I've noticed in the Vishnu section that cars tuned by Vishnu with the XEDE seem to be tuned to run very high boost levels in the mid-range (like 22-25) and then taper below 20 in the upper revs. For example, here is a recent post from the Vishnu section of the boost and AFR of a 91-octane Stage 1+ set-up:


Notice that the boost is hitting almost 24 psi in the mid-range. Obviously this is worth some power in the meat of the torque curve and in the RPM ranges where the 16G is still efficient vs. just holding a steady 19-21 psi throughout the whole rev range -- assuming that this is done without detonation, which I assume it is.

Right now I've got a Dynoflash and a Blitz ebc. With my electronic boost controller, I can set it to run more boost at lower speeds (say 24 psi) and then taper once the car gets up a higher MPH (say to 19 psi). The ebc is linked to the speed sensor, so I can adjust it to change boost settings by MPH. This is a feature that I haven't used and is mostly intended to allow boost to be ramped up with MPH on traction limited cars (ie, 2wd).

Is this a reasonable idea? Is it safe with my Dynoflash tune? Assuming I hook up my OBDII scanner and see no timing retard, does that mean that I'm good to go?

Hoping some tuners will jump in here with a comment or two.

Thanks!

 

Here's one more than just went up in the Vishnu forum:

 

I hit 24~25 psi in the mid range and I have never had any knock (at least I did not hear anything)

BTW I dont have the stock turbo but I was tuned by Shiv. I truly belive that if the tune is good you should be fine with 93 gas that we use on the east coast. However, I keep holding that until redline.

 

FWIW, the 24psi boost midrange boost level was on race gas, not 91 as the notes suggest. On 91, peak boost is usually around 21-22psi with taper down to 17-18psi. On the first graph, the brown line is the race gas map and the blue line is the pump gas map.

Cheers,
shiv

 

My boost curve looks very similar with my AVCR. The AVCR also has the ability to tune boost based on rpm, however I have found that the turbo does a good job of tapering the boost itself.....in my experience if you set your boost controller to try and hit 25 psi it will do so in the midrange, but will be unable to hold the boost at redline. I usually can't hold more than about 20-21 at redline.