Forge BPV install and impressions.

[Smokehouse]

Let me start off with this…of all the bolt on mods I’ve ever installed on the cars I’ve had in the past, the Forge BPV is by far the best value, bang-for-the-buck mod I’ve ever had.

BEST.

Not only is this the easiest install on the planet (10-15min max, a 10mm socket and a pair of pliers), it’s also the best.

This car lives and dies by it’s turbo…this is no V8 so if you want to go fast, better build (and hold) the boost. I had a suspicion my stock BPV was leaking boost after I installed a SRI and heard a hissing sound while cruising in the higher RPMs in 5th and 6 and when it wasn’t holding boost on harder acceleration…this suspicion was confirmed after installing the Forge, popped in blue with 2 shims and no more hiss. ON top of that, on harder acceleration the boost builds quick and stays there. Speaking of building boost, this thing builds up FAR faster than stock, the difference is instant. Of course you get the trademark “SsssshING!” when you let off the throttle but this is nowhere near the horror stories I’ve read…you think this thing is loud? Try the blower scream on a Terminator Cobra or a B&M shifter with no bushings bolted directly to the top of a Tremec T56 transmission…if this and a SRI is bothersome to you, you should buy a minivan. (Funny thing, on my first test drive, I drove past some teens walking aside the road and decided to try it out, the noise actually startled them!)

Needless to say, for an entry fee of $170, this thing should be the first thing you do to this car (followed by some better motor mounts and a different intake)…this car needs boost to be fast and this thing lets you use what the car makes, something the pile of shit stocker does not. Shame on Mazda for skimping on that plastic pile of crap.



Lastly, no need for pics…there’s 4000 of them floating around so do a search.


…next up, TRZ motor mounts…

[Hectik1]

Great review. I agree 1000%, BPV should be first on the list....next to the rear MM and shifter bushings.

[ctbadley]

How does the sound of the forge BPV compare to any of the BOV's? I've read that you hear a Ssshing with the BPV, but is this in any way comparable to a BOV?

[knyghtryda]

Originally Posted by ctbadley How does the sound of the forge BPV compare to any of the BOV's? I've read that you hear a Ssshing with the BPV, but is this in any way comparable to a BOV?

The forge has the most distinct sound of really any BPV. The general consensus is that it sounds like when get coins in Mario Bros. for NES. Its more of a "ping!" sound than a clean "shhh" sound. Look for a a couple videos in youtube to really hear them. I think its kinda neat, but non-car people will probably look at you funny the first time they ride in your car

[johnnyspeed6]

Originally Posted by knyghtryda The forge has the most distinct sound of really any BPV. The general consensus is that it sounds like when get coins in Mario Bros. for NES. Its more of a "ping!" sound than a clean "shhh" sound. Look for a a couple videos in youtube to really hear them. I think its kinda neat, but non-car people will probably look at you funny the first time they ride in your car

I actually installed mine last night that I bought from booyah on this site ... It was about a 3 min. install ... super easy and its alot heavier and better feeling than the plastic stocker ... The best way i describe the sound in like a PLINK! take 2 hammers and bang them together ... but make it more cartoony ... the look on my face after the 1st boosted shift was this exactly >> .. but it does hold boost better and smooths out the shifts.. under low boost you really cant hear it other than a small hiisshh ... I guess would be a good word to describe

[Smokehouse]

I can't honestly say I know how it compares to others on the market...I bought it used from a member over at 24/7 for $110. I won't be buying any of the other expensive units to do a comparison. All I can say is that after doing some reading/searching, the Forge seems to be the best bang for the buck BPV out there. It's adjustable, it's well built and it's relatively cheap. I haven't installed a boost gauge yet and but I will be doing it in the future. At that time I will reinstall the stocker and run some real tests. For now my only proof is my knowing how the car behaved before and after install thanks to having a SRI and being able to actually hear the boost.

This thing doesn't give you more boost, it simply let's you better use what you have. It builds much quicker and hold far better than the stocker.

[06turbospeed]

how do u think it compars to the cpe hks???

[martyxattack]

Originally Posted by 06turbospeed how do u think it compars to the cpe hks???

wut

[subparpunk03]

If you're using the forge just remember to take it off and re-grease it with synthetic grease each oil change. It does need to be serviced regularly.

I've tried this and the HKS valve... and while the forge is a decent replacement... I personally find that the car runs MUCH MUCH MUCH better with the stock bypass valve... but that may be due to the quirks in my specific setup.

The customer service at Forge is amazing... I broke one of the O-rings and emailed them asking for a replacement set and had it in my hands within a week.

[DaleNixon]

Can you recommend a good synthetic grease? And how do you clean up the old grease? Just a rag?

