? boost gauge
- Thread starter MS3Chik
- Start date
Newter said:
Whaaaaaaaat? the hell are you talking about bypassing the rev limiter with a boost gauge?
I put mine on top of the steering wheel column. Defi Blue Racer boost gauge with a Defi Link Fitting Kit.
http://www.mazdas247.com/forum/showthread.php?t=123652762&page=6
Newter said:
I don't think you've ever owned a turbo car, have you? Regardless of the max boost pressure, it's always a good thing to have a boost gauge. Lets you know what's going on with the car, and also gives you first indication if you have a boost leak.
And it's not always the same. Boost builds with RPMs. From your post, it seems that you think boost is always at 15-16 PSI.
justa4banger
Member
- :
- 2007 SILVER MS3
dommo_g said:
This isn't a procharger my friend. it may seem that boost builds with Rpm due to the elaborate ECU system on the MS3, but turbo's don't do anything rpm related. Wastegate controls all. Granted you can't build boost till a certain rpm but if we had true boost controllers it wouldn't matter if it was 15psi at 3k rpm or 7k rpm. 15 psi is 15 psi unless you have serious boost creep.
A turbo car that has no crazy restriction (in the MS3's case, the ECU) will build XX psi of boost and maintain it from where ever to where ever, not progressively get more with RPM. those thingys are called superchargers. (cheers)
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dommo_g said:
This is my first turbo and I'm only speaking from what I've read on how the turbo works with the MS3. My understanding is the ECU controls the psi and when you get it and it would be in theory always the same. e.g. 3rd gear at 4k 15psi. And it will always be the case unless like you said there is a leak or some other abnormality which would be a good reason to get the gauge.
BK's black P5
Member
Newter said:
ECU does not really control boost. Boost is created as a function of the pressure built up by the turbo/compressor as it spools up based on the load on the engine. You can drive all day long without creating enough load to go from vacuum to positive manifold pressure, so your boost gauge would not move past the vacuum readings (inches of mercury) to positive (psi or atm) manifold pressure readings. ECU would control other issues such as fuel mapping, timing, etc.
justa4banger
Member
- :
- 2007 SILVER MS3
Ummm Part of what you said above is correct, but the ECU does control boost, If it didn't the turbo would overboost the engine into a pile of scrap aluminum.The ECU controls the solenoid, which controls the actuator, which opens the wastegate. SO YES the ECU controls boost. If you never the load the engine hard enough to create boost then theres need to control it.
As for everything else stated, YES you are correct, thats why turbo fours have the ability to get decent gas mileage. Most of the time to though the drivers right foot is just to heavy, to KEEP getting good gas mileage.
IS a Boost Gauge necessary?? honestly NO , Can it be useful....absolutely..... Will i get one in my MS3 .....sure will since wifey is out of town and i won't have to listen to her b**** about the damn thing. Once its in, ITS IN! Along with a CAI.
As for everything else stated, YES you are correct, thats why turbo fours have the ability to get decent gas mileage. Most of the time to though the drivers right foot is just to heavy, to KEEP getting good gas mileage.
IS a Boost Gauge necessary?? honestly NO , Can it be useful....absolutely..... Will i get one in my MS3 .....sure will since wifey is out of town and i won't have to listen to her b**** about the damn thing. Once its in, ITS IN! Along with a CAI.
There is a stock boost controller and bypass/safety valve in these cars that will protect you from overboosting.
But the wastegate is mechanical, and it functions on its own, and as long as the wastegate operates properly, its impossible for the car to overboost. HOWEVER it DOES happen, and thats why Mazda put in boost cut and defeat systems.
However, it is still a good idea to put a true boost gauge in ANY turbo car, as a first mod because a good second mod is to increase the boost pressure.
But the wastegate is mechanical, and it functions on its own, and as long as the wastegate operates properly, its impossible for the car to overboost. HOWEVER it DOES happen, and thats why Mazda put in boost cut and defeat systems.
However, it is still a good idea to put a true boost gauge in ANY turbo car, as a first mod because a good second mod is to increase the boost pressure.
BK's black P5
Member
Yes, my wastegate is mechanical and not directed by ecu commands.
Wow seems there are a lot of misinformation and misunderstanding on how turbos work in here...
The boost in the MS3 is controlled mechanically with a wastegate actuator (a spring and diaphram device that is forced open from boost pressure) but also electronically with a solenoid that can bleed some of the pressure signal that goes to the wastegate actuator. Pretty much all modern turbocharged cars exert some sort of electronic control over the turbo boost pressure in this manner... though back in the day (1980's Datsun/Nissan Z turbos) there was no electronic control.
And turbo boost often does change with RPM. A turbo has an operating range... floor it at too low an RPM and it builds boost slowly and won't peak until some given minimum RPM. Keep the accelerator floored and on many turbos (smaller ones usually) the boost will drop at very high rpm. This is also a function of how the turbine housing is designed and how restrictive the exhuast is.
Also, you will often see different boost peak levels depending on what gear you're in. The lower the gear = less load on the engine = less overall boost. I've experienced this in cars that controlled the boost electronically as well as cars that only had mechanical control for boost.
The boost in the MS3 is controlled mechanically with a wastegate actuator (a spring and diaphram device that is forced open from boost pressure) but also electronically with a solenoid that can bleed some of the pressure signal that goes to the wastegate actuator. Pretty much all modern turbocharged cars exert some sort of electronic control over the turbo boost pressure in this manner... though back in the day (1980's Datsun/Nissan Z turbos) there was no electronic control.
And turbo boost often does change with RPM. A turbo has an operating range... floor it at too low an RPM and it builds boost slowly and won't peak until some given minimum RPM. Keep the accelerator floored and on many turbos (smaller ones usually) the boost will drop at very high rpm. This is also a function of how the turbine housing is designed and how restrictive the exhuast is.
Also, you will often see different boost peak levels depending on what gear you're in. The lower the gear = less load on the engine = less overall boost. I've experienced this in cars that controlled the boost electronically as well as cars that only had mechanical control for boost.
