Check for a boost leaks first. You may have to turn the boost down as a 16G will flow more air(cfm) than a 14b at that given boost. You'll need to have the supporting mods to turn the boost up on a stock fuel system. Hope this helps a bit.

i'm not trying to run more boost though. I also upgraded to a walbro 190 fuel pump. But when i turn the boost controller either up or down it still does nothing. Thats the main problem that is bugging me because when i drive i have to flutter the gas pedal and keep watching my boost guage. i would just like the mbc to work correctly first so i can put my foot fown on the gas when i'm trying to merge and worry just about driving. Not have to watch my guage and the road while ilm trying to drive on it , if this sounds confusing sorry, just got to work and really don't feel like being awake.

Check the lines on your egr valve. I had this happen to me. I did a boost leak test and for some reason it didn't find it that way. Check all the vaccum lines all over the motor.

Are you runnin on stock 450cc injectors? do you have an adjustable fuel pressure regulator?

If you are using stock injectors then you are out of fuel when that happens.....

If you don't have an adjustable fpr then get one asap! and make sure base pressure is correct.

My car was doing the samething. I changed the plugs and that fixed it.
Check wires and plugs. Also thats alot of boost to be running on a 16g with just a 190lph pump upgrade

check your injector seals as well...

Could you clarify what you mean about the MBC not working? Does it just run at 15psi no matter what? Explain this in a bit more detail, and I'm sure we'll start suggesting other potential problems.

As was already mentioned, the 16g is more efficient than a 14b, so you'll flow more air at the same level of boost, and this puts more demand on the fuel system.

The word on the street is that a 190lph pump *will* overrun the stock FPR at low load and low rpm, but that as you inject more and more fuel per second (increase load/rpm), the overrun will go away. Some folks seem to live with that, but the "right" thing to do is get an AFPR.

Sorry, I will clarify. It will boost up to 20, found that out the first time i tried boosting on the 16g. So i turned it down, went again and it went all the way to 20 again. That is what i mean by not working.

Yes i still have the stock 450cc injectors, and stock fpr. I was planning on upgrading both those in the next 2 weeks after i get paid and have money to do so. Thanks for all the info guys. Now can i still drive my car daily with how it is, or will i just be damaging it more like this, even if i just lay off the boost?

I knew with getting the 16g that it flows more and i would have to upgade the injectors and fpr, but a couple people i talked to said it was ok to run it on those while they are still stock. So i guess now i will def be upgrading sooner than later.

One last thing, if it is still safe to drive daily and boost just to get i traffic and all what is a safe boost level, 10psi I would be guessing with what i have?

Something to consider is you may be getting boost creep. It may be hard to run low boost til redline until you fix the boost creep, if that what it's doing. Regaudless you should be safe @ 12psi or less.

It sounds like it might be boost creep. There are a couple of test you can do to find out if it is actually creep and if so, what options you have.

First test is to disconnect the WGA arm from the lever on the turbine housing and check that the lever turns by hand (cold motor or you'll burn yourself). If it's not turning freely, you need to fix that; the WG can't bypass the turbine if the lever won't turn to open the WG.

If it turns freely, leave it like that and do a pull. If boost stays below 5psi or so, the WG is capable of bypassing enough exhaust around the turbine that it doesn't build boost. If it still creeps up in boost, you have to either do some porting, get an aftermarket WG (external, for example), or you have to get supporting mods to be able to run 20psi or whatever it's creeping to.

But wait...there's more! If you don't creep in that test, reconnect the actuator arm to the lever and run a vaccuum line straight from the j-pipe to the WGA nipple (bypass the MBC) and do a pull. This should limit boost to around 12-ish psi. If it creeps to 20psi again, the WGA is not opening the WG enough, and the flapper is still partially blocking the WG flow so that it can't bypass enough exhaust (until you get to 20+psi). In this case, you can either go external WGA or check out the peepers WGA mod (tech article exists), but that requires hacking and welding and might not be something you're equipped to do. The problem with the WGA is described in that tech article along with other boost creep issues.

For now, you can use your foot to limit boost, but I'd keep it below 12psi or something to be safe. If you have a logger, log a 3rd gear pull where you're limiting boost to 12psi as best you can with your foot and see if everything looks good. If so, you're probably okay to drive the car for now (but limiting boost with your foot) until you can fix the problem.

Thanks i will try to get as much of those tests done today when i get home from work. Another question, I don't know much at all about external wastegates, installation, and all. If i do need to go external: What wastegate is a good choice for me, how would i go about installing one (haven't looked at tech article yet), and i'm confused as to what where the WGA nipple is, do you have a pic that i could look at, thanks.

PCV valve. My car was doing the same as yours and the problem went away when I replaced the bad pcv valve. Just a wee little thing that can cause a headache. I'm not saying that is your problem, it does sound like you're getting boost creep but it's also something to check into. The AFPR is mandatory as well.

