Just installed a boost controller, curious how much boost you guys with 9's are running on 91 pump. I'm holding 22lbs. I've seen people go up to 23 also... Comments?

 

I wouldnt boost that high on 91.

 

what would you reccomend 20, 21 highest, it sucks all we have is **** gas

 

I would recommend not turning it up more than 20, especially without a tune.

 

I am spiking to just over 21 lbs tapering down to just over 17 lbs, tuned though.

 

21.5 with a tune.

 

so 20 sounds like a good general number, im gonna turn down the boost, thanks for the help guys, any others opinions are appreciated.

 

I boosted 23 lbs on 91 octane pump, it was quite fast and had 0 knock. Not sure why so many people think running lower boost than stock is really a good idea, even on 91 octane. Most of the California Shop tuners also tune for 23~ish psi.

 

most boost = less timing....

what do you want for the car to do? hp or fast spool?

 

~24psi...93pump, bolt-ons, stock timing, zero knock.

 

25 psi on 93 pump with tune no problems

 

25 is pushing it, I will try 23PSI and then log from there. 25 is nuts. mike1023 runs 28psi on is 2004 Evo VIII on pump gas. He runs 11.23 @ 120MPH!!!!!

 

With some pretty good weight reduction done.. .

 

23 on 93

 

For Evo VIII's a good rule of thumb is to just match the last number:

91 = 21 psi
92(nw) = 22 psi
93 = 23 psi
94 = 24 psi

For Evo IX's, just add 1 psi for each of those; they have a more efficient head (for multiple reasons) and can handle a more aggressive tune without knocking.

You never want to be under 20.5, that is stock.

In all reality though, you should never really use your boost controller; you should leave it where ever your tuner sets it at.