Hey guys. Before I get too deep here I'll give ya a little history.

Before I bought the car it had a Pettit 3" dp and ss mid pipe with a racing beat exhaust. Naturally I had some boost creep, but it was real manageable unless it was cold outside.
Since then I found out the stock air box wasn't sealin well so I replaced it with an apexi twin intake and surprise surprise, boost creep doesn't really cover it...

I'm not really happy with the idea of blowing up a motor, but I also don't want to spend a ton tryin to manage the creep. I'd like to keep it at about 10psi cuz this isn't how the cars gonna stay.

So! What's wrong with puttin an external wastegate in the ic piping and usin a boost controller to run both the factory system and the external? The only potential problem I could think of is the maf sensor position. It would have to be before that or it would run rich, right? Past that it would keep the whole system at 10psi, or wherever I set it.

Let me know what you guys think. It would sure be a lot cheaper than gettin an ems that I won't use in the end anyway.

Thanks a ton!

 

1. Wastegates don't go on intercooler piping
2. FD's don't have a MAF senor (that i know of anyways)


I would say pull your stock turbo's port the stock wastegate and call it a day.

 

I think you are opening up a whole can of worms here. How exactly would you mount the new wastegate? You'll have to modify the exhaust manifold for sure.

+1
Why spend $200+ on a wategate, piping and figuring out how to set it all up when all you have to do is pull the turbos to port the stock wategate? Nevermind that it's free if you do it yourself...

 

The easiest way is to us restrictor plates in the exhaust, but the best way is to port the wastegate.

 

I think you'd be better off just selling the car and getting an all motor car. How does a 12A powered FB sound?

 

HATERS GONNA HATE DAWG. DONT LISTEN 2 DEZ CLOWNS.

WHY NOT GO WIT DEI INSTEAD THO? ITS MOAR E-FICCENT THAN NORMAL TURBO AND YOU DONT NEED WASTE GATES.

 

so you have boost creep with the high flow cat?

 

holy crap I can't believe I missed that !!!


Are we being trolled right now?

 

Well porting the factory wastegates would be a good option if I consistently heard that it works. But I've heard about as many people say they still have creep issues after doing that.

Second, why couldn't a waste gate go in the ic piping? As a matter of fact I've seen this setup and it worked perfectly. All it's doing is bleeding off excess air. Pretty simple idea...

The money wouldn't be wasted because I'll need both in the future. Even if the wastegate is a little small I can sell it and recoup some of the cost.

Again, this motor setup is not stayin in the car forever. It will be there for the next couple years however and I simply want it to run with the stock levels till then. If nobody can give me a legit reason why this wouldn't work (ie maf sensor, if there is one indeed) then nobody really has the grounds to say it's a bad idea. Opinions are wonderful, but I want a solid answer or nothin at all

 

It works if done correctly, worked for me took about 4hrs of work. It wont cost you anything but time. Search the forums there are lots of write ups on it.

If you think a wastegate works of IC piping you are an idiot.

It's not an opinion it's a fact wastegates go on exhaust, not IC piping. Go look up how wastegates work. I got an idea why don't you just poke a hole in your IC coupler so you get proper boost pressure. I'll say it again THERE IS NO MAF ON AN FD!

Port your turbos, grind out the metal behind the flapper so it can open all the way and report back.

 

I think that what your talking about is not a wastegate, it is called a POV(Pop of Valve), kinda works like a wastegate where you set it at a certain boost pressure and when it hits that it opens up. This mounts on the IC piping.

BTW, it makes a crazy sound when it opens, kinda sounds like you pop a tire..

Greddy is the only manufacturer I know off that makes this, there could be others though.

 

Force, I believe I said if you can't give me a legit answer just don't. Here's the ******** version of that same sentence so you'll understand. If ya wanna run your mouth with no good information just to be a *****, just shut up instead. Instead if bein a helpful individual you're just an *** instead. Your sarcasm proves no point other than your ignorance and unwillingness to help a fellow car lover. So please, find someone else to try and bully into your opinion.

Kai, thank you for the correction. I'm glad someone followed my thoughts. I know that procharger uses a bosche "wastegate" as they call it on their systems. It mounts in the upper ic piping and does exactly what I'm trying to very effectively and safely.

Since I've been so nicely reminded that an FD doesn't have a MAF sensor, can someone tell me what it uses to measure the amount if air entering the motor? MAP sensor possibly? Guess I need a little info there before I can go on

 

The FD uses a Speed density-based system it "guesses" how much air is actually being ingested and cannot compensate for significant changes without being reprogrammed.

 

^^ Sup Kai!



That is because as as FORCE said already they aren't porting enough. Go and educate yourself on how a wastegatge works and you will see that what he said makes PERFECT sense.


A wastegate works off the exhaust. when a desired boost level is reached, it opens up and bleeds off (exhaust) to regulate how fast the turbo is spinning. Now if you are creeping that is because the wastegate can't bleed enough out in order to hold constant boost. So the fix is to OPEN it up! quite a simple concept. So you tell me how are you going to mount the wastegate on the IC when it works off the exhaust?


Wow you must be a joy to be around.... You have no freaking idea WTF you are asking and yet you have the audacity to claim that no one is giving you a legit/solid answer.