Well i just did 2 pulls with the WGA arm still on and it spiked at 20 then went down to 15 and stayed, then the next time it spiked at 18 and went and stayed at 15. I just did those 2 pulls just to be sure of the problem, when i get home i will try to get the arm off and do a couple pulls then and i will report back what happens then.

I dont have my mbc yet but my psi jumps right up to 15-16 psi and hold the whole rev range and no fuel cut. Im going to rewire the fuel pump and run it at 18 psi on the track and turn it back down.

PIMking said:

I dont have my mbc yet but my psi jumps right up to 15-16 psi and hold the whole rev range and no fuel cut. Im going to rewire the fuel pump and run it at 18 psi on the track and turn it back down.

Click to expand...

I would *not* recommend running 18psi on stock fuel. If you lean out the motor, the oxygen runs out of fuel to burn, and it'll find other fuel...namely the aluminum head and piston crown. Don't burn up your motor. Get a logger before you increase your boost and make sure you're not leaning out. You might find that the stock fuel system can support 18psi, but you don't know that without logging at that boost and witnessing good IDC and O2v.

g00s3y said:

Thanks i will try to get as much of those tests done today when i get home from work. Another question, I don't know much at all about external wastegates, installation, and all. If i do need to go external: What wastegate is a good choice for me, how would i go about installing one (haven't looked at tech article yet), and i'm confused as to what where the WGA nipple is, do you have a pic that i could look at, thanks.

Click to expand...

The two options I've seen for external gates are:

- External gate mounted onto an aftermarket exhaust manifold. The manifold has to be flanged for an external gate.

- External gate monted onto an aftermarket O2 housing. You'd remove the stock flapper from your turbine housing so that the hole is wide open. Gated exhaust goes out the hole, and the O2 housing has a flange for the WG, then the outlet from the WG goes into another pipe that rejoins the turbine exit flow. With that design, you don't have to worry about the flapper from the stock WG only opening a little bit. However, this option will not help you if you still creep in the experiment where you disconnected the WGA arm from the lever (in that test, the flapper is all the way out of the way, so if you still creep, an O2-mounted WG won't help).

The WGA is the gold-colored "can" bolted to the turbo compressor housing. It should have a nipple on it. Depending on the turbo, the other end of the boost control vaccuum line where boost pressure signal originates will either be directly on the outlet side of the compressor housing (nipple threaded directly into the compressor housing) or on the j-pipe. For the other test I had mentioned in the earlier post, you'd run a vaccuum line straight from the compressor/j-pipe nipple to the nipple on the WGA. That will feed the WGA an unaltered boost pressure signal (bypasses the boost controller). The WGA has an actuation pressure. If a pressure signal less than the actuation pressure is applied to the WGA nipple, it won't do anything. Once it reaches the actuation pressure, the WGA starts to extend the actuator arm (which turns the lever and opens the WG flapper inside the turbine housing). As pressure increases, the arm eventually is fully extended (the WGA "bottoms out"). The boost controller hides some of the boost pressure signal from the WGA so that the actual compressor boost can go higher than the WGA actuation pressure...the more boost the controller hides, the higher the boost you'll run before the WGA starts to "actuate". So if you bypass the boost controller, you should limit boost to roughly the WGA actuation pressure...which is around 12psi but can vary a bit for different turbo models. Note that it is not possible to go below the WGA actuation pressure via a boost controller; the only way to go lower is to disconnect the actuator arm from the lever...which gives you close to zero boost.

End of WG 101

kenamond said:

I would *not* recommend running 18psi on stock fuel. If you lean out the motor, the oxygen runs out of fuel to burn, and it'll find other fuel...namely the aluminum head and piston crown. Don't burn up your motor. Get a logger before you increase your boost and make sure you're not leaning out. You might find that the stock fuel system can support 18psi, but you don't know that without logging at that boost and witnessing good IDC and O2v.

Click to expand...

I plan on getting a bigger fuel pump and injectors with fpr but the logger will be bought this week.

kenamond said:

The two options I've seen for external gates are:

- External gate mounted onto an aftermarket exhaust manifold. The manifold has to be flanged for an external gate.

- External gate monted onto an aftermarket O2 housing. You'd remove the stock flapper from your turbine housing so that the hole is wide open. Gated exhaust goes out the hole, and the O2 housing has a flange for the WG, then the outlet from the WG goes into another pipe that rejoins the turbine exit flow. With that design, you don't have to worry about the flapper from the stock WG only opening a little bit. However, this option will not help you if you still creep in the experiment where you disconnected the WGA arm from the lever (in that test, the flapper is all the way out of the way, so if you still creep, an O2-mounted WG won't help).

