i have a 2003 msp basically all stock, all i have done is hardpipes ,fmic, and greddy BOV. I installed a Boost gauge and its reading 10 psi. it has a relocated maf, it was reading 10 psi when the car was completely stock with the stock pipes. it does not have a boost controller. i was wondering what would make it run 10 psi? i thought stock was 6? any way to turn this down? the car was stock its whole life, new waste gate, turbo, and manifold installed by dealership 2 years ago.
boost question
- Thread starter 02.5MP5
- Start date
The wastegate on our stock turbos is internal. The dealer definitely replaced it with a stock turbo so you can be pretty sure your spring is stock.
They most likely also replaced your WGA (wastegate actuator). This is the small cylinder with the rod connecting to your wastegate lever on your turbo. I really wish people would stop interchanging WG and WGA; they are very different parts.
The stock WGA is adjustable in that the length of rod can be changed slightly. This does not really change your max psi. It changes how soon or how late in the actuators movement that the wastegate is cracked. If you adjust it too long, the wastegate will be open all the time and you'll take forever to spool. If you adjust it too short, the wastegate will not open completely and you'll get boost creep.
I had one stock WGA replaced under warranty at 30k miles and that one died on me at 50k miles. They are known to go bad. I have the ATP replacement now and it's been good for almost 30k miles. Supposedly, it runs a little higher than stock, but I didn't have a gauge when I had the stock one to verify. It's not enough to worry about.
It is very easy to determine if yours is good though. Disconnect the hose going to the WGA from the nearest coupler and see if you can blow through it. It should pretty much be a wall. If you can blow through it, it means that hose has a crack in it, or your WGA is bad.
If it is solid, then you could still have a boost leak anywhere between the boot source and the WGA so check the rest of the vacuum lines next.
Boost gauges without datalogging are not very useful for problem solving, but it would help if you could describe the boost. For instance, what RPM does it hit 10psi? Does it hit 10psi and hold till redline? Does it creap upwards or diminish? Does it spike anywhere? Etc.
The smart money is on a bad WGA or cracked line, but if everything checks out, you might want try another gauge as people tend to buy ebay specials that don't always work that well.
They most likely also replaced your WGA (wastegate actuator). This is the small cylinder with the rod connecting to your wastegate lever on your turbo. I really wish people would stop interchanging WG and WGA; they are very different parts.
The stock WGA is adjustable in that the length of rod can be changed slightly. This does not really change your max psi. It changes how soon or how late in the actuators movement that the wastegate is cracked. If you adjust it too long, the wastegate will be open all the time and you'll take forever to spool. If you adjust it too short, the wastegate will not open completely and you'll get boost creep.
I had one stock WGA replaced under warranty at 30k miles and that one died on me at 50k miles. They are known to go bad. I have the ATP replacement now and it's been good for almost 30k miles. Supposedly, it runs a little higher than stock, but I didn't have a gauge when I had the stock one to verify. It's not enough to worry about.
It is very easy to determine if yours is good though. Disconnect the hose going to the WGA from the nearest coupler and see if you can blow through it. It should pretty much be a wall. If you can blow through it, it means that hose has a crack in it, or your WGA is bad.
If it is solid, then you could still have a boost leak anywhere between the boot source and the WGA so check the rest of the vacuum lines next.
Boost gauges without datalogging are not very useful for problem solving, but it would help if you could describe the boost. For instance, what RPM does it hit 10psi? Does it hit 10psi and hold till redline? Does it creap upwards or diminish? Does it spike anywhere? Etc.
The smart money is on a bad WGA or cracked line, but if everything checks out, you might want try another gauge as people tend to buy ebay specials that don't always work that well.
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thanks for the replies.. boost starts around 2500, it holds its boost until redline which i rarely do. even in half throttle the boost is held. it really doesnt spike it just boosts up to 10 psi, although there is a bit of hesitation in the car and after a certain bit it gets it full power. i found that easing into the throttle till full throttle is the way the hesitation goes away.im sure this also has something to do with tuning but the car is stock. ive read about the ecu reflash, but im more concerned about the psi being high as if i reflash before fixing psi then i risk running lean and pinging. any thoughts?
This really should have been made a sticky.
http://www.mazdas247.com/forum/showthread.php?123792646-Hesitation-explained-with-pictures.
As for the boost running high, did you try the tests I explained before? Have you blown into the WGA? Have you worked your way back on the lines? Have you verified the reading with another boost gauge?
Don't worry about running lean at high rpms. The car runs incredibly rich as it is and a boost leak isn't going to make you run leaner even if you have a relocated MAF.
Consider buying a wideband, but definitely get yourself a elm327 OBII bluetooth device. If you have a smartphone, you can get decent apps to meter all your diagnostics for $5.
The behavior you are describing sounds like typical MSP behavior. My guess is that the boost gauge you have is off. What does it read at idle?
http://www.mazdas247.com/forum/showthread.php?123792646-Hesitation-explained-with-pictures.
As for the boost running high, did you try the tests I explained before? Have you blown into the WGA? Have you worked your way back on the lines? Have you verified the reading with another boost gauge?
Don't worry about running lean at high rpms. The car runs incredibly rich as it is and a boost leak isn't going to make you run leaner even if you have a relocated MAF.
Consider buying a wideband, but definitely get yourself a elm327 OBII bluetooth device. If you have a smartphone, you can get decent apps to meter all your diagnostics for $5.
The behavior you are describing sounds like typical MSP behavior. My guess is that the boost gauge you have is off. What does it read at idle?
