ioTus

iTrader: (5)

The blow off valve relieves incoming pressure after the throttle plates close. Without a blow off valve, the intake charge backs up against the throttle plates and pushes back against the cold side turbine, slowing the turbo, which then has to spool back up once throttle is opened again.

At least that is my understanding of why you put a blow off valve on a turbo. I could be mistaken.

craaaazzy

iTrader: (9)

What you are describing is surge but that really only happens if the BOV fails or is opening very slow. If his stock system is working as it should, a new BOV will not help in reducing lag.

DreamInRotary

iTrader: (49)

I know I'll love it! The old system was probably really heat soaked (never got air scooped to it, just passed over it at best) and I never really enjoyed it much.

This is true, I hear your point. More on that later in this post.

It would only melt the W/L (White/Blue) wire from the 2nd gen fuse box to the Main Relay. That's how I thought it was the main relay that was the issue. Nothing else was effected or had issues so that's what I figured it was.

I'll grab some specs on the air filter Wednesday if I remember. It's just a cheap-o from O'Reilly I suspect (came with the FC) and it's working just fine. Will probably be buying a new one of a shorter variety just to help with fitment but I'll have to see while doing the CAI setup on Wednesday morning.

Yeah, this is my understanding of the workings of a BOV as well. Obviously I still have to hook the BOV up to the intake via a vacuum hose to detect the surge back towards the turbo after the throttle closes.

ioTus was right in the fact that it will help my turbo response and lag, here's why:
I never had the stock diverter valve hooked up. You may be wondering why in the world I would do that to myself - running the turbo with no stock BOV. The truth is that it would not work properly for me. As soon as I'd start to build boost, right around the 3500-4000RPM range it would open the BOV. I don't know if it's just something with the unit itself or if it was just my error. I just ran the car without it the whole time it's been swapped in.
So when I'd build boost running without it and shut the throttle there would be a surge backwards towards the cold turbine and it would slow it down I'm sure which resulted in turbo lag. Now that I have a BOV that will be functional I think I'll be able to notice the difference between my throttle play with the new BOV and the old way without one. That and the colder and denser air due to it actually being cooled will help out immensely.

It Runs Again!
I was able to get the Turbo FB running again today! I finished up the wiring enough to start the car (really ghetto way of hooking up the battery, I'll post a pic tomorrow or Wed) and she cranked right over!

Turned out to be the Main Relay that must have popped when I was boosting the car in the yard a while back. Not sure if I have something wired wrong in the car or if that relay was going the entire time. As soon as I plugged it in, hooked up the battery, said a few quick prayers and hoped for the best - cranked the car and it brapped to life! I let it idle for a few minutes and shut it back off and that's as far as I was able to get before work.

Wednesday Morning Plans
Finalizing the mount of the FMIC and its piping
Custom CAI using the stock MAF and aftermarket air filter I have now with some leftover 2.5" FMIC piping and a silicone adapter from the piping to the MAF I bought for this purpose
Wiring in the battery to the storage bin - went and bought some more wire to make it reach the bin since the route is a little longer than expected
Clean the car up, inside and out to make it presentable
Take it down to the buddy's house I was at tonight, working on his monster S4 Audi, and help him finalize his FMIC
Cruise with him and his dad in his dad's 800RWHp Saleen Mustang
Make it out to the local Wednesday night meets I like to attend but have missed the last two
Take some pics and talk with some fellow local rotor heads

Qingdao

iTrader: (3)

Well... I'm gonna chime in on BOV.

I don't think the turbine will be slowed that much by the cold side of the turbo (any more that just normally pushing boost). If it did it would only affect it at idle, and as soon as the throttle is opened the pressure would equalize.


I think the main reason for BOVs are so that the residual boost doesn't blow the throttle butterfly vavles in half when they close. Vacuum on one side with boost on the other doesn't seem like a good idea.


