On the dp/rp issue, see my sig. You can run either a catted or catless (me) dp/rp 3 inch combo into the stock CBE. It will make serious power. I am catless and do not have boost creep and get excellent flow through with the Mazdaspeed CAI on the intake side and this setup on the exhaust side. But some do see creep unless they have some slight restriction below the downpipe either with the stock midpipe's cat, or with a high flow catted midpipe.
If you are in a state where you do not have to be tested, consider running catless. If you do have boost creep, you will probably put your catted midpipe back on and solve that. If you dislike the drone that the big dp/rp will introduce at around 2,500 rpm, you can cut your aftermarket rp and weld a good reso (see sig again) into the rp section. That will tame the drone and bring the total volume of the now much louder exhaust down a notch while still letting it be very healthy sounding compared to the stock system. And it will not measurably affect power. That big high flow straight through reso may provide just enough of a slight reduction in flow to explain why I do not see any boost creep.
Another thing. On the gen 2 car, you have a rinky dinky boost gauge that only goes to +1 bar, if I recall. That is only 14.7 psi. A downpipe and racepipe upgrade will raise your boost about 2 psi above stock due to better flow. You need a good aftermarket boost gauge. I mean you REALLY need a boost gauge that will read higher. I prefer a true vacuum/boost actuated fully manual gauge. Some kind of aftermarket boost gauge that goes up to about 25 psi the only way you will know what is going on and the only way you will be able to tell if you boost is creeping above 17-18 psi under load in the higher gears. Momentary spikes are not a problem and are to be expected on stock tune, provide they immediately settle to no more than 17-18and hold without rising further as rpm increases.
And yes, stick with the stock BPV to begin with. I can't make mine leak at now 37,000 hard miles. You will notice that it is a good bit louder after you upgrade your intake, and for gosh sakes, this engine hates VTA setups. Just don't do that. It will not make more power and will hurt performance and drivability. You are just farting already metered air to atmosphere when the engine has already calculated the fuel load and fired it into the engine through the injectors. Forgive me for saying it, but VTA is for "looky, lookey, look at me" ricers and I'm sure you are not interested in that profile. Spend your money on things that work and benefit your performance.
On intake models, any good SRI or CAI. Many of us are happy with the AEM or Mazdaspeed CAI (they are the same since Mazda rebrands the AEM). If either is available for the Gen 2 give them a strong consideration. They can be configured to run either CAI or SRI mode. They cost a bit more, but quality of construction, "get it right the first time" manufacturing, and adaptability are outstanding. Without starting a war on CAI v. SRI, I just prefer getting ambient air from the wheelwell rather than hot air from under the hood, so I mostly run in full CAI mode.
Oh, and guys making recommendations: Remember he has a Gen 2 car.
If you are in a state where you do not have to be tested, consider running catless. If you do have boost creep, you will probably put your catted midpipe back on and solve that. If you dislike the drone that the big dp/rp will introduce at around 2,500 rpm, you can cut your aftermarket rp and weld a good reso (see sig again) into the rp section. That will tame the drone and bring the total volume of the now much louder exhaust down a notch while still letting it be very healthy sounding compared to the stock system. And it will not measurably affect power. That big high flow straight through reso may provide just enough of a slight reduction in flow to explain why I do not see any boost creep.
Another thing. On the gen 2 car, you have a rinky dinky boost gauge that only goes to +1 bar, if I recall. That is only 14.7 psi. A downpipe and racepipe upgrade will raise your boost about 2 psi above stock due to better flow. You need a good aftermarket boost gauge. I mean you REALLY need a boost gauge that will read higher. I prefer a true vacuum/boost actuated fully manual gauge. Some kind of aftermarket boost gauge that goes up to about 25 psi the only way you will know what is going on and the only way you will be able to tell if you boost is creeping above 17-18 psi under load in the higher gears. Momentary spikes are not a problem and are to be expected on stock tune, provide they immediately settle to no more than 17-18and hold without rising further as rpm increases.
And yes, stick with the stock BPV to begin with. I can't make mine leak at now 37,000 hard miles. You will notice that it is a good bit louder after you upgrade your intake, and for gosh sakes, this engine hates VTA setups. Just don't do that. It will not make more power and will hurt performance and drivability. You are just farting already metered air to atmosphere when the engine has already calculated the fuel load and fired it into the engine through the injectors. Forgive me for saying it, but VTA is for "looky, lookey, look at me" ricers and I'm sure you are not interested in that profile. Spend your money on things that work and benefit your performance.
On intake models, any good SRI or CAI. Many of us are happy with the AEM or Mazdaspeed CAI (they are the same since Mazda rebrands the AEM). If either is available for the Gen 2 give them a strong consideration. They can be configured to run either CAI or SRI mode. They cost a bit more, but quality of construction, "get it right the first time" manufacturing, and adaptability are outstanding. Without starting a war on CAI v. SRI, I just prefer getting ambient air from the wheelwell rather than hot air from under the hood, so I mostly run in full CAI mode.
Oh, and guys making recommendations: Remember he has a Gen 2 car.
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