I an HKS b.o.v. on my mr2 and when it blows off it smells like fuel n stuff. I guess thats normal? Its starting to bother me and especially when I have a passenger..I guess I'll just reroute it back to the intake or put the stock one back on..All that stuff that it blows off I know for a fact is bad for your health. Do you guys get that smell??
All that blows off is the air in your intake ... which is just air from outside.
I agree it is bad for your health, but I assure you it is much worse not having air to breathe
Seriously, you should not have a "smell" from your BOV. It is just outside air.
I'm not sure what you are smelling, but I doubt it is coming from your BOV.
i have oil coming out of the bov...but it doesn't smell at all....it's just a small amount of oil..well..i never actually tried smelling it..but never smelled anything when im driving...
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What Can it be? B/c everytime I blow off it smell like gas. I wonder now??..When I had the stock by-pass valve I never had the smell. What else can it be? I have to get it checked out by my local shop.
Aftermarkets valves that "blow off" to atmosphere are getting rid of air that has already been measured by the AFM. The ECU has already sent the correct amount of fuel to blow up that air. However, you blew that air off ... so now your mixture is VERY rich (too much fuel, not enough air). So it makes sense that you are smelling because you are not burning it all.
Aftermarket valves rob performance. The OEM valve is the best performance you can have.
turbo_GT, if you are getting oil out of your valve it can be from only one of two placeS:
1. Turbo seals are goign and yo uare blowing oil through
2. Your PCV is having some oil blow through (not unusual on an older engine).
if oil is comming out of the bov, there might be oil in the intercooler pipes and the intercooler it self. Try getting gasoline, paint thinner. put it in the intercooler and clean it out and wait unit it drys up. thats why people get oil catch cans for.
turbo_GT, if you are getting oil out of your valve it can be from only one of two placeS:
1. Turbo seals are goign and yo uare blowing oil through
2. Your PCV is having some oil blow through (not unusual on an older engine).
there's not too much oil....not at all....i have the bov right next to the turbo so that's probably the reason....
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Aftermarkets valves that "blow off" to atmosphere are getting rid of air that has already been measured by the AFM. The ECU has already sent the correct amount of fuel to blow up that air. However, you blew that air off ... so now your mixture is VERY rich (too much fuel, not enough air). So it makes sense that you are smelling because you are not burning it all.
Aftermarket valves rob performance. The OEM valve is the best performance you can have.
Actually, this is not entirely true. While the blown off air is causing the rich condition, it is still something that can easily be overcome, if you have the money to spend on it. For roughly $300 you can buy A'pexi's SAFC or SAFC II, both of which have a built in function designed to compensate for an open atmosphere BOV. This device is used to tune the fuel curve throughout the rpm band (like 8 or 10 rpm points, fully adjustable) in increments of + or - 50%. It intercepts the MAF signal for adjustable modification.
While you won't really need to adjust the fuel curve (unless you have a wideband O2 setup with data logging and know how to tune...and have a dyno), you could incorporate the open atmosphere BOV function.
Why bother with all this when you could re-use the OEM BOV?
Well, the OEM BOV is NOT the best performance BOV setup. Why? Well, the air being blown off is recirculated into the intake system, to be re-used. When air is compressed, it generates heat. Heated air contains less oxygen content. Now, you have heated low oxygen air going through the compressor to once again be compressed and heated, thus resulting in higher intake temperatures, lower performance and more opportunity for detonation under heavy load/high boost.
Open atmosphere BOV setups allow that heated, low oxygen air to be purged, resulting in fresh air into the compressor, ultimately lowering intake temps and reducing the above described negative attributes.
I have seen this proven time and time again on the Nissan 240sx, which is my other project car. While the two engines used in the 240sx (JDM SR20DET 2.0L turbo, USA KA24DE 2.4L add-a-turbo) are entirely different from the 3sgte, the concept is still the same. I see KA24DE engines (the add-a-turbo US engine) that are cranking out 350-380whp on only 15psi with this setup. I see the 2.0L JDM engine (SR20DET) cranking out 350whp on 17-19psi using this setup. I see 3sgte cranking 350whp on 22psi. using the stock BOV.
