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-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   Recommend the best BOV for my boost levels. (https://www.miataturbo.net/diy-turbo-discussion-14/recommend-best-bov-my-boost-levels-81073/)

Ds1 10-16-2014 11:09 AM

Try now: http://vid745.photobucket.com/albums...5F589251FE.mp4

18psi 10-16-2014 11:32 AM


Originally Posted by blaen99 (Post 1175937)
"@Vlad: Sure, you can do it that way, if you want to potentially take in unmetered air. I would just tune for idle if I had a stock or junkyard engine, but with a TSE engine, I'm not taking any chances. For a BOV like the Forge, all the spring's real job is to keep it shut during vacuum - although Forge may label their weakest spring as a "5-15psi spring", even the weakest spring should be enough to keep the BOV shut under boost in any situation Miata owners run into. Of course, assuming the BOV is properly hooked up, which I seriously doubt it is if it works as the OP says.

TL;DR: Stronger spring = keeps it shut under vacuum easier, opens under boost harder. Find weakest spring that keeps it shut at desired vacuum, done.

unmetered air? who here is still using a MAF? lol


You realize that decel provides the maximum amount of vacuum, so if the bov stayed closed at decel, it would ALWAYS STAY CLOSED right? As in, even after you get into boost and let off, it would remain closed. It would never open, unless being forced open by the charge in the pipes, and if that was the case you'd get compressor surge 100% of the time.

think about it for a second.

Girz0r 10-16-2014 11:45 AM


Originally Posted by Ds1 (Post 1175930)
The EBC works fine, I just haven't tuned it that much yet. Honestly I don't really care about it at this point but I appreciate the input.

:facepalm: You should disconnect your ebc, just sayin

I don't have any vacuum fittings around the house so I'll try and pick some up today and make all of you happy when it ends up being something stupid and I look like an idiot. Thats usually how most threads end for me ;)

Why buy more hose, you have most of it under the hood.

:hustler:

Ds1 10-16-2014 12:06 PM

1 Attachment(s)
I meant fittings, but I ended up finding some.

Mom! Dad! Look! I did a thing!
https://www.miataturbo.net/attachmen...ine=1413475585

Okay, so now the BOV is defiently opening, I can now hear it "woosh" even at lower boost levels....

But it still does that "te te te te te" sound after venting.

BUT, I noticed that it makes that sound even when in vacuum still. Logic tells me it's not possible to have compressor surge in vacuum, even if it's almost to boost levels (0-10 vacuum In.Hg).

So... Not compressor surge, but BOV flutter?

18psi 10-16-2014 12:11 PM

ok, now you're getting somewhere.

does swaping springs change the flutter at all? I can't remember which would tend to make it do that more (there are valid arguments for both stiffer spring and softer spring)

Girz0r 10-16-2014 12:17 PM

I'd expect a little chatter from the bov, but now its prob a better sounding "te te te te te" than before.

The next thing I'd do is disconnect your EBC and run from the compressor housing strait to the wastegate. (very easy, just leave the wastegate line plugged in, swap from the EBC to the compressor house)

You'll have lower boost, possibly not as quick spool up when building boost. BUT! I bet this eliminates some of the extra "te te te te" after it vents. I only experience bov chatter in very low 0-5psi range, not really pushing the car.

Edit* Also, try swapping springs as 18 mentioned! ^^

Ds1 10-16-2014 07:29 PM

Bypassed the EBC. Didn't really do much. I mean maybe it helped a tiny bit but that's it. Using the wastegare directly actually wasn't horrible. I only went for a very quick drive though so couldn't evaluate much.

I can try another spring tomorrow but I don't see why either springs getting heavier would help. I also still don't know if I have BOV flutter or compressor surge lol, but at this point I would assume it's flutter since I definetly hear the valve opening on throttle lift. I don't see how a valve that large could not be venting enough air, unless it has to do with the second smaller spring closing too fast or something.

triple88a 10-16-2014 08:57 PM

Te te te te is caused by the secondary valve. On mine i had to install a thinner spring. Unfortunately they dont sell thinner springs from forge for it so I had to go get one from ace hardware.

It's caused by the pressure wave forcing the valve open as it bounces back and forth. It opens at higher boost however at low boost it's not enough so it's not blown open.

Ds1 10-17-2014 01:00 AM

Why didn't you say that before :-|

Does it leak at idle now that you have the thinner spring? I hate that sound and I'd like to get rid of it.

So good news is it looks like my BOV is fixed. Bad news is it sounds like a gay fish.

triple88a 10-17-2014 01:20 AM


Originally Posted by Ds1 (Post 1176258)
Why didn't you say that before :-|

Does it leak at idle now that you have the thinner spring? I hate that sound and I'd like to get rid of it.

So good news is it looks like my BOV is fixed. Bad news is it sounds like a gay fish.

Well i'm pretty sure i explained it when i said to remove the small valve and test it. It only leaks between 60 and 80kpa because theres just enough pressure made by the turbo to force it open and the main valve is still open. Over 80kpa the main valve closes and the leak goes away.

Ds1 10-17-2014 12:10 PM

I see. So mine must be venting all it needs down to about 80kpa, but thats when I hear the flutter.

Now I'm wondering what the TurboSmart valve would be like, hahaha....

18psi 10-17-2014 12:13 PM

turbosmart is a single, so it shouldn't have that issue

I guess now we know why forge sells both the dual and the single, and the dual is cheaper huh? lol

Ds1 10-17-2014 12:46 PM

Hahahah seriously. I guess sealing at idle as requires a mandatory ricer sound.

triple88a 10-17-2014 08:15 PM

The dual valve is 10 bucks more expensive than the single... quit spreading nonsense guys.

DNMakinson 10-17-2014 10:03 PM

This is what I bought: 007P in Black

Recommended to put side outlet to pressure, 1" filter on the other. Works well, and more consistently than the MITSUBISHI I pulled off.

I don't think it even leaks at low vacuum, but I'm running the blue spring.

Yes, less expensive than the double piston, especially since it came with the 3 springs.

Ds1 10-18-2014 12:41 PM

How much boost do you run with the blue spring?

DNMakinson 10-18-2014 01:01 PM

Max at this time is 8 psi. I agree with Vlad, I think that is nearly irrelevant. I don't want my BOV to act as a boost fuse. To be honest, not a lot of difference between the various springs. The manifold line is the main component driving the action.

triple88a 10-19-2014 01:06 AM


Originally Posted by DNMakinson (Post 1176573)
Yes, less expensive than the double piston, especially since it came with the 3 springs.

If they have specials sure.. Mine didnt come with any springs but the stocker.


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