[ms3jake]

Originally Posted by subparpunk03 If you're using the forge just remember to take it off and re-grease it with synthetic grease each oil change. It does need to be serviced regularly. I've tried this and the HKS valve... and while the forge is a decent replacement... I personally find that the car runs MUCH MUCH MUCH better with the stock bypass valve... but that may be due to the quirks in my specific setup. The customer service at Forge is amazing... I broke one of the O-rings and emailed them asking for a replacement set and had it in my hands within a week.

Smokehouse and others say the forge bpv is so great and you say stock is much better. Why is stock so much better for you?

[MZRDISI4]

That's probably what the stock valve was designed for, smooth driving and no maintenance.

[subparpunk03]

Forge reccommends mobil 1 synthetic grease, which you can pickup at autozone or advance: Mobil 1 Store - Mobil 1 Synthetic Universal Grease Cartridge (12.5 oz.)

They seem to only sell it in huge tubs even though you only need a little (not unlike crisco)

Subparpunk03 reccommends AMSOIL!
AMSOIL Synthetic Grease

Of those, use either the racing grease (adds at least 10 whp) or the multi purpose grease (only adds 4 whp)

[redwinqs]

thanks for the info!

[JmkC]

I too just installed the forge bpv recently. The sound is very distinct, and at first I wasn't to fond of it, but grew into it. The car defiantly builds boost and holds it better over stay, and the lag in between shifting gears and waiting for the boost to come back has been eliminated. I'm satisfied. I ended up using the blue spring with one shim.

[mike8748]

I have been very happy w/ my Forge BPV...

[ctbadley]

Originally Posted by subparpunk03 Forge reccommends mobil 1 synthetic grease, which you can pickup at autozone or advance: Mobil 1 Store - Mobil 1 Synthetic Universal Grease Cartridge (12.5 oz.) They seem to only sell it in huge tubs even though you only need a little (not unlike crisco) Subparpunk03 reccommends AMSOIL! AMSOIL Synthetic Grease Of those, use either the racing grease (adds at least 10 whp) or the multi purpose grease (only adds 4 whp)

How would the racing grease give you 6 more WHP than the multi purpose grease? It seems like thats a big difference in performance simply due to a different type of grease.

[DaleNixon]

Originally Posted by subparpunk03 Forge reccommends mobil 1 synthetic grease, which you can pickup at autozone or advance: Mobil 1 Store - Mobil 1 Synthetic Universal Grease Cartridge (12.5 oz.) They seem to only sell it in huge tubs even though you only need a little (not unlike crisco) Subparpunk03 reccommends AMSOIL! AMSOIL Synthetic Grease Of those, use either the racing grease (adds at least 10 whp) or the multi purpose grease (only adds 4 whp)

Would Redline extreme pressure grease work? I have a tube of it that I bought to lube my swaybar bushings with.

Red Line CV-2 Extreme Pressure Grease :: Fluids & Coolants :: Solo Moto Parts

[subparpunk03]

Originally Posted by DaleNixon Would Redline extreme pressure grease work? I have a tube of it that I bought to lube my swaybar bushings with. Red Line CV-2 Extreme Pressure Grease :: Fluids & Coolants :: Solo Moto Parts

Should work fine.

The reason you "want" flutter is that it means the spring is juuuust as stiff as it needs to be. Too stiff and you get compressor surge. Not stiff enough and you just vent all the pressure out of the system. When its stiff enough to overcome a slight pressure difference you can keep a bit more pressure in the system so you can hold boost better between shifts.

[Snyeed]

I love my forge and the ninja sword fighting it brings.

[Moonpie.Express]

Have had mine on for +40K. Works like a champ.

[subparpunk03]

It adds more horsepower the same way a type-R badge does. Clearly I was a bit too subtle with my humor.

But if you must know the reasoning behind it... the racing grease has Amsoils special blend of performance enhancing nanoparticles that are able to take the back and forth motion of the bypass valve piston and convert it to a nitrous like substance which is recirculated back into the intake track.

[DaleNixon]

roofl cooptr

[Moonpie.Express]

subparpunk with the grease analysis win/win!

[08MazdaspeedSleeper]

has anyone used the red spring?

[MZRDISI4]

Originally Posted by 08MazdaspeedSleeper has anyone used the red spring?

It's stiffer than blue, so unless you're running 19+ it's really not necessary. Blue with shims should suffice.

[Mistersix]

any way to get rid of the flutter during partial throttle release.

for instance, cruising in say 5th gear, lite acceleration to pass some one, builds a lil boost, (say 4-7 lbs), let off the throttle, and it flutters softly.

or is this normal.

currently running the yellow spring. blue fluttered even more.

