Mazdaspeed Protege Blow Off Valve question

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Dr.Sound

:
03 MSP > 03.5 MSP > 05 Evo8 GSR > 10 EvoX MR-t > 96 MX-5
Hey everyone,
I'm looking for a good blow off valve for my MSP.

What do you guys recommend?

Also I have read on one of the posts that MSP does not have a factory blow off valve, it has a bypass valve.

What is a bypass valve? How is it different from blow off?

I would like to vent to atmosphere so i get that famous "psssssst". Which one should i use?

Thanks.
 
The function of a blow-off valve is the same as that of a bypass valve (called a diverter valve in the VW world) which is to vent excess pressure when you let off the gas, but the turbo is still spinning. This keeps the turbo spinning by not allowing the backup of pressure to stop the compressor wheels, so when you are done shifting and hit the gas again, you don't have to wait as long for boost return.

The difference is that a blow of valve vents the air into the atmosphere, and a bypass valve vents it back into the intake system. The engine has been designed to measure all of the incoming air (Mass AirFlow sensor, or MAF) so it can accurately calculate how much gas to squirt into the cylinder to mix with that air. If you put a BOV on an engine designed for a bypass valve, it will miscalculate because air that has been measured is being released before it gets into the cylinders.

A lot of aftermarket blow off valves can be run in bypass mode, but this does diminish the cool sound you are looking to achieve. You can often regain much of this sound by putting a nice free flowing intake on your car, such as a cold air intake or cone filter. The stock airbox muffles a lot of engine noise, including the bypass valve noise. A good intake combined with an aftermarket bypass valve will probably give you the sound you want, and keep your engine running the way it's supposed to.
 
yo thanks mikey,
ok.....
A pretty famous and good shop made me a custom intake with a K&N aircharger filter.
That was last week.

I drove the car for about 4 days and noticed that the power went down......

also the gas milage droped, but i think this happened because of power loss............. i was trying to squize out more.

the sound (ithink of the bypass valve) became about 10 times louder.
I sounded like FFFRRRRRRRR every time i let go off gas to shift.
I didnt mind the sound - I liked it.........

The problem was with dramatic power loss........

BTW i did unplug the battery for about 15 min so that the computer can reset to count for increased airflow. DIDNT HELP.

Now i drive with a stock airbox - power's back, pick up is way better.

OK..........question is...........
Did all this happen because the stock bypass valve is too small to handle increased airflow???
 
I doubt your problem was due to the bypass valve. An intake isn't going to actually increase the amount of boost your turbo makes, it just offers less resitance to the turbocharger getting that air, which allows it to spin up quicker and run more efficiently. I don't know enough about our cars to be positive about this. But when I had my VW 1.8T a lot people with cone filters in the engine bay had problems due to heat. Turbo engines generate a lot of heat, and hot air doesn't carry as much oxygen, so will cause power loss. This is why you see so many cold air intakes with the cone stuck somewhere it can pull in fresh air.

That's the only reason I can see for a cone causing a loss of power, but like I said, I'm new to this car, so maybe someone else has a better answer.
 
cool mikey

My setup looks identical to this:

47b3db24b3127cce97c6dad2d1a10000001610
 
another thing......

why would it make a difference between the short ram and cold air if the turbo is intercooled?
 
I tried the same thing. Mine looked pretty close to yours and I had the same problem. Its gotta be the heat. Also just like you said the valve got louder. My suggestion in to just wait till a company makes one. Or reroute it through the hole next to your waterbottle and move the bottle. Oh, about your valve quetsion, I personally have a Turbo XS recirculation valve. It doesnt make any noise but it did stop my stalling problem
 
hey u right alldat,

I had an AEM cold air on my previous car 2000 Civic Si (until it got stolen).
And the sound was great all the way through the RPM range, but especially when VTEC kicked in.

The reason MSP doesnt make this sound is because the intake does not go directly to the engine, it goes to turbo first. And if you look on your intake pipes (all of them), they have "ribbed" sections - that's to bring the noise level down.

Hey question?
does the Turbo XS recirculation valve recirculate air back to the intake?
 
and how much was the XS valve? installation?
did you have to make any mods in the engine bay?
 
there are hybrid blowoff valves out there. ones that recirculate and vent to atmosphere.
 
The intercooler on the Mazdaspeed is pretty tiny. Many will say too tiny. So it has a limited capacity to cool down the air. If the air going into a turbocharger is 10 degrees cooler, hopefully the compressed air will also be a few degrees cooler before entering the intercooler. We want as cold as possible. When I was part of the VW 1.8T world I read of people with intercooler misting kits that would spray water, or alcohol, or in some cases even Nitrous on the intercooler to make the charge air even colder before it hit the cylinder's. So basically, whatever you can do to fight heat is good thing.

