the old mustangs used to accelerate better by not shifting all the way at the redline (by that point horsepower had fallen off)...so instead you "short shifted".

With the boost and torque of the Evo being better mid range, has anyone pissed around with shifting at 6500rpm vs 7000rpm vs 7500rpm?

Not sure if anyone had a Gtech or something that was at lease a little bit reliable.

my car sure seems like it runs out of steam up top.

 

Two words... boost controller.

Otherwise you are likely better off shifting at the 6500 point, due to the boost falling off and how rich the ECu makes things above 5K RPM.

 

does a boost controller void the warranty? I have seen a few cars on the dyno with programable a/f mixture and you can make big numbers just pissing around with it.

thanks

 

Yeah, that's most likely not warranty safe. However, you get huge gains just running the stock 18.5 all the way to redline. oN 93 octane you can safely go to 21 psi all the way to redline. If I remember correctly, that's good for like 50 or so HP, especially with a turbo back exhaust. Then you're looking at 60+ HP (according to an RMR guy I talked to).

You can always easily remove the boost controller.

 

If you pull into a dealership with any boost controller/AF controller, likely they will void the engine warranty on the spot.

So take em off if you are going to the dealership.

And yes, leaning out the mixture some with an S-AFC does seem to make a noticeable power increase. But playing with that is best done on a dyno with proper measurement devices (AF ratio, EGT, and possibly 4 gas analysis as well). Too lean = detonation = dead motor if you aren't careful.

 

I guess to lean it out a little, an open airfilter kit of some sort would certainly help. I don't think I will be doing the boost controller option.

Any open airfilter kits out yet?

 

An MBC only takes minutes to install and remove. Getting to full boost immediately and holding that boost to redline definitely results in more power and a quicker car. The WRX is another car that is factory boost limited in lower gears to 8-10 psi then in the 3rd and 4th gear ramps up to 12.5-13 psi then tapers back off. Just installing a boost gauge, and an MBC set for 14.5 PSI makes the car immediately jump to 14.5 in the lower gear through redline.

You can only guess that the resulting power will be noticeably different than stock. More power quicker and longer, but the drivability will be more abrupt and less user friendly. I gained about 4 tenths of a second with my stock wrx set up with an MBC adjusted to 14.5 psi.

Obviously the MMC engineers programmed the FBC and ECU to provide boost ramp and taper to avoid any possible detonation issue's particularly at higher rpm's under high load conditions. I can only guess that the cars are programmed with a safety buffer in place for poor octane fuel, etc.... .In additon smooth driavbility is certainly a factor of the stock boost map.

An EBC like the AVCR or SBCID or new Profec E-01 are all rpm or speed programmable to allow the user to build in some boost ramp/taper at lower/higher rpm's. Certainly a more expensive alternative to an MBC.

I have an XBC ball and spring MBC off of my old WRX sitting in my parts drawer. As soon as I can get a decent boost gauge installed I may try installing it and experimenting a bit.

Obviously you have to approach this with an air of caution as certain side affects like part-throttle high egt's can result from the use of an MBC.
As Coolguy949 mentioned even setting the MBC boost at a safe level ...say 18.5-19.0 (even though this doesn't exceed the stock max boost)can certainly still have big peformance returns with few risks as long as you run a high octane fuel.

On the downside, unbridled testing at higher boost levels will get you fuel cut , or worse!

I also agree with the comments regarding the use of caution with SAFC type devices. More than a few engines have met an untimely demise as the result of improper A/F modification. Dyno tuning takes the guess work out and helps guard against expensive mistakes.