Torqstorm BOV setup
Thread Starter
Joined: Aug 2011
Posts: 4,732
Likes: 815
From: Portland, OR
Torqstorm BOV setup Hey folks. A customer of mine has installed this system on his 5.3 Silverado. I’m tuning it.
It’s running after fixing a few issues. I tuned it NA, so fairly straight forward.
His BOV is plumbed to the intake manifold. I’ll assume per the instructions.
It’s full open at idle. Right smack behind the radiator and fans. This is not good!
Not only will we have 190 degree IAT’s, it’s all unfiltered air.
I’m not seeing any optional springs on their web site.
Ideas?
This setup only makes 8 psi. Maybe we don’t need it?
Ron
It’s running after fixing a few issues. I tuned it NA, so fairly straight forward.
His BOV is plumbed to the intake manifold. I’ll assume per the instructions.
It’s full open at idle. Right smack behind the radiator and fans. This is not good!
Not only will we have 190 degree IAT’s, it’s all unfiltered air.
I’m not seeing any optional springs on their web site.
Ideas?
This setup only makes 8 psi. Maybe we don’t need it?
Ron
Eh, not really needed either IMO. They are mainly to keep shaft speed up between shifts. (or so they claim)
Not prevent damage from the comp stall after a pass when we shut the TB. Relatively large units like we run aren’t likely doing anything detrimental when we stall them a bit after a pass.
OEM cars like the Grand National didn’t have a BOV for that reason. They had very long service lives without one. Way more than I’d ever get out of an engine/turbo anyway. I haven't run one since 2012 on anything I've built. I know that's not very scientific, lol. But I've read into it a lot as well. Big turbo autos really don't need them. I quit running them, so far so good. (unless you just like th noise). Figure its just one more thing that can fail, plus the cost and time to install one. Tiny bit of weight savings too.
Also FWIW.
I always though the surge noise meant the turbine speed was dropping a ton. There's a thread on here floating around where a manual trans road race guy installed shaft speed sensors and tested/logged his lap times with and without a BOV. He found that without the BOV the turbo shaft speeds were actually higher at the shift. He had less lag and faster lap times without a BOV.
Not prevent damage from the comp stall after a pass when we shut the TB. Relatively large units like we run aren’t likely doing anything detrimental when we stall them a bit after a pass.
OEM cars like the Grand National didn’t have a BOV for that reason. They had very long service lives without one. Way more than I’d ever get out of an engine/turbo anyway. I haven't run one since 2012 on anything I've built. I know that's not very scientific, lol. But I've read into it a lot as well. Big turbo autos really don't need them. I quit running them, so far so good. (unless you just like th noise). Figure its just one more thing that can fail, plus the cost and time to install one. Tiny bit of weight savings too.
Also FWIW.
I always though the surge noise meant the turbine speed was dropping a ton. There's a thread on here floating around where a manual trans road race guy installed shaft speed sensors and tested/logged his lap times with and without a BOV. He found that without the BOV the turbo shaft speeds were actually higher at the shift. He had less lag and faster lap times without a BOV.
Last edited by Forcefed86; Jun 11, 2025 at 11:07 AM.
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I've always ran a BOV on a turbo setup, my thought is after a hard pull, TB slams shut, pressure inside charge piping rises, maybe less chance of blowing a coupler off, idk?
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Not running a bov on a centri supercharger will cause the belt to slip. I only know this because I ran too small of a bov (recirculated) and it caused a ton of slip when I would shift or let off the throttle at high rpm. Once I added a 2nd bov it completely fixed all my problems.
you’ll see a bunch of rubber powder all over your head unit and engine bay and it’s really fun to clean up.
you’ll see a bunch of rubber powder all over your head unit and engine bay and it’s really fun to clean up.
I pulled it apart and fixed it, but then I noticed the lag between shifts (T56 car) was way more noticeable.
It pulled harder with way less boost drop between shifts when the BOV was stuck closed.
Kinda wish I'd left it that way lol.
Thread Starter
Joined: Aug 2011
Posts: 4,732
Likes: 815
From: Portland, OR
Yep, blower car, I mean truck.
I got back over yesterday after he fixed a couple things.
Of course you guys were correct, air coming out. A lot of air coming out!
I had tuned this NA so it’s been mostly easy to get it up and running. All new stuff.
For whatever reason he chose a 102mm TB. Nick Williams actually. He bought GM IAC and tps as well.
With the throttle screw backed all the way off, the IAC still hits 0 counts pretty quickly. I’m wondering if part of that bypassed air hitting the throttle plate is having an effect.
I also noted that at slight throttle opening the trims were adding 20% fuel. Which causes the VE table to be much higher in those areas than normal.
Easy to test. The truck isn’t driveable yet, so just getting started. Turbo guy tuning a centri…,
Here is a good one…..this is the same 5.3 that was in there NA. Well…..the customer mentioned it has a new crank. Says there was some issue with the old one. Then mentioned they had to bore it way out. So I ask him what the cubes are now? He said, I don’t know, 5.9L?
Geeze, why consult with the tuner ahead of time?
Anyway, the engine builder is a good friend who also does my machine work. So I asked him!
383
Nice
I got back over yesterday after he fixed a couple things.
Of course you guys were correct, air coming out. A lot of air coming out!
I had tuned this NA so it’s been mostly easy to get it up and running. All new stuff.
For whatever reason he chose a 102mm TB. Nick Williams actually. He bought GM IAC and tps as well.
With the throttle screw backed all the way off, the IAC still hits 0 counts pretty quickly. I’m wondering if part of that bypassed air hitting the throttle plate is having an effect.
I also noted that at slight throttle opening the trims were adding 20% fuel. Which causes the VE table to be much higher in those areas than normal.
Easy to test. The truck isn’t driveable yet, so just getting started. Turbo guy tuning a centri…,
Here is a good one…..this is the same 5.3 that was in there NA. Well…..the customer mentioned it has a new crank. Says there was some issue with the old one. Then mentioned they had to bore it way out. So I ask him what the cubes are now? He said, I don’t know, 5.9L?
Geeze, why consult with the tuner ahead of time?
Anyway, the engine builder is a good friend who also does my machine work. So I asked him!
383
Nice
Last edited by RonSSNova; Jun 14, 2025 at 12:03 AM.
What spring rating is common for LS3 intakes with smaller cams (235/236 .665/.667 117+4 for example) on S400 frame turbos?
I hear that the lighter springs are recommended (8-10Hg) but this article says otherwise:
Three Cam Tests on an LS3 Engine - GM High-Tech Performance
I bench tested the BOV's that I have and with the light springs in them, at 7 Hg they start to open and at 10 Hg they are stay held open.
I plan to test the actual vacuum on the intake when at hot idle and choose the correct spring based on that, but something tells me I should put the stiffer springs in (14-16) off the go and save time from having to take the BOVs apart again because the spring pressure was too low lol
I hear that the lighter springs are recommended (8-10Hg) but this article says otherwise:
Three Cam Tests on an LS3 Engine - GM High-Tech Performance
I bench tested the BOV's that I have and with the light springs in them, at 7 Hg they start to open and at 10 Hg they are stay held open.
I plan to test the actual vacuum on the intake when at hot idle and choose the correct spring based on that, but something tells me I should put the stiffer springs in (14-16) off the go and save time from having to take the BOVs apart again because the spring pressure was too low lol