At any rate we can all agree: Having BOV good; Not having BOV bad.

ioTus

iTrader: (5)

Sorry to threadjack for a second Austin - just need to clear some things up here.

you guys got me thinking i'm taking crazy pills here, so i went and looked it up.

http://en.wikipedia.org/wiki/Blowoff_valve
and if you're an anti-wikipedia fanboy, here's something from real tuners

Blow Off Valve FAQ: Read if you are thinking of buying one! - NASIOC

craaaazzy

iTrader: (9)

Glad you found the issue with the wiring. At least it didn't do more damage. And if your stock BOV was not working, then a new BOV will at least help you build the appropriate amount of boost.

iotus, what part are you referencing in the 2 links? The bad part is the rich mixture during lift of, right? But nothing about lag...at least through my quick glance over my phone. The BOV is necessary so that the pressure can be vented somewhere and not cause surge which is bad for the turbo...much like running at full speed and all of a sudden, a brick wall appears in front of u...lol.

ioTus

iTrader: (5)

Not sure about rich mixtures at liftoff, those links point to the definition and function of blow-off/bypass valves.

Which, as you and i have both pointed out, is to eliminate surge. Austin had no functioning blow-off valve, hence adding a functioning blow off valve will decrease turbo lag (and wear) resulting from surge.

We are saying the same thing

82transam

iTrader: (18)

He didn't have one at all? I guess I missed that part. If he was using the stock TMIC I would have assumed he was using the stock inlet pipe (which has a recirculation valve built into it)

Anyway, as said above, most of us (there's a few exceptions) agree that a BOV is a good thing to have, especially if you want your turbo to last.

You guys are all leaving out the most important part - they just sound cool

Also, not to derail the thread too much, but as far as the Suby guys having overly rich mixtures and backfireing/popping etc with an atmosphere dump BOV is because their MAF system is overly sensitive to such things. The FC computer is archaic enough that it doesn't really matter to it what you do with that excess air (the computer isn't precise enough to notice that it's missing lol) at least in my experience. My cars run just fine

DreamInRotary

iTrader: (49)

I think we all completely agree

I actually went through and read those links - thanks man!

It did help me build the amount of boost I'm looking for today, more on that later

Correct sir, no functioning BOV before and now I do have it hooked up.

Some good discussion going on here though - fine with me!

Correct Sean, I did have the stock recirc valve installed but didn't have it working. When I hooked it up to vacuum one time it was constantly opening and not letting me actually boost. Not sure if it was just me or the part, still don't know. All I know is that the car rips now

You're probably a member on that forum that Geoff referred to above I'd bet haha.
But yes, they do sound cool and help build boost safely but you're forgetting something - I can't hear it! With the RB 2.5" down pipe ending right by my feet I can't hear it at all. Sucks.

I took the car out and ripped around in it for a few miles. It builds boost so fast now and there is absolutely no lag whatsoever! I'm making 10psi of boost safely according to AFR's and the car is working amazingly now.

I'll update with pics later tonight, we will have to see how the evening progresses

ioTus

iTrader: (5)

Dood that's such great news! So glad to hear it!

ioTus

iTrader: (5)

(I'm also a member of that forum - used to be a WRX dood)

DreamInRotary

iTrader: (49)

The ghetto way I had the wiring done just to get the car to start:


Where the battery ended up going for now:


Set the Throttle Position Sensor TPS to 1.00v at idle, is much better now!


A couple shots of the Cold Air Intake CAI I made custom just for my application. Will eventually switch spots with the intercooler piping in the radiator surround and the filter will go outside and in front of the radiator

82transam

iTrader: (18)

Amazing how cramped that engine bay starts to get with all the piping isn't it? It's worth it though

And yes I'm on Nasioc, it's where I found my Impreza, but honestly I rarely go on there unless I need parts. To say those guys are immature is probably an understatement...

DreamInRotary

iTrader: (49)

Thanks man!

And I remember, you had a bugeye hatch right? I'm tempted to get a Subi for a winter and daily driver.

It does really start getting cramped fast. I couldn't imagine having the A/C still in there, woulda taken it out no matter what I think.

Good to hear our forum isn't too much like that! I've only been on a few with some 13yr olds (at least that's how old they act) and couldn't stand it.

Some pics to round off the day:

Qingdao

iTrader: (3)

You should get the vac diagrams from an FC to stick on the underside of your hood. Just to complet it

DreamInRotary

iTrader: (49)

Haha I thought that myself too! But nah, if it's up to me I'll be repainting the entire engine bay and the bottom of the hood as well this winter. Needs to be cleaned and shined up and I think that would hit the spot.

