Stage 2 accessport boost and elevation?
 

Hey,
I just got my 04 wrx tuned by s-squared, with a Stage 2 custom map, and was wondering what kind of boost people are getting in Reno (@4500ft)? Right now I am getting between .09-.1MPa, depending on where I am driving. Is this a pretty normal number for a stage 2 map? I know the target boost range is 15.8psi +-.5psi. When he tuned my car, he couldn't get the boost to go up in 3rd gear, so I only saw gains at the very top end of my curve(6000+rpms), which seemed weird. He thought I may have had a pressure leak some where. However, when i was driving back at sea level I was boosting to .11MPa,(almost 16psi) :) in 4th and 5th gear, I think the ecu learned a little. That was a fun drive.
I know that I have an exhaust leak from the turbo to the dp and I can't tighten the bolt anymore w/o breaking it. Do you think that will cause a problem? My engine feels and drives great, so I'm not really worried about it.
Thanks,
Dave

Sounds normal. I was always around .09 Mpa in Reno with my WRX, maybe a little more in winter. But I saw around .12 in 4th gear at thunderhill, which is near sea level.

I had an accessport stage 2 map, and later a custom ECUTek reflash, they both had the same boost.

BTW what numbers did you put down on the dyno? I am interested in what kind of difference the headers made.

Boost is not a learned attribute, it fluctuates with elevation, not time on the throttle. You'll always see more boost at lower elevations, which is why you won't want to tune for more boost up here- you wouldn't be able to drive to California without overboosting.

my numbers were:
Max HP: 208
Max Torque: 185

These numbers seemed kinda low to me. Nate thought my torque should have definitly been higher. I don't think I have a pressure leak because I checked the connections from header to up-pipe, up to turbo, IC hoses, inlet hose. I put all them on my self too with new gaskets. Also, my boost seems normal. It increases as I shift from lower to higher gears. My car definitly feels faster, which is why I question my dyno numbers. I would like to take it back to get it tested one more time on the dyno, see if it puts out higher numbers. Nate also said that some times on 04 wrx's, cobb saw some cars that took a while to adjust to the new engine parameters. This could be the case with me.

One other thing, I saw that you put out higher numbers at cobb tuning than you did at S-squared, and you had the same mods at both places. Just wondering if there was a reason for that?

That is because Cobb's dyno is calibrated to read extremely high (probably a marketing thing so that their stages sound better), while Nate's dyno is calibrated to read low. In reality, the car was probably making more power when it was on Nate's dyno, since cobb's dyno is at 4500' elevation.

Nate might have the lowest-reading AWD dyno on the west coast. He was the only one who read the instructions and calibrated it the way the manufacturer recommends (you know, accurately...) instead of making the graphs look cool on the interweb.

Thanks for the input, that makes me feel better about the numbers I put out on the dyno.

Over 200 whp on a stock turbo wrx on Nate's dyno is impressive.

We need an AWD dyno up here in Reno, so that we can be tuned for our normal elevation, doncha think?

That would be great as long as you never intend to drive the car at sea-level. Remember, lots of boost up here means too much boost down there.

Plus, lots of boost at high altitude means running your turbo outside of its efficiency range. Which can mean blowing the car up even at high altitude due to the high temps.

HAHA Godd stuff I just spat my lunch on my new monitor.

I think a few other Mustang owners would dissagree with that statement mate as if your referring to doing a onsite parasitics test then I know of 3 Mustangs within 100 miles of San Jose who also did that.

I would also say not to worry about your numbers on the SS dyno as it is as stated a low reading load based dyno and you will see the boost change on the boost gauge at elevation.

I would be more concerned about how the car feels after the tune which as stated the car feels great so all sounds good.

Dave, sorry for the lag in getting back to you, my other job has been crazy. As everyone has been saying, it's normal to make slightly lower boost numbers at elevation; we want to make sure you're happy withthe way the car is driving, though, so keep us posted.

Thanks for the backup, guys :D

that's almost impossible.. rediculous numbers man.. also I am really excited to see if s2 dyno really is the lowest.. i guess we'll see at the next dyno day.. whenever that is. haha going to be awesome

mike

Its stock turbo with: UP, DP, Exhaust, headers, IC hoses, Inlet hose, crank pulley, spings and wheels.

what wheels, and what size tires? That can have a significant effect on how much power makes it from the flywheel to the rollers.

18" Rota subzero's, 225/45,
I have a minor exhaust leak from the turbo to DP, that has probably been there since I had it put on. However, It looks like I am getting full boost. Today on my way to work, in 4th gear I hit .1Mpa. Do you think the exhaust leak has any effect on the performance? Since I am reaching full boost, Does that mean I am getting the most HP? Nate said that you could take the DP off and still get full boost. If you took the DP off(no exhaust), How would that effect HP?

I think this is only true for some. If you have a stand-alone boost controller (manual or electronic) or UTEC in closed loop (I think), then your boost builds to whatever the setting is despite the elevation (assuming the turbo can boost that high in that air). Somebody correct me on this if they know for sure, please. I need to drive down to Sac. to see how my UTEC boost varies for myself.

Exhaust leaks *after* the turbo should not affect anything significantly. Taking the downpipe off would require retuning in addition to earplugs and a gas mask.

I didn't think a DP leak would affect anything, since I am reaching full boost. I know that taking the DP off would result in a annoyingly loud sound and smell. I wasn't planning on taking the DP off, just was interested if it would result in power loss. Since I am reaching full boost, I am guessing I don't have any other leaks to worry about and that I am achieving max power for this elevation(depending on air pressure, density, and Temperature). Thanx

I have a Cu-Seal (copper) DP to turbo gasket I'm not using if you want to buy it. It requires a retorquing after one heat cycle, but should fix your leak.

It is possible to tune a car's boost maps to be elevation specific as WRX's have a barometric sensor that the ECU uses. I get 17 psi all day at any elevation.

I was waiting for someone to say that, very true!!

You have to be careful not to push the turbo out of it's efficiency range though.

True Mike, some would say that I'm pushing too much boost out of the stock turbo, but I trust my tuner and he says 17-17.5 psi is perfectly safe. All I know is my EGT's are never above 1400K degrees Farenheit. I insisted that the longevity of the motor not be sacrificed for performance. As a side note, I don't mind shortening the longevity a stock turbo when they are so readily available used.