[subparpunk03]

A little flutter is normal with a push type valve. The stock flutters but you can't hear it.

[08MazdaspeedSleeper]

yea it should do fine.

[94jedi]

Nice review! If I don't hear something about Cobb's BPV, I'll go forge.

[dutchbuffalo]

I don't get any flutter at all with my forge, I don't see how flutter could be a good thing but what do I know.

[KDiz]

i got my forge yesterday and installed it last night. had a little trouble on the larger hose clamp since my pliers were BARELY big enough to get around it. but it's a very easy install with the right tools. i started with the blue + 1 shim and only got flutter, not the distinct 'coin' sound. removed the shim and been pickin' up coins ever since. i do get the flutter every once in a while in 6th though.

[Smokehouse]

You know...it's funny this came up. In town driving and 3-4K RPM shifts + clutch, the Forge works fine...light throttle + clutch gets me the normal "Pfffffff" blowoff, harder gets me that trademark Forge "SSSSHING"...

I was driving on the freeway in 5th, sped up a bit to get around somebody (no hard throttle but it did build some boost)...when I let off the throttle a bit, I got some compressor surge. Not a ton but it was there.

I don't get it, I'm currently blue-w-2 shims, I think once the weather clears again I'll try blue with one. What I don't understand is why harder driving + clutch to shift is ok is ok, softer driving + clutch is ok but letting off the throttle like that caused surge.

Any help here?

[paulyg]

Originally Posted by Smokehouse I was driving on the freeway in 5th, sped up a bit to get around somebody (no hard throttle but it did build some boost)...when I let off the throttle a bit, I got some compressor surge. Not a ton but it was there.

I have a n00b question. How do you know when you are getting compressor surge? What's the symptom?

[xandrake]

Originally Posted by paulyg I have a n00b question. How do you know when you are getting compressor surge? What's the symptom?

Surge is from too much tension in the valve. The valve won't open because it requires too much PSI to recirculate the boosted air so it sits in the pipe and pushes back into the turbine housing making the noise. There are plenty of videos on youtube with the sound. Check it out.

[subparpunk03]

It all has to do with the pressure difference. The line going to the top of the forge valve is coming off the manifold and the valve sits on top of the cold pipe which is pressurized with air from the turbo. In fifth gear at very low boost there is only a little bit of pressure in the cold pipe, and about the same pressure in the manifold. When the throttle shuts and you aren't shifting, that cold pipe pressure is almost equal to the pressure in the manifold, but you also have the spring so the pressurized air pre-TB is not strong enough to overcome the stiffness of the spring and shims.

One thing you can try is the "pencil test." Take the valve off, push the piston up with the eraser end of a pencil, place and hold your finger tightly over the nipple on the top of the valve and then remove the pencil. The piston should stay in place, and shut once you remove your finger. If the piston doesn't shut then your valve is leaky and the vacuum in the manifold will not help to open the valve quicker, and you will surge.

I found the blue spring and 2 shims to be too stiff. I had the best results with the yellow spring to be honest with you... and even better results taking the forge off and going back to stock.

[TenaciousBoost]

One thing you can try is the "pencil test." Take the valve off, push the piston up with the eraser end of a pencil, place and hold your finger tightly over the nipple on the top of the valve and then remove the pencil. The piston should stay in place, and shut once you remove your finger. If the piston doesn't shut then your valve is leaky and the vacuum in the manifold will not help to open the valve quicker, and you will surge.

Is it strange that I am aroused by this???

[ThrillaSpeed3]

Originally Posted by TenaciousBoost One thing you can try is the "pencil test." Take the valve off, push the piston up with the eraser end of a pencil, place and hold your finger tightly over the nipple on the top of the valve and then remove the pencil. The piston should stay in place, and shut once you remove your finger. If the piston doesn't shut then your valve is leaky and the vacuum in the manifold will not help to open the valve quicker, and you will surge. Is it strange that I am aroused by this???

awesome. now i know if my forge is working properly. it seems to be soundin differently lately. more quiet then usual. havent maintenance since i got it

[blackcherryspd6]

I was looking at these and weight my options HKS or Forge...or (hold your breath) RKM.

[xandrake]

Originally Posted by ThrillaSpeed3 awesome. now i know if my forge is working properly. it seems to be soundin differently lately. more quiet then usual. havent maintenance since i got it

Same exact thing happened to me. I got flutter while boosting and even at part throttle and it seemed really quiet. I did the pen test and it failed miserably. It turns out that the o-ring that sits at the top of the piston end, by the recirc nipple, was mangled. I was later informed by Forge that if you do not slowly tighten the cap when reassembling that you can shear the o-ring and ruin the integrity of the seal.

Xan