Forge Valve install/impressions

sleeper3

Member
:
2008 Mazdaspeed 3 GT
well, last night I put on the Forge Bypass Valve because I just couldn't wait anymore. it's pretty great. I was kind of worried about the sound, but it's not that bad, and if you're not above 5lbs of boost (it doesn't happen that often, but you know) you just get the woosh, and no ping.

the thing that I noticed straight off is that the vent hole on the flange side of the stock valve is TINY. like not even as big around as a pencil. this is where all your boost pressure is venting. seems extremely inadequate. after putting the new valve on (which took no more than 5 minutes), I noticed that the vent is a lot quicker. the upshot to this is that there is less force on the turbo which would cause it to stop spinning, which is the whole point of a blow off or bypass valve. since the impeller is still spinning, theoretically, boost should be instant on fast shifts. I haven't paid that much attention to it, but on the whole, I am extremely happy with the upgrade.

by the way, I didn't see any more boost held or spiked. no noticeable change in power or anything. I am thinking the aforementioned would maybe save a tenth or so in the quarter (total stab in the dark) just because you're in boost quicker on shifts.

so to sum up,
woooOOOOOOSHPINGpshhWOOOOOOOSHPINGpshhhh
 
i'm running vta and can really tell a diff in power cuase its all cold air, there seems to be a tad mnore lag down low but when it comes it comes sharp and HARD cuaseing wiplash
 
with the forge VTA, do you hear that horrendous "ping" noise?

i'm running the trubo xs vta, its loud!! I runs good i'm holding 2 more punds of boost!, it does fart between shifts here and there but Jordan is working on a map for the standback to fix this. If you don't have the stand back you can run vta but youll run rich between shifts and eventually blow out your catalatic converters...
 
i'm running the trubo xs vta, its loud!! I runs good i'm holding 2 more punds of boost!, it does fart between shifts here and there but Jordan is working on a map for the standback to fix this. If you don't have the stand back you can run vta but youll run rich between shifts and eventually blow out your catalatic converters...

hey, it's cheaper than buying a test pipe!
 
hey, it's cheaper than buying a test pipe!

lol... yeah but in the end if you have to get a smell test for inspection your screwed i herad our cats are expensive too there a bunch of platimnum etc in there. But yeah if you run a catless dp and midpipe then who cares if its farting between shift...
 
I used to run emissions all the time for work, and I saw some nasty looking stuff pass. smoke coming out and everything. I'm pretty sure as long as your car is running correctly, you don't even need cats to pass here.
 
it depends where you live now they stcik that thing in your tail pipe and "smell" your butt..lol to fid out if your cats are up to date
 
I used to run emissions all the time for work, and I saw some nasty looking stuff pass. smoke coming out and everything. I'm pretty sure as long as your car is running correctly, you don't even need cats to pass here.

Florida FTW. Other states aren't so "lucky".

so which spring are you using? The forge comes with the yellow spring installed, but if you have a chance, test with the blue and possibly some shims. I was pleasantly surprised by the difference!
 
i'm running vta and can really tell a diff in power cuase its all cold air, there seems to be a tad mnore lag down low but when it comes it comes sharp and HARD cuaseing wiplash

im confused, this is the 2nd thread where I have seen you mention a VTA blow-off valve and how its different because of cold air.

air temperature has nothing to do with a blow-off valve(huh)
 
im confused, this is the 2nd thread where I have seen you mention a VTA blow-off valve and how its different because of cold air.

air temperature has nothing to do with a blow-off valve(huh)

it has alot to do with air temp here is why. The air that goes thorugh the turbo "compressor" is greatly heated up thats why you need an intercooler. so the excess heated air is recuculated back to the trurbo, with vta all that extra hot air is vented to atmosphere, not sent back through, so all the air coming to the turbo is cold wich dramtically decreases the over all temp of the air enterring your engine. this increases horsepower for sure!! you can tell be the way the car throws you back its getting cold boost with good timeing. I think the point of recir is to imporve drivability, makes the car feel more civilized, plus its good for the turbo reduces the load on it cuase its flowing air back to it. From what I understand most race applications for turbo engines are vta cuase you get more effciant boost..
 
The BPV is post intercooler, so it theoretically should be cooler air being recirculated anyways. BPV/BOV have nothing to do with air temps. End of story.
 
The BPV is post intercooler, so it theoretically should be cooler air being recirculated anyways. BPV/BOV have nothing to do with air temps. End of story.


this is correct. the bypass valve is on the "cold pipe" coming off of the intercooler on the intake manifold side. the air has already been cooled, plus it's going back through the turbo and intercooler again. if it's raising the intake air temps at all (which is unlikely) it can't be by more than a degree or two, and only for a split second.

the butt dyno is a funny thing.
 
As SuperStretch18 already suggested, give the Blue spring a try, most on this site seem to prefer it. And I've asked that they are built with the blue from now on.
 
I read up on the valve a LOT before I even bought it. I had the blue spring in as soon as the box was opened. I'm getting a tiny amount of flutter, but I think as the spring breaks in, it will go away. I'm very happy with the results. I think it's going to do a great job protecting my turbo, and obviously, the tunability will be great as the mods increase.
 
also, I'm not sure how familiar you are with the engineering side of the valve, but originally, I was thinking the ping noise was a metal on metal noise. sometimes it almost sounds like a whistle though... like a different version of when you blow across the top of a coke bottle (and by the shape of the casing, I think it's entirely possible that this is the case) do you know what makes the sound? I've been trying to figure it out, and I'm kind of stumped.
 
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Congrats on your new valve. I love mine and the sound it makes.

P.S. I think it's a metal on metal sound. Very "medieval blacksmith hammer" like.
 
sometimes when the valve flutters a bit, it sounds more like a whistle though. very curious. I am a fan also.
 
The BPV is post intercooler, so it theoretically should be cooler air being recirculated anyways. BPV/BOV have nothing to do with air temps. End of story.

from what ive read in turbo magazine is that even though the air going to the bov is after the intercooler it is still much hotter and standard air outside. the turbo dramtically raisees the air temp the intercooler only partially cools it down, so you over all temp of the air entering the turbo is much hotter than vta..The trubo is a compressor its heats the air just like an air conditioning system. Just cuase the intercooler cools it a little doesn't mean it cools it down to room temp... "End of Story"...lol
 
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from what ive read in turbo magazine is that even though the air going to the bov is after the intercooler it is still much hotter and standard air outside. the turbo dramtically raisees the air temp the intercooler only partially cools it down, so you over all temp of the air entering the turbo is much hotter than vta..The trubo is a compressor its heats the air just like an air conditioning system. Just cuase the intercooler cools it a little doesn't mean it cools it down to room temp... "End of Story"...lol

true, but I doubt it makes a dramatic effect.
 

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