Boost normally does increase with a full TBE.

Pill removed on my VIII, it would peak @ 23 and then taper down to 21psi.

With the Xede installed, it toned it down a little
Would peak @ 21 and then taper down to 19psi.


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1. There will always be boost taper with the stock turbo. Those who say that they have eliminated taper on a stock turbo are more than likely relying on a boost gauge and these are not accurate. They are usually off by 1-2 psi. I had a Defi D gauge and it was off by 1.5 psi compared to logging with a MAP sensor. The stock turbo simply "runs out of breath" at the top end and it tapers.

2. It is a bd idea to increase your boost w/o tuning your timing and AFR at the same time. I am especially concerned about timing. When good tuners increase the boost on pump gas, they generally back off the stock timing to reduce the likelihood of knock. When they lean out the AFR, they also back off the timing.

3. Removing the restrictor pill from your boost lines (ie, upping the boost) w/o backing off the timing is not good tuning practice. I had my Xede removed and sent to Vishnu for service. I thought about running w/o the restrictor pill, but then it dawned on me that I am back to the stock timing map whereas the custom map had reduced the timing.

Do yourself a favor and put your pill back in the vaccuum line. Drive the car stock until you have the resoruces/knowledge to do AFR/boost/timing tuning at the same time.

 

but the ecu is programmed for reduced timing on higher boost. and tunners actually significantly increase timing over stock timing while recommending higher boost. the stock timing is just wayyy too little.

 

That may be true if you are running 91.

Evos are designed from the factory to run on 93.
( It states this in the owners manual )

As your logs have shown in the past, The factory tune is pig rich up top.

I run at least 1/2 tank of 100 at all times. With the boost control
pill, the factory ECU will only let you increase boost so much.
Why do you think the Xede recommends removing the pill ?

BTW, I've increased the boost as much as possible with ECU Flash.


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With my Xede on my VIII, I was able to eliminate the taper on a stock turbo, 21 lb from 3500 to 7000. Logged with a map sensor, not a boost gauge.

 

Go to sleep already.





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That is NOT possible on pump gas on a stock turbo. Shiv has said a billion times that there will still be taper even with the Xede. There is no way to hold boost at 21 psi to redline on pump gas with a stock turbo.

 

I have yet to see a pro-tuner increase timing on pump gas while upping the boost and leaning the AFR. I have looked at maps from Shiv and Tuning Tech and both of them back off the timing from stock. Show me pro maps that have added timing on pump gas and leaned AFR with added boost.

 

I mix gas as well. I run on 93. Half a gas tank of 100 is NOT pump gas. I am talking about pump gas.

Shiv removes the pill because the Xede controls boost. He also backs off the timing on his 91 AND 93 pump gas maps. He even pulls more timing on the 05 Evo. Tuning is a three step process of upping the boost, leaning the AFR, and pulling timing. Upping the boost by removing the pill ONLY w/o doing the other two is just not good practice. It is risky.

 

I've seen pro maps posted on here with blocks of 8 timing where the stock ECU runs less, these were maps designed for pump. I think there is a key difference between comparing injector pulse widths and timing values for different boost levels and simply modifying the stock taper by load on the stock timing maps.

My JDM map runs +3 over the US map in places and I've added 1 to that except at 6500 RPM and people think my timing is low, or that may be just because I hold 23.5 PSI through the midrange and only taper to 22 PSI at peak power and 20 at red line. It runs through increments in 1.07 secs where the stock JDM takes 1.47 though, and accelerates in 3rd like an FQ340 (345 BHP) does in 2nd.

 

only area is have seen tuners add timing when upping boost is in the spool up zone where they tend to cap the lowest timing between 5 and 8 degrees, which in comparison to the stock maps would be an increase.

 

I think those all pretty much come from the same source...

l8r)