Ever been done?
06-23-2006, 01:59 PM
#1
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Location: Central FL
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Ever been done?
I am wanting to reduce some of the lag before my S/C builds boost. I have an idea and I just want to know if this is a bad idea, or if I might be onto something. I am thinking of installing a smaller pulley so that my S/C would make more boost earlier, but then using an adjustable BYpass valve to recirculate the air once the boost reaches 10psi, therefore my engine would never see more than 10psi of boost, but I could potentially reach 10psi around 4K rpms. I know this would cause added stress to the S/C but other than that what are some other draw-backs? Lets toss some ideas around, I will be willing to be the guinea pig if we come up with a viable solution.
06-23-2006, 02:23 PM
#2
Retired MF Moderator
Join Date: Aug 2004
Posts: 14,891
RE: Ever been done?
you could put a smaller pulley on and it will build faster, but it's not going to really change the time it takes to start building it. i started building boost at 3k rpm with the stock one and the 10psi pulley. it pulled a lot harder through the whole power band though. 
06-23-2006, 02:25 PM
#3
I ♥ Acer
Join Date: Mar 2006
Location: Concord, NC
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RE: Ever been done?
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
06-23-2006, 02:29 PM
#4
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RE: Ever been done?
one way to doit is to make a third bypass line without a valve, so it would bleed off some of your boost. though i think this might defeat the whole purpose of trying to reduce the boost lag. other than that all i can think of is splicing in a pressure sensitive valve into the bypass vac line.
06-23-2006, 03:01 PM
#6
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RE: Ever been done?
ORIGINAL: 1QuickShortBus
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
ORIGINAL: mustang_montana
one way to doit is to make a third bypass line without a valve, so it would bleed off some of your boost. though i think this might defeat the whole purpose of trying to reduce the boost lag. other than that all i can think of is splicing in a pressure sensitive valve into the bypass vac line.
one way to doit is to make a third bypass line without a valve, so it would bleed off some of your boost. though i think this might defeat the whole purpose of trying to reduce the boost lag. other than that all i can think of is splicing in a pressure sensitive valve into the bypass vac line.
Nanaki I am currently using a 3.60 pulley and I still hit 10psi at 6k rpms, I hit 12 at 6500rpms, your saying the S/C will take the same amount of time to spool up regardless of the pulley size? It will just create more boost faster once it does spool? Kind of defeats the whole purpose of this experiment if that is true.
06-23-2006, 03:14 PM
#8
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RE: Ever been done?
ORIGINAL: blackbetty01
I have a Vortech S/C not a turbo but I appreciate the advice.
I am more less geared toward switching out my whole configuration for a BOV, since BOV's can be adjusted to open when you reach a certain level of boost, in this case 10psi.
Nanaki I am currently using a 3.60 pulley and I still hit 10psi at 6k rpms, I hit 12 at 6500rpms, your saying the S/C will take the same amount of time to spool up regardless of the pulley size? It will just create more boost faster once it does spool? Kind of defeats the whole purpose of this experiment if that is true.
ORIGINAL: 1QuickShortBus
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
ORIGINAL: mustang_montana
one way to doit is to make a third bypass line without a valve, so it would bleed off some of your boost. though i think this might defeat the whole purpose of trying to reduce the boost lag. other than that all i can think of is splicing in a pressure sensitive valve into the bypass vac line.
one way to doit is to make a third bypass line without a valve, so it would bleed off some of your boost. though i think this might defeat the whole purpose of trying to reduce the boost lag. other than that all i can think of is splicing in a pressure sensitive valve into the bypass vac line.
Nanaki I am currently using a 3.60 pulley and I still hit 10psi at 6k rpms, I hit 12 at 6500rpms, your saying the S/C will take the same amount of time to spool up regardless of the pulley size? It will just create more boost faster once it does spool? Kind of defeats the whole purpose of this experiment if that is true.
06-23-2006, 03:47 PM
#9
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Join Date: Mar 2006
Location: Concord, NC
Posts: 1,278
RE: Ever been done?
ORIGINAL: blackbetty01
I have a Vortech S/C not a turbo but I appreciate the advice.
ORIGINAL: 1QuickShortBus
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
Do you have a blow through or draw through MAF? If it's blow through, just dump the excess no need to recirculate the air (as it will be getting very hot recirculating). If it's draw through, you may want to consider changing to a blow through.
It would probably be best to use a waste gate as they are designed to modulate pressure although they normally go on the exhaust side of a turbo to modulate the amount of air going through the turbo. The nice thing with a wastegate is you could keep say a 10lb spring in it and then have a boost controller so that you could turn the boost up some at the track.
BOV are only designed to release pressure when the throttle body is closed to prevent compressor surge, they aren't adjustable to control a set level of boost.
A BOV or bypass valve is operated by vacuum and opens only when vacuum is present (when the throttle is closed). They are not a means to regulate boost, only bleed off pressure when the throttle is closed to prevent compressor surge.
However, a wastegate is used in the exhaust to route exhaust gas past the turbine wheel in a turbo to keep the turbo from spinning faster and making more boost. This same principal could be used on the discharge side of a S/C, with a vacuum line hooked to the wastegate when pressure exceeds the pre-determined boost level the wastegate would open. This would vent excess boost pressure and allow you to regulate boost.
If you can show me a BOV that will do this I will be interested but that is not how they are designed.
06-23-2006, 04:05 PM
#10
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Join Date: Nov 2005
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RE: Ever been done?
Sorry, I misuderstood you, I am just now starting to learn about turbos and when you talk about a wastegate I immediately think turbo. Adjustable BOV check it out, maybe I am just interpreting it wrong but I was talking to a gu with an SVO and he said that is what he used and he said it is adjustable and easy to use. You are just adjusting the spring rate. Let me know if I am making sense still.