Is this a problem?

[USAFVMI08]

I've got the full PG intake set up plus a Forge BPV and I used the Cobb AP to put it to Stage 1+. I've noticed that when I let off the gas, it does make that distinctive CLANG noise (which I love, by the way) but it also makes a slight knock sound or a chuff. I was running the yellow spring plus two shims but it was leaking boost so I switched to the blue spring. Do you all experience this too? All my fittings are tight so I know I'm not leaking any boost.

Also, this set up is so incredibly loud. I sound like a damn semi truck when I get on it

 

[zinger002]

The Forge bpv is known to make a clashing sound when opening. the after sound is just the air escaping out the bpv's opening.

 

[Mistersix]

knock sound? if i'm correct you can datalog with your ap to see if you getting to much knock. if you got knock you can hear audible, you need fix that s***.

you are running the highest octane fuel available in your area, right?

 

[USAFVMI08]

Yeah I'm running 93. It's not a knock sound. it's more of a clap or a dull thud sometimes it kind of makes a "chuff" kind of sound. I'm inclined to think that it's what zinger is thinking. But I'll run a datalog on this and post it up just to check with you all.

 

[Mistersix]

you may wanna datalog some stuff to refer back to for future reference anyway.

 

[zinger002]

knock sound? if i'm correct you can datalog with your ap to see if you getting to much knock. if you got knock you can hear audible, you need fix that s***.

you are running the highest octane fuel available in your area, right?

i have run 89 Octane and my car still made full boost, no knock. 89 was the highest the stupid gas station had, and i really needed gas.

my dsm bpv makes a very distinct woosh when it opens, but under the right conditions it makes a "nails on a chalk board" screech when closing. its not loud, but loud enough to hear still.

 

[Mistersix]

you can get away with lower octane fuel. the manual says as low as 87 in emergency situation.

never tried it my self. i love when people tell me i'm wasting my money buying premium fuel, as they smoke there ciggaretes and drink theyre starbucks.

not that theres anything wrong with that

 

[USAFVMI08]

you can get away with lower octane fuel. the manual says as low as 87 in emergency situation.

never tried it my self. i love when people tell me i'm wasting my money buying premium fuel, as they smoke there ciggaretes and drink theyre starbucks.

not that theres anything wrong with that

Same here. but the one time some knucklehead at a full service station did put in 87 with octane booster, my car ran like crap.

 

[tunersteve]

Between my car and two other MS3s in the area with different intake/inlet/BPV combos, our cars all sound different. Depending on several factors, including which spring & shim combo you're running, material and length of intake, and material of inlet, you'll get a wide range of sounds.

Also, you may want to remove the Forge, take it apart, and check all the o-rings for wear. After that, re-grease it up, and reinstall in the vehicle.

 

[USAFVMI08]

Also, you may want to remove the Forge, take it apart, and check all the o-rings for wear. After that, re-grease it up, and reinstall in the vehicle.

Really? I just installed it about a week ago brand new.

 

[kendon]

lol! i thought the same same on the way into work, my car sounds like a freakin' semi! i love it.

 

[coyfish]

You sure its just not the normal sound?? Depending on how harshly you take your foot off the gas = varying noise from the bpv. If your in boost but gently let off you might not hear a loud clang but you will hear a chhhh / thud noise. Play with how abrubtly you take your foot off the gas and see if you can recreate the noise. If you can its probably just ur bpv doing its job.

 

[Blendercloud]

Between my car and two other MS3s in the area with different intake/inlet/BPV combos, our cars all sound different. Depending on several factors, including which spring & shim combo you're running, material and length of intake, and material of inlet, you'll get a wide range of sounds.

Also, you may want to remove the Forge, take it apart, and check all the o-rings for wear. After that, re-grease it up, and reinstall in the vehicle.

USAFVMI08,

Steve has gotten you on the right track. When my Forge was making the exact sound you're describing it was because I was running too stiff a setup for my boost level. I would venture to say that you're probably getting a real sluggish entrance into the next shift, or maybe some hesitation. That feeling is because you're not recirculating all the boost. The valve is so tight that it cuts itself off before it's supposed to.

I would encourage you to dial it back now that you have found where that threshold is. Go back to yellow and two shims. If it still makes that sound, remove one shim, etc. The yellow spring is ideal for what you're working with. And if I had to guess, you're probably misunderstanding what you think might be a boost leak.