Iwas just in steamboat/dillion this weekend with my friend in his STi, and we were getting really bad compressor surge. Anybody have a reason for this, first time driving a boosted car 9k above sea level. and ideas?

PS the car ran fine in michigan and the whole way there




Modified by Orangeciv at 5:13 PM 11/13/2007

 

any ideas?

 

your tune may not be up to par with the defference in air density/climate and such.

 

Thats what happens at high altitude. You end up running a much higher PR and hit the surge limit.

Solution: get a bigger turbo, or lower the boost.

 

lower boost huh? he is running Wastegate right now on an FPGreen(15PSI) which is much bigger then stock. wut do you guys think?10 psi?

 

If its at wastegate pressure, then he'll have to just not use so much throttle.

You sure its compressor surge? When I took my car up in the mountains, the BOV spring pressure was way to high and it had a hard time blowing off. So part throttle the bov wasnt opening properly. If I lived up there, I would have to run a 7psi spring in my Tial so it would blow off correctly.

 

Im pretty sure its compressor surge. we loosened his Turbo xs RFL pretty much all the way. when he goes to shift it seems like the BOV hesitates and thats when it surges, just before it blows off. he is gonna try running an independent vac line to the BOV cuz right now it also goes to the boost gauge, which shouldnt make a diff. but wut ever. any other ideas?

Thanks for all the input

 

anybody else have any ideas????

 

Get a good BOV. Hell, even the stock one is better that the shitbox XS one.

Remember, the pressure ratio changes rather dramatically with altitude to maintain the same level of 'gauge' boost pressure. Check out a compressor map and think about 15 PSI at sea level and 15 PSI at 9k feet. The compressor has to spin significantly faster to achieve that same 15 PSI of boost.

 

steamboat?

 

yea, a car tuned for sea level will definately suck up here, i would try and get it retuned before trouble shooting anything with the setup.