I did actually get a lot done to the car today and I'm pretty proud of the progress so far.

Got the car in a familiar position


Had these two goals


Found out why my shifter felt so loose - it has eaten the bushings! The spec on the top of the mount there is the biggest piece of bushing I can find. I could feel a few on the top of the shift rod but don't know where the rest went (I do know, I just don't wanna say it out loud or type it).

So short throw shifter will be ordered way ahead of its time to say the least.


Remounted the engine with the Racing Beat 12a to 13b conversion engine brace


The transmission mount now looks like swiss cheese since I had to remount the transmission when I did the engine. Ah well, it's only temporary anyways


Installed the 2.5" Racing Beat presilencer that I bought used in a package deal with the downpipe but never installed


Didn't get any pics of the engine mount in but whatever.

Car is like 4 times quieter with the presilencer on there, not sure if I like it or not yet - will have to see. Maybe when the rest of the exhaust is on there I can have an opinion. I don't like the angle of the presilencer since it's made for an FC and goes right to the middle of the driveshaft.

Also have cheated on my car with this one:

Thought about trading him even up for the Turbo FB (needs some wiring work). I've always wanted one of them and will have at least one in my future. Ah, I'm terrible.

ioTus

iTrader: (5)

Omg do it

craaaazzy

iTrader: (9)

If that FD is clean, running properly, and he takes an even swap, DO IT!

DreamInRotary

iTrader: (49)

C'mon guys, between you and my fiance my car is already gone and I have this one!

In his ad he says "no trades cash only" but I'm talking to him today on the phone and I'd like to go down and see the car tomorrow night. It has 1,000mi on an engine and turbo rebuild from a local builder who I've met and is good at his craft. You can see that it isn't an unmodded car either (tinted windows, aftermarket rims, drilled and slotted rotors, etc.). An FD has been my dream car since I was 10yrs old and I've caught myself more than once wishing my FB was an FD. It doesn't help that I look at the 3rd Gen Classifieds weekly to look at FD prices. For a running and driving car you're gonna spend $10,000 pretty much and for a modded one it's gonna be $15,000 and more. Jeez, just a shell goes for almost $5,000. So getting a running and driving FD with a fresh rebuild on an even trade for an FB is practically unheard of.

I'll probably just drive down in my 7 to look at it and see if he'd go for it. I don't think I could sell my car on the whim that I could buy an FD though. It would take a while for my car to sell for the price I want for it. If he doesn't want an even up trade I'd probably be OK just walking away and keeping my car and getting an FD in a few years (after college and a wedding, ya know - the important stuff) while still having a Turbo Rotary.

Ugh, decisions and dreams

One more pic, when the ad comes down these'll come out of the build thread anyways:

Shrimp

Lucky. I can't find an FB worth buying to save my life. Damn Louisiana and your big trucks and ****...

Qingdao

iTrader: (3)

Well.... I guess I'm the only one here that wouldn't trade for an FD.

I would trade for a duce or an RX3 in a HURRY!*


*massive rust being a trade breaker.

cfamilyfix

iTrader: (15)

An R100 FTW!!! with an RX3 sp running a close second and would never turn down a duece. FD's are pretty though and I always find myself checking prices locally...

DreamInRotary

iTrader: (49)

Haha if it's up to me, my next vehicle will be a big truck!

I'd much rather have an FD personally, deuces and 3's are sick too but there's always been something about the FD with me.

Same here man, good rundown there!

I'm not really in the mood to update with any details, but:
I've listed up the car for sale. There's a link in my sig to my local CL ad and will list up the 7Club one as soon as I can.

Sad, sad day

ioTus

iTrader: (5)

damn dood if i was a rich sonofabitch i'd buy that and hold on to it until you're better off financially.

its my favorite color, and turbo.

don't budge on the price - it will be hard to move at $7k but i dont want you to sell it really. So you should probably say like $7500 or something.

or add a leading 1 to that number.

Shrimp

How many miles does the engine have on it?