Forge BPV... what springs/shims w/AP

[marathonman08]

Ok, so i have been reading all the posts and read every forum for the speed3 and i can't come up with one straight answer of what spring and shim to use with the Forge BPV. My mods are Cobb SRI, Cobb AP running Stage 1.(soon to come: Cobb inlet, Cobb DP, Cobb FMIC, Stage 2 which will change everything) I know that Cobb doesn't tune the car with anything but the stock BPV but i like the Ping sound and I know with the right setup this thing is better. Can anyone out there give me a good answer??!!!

I have tried the blue with 1 and 2 shims and the red spring and my boost is WAY lower then stock on the same day same temperature outside...same gear. I was around the 19 -17 range with stock. With Blue and two shims i only spiked to 16 with it settling at 14... WTF? Can anyone explain this? Will the yellow springs compare to the stock BPV. Since Cobb tuned the maps with the stocker i think finding the forge setting that is comparable would be the answer. If not, im giving up and selling the damn thing.

 

[GoFast]

what is stage 1 or stage 2?? As far as I know there are no "stages".

Instead of trying to tune the forge bpv to operate like the stocker, you should just put the stocker on.

 

[CWPspeed3]

with my stock bpv i would spike 16 and bleed off until 11 with the forge with blue and 2 it would peak 18 and hold 14-15. Since then I have removed the two shims but the weather has been much colder so i havent compared it to the other numbers. Couldnt hurt to try the yellow spring with or without shims though.

 

[marathonman08]

stage 1 is the map on the ap Stage 1 v103

 

[GoFast]

You may want to PM Patty @ Forge I am sure that HE can help.

 

[eg6motion]

Ahhh. just as an FYI, there aren't "stages" They are are just versions. I.E. V1.01 V1.03 When you say stages you imply some kind of ricer'ish talk and nobody knows what you are actually referring too so, it could be tough when trying to diagnose any problems.

guess you should let cobb know, as they refer to their maps as stages...

as for the "versions", those are just revision numbers and in no way an indicator of which map you are running....
Currently they offer 1.03 on their site...which is the revision number for every single map.

 

[marathonman08]

Then why do the Maps name say "Stage1+SF 91 Octane - Stage1 for Stock Vehicles with a COBB Tuning SF Intake System only. 91 Octane fuel."
I think everyone knows what im talking about when it comes to downloading maps for the AP. The 1.03 stands for the revision to the software.

Anyway, there has to be a good answer from someone on this forum.

 

[GoFast]

well call me a dumbass (uhm)(bang)(bang)

 

[SubieKiller3]

go with the yellow spring and just play with the shims on that spring as long as your running on stock boost psi. i dont know why people even think they need to be using the blue spring. its probably only gonna mess up your turbo in the long run. if you go to the forge website it say on there yellow is 15-23 psi and blue 23-30 so you do the math. i had the yellow spring in mine when i had it and it ran just fine. the blue actually gave me a CEL.

 

[Bravnik]

Yellow is WAY to light. Forge recommends the BLUE spring with our car stock. I would recommend the Blue with one shim for your mods. You want to hear a flutter when you are at low boost and push in the clutch. This tells you that the BPV is setup right. If you don't hear a flutter with one shim, go to 2 shims.

 

[DaleNixon]

I might try yellow with 2 this weekend just for the hell of it. I'm sure it won't be enough.

 

[Bravnik]

go with the yellow spring and just play with the shims on that spring as long as your running on stock boost psi. i dont know why people even think they need to be using the blue spring. its probably only gonna mess up your turbo in the long run. if you go to the forge website it say on there yellow is 15-23 psi and blue 23-30 so you do the math. i had the yellow spring in mine when i had it and it ran just fine. the blue actually gave me a CEL.

The blue is what Patty recommended to us. The Forge Website is wrong on that recommendation and was suppose to be fixed about a year ago and never has been. Yellow is just too soft. Blue for stock. I ran Blue with 2 shims with my old setup and did just fine. Hell I even ran Red for a bit but it was just a bit too stiff and got surge a couple times.

 

[MicaSp33d]

i switch springs depending on weather since its winter, i usually use the blue w/no or yellow w/ 2... to me it almost feel the same but maybe the yellow is a little softer.

the other day i spiked to 20psi then settle to 14-15 with the yellow and 2 ... it kind of surprised me so i floored it again and it spiked to 20 again .. i think i was in 3rd. Probably being colder out made the spring stiffer.

but to me ... blue probably feels the best and maybe adding shims based on weather

 

[funksilver07]

I've tried all of them, started with blue/2 shims. Tried red no shims, blue no shims, yellow 2 shims, I'm now back to the blue/2 shims. Seems to work best with my current set-up... There is a difference depending on your car and what mods you have. Switch em' up till you find the right combo for your own car. (thumb)

 

[patty AT forge]

Ok this is my cut and paste reply when ever I get asked this question:

The springs are used to account for variances in atmospheric conditions, and the relationship between boost and vacuum that different cars will see. To simplify it greatly the more boost that you are running the stiffer a base spring pressure you will need to compensate for the pressure differential between the manifold and the charge piping right at initial boost onset. Cars with few modifications running at or near factory boost seem to respond best with the yellow or blue springs. Cars running a bit more boost the blue and a few shims. The red spring is best used on cars running upper teens or low twenties.

That out of the way let me quickly go over how to adjust the valve. I recommend using three different spring tensions and performing some real world testing. Say for instance the yellow, blue, and blue with shims. Drive normally for a few miles (part throttle shifting, stop and go, merging and passing for some wide open data) then do a few wide open throttle runs. Do this with all three setups and compare the results, with "seat of the pants" or with data logging. If there is no difference use the softest setup. If the middle seems best that is the setup to use, if the stiffest works best perform the same tests with the next stiffest and compare.

That is the more complex answer. The easy quick answer is "use the blue spring if the cars is modified, if the car seems sluggish add two shims to the valve". 95% of the cars out there using the valve are using the blue spring.

Hope this helps. Let me know if you have any other questions.

 

[ElGaspo]

(iagree) listen to what Patty sez...he works for Forge, so if anyone knows, it's him. (bow)

 

[08cosmic3]

Blue W/2.

 

[UHATEIT]

oh man yet another Forge thread about springs and shims!!!!! Im going insane!

 

[vrspeedemon]

well I have a MS6 so may not be entirely the same but I swap springs based on weather temps.
Blue...in warmer temps
Yellow + 2 shims in cooler temps.

seems to work best for my setup.