The WGA is the gold-colored "can" bolted to the turbo compressor housing. It should have a nipple on it. Depending on the turbo, the other end of the boost control vaccuum line where boost pressure signal originates will either be directly on the outlet side of the compressor housing (nipple threaded directly into the compressor housing) or on the j-pipe. For the other test I had mentioned in the earlier post, you'd run a vaccuum line straight from the compressor/j-pipe nipple to the nipple on the WGA. That will feed the WGA an unaltered boost pressure signal (bypasses the boost controller). The WGA has an actuation pressure. If a pressure signal less than the actuation pressure is applied to the WGA nipple, it won't do anything. Once it reaches the actuation pressure, the WGA starts to extend the actuator arm (which turns the lever and opens the WG flapper inside the turbine housing). As pressure increases, the arm eventually is fully extended (the WGA "bottoms out"). The boost controller hides some of the boost pressure signal from the WGA so that the actual compressor boost can go higher than the WGA actuation pressure...the more boost the controller hides, the higher the boost you'll run before the WGA starts to "actuate". So if you bypass the boost controller, you should limit boost to roughly the WGA actuation pressure...which is around 12psi but can vary a bit for different turbo models. Note that it is not possible to go below the WGA actuation pressure via a boost controller; the only way to go lower is to disconnect the actuator arm from the lever...which gives you close to zero boost.

End of WG 101

Click to expand...

also off the exhaust housing as with forced performance turbos

sounds like a boost leak. i would check your intercooler piping.

kenamond said:

The two options I've seen for external gates are:

- External gate mounted onto an aftermarket exhaust manifold. The manifold has to be flanged for an external gate.

- External gate monted onto an aftermarket O2 housing. You'd remove the stock flapper from your turbine housing so that the hole is wide open. Gated exhaust goes out the hole, and the O2 housing has a flange for the WG, then the outlet from the WG goes into another pipe that rejoins the turbine exit flow. With that design, you don't have to worry about the flapper from the stock WG only opening a little bit. However, this option will not help you if you still creep in the experiment where you disconnected the WGA arm from the lever (in that test, the flapper is all the way out of the way, so if you still creep, an O2-mounted WG won't help).

The WGA is the gold-colored "can" bolted to the turbo compressor housing. It should have a nipple on it. Depending on the turbo, the other end of the boost control vaccuum line where boost pressure signal originates will either be directly on the outlet side of the compressor housing (nipple threaded directly into the compressor housing) or on the j-pipe. For the other test I had mentioned in the earlier post, you'd run a vaccuum line straight from the compressor/j-pipe nipple to the nipple on the WGA. That will feed the WGA an unaltered boost pressure signal (bypasses the boost controller). The WGA has an actuation pressure. If a pressure signal less than the actuation pressure is applied to the WGA nipple, it won't do anything. Once it reaches the actuation pressure, the WGA starts to extend the actuator arm (which turns the lever and opens the WG flapper inside the turbine housing). As pressure increases, the arm eventually is fully extended (the WGA "bottoms out"). The boost controller hides some of the boost pressure signal from the WGA so that the actual compressor boost can go higher than the WGA actuation pressure...the more boost the controller hides, the higher the boost you'll run before the WGA starts to "actuate". So if you bypass the boost controller, you should limit boost to roughly the WGA actuation pressure...which is around 12psi but can vary a bit for different turbo models. Note that it is not possible to go below the WGA actuation pressure via a boost controller; the only way to go lower is to disconnect the actuator arm from the lever...which gives you close to zero boost.

End of WG 101

Click to expand...

Thanks a lot, i will be doing the tests this weekend at my parents, along with installing a fuel lab 515 complete AFPR kit. Been using the gf car cause i don't want to be taking any risks.

And i wish i would've known about going external before, my new evo III manifold was pretty much a waste then.

g00s3y said:

Thanks a lot, i will be doing the tests this weekend at my parents, along with installing a fuel lab 515 complete AFPR kit. Been using the gf car cause i don't want to be taking any risks.

And i wish i would've known about going external before, my new evo III manifold was pretty much a waste then.

Click to expand...

You can still do an external WG mounted on an O2 housing. Or you can sell the evo mani and buy one flanged for a WG. I personally prefer the O2-mounted WG setup to the typical #1 runner WG, but plenty of folks mount it on the mani without problems.

EDIT: As far as the big boost spike you're seeing, how is your MBC hooked up? Shorter lines tend to decrease spikes. And you should get your boost source from the compressor outlet, not the BOV line (not saying you are, just saying you shouldn't) My Joe P IL MBC would spike to 16 and settle on 15. The lines are maybe 2 feet total, but if I wanted to, I could make them about 6" or so total...but I don't have any boost control problems, so I won't bother.

Ok well i got the afpr on, big difference. Runs much much smoother, and i feel like i gained a little bit of low end torque. Boost problem is still there, but no more bad jerking when i hit 15, now it just feels like its pre-igniton or a tiny backfire. I will most likely be going the exhaust manifold wastegate way. I don't really know much on what i need to do a o2 wastegate setup. Soooo anyone looking for a practically brand new evo III exhaust manifold?