elderlycoffee
Member
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- 2007 Sunlight Silver mazdaspeed 3
better to vent or recirc?
Well?
Well?
Bov Faq
- Thread starter AAMguy
- Start date
elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
why is recirc better?
elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
so what does a noob like me need to do to keep from having these problems everyone speaks of?
I think it is explained in detail at the beginning of this "sticky."
To recap, think about it this way:
Your ECU receives input from the MAF sensor which is located just behind your air filter and way ahead of the point where your BPV would inject air back into the intake.
Your ECU relies on the MAF sensor to tell it the amount of air mass the intake is receiving so it can then match this exact amount of measured air mass with the proper amount of fuel for optimal performance.
If you then fart into the air part of that already measured air mass after your ECU has calculated the amount of fuel needed, that fuel is still being sent into the combustion chamber expecting to be matched with ALL of the metered air, not merely part of it.
This results in a mis-match and an improper richening of the air to fuel ratio.
At a minumum this usually causes rough idling, poor light throttle performance and other adverse effects on the smoothness of engine performance.
The ECU will yo-yo back and forth trying to make adjustments which it cannot make for the constantly changing mis-match conditions which come and go as you vary driving and shifting. Many believe this results in the ECU eventually adjusting and detuning itself. There are some on this board who have been to dyno days and seen cars with similar mods dynoed back to back and noticed that the VTA cars are dynoing lower for no other apparant reason than running VTA.
To say that running 50-50 solves the problem is to misunderstand what is happening. It may help in restoring some of the lost smoothness, but just remember that the air being farted outside the car in ANY amount was air that had already been metered and for which fuel has been calculated by the ECU and shot into the combustion chamber by our direct injection system, expecting to find matching air there which got diverted to the outside where it cannot provide the oxygen to that fuel to make the power the fuel is capable of making.
This car was designed to run in full recirc. The location of our MAF means that air lost behind the MAF to VTA in ANY amount results in air to fuel mismatch.
As pointed out by others, there is no way to correctly tune around this. All attempts are just guesswork and estimates.
The only way to run any degree of VTA and keep the AFR's the way the ECU is expecting to produce them based on the air mass info from the MAF sensor would be to relocate the MAF sensor to a position closer to the intake manifold and behind the point where the blow off valve is discharging air. This would be fully pressurized boosted air flowing through the sensor. it's called having a blow through MAF. If you can't do that (and it ain't easy), then for gosh sakes, run the thing full recirc. Not VTA, not 50-50, not 90-10, not 99-1. Full recirc. Use any BPV or BOV you like, just hook up that hose and run it full recirc. Period.
Run full recirc. Period. BTW: unless you can prove that your stock BPV is leaking, just use what you have. If it ain't broke, don't fix it. If you are having trouble with an aftermarket valve, put the stocker back on. Problem solved. There are some pretty knowledgeable guys here that have put a lot of development time into modding this engine for performance who have concluded that the stock BPV is the best BPV for performance on this engine. I'm not that smart or knowledgeable, but I've been around a while, learned a few things, sometimes the hard way, and happen to agree with them. Mazda's stock BPV works very well if it is performance you are looking for.
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elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
nvm ;-)
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7
79535
You have to buy a recirc fitting. You then undo the hex screws around the BOV fitting and swap them out.
I'm sure some vendors on the forum have them available. Street Unit, CP-E and other companies have them.
I'm sure some vendors on the forum have them available. Street Unit, CP-E and other companies have them.
elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
To keep the outlet from breaking on the hood of my car I've got my HKS turned sideways which puts a kink in the inlet. Is this going to damper my performance?
I've already had to rehose twice because it was facing up and it blew because the hood was crushing it.
I've already had to rehose twice because it was facing up and it blew because the hood was crushing it.
Yes, it will adversely affect performance for all the reasons stated above. Even if you do get it properly hooked up to run pure VTA, it sounds like you will have a fitment issue. Why not just put the stock BPV back on and enjoy its excellent performance?
I can't cross link to another forum under our rules. I can cut and paste a post from another Mazda forum with "speed" in its name from Fordza 1 (also a member here), whose opinions I greatly respect on this subject:
________________________________________________________
"My results prove to me that the OEM BPV is the BEST for PERFORMANCE and price(free?), but doesn't stick closed long enough at throttle close to make the big whoosh sounds so many seem to want..."
"I'm running (over 2 years & 20k miles) a highly bolted car with my own ECU tune first via Xede piggyback EMS and more recently via ATR ECU reflash and the OEM BPV (still) works perfectly at 20+psi. I've run several aftermarket BPVs and NONE work as well as the stock BPV. In fact, I think the cheezy aftermarket BPVs may be a contributor to early turbo seal failures(smoking...) due to the shock of the pressure spikes at throttle close when shifting at high boost levels. The big pressure hit bounces the compressor wheel against the thrust bearing which MAY contribute to the oil leakage into the intake manifold/intercooler, etc." Fordza 1.
