questions about the types of motors?

[97gstnick]

i've noticed you guys mentioning 6 bolts or 4 bolts or something like that, correct me if im wrong. but what is it that you are talking about? what bolts? location? and also about the blow off valve venting, i have noticed like everyone else that my car has problems building boost and idling when i take the dump tube off. but none of you guys have explained why, alot have said that its because the ecu doesnt detect that air recirculating back in, but that is not the cause. and i back this up from trying it. the reason it has problems is because the blow off valve like to stay open alot thus creating a vacuum. everytime you build boost and let off, the air pressure is released and continues to follow that path through the bov, causing the engine to choke. i was wonderin why it kept doing that until i started thinkin about physics. so i put a piece of duct tape over the opening of the blow off valve and punched a hole in it about the diameter of an index finger. it worked so much better because it caused greater back pressure and mostly eliminated the vacuum effect. i know you guys would say that it is not good for the turbo, but i saw no problems other than the hole rippin open more and more as i drove, than creating the cycle over again. i did that for experimenting, because, like many other people i like experimenting. but i do also add that i dont go crazy with it. i very much like advice and opinions. with that said....is it true that the greddy type s bov does not need to be recirculated? thanx

 

[kpt4321]

Originally posted by 97gstnick
i've noticed you guys mentioning 6 bolts or 4 bolts or something like that, correct me if im wrong. but what is it that you are talking about? what bolts? location?

6 bolt and 7 bolt. The two different variations of motors, which have different amounts of bolts holding the flywheel to the crank.

4 bolt and 3 bolt describes the two different rear ends.

and also about the blow off valve venting, i have noticed like everyone else that my car has problems building boost and idling when i take the dump tube off. but none of you guys have explained why, alot have said that its because the ecu doesnt detect that air recirculating back in, but that is not the cause. and i back this up from trying it. the reason it has problems is because the blow off valve like to stay open alot thus creating a vacuum. everytime you build boost and let off, the air pressure is released and continues to follow that path through the bov, causing the engine to choke. i was wonderin why it kept doing that until i started thinkin about physics. so i put a piece of duct tape over the opening of the blow off valve and punched a hole in it about the diameter of an index finger. it worked so much better because it caused greater back pressure and mostly eliminated the vacuum effect. i know you guys would say that it is not good for the turbo, but i saw no problems other than the hole rippin open more and more as i drove, than creating the cycle over again. i did that for experimenting, because, like many other people i like experimenting. but i do also add that i dont go crazy with it. i very much like advice and opinions. with that said....is it true that the greddy type s bov does not need to be recirculated? thanx

I'm not sure what all of this means. The reason the car runs terribly with the BOV vented, is because it's a big boost/vacuum leak. Whenever the BOV opens (at idle, part throttle, or on a shift) there is a bigass hole after the MAF that is either letting air in or out. Because of this, the MAF is not counting the proper amount of air entering the motor, and therefore cannot inject the correct amount of fuel.

It's not because the BOV opens and no air goes into the motor.

You need to recirculate any BOV that is used with a stock MAF. If you set the tension really tight, then it will not be as bad as the stock BOV, but it still isn't as good as it could be.

 

[nine5raptor]

Originally posted by 97gstnick
[B i know you guys would say that it is not good for the turbo, [/B]

If you do not have enough flow through the bov, the pressure wave coming back from the throttle body will continue on past it and slam right into your compressor and attempt to turn the turbo backwards. Not good.

 

[talon1979]

Originally posted by 97gstnick
i have noticed like everyone else that my car has problems building boost and idling when i take the dump tube off. but none of you guys have explained why, alot have said that its because the ecu doesnt detect that air recirculating back in, but that is not the cause. and i back this up from trying it. the reason it has problems is because the blow off valve like to stay open alot thus creating a vacuum. everytime you build boost and let off, the air pressure is released and continues to follow that path through the bov, causing the engine to choke. i was wonderin why it kept doing that until i started thinkin about physics. so i put a piece of duct tape over the opening of the blow off valve and punched a hole in it about the diameter of an index finger. it worked so much better because it caused greater back pressure and mostly eliminated the vacuum effect. i know you guys would say that it is not good for the turbo, but i saw no problems other than the hole rippin open more and more as i drove, than creating the cycle over again. i did that for experimenting, because, like many other people i like experimenting. but i do also add that i dont go crazy with it. i very much like advice and opinions. with that said....is it true that the greddy type s bov does not need to be recirculated? thanx [/B]

Let me see if I can clarify things a little more for you. The ECU doesn't detect the air that is coming back in, it simply counts on air to come back in and therefore it adds fuel. If you do not have it connected you will run rich when it should blow off and the car may backfire or stumble when you try to get going again.

