Mahalas
New member
Connecting the FPR line to the manifold is wrong. The vacuum created before the TB is COMPLETELY DIFFERENT then after the TB.
(Before I start is any one 100% sure this is the fuel pressure regulator, I traced the vacuum hose and it looks like it but this was a quick look and maybe its a vacuum solenoid for something else that looks like a FPR)
Yesterday I finished my ISR mod. After a longer test drive it seemed that the ISR provided more torque when in lower load situations (part throttle) but at the same time it seamed like there was no improvement maybe even a little loss at full throttle. "Cool, I spend more time driving in very low - moderate load conditions, this is a great mod for me."
While falling asleep I thought more about it and something seamed off. First why would I lose top end power, and second more importantly all my experience from turbo charging and racing cars was telling me the vacuum line connected to the IM was wrong.
Today I decided to add a nipple to the pipe and connect the vacuum line properly.
BUT FIRST I SHOULD TEST THIS !!!
I installed the factory silencer, grabbed my extra boost gauge and started testing.
Yesterdays ISR mod.
Reinstalled silencer and boost gauge attached to the factory vacuum line.
Pretty much 0 vacuum created at idle. If you remove the vacuum line while the engine is running it doesn't skip a beat. This is a leak after the MAFS and should cause some fluctuation the same way if you loosened the intake pipe off the TB and created the same size hole.
Went for a test drive. This is the max vacuum created at full throttle. Its pretty much nothing, I can probably fart with more pressure then this.
I slowed the truck down enough so it shifted down to first when I mashed it, let the gears wind out and the picture was taken at 75-80 miles.
<a href="http://s61.photobucket.com/user/mahalas/media/isr3.jpg.html" target="_blank"><img src="http://i61.photobucket.com/albums/h42/mahalas/isr3.jpg" border="0" alt=" photo isr3.jpg"/></a>
I already new this was 100% different then the manifold pressure behaves. But, just for you guys I did the test.
Vacuum at idel.
Part throttle.
Full throttle.
I decided to see what happens if you just connect the FPR line to the manifold. The truck was a dog. Very noticeable power loss in part throttle. (Cant remember full throttle but at this point its irrelevant, the connection is already wrong)
So I started adding a nipple to my ISR pipe.
The angle is to make a slightly bigger wall facing towards the stream of air flow and thereby creating more vacuum as the air flows over the hole.
In theory my nipple is the opposite angle at which it should be, but I tested this with an air blower and my tongue, it works.
I recommend that every person running this mod find a way to connect back to the proper vacuum source. Personaly I would rather leave the line disconnected then having it connected to the manifold and causing more harm then good.
(Before I start is any one 100% sure this is the fuel pressure regulator, I traced the vacuum hose and it looks like it but this was a quick look and maybe its a vacuum solenoid for something else that looks like a FPR)
Yesterday I finished my ISR mod. After a longer test drive it seemed that the ISR provided more torque when in lower load situations (part throttle) but at the same time it seamed like there was no improvement maybe even a little loss at full throttle. "Cool, I spend more time driving in very low - moderate load conditions, this is a great mod for me."
While falling asleep I thought more about it and something seamed off. First why would I lose top end power, and second more importantly all my experience from turbo charging and racing cars was telling me the vacuum line connected to the IM was wrong.
Today I decided to add a nipple to the pipe and connect the vacuum line properly.
BUT FIRST I SHOULD TEST THIS !!!
I installed the factory silencer, grabbed my extra boost gauge and started testing.
Yesterdays ISR mod.
Reinstalled silencer and boost gauge attached to the factory vacuum line.
Pretty much 0 vacuum created at idle. If you remove the vacuum line while the engine is running it doesn't skip a beat. This is a leak after the MAFS and should cause some fluctuation the same way if you loosened the intake pipe off the TB and created the same size hole.
Went for a test drive. This is the max vacuum created at full throttle. Its pretty much nothing, I can probably fart with more pressure then this.
I slowed the truck down enough so it shifted down to first when I mashed it, let the gears wind out and the picture was taken at 75-80 miles.
<a href="http://s61.photobucket.com/user/mahalas/media/isr3.jpg.html" target="_blank"><img src="http://i61.photobucket.com/albums/h42/mahalas/isr3.jpg" border="0" alt=" photo isr3.jpg"/></a>
I already new this was 100% different then the manifold pressure behaves. But, just for you guys I did the test.
Vacuum at idel.
Part throttle.
Full throttle.
I decided to see what happens if you just connect the FPR line to the manifold. The truck was a dog. Very noticeable power loss in part throttle. (Cant remember full throttle but at this point its irrelevant, the connection is already wrong)
So I started adding a nipple to my ISR pipe.
The angle is to make a slightly bigger wall facing towards the stream of air flow and thereby creating more vacuum as the air flows over the hole.
In theory my nipple is the opposite angle at which it should be, but I tested this with an air blower and my tongue, it works.
I recommend that every person running this mod find a way to connect back to the proper vacuum source. Personaly I would rather leave the line disconnected then having it connected to the manifold and causing more harm then good.
