BOV qustions - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

trans665 · 01-26-2018, 10:17 AM

I currently have a Turbonetics due 35mm blow off valve.. I've been running it to my knowledge with good effects... I looked up the specs on it since I'm redoing my whole Turbo System and they're saying it only holds up to 500 horsepower. Is that the reason why I lose boost pressure in upper RPM? I was pushing about 700 to the crank. Now they're telling me that the pressure is the same on the manifold side and the intake piping. So wont my pressure from a manifold hold the valve closed at any PSI? Long story short I need to know if I have to buy a bigger and badder bov or if the one I have right now I will work with the 800 rear wheel horsepower I want?.. also my other question is should I just buy another bov like the one I have and added to the intake pipe. Will that work? Everything with the bov is confusing me right now just like spring pressure for them sorry for the rant

dreksnot · 01-26-2018, 11:21 AM

I'm guessing here, but I think you're getting Blow-off Valve (BOV) and wastegate spring (WG) confused, as well as a few other things. That system is "rated" for 500hp. That means you could expect to get that much HP with ideal conditions and setup. It like saying the weather temperature may get up to 80*F today, but it's not there most of the day (like in Montana). Anyway, depending on if your have WG springs only or a boost controller (either manual or electric): I'm going to presume you just have WG springs. They're a constant, like 4psi, 8psi, 12psi, and so on. You can expect to get near that amount of boost with the # spring you have. My increasing spring force (pressure), that allows more boost, and more power. Caution: you need enough fuel and proper timing to account for this - just changing the spring without proper tuning can scatter your motor (highly discouraged in this establishment).

As for the boost bleed-off, that can be expected in many turbo setups, but most only see 1-2psi boost tapering off (spring and manual). Some electronic controllers account for this, and sometimes relocating the boost sensor solenoid can reduce the effect. I don't quite recall the reason why, maybe cam setup, not recalling at the moment.

trans665 · 01-26-2018, 05:48 PM

No I'm not getting them confused I know it difference between a bov and a wastegate. All bov come with pressure Springs. I am trying to get a teal Q50 blow off valve. But they're asking me what spring pressure I want that is why I'm asking all of you what that stuff means

Nick@UPPturbo · 01-26-2018, 06:10 PM

Tial sells their blow off valves in terms of spring sizes. Spring size is dictated by vacuum pulled at idle. Here is a link to their table: http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf

Hope this is helpful

dreksnot · 01-26-2018, 07:44 PM

Ah, totally missed what you were trying to say.

Stock cam: -8psi spring
Mild cam (like Stage I or II): -7psi spring
Moderate (like Stage III): -6psi spring

scv_guy · 01-26-2018, 08:55 PM

Quote:

Originally Posted by trans665

I currently have a Turbonetics due 35mm blow off valve.. I've been running it to my knowledge with good effects... I looked up the specs on it since I'm redoing my whole Turbo System and they're saying it only holds up to 500 horsepower. Is that the reason why I lose boost pressure in upper RPM? I was pushing about 700 to the crank. Now they're telling me that the pressure is the same on the manifold side and the intake piping. So wont my pressure from a manifold hold the valve closed at any PSI? Long story short I need to know if I have to buy a bigger and badder bov or if the one I have right now I will work with the 800 rear wheel horsepower I want?.. also my other question is should I just buy another bov like the one I have and added to the intake pipe. Will that work? Everything with the bov is confusing me right now just like spring pressure for them sorry for the rant

I made 750rwhp with that BOV. I didn't have any issues

trans665 · 01-27-2018, 08:16 PM

Thank you scv_guy... like my dad used to say if it's not broke dont touch it...lol...

Batmanntexas · 01-28-2018, 09:49 PM

I think the HP rating on the BOV is tied to the diameter of the BOV. Since it is there to relieve pressure in the intake tract upon throttle release, the airflow difference between 500 and 700HP should be pretty significant, requiring the benefits of a larger diameter BOV to rapidly release the excess pressure upon release of the throttle. I'm sure the 35mm would continue to work, well past the 500HP mark, it just wouldn't relieve the intake pressure as fast.

I could be out in left field, but that's just my thinking.

01-26-2018, 10:17 AM	#1
trans665 Drives: 2013 2ss Join Date: May 2011 Location: corpus christi Posts: 488	BOV qustions I currently have a Turbonetics due 35mm blow off valve.. I've been running it to my knowledge with good effects... I looked up the specs on it since I'm redoing my whole Turbo System and they're saying it only holds up to 500 horsepower. Is that the reason why I lose boost pressure in upper RPM? I was pushing about 700 to the crank. Now they're telling me that the pressure is the same on the manifold side and the intake piping. So wont my pressure from a manifold hold the valve closed at any PSI? Long story short I need to know if I have to buy a bigger and badder bov or if the one I have right now I will work with the 800 rear wheel horsepower I want?.. also my other question is should I just buy another bov like the one I have and added to the intake pipe. Will that work? Everything with the bov is confusing me right now just like spring pressure for them sorry for the rant __________________ 2013 auto ss..full bmr suspension..3800 stall...s475 turbocharger on 16 psi with 150 nitrous outlet plate...,BTR stage 3 turbo cam.....100% Methanol injection....LY6 6.0 iorn block ...

