Yea yea i dont have my boost guage in yet, BUT I need to know if the EVO, in stock form, using the stock boost controller can hit full boost at just part throttle. Can someone do a test run, preferably on the freeway. Just keep it in 4th or 5th and give it 1/4 to 1/2 throttle and see where the boost goes. Im guessing it will hit full boost and part throttle, unlike the WRX could in stock form. For me, i can feel the turbo spool all the way up in 4th especially, so I am betting that the EVO was designed to hit max boost when not flooring it.

Im worried about getting a boost controller that does not vary boost depending on RPM. If the EVO CAN hit full boost at part throttle, then Im all good, and i'll just get a $90 mbc. But if it cant hit it at part throttle, I dont want it to run lean and will invest in a AVCR or the like.

 

it wont give u full boost unless ur at wot

 

ghey.... sure feels like it does...

Looks like I will be looking for an RPM dependant boost controller..

 

damn.. bump...damn

ya yea, im putting my damn boost guage in this damn weekend, so I can answer my own damn post! LOL!

 

WOT only, it just feels like it kicks more at 1/2 throttle because well.........you're only at 1/2 throttle, and when you hit some boost you feel it a lot more.

 

Does the Evo have PTHB issues with a man controller? Is it set up the same way as the WRX?

 

PTFB, is not a good idea IMO. Just as on the WRX, you run the risk of getting knock due to a lean condition during PTFB. As you know, when detonation occures it triggers the knock sensor which pulls timing.

 

Hmmm...i wonder what max part throttle boost is then... it would be worthwhile to have a hi/lo setting on a boost controller. I know most EBCs have several boost settings, but the only two stage manual bc is the TurboXS one... Then you could keep it at low boost when you are like cruising on the freeway and what not. When you punch it to pass someone, you wont hit full boost. Then when you want wood it, just switch to hi boost.

 

On a stock motor I get around 1 bar at probably 1/2 throttle. It was a lot higher than I expected it to be. I'm constantly hitting 0-.15 bar while just cruising down the freeway.

 

Well, when my boost gauge was hooked up I had no problem hitting 10psi at part throttle, much more required WOT whic actually feels slower a lot of the time.

 

What causes a WRX to run lean at PTFB? I'm a little lost here. Why would you want to run PTFB? I seem to be missing the point here. Isn't the purpose of the throttle to regulate how much air gets into the engine?

 

The SRT4 does this too (with a boost controller, I can't imagine any factory turbo car doing this without some sort of aftermarket boost holding mod), I have a turboXS DSBC and it (at one time, before I tapped into the the pressure line differently) would throw a CEL, something to do with the TIP sensor (throttle inlet position). Same as the WRX (and the Evo as well I'd assume) PTFB is bad because there isn't enough fuel at part throttle to handle full boost. You could blow your engine if it were a large enough boost vs fuel ratio (A/F). When you put on a boost controller you get boost quicker (at least I do), so the throttle is still doing it's job, it's just that the turbo is just doing it's job too well and chancing major engine issues in doing so. PCM says "oh ****!!" then pulls timing, you get choppy boost, car goes slower, etc, etc.....

 

Thats why I want to set my LOW boost exactly where the car in stock form, limits boost at part throttle. So in essence if it limits it to 1bar, or 14.75psi, thats where I will set my LOW boost setting at. So I cant go any higher while the car is under closed loop (someone correct me here, it may be open loop, I always forget which is which...)

When I want to go full throttle I will just switch to HIGH boost. That way I will never hit higher than factory boost at part throttle. Did that make any sense???

 

Somewhere in the owners manual is a chart of boost v.s. RPM. Max boost is at about 3500RPM, and if you've ever seen a dyno chart off an un-modded Evo, you can watch the HP start dropping off at about 5000 RPM when I'm guessing the stock boost controller is opening the wastegate.

So for part-throttle situations I believe you'll be fine. The wastegate isn't bleeding boost in stock form under 3500 RPM, so if your MBC keeps it sealed up tight there also, no big deal.

-Edit

This link is chock-full of turbo info goodness:

http://www.1300cc.com/howto/how2/turbo.htm
The nice thing is you can pick up close to 30HP at redline with an MBC, since Mitsu chose to take such a conservative approach with the boost curve.

MBC is my next mod, for sure.

 

Yea I have seen the dyno graphs and the power does drop tremendously after 5000. Ive seen dynos with MBC or EBCs hooked up and the power still drops, just not nearly as drastically!

That Max boost at 3500rpm is prolly at WOT, and not half throttle on the freeway...