The BOV should not open and work as a source of vacuum. If it does then your bov is probably bad. The only time air should come out of your bov is when the throttle body closes such as when you are shifting or let off the gas. When air passes through the bov through times like this that airl goes back into the intake and helps to spool the turbo.

Covering your BOV w/ tape is an extremely bad thing. The whole purpose of the BOV is to keep your turbo from experiencing compressure surge. Someone already talked about it, but let me go into a little more depth. Compressure surge is when the air bounces off of the throttle body when closed then bounces off of the compressor side of the turbo suddenly causing the blades to stop. This sudden stop of the blades/fins is extremely bad for the turbo and will cause premature failure. You probably noticed the sound the BOV made was sort of a studdering sound. This is an extremely bad thing.

The only reason a Greddy type S may not need to be recirculated is because it does not leak like a stock bov will. You will still encounter the same problems venting a Greddy type S to atmosphere as you will a stock BOV. The only times you can vent a BOV to atmosphere is when the mass airflow meter (such as a GM mas, or w/ a VPC) is when mass airflow meter is between the throttle body and the bov. In this case it will not notice the air that is being sucked in and then put back out by the BOV.

 

[97gstnick]

so why does everybody want a 6 bolt rather than a 7? would 7 be stronger? also...are the 1g blocks stronger? what is a very well built set up that can handle gobs of boost yet be streetable....a la supra motor. my friend has a 94 and damn...thats all i can say...damn. it can handle so much power and under stock parts...wow... well im looking to build a bottom end that is bullet proof to.... where to start...where to start? should i just go to about 350-400hp with 90,000 miles.... then build the bottom end..? and with what parts...and i mean bullet proof.....

 

[kpt4321]

Originally posted by 97gstnick
so why does everybody want a 6 bolt rather than a 7? would 7 be stronger? also...are the 1g blocks stronger? what is a very well built set up that can handle gobs of boost yet be streetable....a la supra motor. my friend has a 94 and damn...thats all i can say...damn. it can handle so much power and under stock parts...wow... well im looking to build a bottom end that is bullet proof to.... where to start...where to start? should i just go to about 350-400hp with 90,000 miles.... then build the bottom end..? and with what parts...and i mean bullet proof.....

Please do a search for 6-bolt and 7-bolt, and look at the FAQ.

In short, 6-bolts are stronger and are less susceptible to crankwalk. 7 bolts are usually not given the credit they deserve either.

You just said that a stock bottom end in your friend's car is bulletproof, what do you want to know?

 

[98autogstspyder]

someone said that you would be hearing a stuttering sound if you had compressor surge. well my bov kinda sounds like that. i have a hks super sequential bov recirculated. everytime i let off it makes that sound. whoosh whoosh whoosh. is this the normal sound for that bov to make recirculated?

to everyone that has the hks bov RECIRCULATED, what sound does it make on your car?

car has had the evo3 16g turbo on with that bov set up that way for about 4 months now. how long would it take for the compressor wheel to begin to get play in it?

Tyler

 

[talon1979]

All you need to do is adjust it and that sound should go away. I have heard the HKS both go whooosh, and chugh chugh chugh chugh. The second sound is cool to listen too, but it scares me. Even a stock BOV will do it every great once in a while if there isn't enough air to hold it open.

 

[98autogstspyder]

Yea i feel similar to you on that one. But i still not know if this sound is compressor surge. Anyone??

 

[nine5raptor]

If you want to hear compressor surge for comparison, go out and put a piece of duct tape over the bov outlet. Go out and pop the bov once (from low boost) just to hear it. If it sounds the same, take the tape back off and loosen the bov until that sound becomes more of a swoosh or sneeze sound.

Your car should sound like it has allergies.