A lot of people are looking into Front Mount InterCoolers for our car, but I think that will turn out bad. Without serious engine mods, our cars are only going to push about 10psi reliably, that is too little boost to make an FMIC feasible. It'll be so big that it's negative effect on lag and pressure drop will outweigh the benefit of the cooler air it provides.
 
MikeyG_U2 said:
The intercooler on the Mazdaspeed is pretty tiny. Many will say too tiny. So it has a limited capacity to cool down the air. If the air going into a turbocharger is 10 degrees cooler, hopefully the compressed air will also be a few degrees cooler before entering the intercooler. We want as cold as possible. When I was part of the VW 1.8T world I read of people with intercooler misting kits that would spray water, or alcohol, or in some cases even Nitrous on the intercooler to make the charge air even colder before it hit the cylinder's. So basically, whatever you can do to fight heat is good thing.

A lot of people are looking into Front Mount InterCoolers for our car, but I think that will turn out bad. Without serious engine mods, our cars are only going to push about 10psi reliably, that is too little boost to make an FMIC feasible. It'll be so big that it's negative effect on lag and pressure drop will outweigh the benefit of the cooler air it provides.
Click to expand...
Very well said and thought of.
 
Any progress on this matter Dr. Sound? I was planning to do the very same cone set-up you showed before but I now have my concerns.

You would have gotten more help if your post didn't start off being BOV/Bypass valve related which people are burnt out on.

Your cone filter issue is an interesting one and I MUST KNOW MORE!
 
Dr sound
My valve does go back into the intake, and as far as mods to engine go. I had the change the hoses from the factory bypasss valve and use bigger hoses. it was really simple. if u have any basic knowledge of cars u can do it. Like I said before it doesnt make any noise but the fact that it stop stalling pays for itself. I supposedly got it on sale for 169$.

Heather, the make shift intake isnt worth it, believe me. It takes power away and worst of all, DOESNT MAKE ANY NOISE. what for the real DEAL!!!!!!!!
 
ok heathen, check it out.....

This matter of the intake has been pissing me off for the past week.

I got the intake 2 weeks ago, drove with it for a week.......didnt like the performance. Put the stock one back in last week.......performance went back up.

Now i'm thinking.......something's wrong here.

I was supposed to study for my final today, but spent half the day trying to figure this thing out.

I think i did!

1st, the freaking intercooler (i love my car) is mounted sideways (not on the bottom like let's say Lancer Evo). The fen of the intercooler is 4 inches away from the intake - so ofcourse out of the whole ammount of air the intake suck in 2/3 come from the HOT-ASS intercooler.

This can be easily avoided with a shield. I actually tried it with some soft plastic and IT WORKED !!! for about 20 minutes until the plastic got warped (it was fucken 95 today in LA). So i think tomorrow i'll go hunting for a better material.

2nd, i think this only applies to me (but who knows). Gas milage and power went down with the install of the intake. Taking heat problem out of consideration......

I was shifting too soon. Pushing the car to hard on low RPM's. Reason being is that the sound of the turbo spooling got 20 times louder with new intake. Instead of listening for the engine to shift, i was going by the tubo sound (mind you this is my first turbo car). This time, when shifting, i was actually looking at the dash - WAY BETTER!

Power came back like with the stock box, i think even more. And the sound is great - SCREW YOU GTI's MY TURBO SOUNDS BETTER!

Mean-ass sound.

I'll post on the gas milage in couple of days.
 
Thanks Dr. Sound! I have noticed that several people with larger cone filters have had to use makeshift heat shields around the portion of the cone towards the intercooler and engine block. Because a larger cone (or an extension arm in your case) puts the filter too close to "hot zones" you must find a way to shield hot air unlike MSP's with just a K&N. This is very good to know and I will look into ways to shield hot air when I undertake this project. Thanks again Dr. Sound! Good luck on your final(thumb)
 
I drove the car for about 4 days and noticed that the power went down......

also the gas milage droped, but i think this happened because of power loss............. i was trying to squize out more.

the sound (ithink of the bypass valve) became about 10 times louder.
I sounded like FFFRRRRRRRR every time i let go off gas to shift.
I didnt mind the sound - I liked it.........

The problem was with dramatic power loss........

BTW i did unplug the battery for about 15 min so that the computer can reset to count for increased airflow. DIDNT HELP.

Now i drive with a stock airbox - power's back, pick up is way better.

OK..........question is...........
Did all this happen because the stock bypass valve is too small to handle increased airflow??? [/B]
Click to expand...

well just out of curiocity, most of the BOV iv'e been exposed to are all adjustable, Meaning you can stiffin the spring inside you cause boost to spool up for longer period of time, increasing the power or pull if you will. the loss may be do to incorrect setting of this feature. short of pacesetter headers on a vehicle you should almost always see some type of gain wether it be by ass dyno, or a real dyno. the benefit may not always be across the power band either. just my .02$
 
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