That's just my 2 cents, but do whatever you wanna do.
Last edited by jackcannibal; 12-26-2004 at 09:22 PM.
And where do you suppose the oxygen went that was present before it was heated?
As for recirculating "heated air" into the compressor, it is never going to get hotter than when it was compressed, so recompressing it will not increase its temperature. That has been shown plenty of time on MR2s that montior air intake temps.
Regardless, this is all happening pre-intercooler.
Lastly, if you really want to evaluate valve design, you can throw out 99% of aftermarket valves because they a re primarily based on a spring which will never respond as fast or as accurately as the OEM valve (based primarily on air pressure differentials).
Make this easy:
All you want/need from a BOV/BPV is fast response when you need it and the ability to stay closed under pressure.
Only one variation of the HKS valve will perform as fast as the OEM MR2 valve and hold any level of boost pressure equally.
As I stated before, I know we're not talking 240's. Thanks for the observation.
As the heated air enters the air boot pre-compressor, it cannot all travel through the compressor again, since it's compressed and air travels from high to low pressure. Guess where it goes....outward toward the MAF...thus you have less mass in the intake system. So, a 3" pipe with cold air has a higher oxygen content because there is MORE MASS. Furthermore, the intercooler can only cool so much. Are you saying that cooling the air pre-intercooler wouldn't help lower manifold air temp? I don't see it.
Anyhow, dude, just do whatever you want or whichever is cheapest. I see 2.0L and 2.4L engines making 400+ whp with stand alone ECU's and still utilizing the SAFC for open atmosphere BOV setups. These don't need to be running crazy boost psi to accomplish high numbers, either. But, I don't know what I'm talking about.
1. The MAF "door" would be closed. I assure you the air is not leaving there.
2. Even if the MAF door was open, the air would be sucked into the Idle Control Valve hose (between the AFM and the Compressor) which is where the car gets air at idle.
3. "So, a 3" pipe with cold air has a higher oxygen content because there is MORE MASS" ... although this is true, after you start boosting again the air would be compressed to the same psi ~ so you have the same volumn of air at a temperature equal to what it was leaving the compressor housing.
4. "Are you saying that cooling the air pre-intercooler wouldn't help lower manifold air temp?" I am not saying that. I am saying that whether you are using "blown off air" or "ambient air" the temperature coming out of the hot turbine is not going to significantly different. The problem with the words I quoted here is you refer to "cooling" pre-intercooler and there is no cooling going on in the scenario you described.
5. Why on Earth would anyone use the SAFC with a "standalone ECU" ????? The SAFC is a piggyback system to the OEM ECU. The whole point of going to a stand alone is so you can accurately control your combustion ... why would you want to use something as limiting as the SAFC with a Standalone.
6. If you are using a standalone, you are most likely NOT on the AFM any more since most of those systems work on a speed density system, not a AFM/MAF system.
If you know people using a AFM/MAF & SAFC with their stand alone, you know some pretty screwy people.
Well, there are so many ways to skin a cat, and this post isn't the post where you and I do knowledge combat. I'm ready to get this guy's car running right for him. As far as the stand alone units and SAFC, they just use the SAFC on cheaper setups solely for the open air BOV control. And yes, I know some REALLY screwy people.
But I did have an idea to run past you, Hyde. Say someone is dead set on using an open atmosphere BOV. What do you think about a blow-thru MAF setup? I've never used one, so I don't know. Then again, there's not really a whole lot of room in the engine bay for that on an MR2...so nevermind. Oh, I'm not currently using a stand alone myself, so my stand alone knowledge is limited. I should retract some of my comments. Sorry bout that.
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