shiv@vishnu

iTrader: (20)

There are two ways to control boost with the XEDE. One is stand-alone-mode and the other is intercept-mode. Stand alone works as its name implies. That is, the XEDE drives the factory boost control solenoid directly. You put in duty cycle value in the boost tables and the solenoid works accordingly. The factory ECU, which used to drive the boost contorl solenoid now drives a little relay on the XEDE harness board. It has to drive something or it will throw a check engine light as if it where saying "hey, where did the boost control solenoid go?" We are currently doing all our map developement in Stand alone mode. The results are faster spool-up/boost response and very easy mappability (even someone with no experience in engine management can map his own boost curve).

The other method (intercept-mode) is for the XEDE to take in the stock ECU's pulse-width modulated (PWM) signal, modifiy it (up to +/- 100%) and send it along its way to the factory boost control solenoid. This way also works just fine but more testing needs to be done to ensure stabliity and boost response characteristics.

As for harness availability, there are new updates at: http://www.vishnutuning.com/xede_evo.htm (at the bottom of the page)

JRock-- Using 91 octane maps for your 93/94 application will certain err on the ulta conservative side. Perhaps a bit too conservative in my book. It's perfectly safe but you'll be giving up 10-15 wheel hp. Won't know for sure until I come out to the east coast for another tuning trip at Pruven Performance (oct 4th and 5th). I'm looking foward to testing and developing some higher octane maps. Until then, I have to mix my own 93/94 octane coctail using regular 91 octane pee and 100 octane race gas. While this theoretically works, I've gotten better results using actual out-of-state pump gas (which was shipped to me along with a car not too long ago )

jfh-- More testing/traveling needs to be done before I can give you a reasonable answer for your question. But based upon what I've seen here, the addition of boost control will have substantial benfitrs to you system. This is why boost control has bee such a priority for us to bring to market with the XEDE. During my last tuning trip to Portland (at Matrix Engineering), the addition of boost control was worth 10-13 wheel hp on all the EVOs that we tried it on. More imporantly, it allowed me to run more boost in the midrange and upper midrange while still trimming boost back a bit towards redline where these cars as especially knock prone. I've actually been talking to Altered Atmosphere about XEDE tuning during this past week. They may become one of the first few authorized XEDE tuning shops.

Also, SAE correction factors on dynos don't work very well for turbocharged and supercharged cars. Especially those which operate at their knock thresholds (like EVOs and WRXs). The SAE calculations merely account for simple air density changes induced by temp and humidity variables. They don't account for turbocharged cars being more knock prone during hotter conditions. Such cars take a double hit: 1) lower air density means lower power and 2) hotter air means less allowable ignition advance. The latter his a massive result on wheel hp and goes unaccounted for by the SAE calculations.

As for hp output on out-of-state Dynojets, I'm just guessing based upon what I've seen in the past. So far my guesses have been pretty good. But it remains to be seen if the trend keeps going in the future

Gotta go home...

Cheers,
shiv

Liandrin11

What're you guys referring to saying for $795 you will not be getting the harness. The Vishnu website says $795 includes Xede, plugin harness, and 6' serial cable. I just ordered this last Tuesday night so I most certainly HOPE I'm getting the full deal, including boost control . I'm also assuming, Shiv, that all orders taken this past week will not be shipped out until everything is ready (ie. not shipping out the earlier releases of the Xede?)? Let me know if I am mistaken.

limey

It says on his site that the P&P harness is $90.00....this looks as if it is additional to the $795.00....just my observation...could be wrong

freedom

iTrader: (1)

N10S

iTrader: (4)

Excellent information on the XEDE w/boost control. Moreover, the details on the impact of the exhaust changes really spells-out the differences that the mid-pipe makes over the axle-back alone. Thanks for providing the details and helping clarify the deltas!

N10S

shiv@vishnu

iTrader: (20)

Hi guys,

Here are the dyno graphs from the Stock, Stage SubZero and Stage Zero tested we did this past week. All results are on the *same* car, over just 2 days. Weather in the SF Bay area has been essentially constant this past week so I don't think there are too many variables involved. All testing was even done on the same tank of gas (76 brand, 91 octane). I can only post one graph at a time so bear with me.

Attached below is the hp/torque results from a completely stock EVO, belonging to a local owner. These results are completely in-line with most other EVOs we've tested. These results were backed up consistently on the dyno on a fully warmed up car. Again, all testing is done in 3rd gear with a ~10 second run time.

Stock EVO-- Wheel hp and Torque

shiv@vishnu

iTrader: (20)

Stock EVO
Boost and Air/Fuel Ratio

Boost on the LEFT axis. Air/Fuel on the RIGHT. Careful not to mix them up

shiv@vishnu

iTrader: (20)

Next, we added a boost control enabled XEDE with tuned it. No other upgrades were installed.

Stock vs. Stage SubZero
Wheel hp and Torque

shiv@vishnu

iTrader: (20)

Stock vs. Stage SubZero (as above)
Boost and Air/Fuel Ratio

shiv@vishnu

iTrader: (20)

Next, we added our 3" cat-back and retuned the EVO.

Stock vs. Stage Zero
Wheel hp and Torque

shiv@vishnu

iTrader: (20)

As above

Stock vs. Stage Zero
Boost and Air/Fuel Ratio

shiv@vishnu

iTrader: (20)

On Tues and Wednesday, I'll be spending some more time on our dyno developing 93/94 octane maps. The same car is coming back for more running.

On 93/94 octane, we expect a few things to happen:

First, output should go up by at least 10 wheel hp on both Stages. These gains will come from running ~0.5 points leaner with fueling. As most can see, we still have to run quite rich for consistent knock-free performance.

Second, the little non-linearity spot at 5600rpm should go away (that's a real knock-sensitive zone on 91 octane and we have to pull a little timing there (just an extra 0.5 degrees) to keep output consistent.

That's about it. More updates next week. I'll also put the new XEDE maps on the website for anyone to download and look at (through the free XUpdate software).

Cheers,
shiv

tom@kartboy

iTrader: (21)

I'll be seeing you soon Shiv!!!

tom@kartboy.com

jman425

iTrader: (1)

Shiv, the people here in the Pacific Northwest are at a dilemna. We have 92 octane pump gas. Do we use the 91 Cal maps or the 92/93 maps ?

shiv@vishnu

iTrader: (20)

Hi strat,
The only traveling plans I have at this time is to CT (pruven perf) on Oct 4-5 and then to Houston on Oct 11-12. I'm always up to a midwest tuning trip if there is enough demand and an available AWD dyno (anything but Dynapack which take too long to set a car up).

As for knock sensor signal adjustments, we do it with the XEDE to induce a more aggressive ignition learning behavior. In fact, on most EVOs, this feature alone has been shown to raise output by 7-8 wheel hp on 91 octane fuel by making the stock ECU more eager to add in spark advance. The attenuation amount is quite small so that actual knock is still easily detected if it were to ever occur. This is another feature we spent a lot of time on-- trying different attenuation amounts in different rpm/load points.

Cheers,
Shiv