How about next time you search and read up on your car before you even attempt to post and maybe you will realize what a legit answer is.

 

Hahaha... Tag team of the ********. Sweet. Believe me I understand how a wastegate works. Excuse me for using the term in the same application as a major manufacturer of aftermarket performance enhancing forced induction units. The thought didn't cross my mind that they had termed their device technically incorrect. However, that doesn't mean you can't excuse the slip of terms and POLITELY correct me like Kai was kind enough to do so we could continue in a productive fashion, again like Kai...

Thank you for the info Kai. Can you tell me if that's run through the computer or if there's anything mechanical involved? Definitely somethin I'll have to look up a little more cuz I'm clueless about that one

 

Read the first sentence of my post what dose it say. That is a legitimate answer. Hell here are pics on what you need to do.
Removed that piece of metal so the wastegate door can open

Like so

Now paint the flapper/wastegate door so you know how big you can make it

Grind away stop when you get close to paint

Bleeding off the excess air in your IC system does not fix your problem. The problem being you have to much air going through your exhaust. The wastegate can't compensate for it. Port wastegate or increase back pressure.
MAP is correct.

 

No you don't understand dumbass (well maybe now you do, thanks to us ). If you did you would had never thought it could go on the IC...

Nope you coined the term right. Boost creep and wastegate go hand in hand. You just didn't have any freaking idea where it went or how it works. Now the reason we got on you was not because you used different terminology it was becasuse you are an asshat. Claiming no one gave you a legitimate answer when in fact we did.

Quit being such an pansy and man up you aren't fooling anyone.

 

Sup Elliot! Been a while...I'm suprised Godzilla has not come out yet...LOL



Map(Mass Air Pressure) sensor or commonly referred to as a boost sensor measures boost and sends a signal to the computer so that it can decide which part of the fuel/ignition map to go to. The ECU referrences boost and rpm's and takes the value within that map and applies it to the necessary injectors/ignition.

 

I have a greddy pop off or safety bleed valve with the adjusting screw all the way out at the lowest setting which I think is 0.8bar or near 12psi and I still creep to 1 bar according to the commander. Of course I have a 4" SMB DP and 3.5" open exhaust on stock twins

 

Go get a POV and let me know how it works. I've always wondered why we don't see these often. We're the perfect use case.

 

Actually they were factory on 1st gens:





1st gen turbo engines had that cast piece (no intercooler) between the turbo and the downdraft-style throttlebody and intake manifold. Nissan also use pop off valve on L28ET and VG30ET engines:



You mostly find them on early 80s cars, probably because they did not have an overboost fuel cut or some other electronic way of limiting boost.

Well there's really not much of a point in them anymore. If I overboost enough in our shop STi, it will

1) cut fuel
2) throw a check engine code
3) in the event of knock it will disable the boost control solenoid, retard ignition timing, and revert to the failsafe fuel map which dumps in fuel.

all of that is programmed into a Subaru ECU from the factory. The FD also has a fuel cut to protect the motor and so does every standalone basically. I have ranted about this before. For 95% of applications, disabling the fuel cut when you don't have to is risky and doesn't provide any real benefit.

 

What's your take on them arghx? I realize there's no replacement for solid boost control, but with the stock(ish) twins setups I think they are valid.

 

I'm not against installing them, but I don't think they are necessary. If you overboost enough on a stock ECU you will hit fuel cut. If you overboost on a PFC or any other computer you will hit fuel cut, or you can configure it to retard timing significantly.

If you are overboosting frequently then you have a more fundamental problem that needs to be addressed: either increase wastegate flow or increase restriction in the exhaust. Using a pop off valve is not ideal from a performance standpoint, and as has been pointed out there isn't a 100% guarantee it will vent enough air fast enough.

 

Oh my god, this is a perfect example why this forum is no longer the resource it once was. Noobs coming on here running their mouthes, even to senior members who just gave them the info they need. But they are too stupid to even realize they just got helped, instead they jump on them for pointing out that they obviously know nothing about what they are asking about.

CrewDJ, the reason nobody runs a pop off valve on the charge piping is because it is not the most efficient way to control boost. That is not to say these are not used in other instances, like a supercharger which is nothing like a turbo. On turbocharged cars if you control boost via a pop off valve, this lets the turbo overspool badly to potentially its terminal rpm. Sure you might only be seeing 10psi at the intake manifold, but the turbo is putting out a pressure much higher than that.

The correct way is to use a wastegate. Internal or external achieve the same thing. They just open and close to route more or less exhaust into or around the turbo, thus maintaining a maximum boost level. If you are getting creep that means your wastegate cannot reroute enough exhaust around the turbo to keep the pressure at the desired level. You need to port your wastegate. Plain and simple.

In the future I suggest you dont take offense to people pointing out your errors in logic, rather just listen to the good info they are saying. You must realize this info is very very basic and has no place being discussed on the first page of this forum. A simple set of searches would have led you to this info. Please use the search function.

 

It's possible but it seems like it would take an extreme situation for that to occur. But it gets back to the main point that it is much more efficient to control boost from the turbine side (with a wastegate) than on the compressor side.