________________________________________________________
I'm not saying the HKS is cheap or cheezy. It's not. But it's just not a good choice for our application's location or for our need to run full recirc, or as anything which would improve performance over the stock BPV.
Switch back, fix your hoses and enjoy excellent performance, IMHO.
I can't cross link to another forum under our rules. I can cut and paste a post from another Mazda forum with "speed" in its name from Fordza 1 (also a member here), whose opinions I greatly respect on this subject:
________________________________________________________
"My results prove to me that the OEM BPV is the BEST for PERFORMANCE and price(free?), but doesn't stick closed long enough at throttle close to make the big whoosh sounds so many seem to want..."
"I'm running (over 2 years & 20k miles) a highly bolted car with my own ECU tune first via Xede piggyback EMS and more recently via ATR ECU reflash and the OEM BPV (still) works perfectly at 20+psi. I've run several aftermarket BPVs and NONE work as well as the stock BPV. In fact, I think the cheezy aftermarket BPVs may be a contributor to early turbo seal failures(smoking...) due to the shock of the pressure spikes at throttle close when shifting at high boost levels. The big pressure hit bounces the compressor wheel against the thrust bearing which MAY contribute to the oil leakage into the intake manifold/intercooler, etc." Fordza 1.
________________________________________________________
I'm not saying the HKS is cheap or cheezy. It's not. But it's just not a good choice for our application's location or for our need to run full recirc, or as anything which would improve performance over the stock BPV.
Switch back, fix your hoses and enjoy excellent performance, IMHO.
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elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
I already cut the big hose to fit. I'd love to be able to make the hks work.
I guess y best bet is to get a new hose? What size is the bigger hose?
I haven't measured it. I did recall that one vendor selling the HKS valve and trying to make it work in recirc on one of their test MS3 vehicles suggested this:
"Because the new valve changes the positioning of the fitting, modification to the stock rubber recirculation hose is necessary, but that isn't anything that a trip to Home Depot can't fix. I used a small length of copper piping and some hose clamps to extend the recirculation hose into the proper position." This means you cut the hose, insert some copper pipe the right diameter in the middle with hose clamps and bend the pipe as needed. Take the hose with you to Home Depot (or other similar place) so you are getting a tight fit. Seems like a lot of trouble to me just to use that valve.
I still say, with respect, that you are sort of trying to fit a square peg in a round hole. The HKS valve is designed for very high boost aggressive driving in which large amounts of highly boosted air need to be rapidly discharged from big turbos. It will be slow to respond under low power, light throttle situations, even when run full recirc.
"Because the new valve changes the positioning of the fitting, modification to the stock rubber recirculation hose is necessary, but that isn't anything that a trip to Home Depot can't fix. I used a small length of copper piping and some hose clamps to extend the recirculation hose into the proper position." This means you cut the hose, insert some copper pipe the right diameter in the middle with hose clamps and bend the pipe as needed. Take the hose with you to Home Depot (or other similar place) so you are getting a tight fit. Seems like a lot of trouble to me just to use that valve.
I still say, with respect, that you are sort of trying to fit a square peg in a round hole. The HKS valve is designed for very high boost aggressive driving in which large amounts of highly boosted air need to be rapidly discharged from big turbos. It will be slow to respond under low power, light throttle situations, even when run full recirc.
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elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
Well I see what you're saying... But respectfully, I already have the bov. It's not like I'm still in the shopping stage and I already cut the stock hose into the bov so it won't make it to the stock bpv anymore.
So thats my situation. Everything is working for now, Except the outlet nipple of the HKS is bent now from hitting my hood and there is a kink in the large hose.
elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
It was and would have been helpful except I am already in ownership of the BOV and it was purchased use from a person not a store I can send it back to.
7
79535
What I did when I was running my HKS was cut about 1.5" off the stock hose. It worked just fine. It straightened the hose up and I had no issues.
The only issue that I had was with the location of the BOV itself. It rubbed my hood to the day I uninstalled it. The only issue I had from it rubbing, was the paint came off the valve.
The only issue that I had was with the location of the BOV itself. It rubbed my hood to the day I uninstalled it. The only issue I had from it rubbing, was the paint came off the valve.
- :
- 06 LS MS6
07 BM GT (shell has been struck from the roll)
sell valve to someone else, buy a relpacement hose, call it a life lesson.
and move on
elderlycoffee
Member
- :
- 2007 Sunlight Silver mazdaspeed 3
What should I plug the hose with if I try it in VTA?
