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High Altitude Tuning

64K views 123 replies 63 participants last post by  WRXnBRZ 
#1 ·
We created this forum so that you guys would have a place solely for discussion of high-altitude specific technical topics. This should mean that folks don't have to wade through bunches of OT posts in the Mountain States forum in order to find the technical posts of interest. Hopefully it will keep things a little more organized while permitting you to keep some tech in the regional area.

OT posts, regular regional discussion, or technical posts that do not relate to high-elevation driving should not be posted here, otherwise they will be moved.

-pace
 
#7 ·
Hooray!
 
#12 ·
new guy Questions

i have a couple questions to ask. the first one is i just bought my 2002 WRX like 5 days ago i sold my 1995 eclipse GS-T. i was just wondering if anyone knows a place where i can get it dyno tested in Utah i live in Roy near Ogden. im guessing that the nearest place would be salt lake city. the second question is that every one i know has hondas and DSMs i have only 2 people i know with EVOVIII's. i was wondering if there is anyone in my area that i can get together with and talk cars. My WRX is subaru blue with 17" gold rims i think they might be the stock 17" gold ones. the last question is about my boost. im just wondering what is the stock boost setting for my WRX. im only pushing about 0.700 thats about 10.5Psi i don't think thats right. don't get me wrong have an AWD power house is fun. (alot more fun than my eclipse even thought it is much faster than my WRX. i was pushing 21Psi every day fun stuff)
 
#13 ·
You may want to check out Cobb Tuning in SLC. They have a lot of the members and car buffs. They can definitely answer your questions and see to it that you meet the right people. www.cobbtuning.net

If you were in Denver, I could help you out, but, Utah is practically a foreign state. :rotfl:
Just kidding. Seriously, the TD04 is a small turbo and you won't get more out if even if you go past 15 psi. You'll just be working it to death. It has been a while since I thought of it but the stock settings for the stock TD04 turbo's psi should be about 14.5 -max. Get yourself a new turbo, I have had the VF34, my friends have had the VF22, VF30, VF39 and the mitsu turbos like the 16G and the 18G. The stock wrx engine isn't capable of maintaining boost safely over 19 psi for longer periods of time if you want to keep the block due to its open deck design. However, if you need to maintain boost and get strong pulls, try the new momentum ej05-40T - www.boostbuddy.com carries them EJ5-40T and they maintain boost in a beautiful way when combined with a custom tune up to 18psi.Should net you 255 - 260 whp at 5600 ft altitude with an STi I/C and 565 cc injectors and a turbo back exhaust with uppipe.
 
#17 ·
Quick question

Okay, since I live in Colorado Springs, should I hav emy STi tuned? I was wondering that since the stock ECU was most likely not tuned for this kind of altitude. And if I should get it tuned, where is a good shop to go to.
 
#109 ·
Okay, since I live in Colorado Springs, should I hav emy STi tuned? I was wondering that since the stock ECU was most likely not tuned for this kind of altitude. And if I should get it tuned, where is a good shop to go to.
Whatever you do, Bionic, don't go to Under Pressure. Had a 3000GT VR4 that they litterally destroyed (improperly installed two headgaskets causing the engine to explode), stole my alternator, charged me for the same alternator to be put back on. They also redid a buddies STI with nearly $15k worth of work. They took his car while he was deployed and showed it off at shows to compete in BOV (TurboXS RFL BOV) and blew his engine without repairing it saying the damage was done before they took his car.
 
#24 ·
Bionic1 said:
Okay, since I live in Colorado Springs, should I hav emy STi tuned? I was wondering that since the stock ECU was most likely not tuned for this kind of altitude. And if I should get it tuned, where is a good shop to go to.
+1 on this. My bugeye runs like crap in open loop, can/does the dealer flash high altitude maps? I did find an oddball spark plug ( different brand and heat range from other 3 ) that seems to be helping else I am too accustomed to my old V8 Hemi. 300wtrq at 2600rpm would make anything feel sluggish....
 
#26 ·
Tru3th - Look into high altitude turbos. They should have compressor maps with higher pressure ratios (2.5-3.0 OK), and low flow surge lines. Surge is a possibility at high altitude much more than at sea level due to the lower density air and higher boost we typically run. Remember 20 psi at 5280 is a pressure ratio of around 2.8, compared to a sea level ratio of 2.36. Some turbos really won't like that, overspeeding and ruining the bearings.

ktmrider - Sluggishness, especially if you can tell it's worse in open loop, is probably due to a mixture that's too rich. I suggest you get some wideband readings, whether installed and on the road, or even a tail pipe sniffer on a dyno. Tailpipe will run around 1.0 to 1.5 more lean than pre-cat, but you'll get an idea how rich it's running. Are you tuned, or is this the ECU? If you're just getting used to turbo lag, then welcome to the club. De-restricting your uppipe and exhaust will help immensely.

davidcommons - high altitude costs a lot of power. The SAE correction on the dyno usually adds around 50 hp to correct to sea level (stage 2 STi). The good news is that you can take more advantage of the turbo at low RPM. At altitude we can typically run 20 psi of boost without endangering the engine, since the absolute manifold pressure is still below what it would be on a slightly tuned stock car at sea level running 16.3 psi. The problem is in the turbo's compressor map (tho none exist for the VF series). 20 psi at altitude is a high pressure ratio (2.8). That high of pressure ratio pushes the speed of the turbo up, near the limits (if we knew what the limits were). Turbos get more of a workout, increasing the chances of them failing. Watch for oil consumption getting out of hand. It can mean failing turbo bearings. High altitude (high pressure ratio) turbos can last longer in this service, and provide better results. And get used to lag. You thought it was bad, but you had no idea.
 
#27 ·
ktmrider - Sluggishness, especially if you can tell it's worse in open loop, is probably due to a mixture that's too rich. I suggest you get some wideband readings, whether installed and on the road, or even a tail pipe sniffer on a dyno. Tailpipe will run around 1.0 to 1.5 more lean than pre-cat, but you'll get an idea how rich it's running. Are you tuned, or is this the ECU? If you're just getting used to turbo lag, then welcome to the club. De-restricting your uppipe and exhaust will help immensely.
Thx, you're right on the turbo lag. My previous vehicle was a 5.7L Hemi truck with a 2600 stall. All the years of V8 pushrod engines has me jaded ( at least off the line ). The AWD and 4EAT are not helping my butt dyno either. :tongue:
On the open loop stuff, I did the home made grounding mod and seafoamed the engine, fuel system, and crankcase. Although I made 3 changes at once ( synthetic oil change ) I believe the grounding mod was the key. The car idles smooth as glass, first tank fuel mileage went up from 20 to 23, and it runs perfectly in open loop/when cold. I was extremely skeptical about the ground stuff but since I had a few hours watching the kiddos one morning I decided to do it. $15 and 1 hour later I'm all smiles!!!!
 
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