01-26-2018, 11:21 AM	#2
dreksnot Served USN - Atomic Chimp Drives: 13 Camaro LSX434 TT M6, 21 ZLE A10 Join Date: Jul 2012 Location: Fort Collins, CO Posts: 1,605 View My Garage	I'm guessing here, but I think you're getting Blow-off Valve (BOV) and wastegate spring (WG) confused, as well as a few other things. That system is "rated" for 500hp. That means you could expect to get that much HP with ideal conditions and setup. It like saying the weather temperature may get up to 80F today, but it's not there most of the day (like in Montana). Anyway, depending on if your have WG springs only or a boost controller (either manual or electric): I'm going to presume you just have WG springs. They're a constant, like 4psi, 8psi, 12psi, and so on. You can expect to get near that amount of boost with the # spring you have. My increasing spring force (pressure), that allows more boost, and more power. Caution: you need enough fuel and proper timing to account for this - just changing the spring without proper tuning can scatter your motor (highly discouraged in this establishment). As for the boost bleed-off, that can be expected in many turbo setups, but most only see 1-2psi boost tapering off (spring and manual). Some electronic controllers account for this, and sometimes relocating the boost sensor solenoid can reduce the effect. I don't quite recall the reason why, maybe cam setup, not recalling at the moment. __________________ In excess of 1,000WHP* LSX434 \| AGP 65/65 TT \| BTR Equalizer Intake \| Trickflow 245cc cathedral \| BTR custom cam \| Cortex EBC \| n2mb WOT \| ID-1700x \| Brisk GR12S \| RPM Lv 7 TR6060 \| AGP's Triple 525LPH Fore Fuel \| Monster LT1-S Triple \| 4.11 DSS Proform 9", CF driveshaft, 1400hp axles \| Hurst Line Lock \| MGW Retro Short Throw w/old skool Hurst T-handle \| ADM solid subframe mounts \| Prothane Motor Mounts \| Revshift Poly Trans insert \| Moreno camber/caster plates

01-26-2018, 05:48 PM	#3
trans665 Drives: 2013 2ss Join Date: May 2011 Location: corpus christi Posts: 488	No I'm not getting them confused I know it difference between a bov and a wastegate. All bov come with pressure Springs. I am trying to get a teal Q50 blow off valve. But they're asking me what spring pressure I want that is why I'm asking all of you what that stuff means __________________ 2013 auto ss..full bmr suspension..3800 stall...s475 turbocharger on 16 psi with 150 nitrous outlet plate...,BTR stage 3 turbo cam.....100% Methanol injection....LY6 6.0 iorn block ...

01-26-2018, 06:10 PM	#4
Nick@UPPturbo Drives: Twin Turbo Join Date: Jan 2018 Location: Colorado Springs, CO Posts: 16	Tial sells their blow off valves in terms of spring sizes. Spring size is dictated by vacuum pulled at idle. Here is a link to their table: http://www.tialsport.com/documents/w3_tial_qqr_sp.pdf Hope this is helpful __________________ Underpressure Power & Performance

01-26-2018, 07:44 PM	#5
dreksnot Served USN - Atomic Chimp Drives: 13 Camaro LSX434 TT M6, 21 ZLE A10 Join Date: Jul 2012 Location: Fort Collins, CO Posts: 1,605 View My Garage	Ah, totally missed what you were trying to say. Stock cam: -8psi spring Mild cam (like Stage I or II): -7psi spring Moderate (like Stage III): -6psi spring __________________ In excess of 1,000WHP LSX434 \| AGP 65/65 TT \| BTR Equalizer Intake \| Trickflow 245cc cathedral \| BTR custom cam \| Cortex EBC \| n2mb WOT \| ID-1700x \| Brisk GR12S \| RPM Lv 7 TR6060 \| AGP's Triple 525LPH Fore Fuel \| Monster LT1-S Triple \| 4.11 DSS Proform 9", CF driveshaft, 1400hp axles \| Hurst Line Lock \| MGW Retro Short Throw w/old skool Hurst T-handle \| ADM solid subframe mounts \| Prothane Motor Mounts \| Revshift Poly Trans insert \| Moreno camber/caster plates

01-27-2018, 08:16 PM	#7
trans665 Drives: 2013 2ss Join Date: May 2011 Location: corpus christi Posts: 488	Thank you scv_guy... like my dad used to say if it's not broke dont touch it...lol... __________________ 2013 auto ss..full bmr suspension..3800 stall...s475 turbocharger on 16 psi with 150 nitrous outlet plate...,BTR stage 3 turbo cam.....100% Methanol injection....LY6 6.0 iorn block ... Last edited by trans665; 01-28-2018 at 08:00 AM.

01-28-2018, 09:49 PM	#8
Batmanntexas Drives: 2012 Camaro SS (2SS) Join Date: Aug 2012 Location: Stafford, VA Posts: 1,374 View My Garage	I think the HP rating on the BOV is tied to the diameter of the BOV. Since it is there to relieve pressure in the intake tract upon throttle release, the airflow difference between 500 and 700HP should be pretty significant, requiring the benefits of a larger diameter BOV to rapidly release the excess pressure upon release of the throttle. I'm sure the 35mm would continue to work, well past the 500HP mark, it just wouldn't relieve the intake pressure as fast. I could be out in left field, but that's just my thinking. __________________ 745RWHP/634RWTQ on 93 @ 10psi 806/676 on E85 @ 10psi COTW 9/8/14