is that something else? Load cells don't really make sense for a boost controller since load is essentially just another way of expressing boost.

 

Thanks, will do that.

 

Geeze Shape do you ever quite? Datalogging is coming then we wont have to listen to you- well youll still prolly complain that the Xede doesnt come with a stick of bubblegum As far as your current ASSumption dont worry about it the Xede does a fine job of actually controlling and firing the FBC No BS here

 

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Sometimes it does but it really depends on what RPM you are at and what turbo, The factory tubo can hit REALLY high boost from 3500-48-4900 but after that you can set it to 100% and be fine, I think 4500 was the hardest to tune good and keep boost down in the higher gears becase going through 2nd from 3000rpm to redline is fine but dropping into 4th from 5th at 4500 and hitting the gas would cause the spike, I did add some additional RPM ranges to help this and now it works pretty damn good, I think with the xflash the boost spike will not be as big a deal because it just spikes for a second or 2 but enough to hit boost cut, if boost cut is raised it will be fine. If you are getting on it 1-4th I have 20psi all the way. Also in my old TT rx-7 boost was a real pain in the *** with the 2 turbos lol. The evo's turbo is MUCH easier to work with.

 

Actually, I was just trying to find out what the numbers on the vertical axis were. It makes no sense to use load on the vertical axis since the numbers you enter in the boxes are also a form of load. So essentially you would have a 3D map, but with 2 of the axes being the same. That basically boils down to a 2D map. That doesn't make any sense. So, what are the numbers on the vertical axis?

I'd ask you if you ever stop, MP5, but I already know what it takes to make you stop. Welcome back.

 

I presume the numbers in the table are the duty cycle of the boost control solenoid, and load is the vertical axis. Less duty cycle = less boost.

Lowering the duty cycle at lower load points would help catch transient overboosting too.

 

Aaah, that makes more sense. And that is a good point. That could help out. It would be helpful to know what the load roughly translates to in psi. I know I can do that on my car with the airflow per rev (what the ECU uses for load) that my datalogger spits out using a multiplication factor. You would be amazed at how well it tracks the datalogged boost value.

 

Yes indeed. Also, the load axis represents MAF. It's also very easy to eliminate boost spikes if they get out of hand. With the EVO, it's not unusual to see a 1-1.5psi boost spike upon full throttle. While it is possible to tune it out, doing so isn't necessary. In fact, the factory ECU allows for a brief boost spike upon WOT to improver perceived power response. Not a bad thing as long as it's kept in check.

Regards,
shiv

 

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On the 93 octane you guys get down there, that is just fine.

Cheers,
shiv

 

Personally, I place very little stock in airflow values from a MAS when the flow is dramatically increased over the stock values. Unless there happens to be a calibration curve of the sensor handy and you can log MAS voltage/frequency directly...

Which isn't to say that it's untuneable, quite the contrary, just that I'd take the "airflow" values themselves with a grain of salt.