Dual BOV set up.

[Kevin Jewer]

I think 1 Tial will vent enough for 99% of the poeple. Especially if you actually choose the right spring. Of course, if you have to recirculate it gets more complicated But if running 2 smaller ones makes more sense financially or because to have to recirc, I dont see a problem with that.

 

[JamiesTSI]

I already had one HKS ssbov I picked the other one up for $165.00 with weld on flange. This project is already done. I just wanted to be sure I did it the best way possible. I ended up tiging the flanges on the intercooler pipe across from each other. Running one vaccum line then tee'ing off at the BOV's.

I think I am going to end up running dedicated vacum lines to each of the BOV's.

 

[kaslasma]

ever heard of cutting costs? by the time there is a problem with the turbo on any of those cars they would be out of warranty, so its no longer the dealers problem until they get paid to fix the car

I can't comment much on the purpose of running multiple blow-off values, but what I can comment on is the fact that Buick GNs do not run them at all, never have. Infact my friend's GN is putting down over 800 HP and he doesn't run a BOV, nor does he have any problem with the turbo. Anyone ever heard a BOV on a diesel truck? Or an 18-wheeler? Maybe its that the turbos are much larger than ours but I find that hard to believe that is the only reason. Maybe its because the GN only came in autos so the additional wear would only be when letting out of boost since they don't loose it on shifting, I dont know. But then again 18-wheelers aren't auto, so that contradicts my previous theory.

Best of Luck with the Twin HKS SSQ,

Matthew.

 

[98spydert]

I already had one HKS ssbov I picked the other one up for $165.00 with weld on flange. This project is already done. I just wanted to be sure I did it the best way possible. I ended up tiging the flanges on the intercooler pipe across from each other. Running one vaccum line then tee'ing off at the BOV's.

I think I am going to end up running dedicated vacum lines to each of the BOV's.

Can you show us a pic of your progress?

 

[Kevin Jewer]

I can't comment much on the purpose of running multiple blow-off values, but what I can comment on is the fact that Buick GNs do not run them at all, never have. Infact my friend's GN is putting down over 800 HP and he doesn't run a BOV, nor does he have any problem with the turbo. Anyone ever heard a BOV on a diesel truck? Or an 18-wheeler? Maybe its that the turbos are much larger than ours but I find that hard to believe that is the only reason. Maybe its because the GN only came in autos so the additional wear would only be when letting out of boost since they don't loose it on shifting, I dont know. But then again 18-wheelers aren't auto, so that contradicts my previous theory.

Best of Luck with the Twin HKS SSQ,

Matthew.

Diesels dont have an air throttle, so there is no need for a BOV. You cant have pressure backing up to the turbo when there is no throttle plate to close

JamiesTSI, sounds like you did well. I would run dedicated lines, but you may not need to if they open fine. They may also not need to open as quickly since there are two of them. Even at low lift two BOVs may flow well enough.

 

[JamiesTSI]

I'll post a pic. in the next day or two.

 

[Mirage2LTurbo]

Diesels dont have an air throttle, so there is no need for a BOV. You cant have pressure backing up to the turbo when there is no throttle plate to close

JamiesTSI, sounds like you did well. I would run dedicated lines, but you may not need to if they open fine. They may also not need to open as quickly since there are two of them. Even at low lift two BOVs may flow well enough.

Would you care to explain how a diesel works then(without a t/b)?

 

[djpast]

Would you care to explain how a diesel works then(without a t/b)?

Diesel engines are unthrottled which means engine speed and power are controlled by the amount of fuel injected into the engine rather than airflow. When you press on the "gas pedal" in a diesel, you are actually controlling fuel flow. When you press the "gas pedal" in almost all Fuel Injected Gasoline cars, you are controlling the throttle which is controlling airflow.

 

[Kevin Jewer]

Yes, what he said. In addition, the amount of fuel injected determines both rpm and boost, thereby controlling airflow via the turbo. Most turbos on diesels are non-wastegated. In these setups injecting excessive amounts of fuel will overspool the turbo. In my truck, there is a WG, but its more of a safety thing. I dont believe it ever opens in normal operating conditions, since factory boost is ~18 psi, but fuel modules raise it to the low 20s I hear. And adding too much fuel will raise the boost too far, and the ECU senses this via the MAP sensor and starts to defuel the motor. I'm no expert on diesels, just getting to know them recently thanks to the new tow vehicle. Pretty interesting motors. Sorry for the OT.

 

[Maglin]

Would you care to explain how a diesel works then(without a t/b)?

Diesels are a totally differnt beast than a gas motor. They use compression ignition. Have no spark plugs or throttle boby. You pump as much air as you can into them and meter the amount of fuel that is injected into them. That is how you control their power output and speed. Same basic principles apply. Suck-Squeeze-Bang-Blow. The diesel fuel is like kerosin (<-Sp) and burns a whole lot slower that gas does, so their is no knock in diesels. Thus they don't have to meter that amount of air going in. Also their CR is like 18:1+. Been to long since I worked on them to remember all the details but that is that basic principles.

BTW this is for like 425HP CAT, Cummins that you find in Semi's. I actually don't know what the automotive industry has done for the end user segment for diesels.

 

[kaslasma]

Wow, I learn something new everyday.

So that solves the question about the trucks, what about the GN and other vehicles that don't run them?

 

[JessesTalon]

there are tons of factory turbo cars that didn't come equiped with a BOV from the factory. all the ford turbo cars ( SVO XR4Ti Turbo Coupe), Dodge turbo cars (Laser, Shadow, Daytona, Shelby), Buick GN's, I think Syclone, and Typhoons don't either and thier turbos last.

no they don't... my buddies syclone we incorporated my 1g bov on his car because his stock 17g turbo died after 75k miles... because no bov...

 

[JamiesTSI]

Here are some pics. of my work in progress. Let me know what you think of the dual BOV set up.

 

[SuperSleeper]

...Most turbos on diesels are non-wastegated. In these setups injecting excessive amounts of fuel will overspool the turbo. In my truck, there is a WG, but its more of a safety thing. I dont believe it ever opens in normal operating conditions, since factory boost is ~18 psi, but fuel modules raise it to the low 20s I hear. And adding too much fuel will raise the boost too far, and the ECU senses this via the MAP sensor and starts to defuel the motor...

This is commonly referred to as "overboost shutdown". The MAP sensor informs the computer that the boost maximum has been reached, and the computer then temporarily turns off throttle to allow everything to catch up.

there are tons of factory turbo cars that didn't come equiped with a BOV from the factory. all the ford turbo cars ( SVO XR4Ti Turbo Coupe), Dodge turbo cars (Laser, Shadow, Daytona, Shelby), Buick GN's, I think Syclone, and Typhoons don't either and thier turbos last.

Just to clarify, most of the Turbo Dodge vehicles DID in fact come with a factory blow-off valve. It's a crappy, plastic piece of junk located in the airbox.