Is it safe to run more than 21 psi in the mid-rpm range on pump if boost is tapered at higher RPMs? Vishnu seems to tune this way (I've seen as much as 24-26 psi in the mid-RPM range on pump) and it seems like it would give more kick in the mid-range if it doesn't cause detonation. Does the standard Dynoflash have too much timing to accomodate this safely?

Thanks.

 

Anyone who tunes on pump gas at 24 - 26 psi is looking for trouble.

I suggest 21 psi as a max

Of course some cas cam be pushed harder - provided that you aware of the warning signs of knock activity

 

To be honest, if you want to run your car that high on boost, i would get an aftermarket knock sensor. it would be cheap insurance, but i would personally stick to about 21 psi max.

 

I posted about this same thing in the general forum too, and put up a graph of a Vishnu 91 octane Stage 1+ tune, showing boost and AFR:

https://www.evolutionm.net/forums/sh...d.php?t=119003

 

do you know if it's the 03/04 or 05 on the chart. my 05 already runs a max of 1.55 bar (22 psi) stock in mid range, i'm sure 2 psi wouldn't hurt, but i would definately run higher octane gas. when i use 92 octane the car runs totally different than when i use 93/94 on 100 octane or toluene. i think stock, the car has a more aggresive map when the knock sensor is not tripped(93 octane?)

 

I have an 03... My ebc peaks around 23ish.... Then around 22-21 midrange and finally 20 up top.... I was also wondering about knock. People say don't go much over 20psi. My midrange is over that....

 

in

 

I know of one member with a untuned / unflashed MR who blew his motor recently with just this kind of thinking

Stock MR's pull timing from detonation on 91 a d 92 octane fuel - raising the boost emerely agrivates the condition

 

Any idea if my boost level is cool?

 

What's puzzling to me is that Vishnu regularly tunes cars to run over 22 psi in the midrange and, while I know that all tuners don't agree on the same approach, Vishnu's customers are hardly blowing motors left and right.

 

the only engine mod i have is an hks intake, when i use 93/94 octane, the diff is considerable, the car runs like a monster, either way 92 or 93 octane, my car will spike @ 1.5-1.55 bar, but on 91 octane... i probably would not go above 22 psi . i guess it sucks to have cali gas, but only 1 octane better here in hawaii. the point is running higher boost is similar to playing with nos. you can do it but pay attention to knock, keep your injectors clean, and pray!

 

How exactly are they mapping out boost on their plots? I would assume that they're somehow tapping into the manifold to get a boost reading. (but would like specific details by those who have had their cars run on the DD dyno)

It also begs the question of how accurate their sensor is. For all we know, it may be off a couple of psi.

Also, the other thing to consider is that you can afford to raise the boost slightly, as long as you have a good flowing exhaust, since the engine won't have to work against the higher backpressure.