Massive Boost Spike w/EVO III 16G w/Bullseye "Monster" Housing

[atlguyinbama]

Ok guys I'm stumped.

Here is a quick mod list to begin with.

Built Motor
-Wiseco 9:1 pistons (.040 over)
-Stock Rods
-ARP Hardware throughout
-MLS head gasket
-Balance Shafts removed
-Brian Crower 272's
-Stock Head and Intake Manifold.

Turbo & Exhaust
-Evo III 16g
-Bullseye Power SS exhaust housing w/38mm flapper
-Evo III Exhaust Manifold and O2 Housing
-3" Turbo-back
-Greddy Type-S
-ETS Street/Strip FMIC
-Dejon Tool MBC

Fuel
-Aeromotive AFPR set at 42lbs
-550's
-S-AFC II


Ok, I just got through with the break in of the engine and clutch, and was out trying to do some 3rd gear pulls to do some tuning with the logger and AFC. When I rolled into it, boost spiked to 25-27 psi just as boost came on, and fell back all the way to 12-13psi the rest of the way up to redline. It seems like whatever I did to the MBC (which is tee-d into the BOV line as there are no other nipples), it changed absolutely nothing with either the spike or the settled boost.

Now, I did have to play with the stock WG actuator some to get it to work with the Bullseye hotside (had to shim it out to get the flapper to get even close to closed). The flapper is not closed all the way when not pressurized. Yet I could not see this doing anything but probably cause some slow spool up times. And it does not seem to be binding at any point.

I have studied a lot of posts on here, but none are anywhere near a 15psi spike. This is a new one on me, as Ive never seen anything like it in my 5 years of DSMing. Please Help!!!

 

[gofer]

im pretty sure this is whats happening, maybe im totally off?
if your wga isn't holding the flapper 110% closed then that could be your really bad spiking problem. your actuator isn't recognizing how much your actually boosting until it spikes deep into the 20's, then it pops fully open... thats what makes sense to me. as im sure you know, there should be tension on that wg flapper post. kind of home depot racing but id put some spacers (washers) in between the bolts that connect the wga to the compressor housing so it holds the flapper shut. im sure you'll still spike but it won't be so bad...

my .02, hope it helps.

before you start doing 3rd gear pulls to make sure things are working take off your mbc and just run a vacuum line from the wga to a pressure source just so you know your wg's working... then start turning up the boost.

 

[silver bullit]

Dont tap the mbc into the bov.

 

[atlguyinbama]

Car was ran off straight wastegate pressure for the duration of the break in. At that point it really only pushing 5-7psi (I'm using a 14b actuator, so it should of been around 10-11psi) , but once again I would assume that was from the wategate flapper being slightly open.

As far a the part about the WGA "recognizing" that it is or isn't closed, I just don't peronally see how that would be so. I mean after all the actuator is basically just a diaphragm that once the pressure exceeds the amount the spring can hold, it pushes the rod and opens the flapper.

I already have somewhat of a home depot hack on it now, as I am using 2 nuts to shim it in the manner that you spoke of, just to get it to where it is.

My train of thought was, if its shimmed all the way closed, wouldn't it spike worse as the flapper would theoretically take a split second longer to open fully from a completely closed state, than from a slightly open state?

 

[atlguyinbama]

I have no other nipples to tap it from. The piping for my FMIC does not have a nipple on the j-pipe. Where else can I get the source from?

 

[silver bullit]

Get a tap and die set and make one.

 

[atlguyinbama]

Where do you suggest tapping it at?

 

[atlguyinbama]

Or how will this work?


FTG-QuickTap-CompHSG: atpturbo.com

 

[kenamond]

Take a pressure tester to the WGA and see what pressure is required to start it opening and how much it takes to open it up all the way. As you know, there isn't any way with a typical MBC to run lower boost than this actuation pressure.

Have you tried running with the actuator arm disconnected from the hotside? You might want to do a pull that way and see what the boost does.

Check the wiki on this site. There's a good illustrated article on tapping your compressor housing and putting a nipple in there for your MBC. I'm not sure if that has much to do with your spiking problem, but it certainly won't hurt to get a good boost signal to your MBC.

I'm not sure what kind of MBC you have, but you might want to re-read the installation instructions. Getting it backward or turning it the wrong way might confuse you.

 

[atlguyinbama]

Thanks kenamond, I have tried a vacuum tester on the actuator before installed, opened at 10-11 psi. I will try the arm off. And I'm sure its installed correctly, and I know which way to turn it. Like I stated in my original post, Ive been in DSM's for 5 years. I have installed 6-7 MBC's on either my previous cars, or on friends cars. I know which end goes where. As far as the BOV line goes, I have done that with all the previous cars and have never had anything like this come up.

I have a major feeling there is another issue here that I'm not seeing. I mean I can see the place where you tap your MBC causing a 3-5 psi spike due to slower response, but 15psi? I find that hard to swallow.

 

[gofer]

if it were me id try to source the wga a little closer to the turbo and get that flapper 100% closed. then if it still spiked like that id swap back to the original 16g exhaust side (if you still have it) and see if it spikes.

 

[atlguyinbama]

Any body else have any ideas?

 

[atlguyinbama]

I don't have the original housing as 3 of the bolt holes were stripped. The "monster" housing was just slightly more expensive than a standard replacement. Its made of Stainless Steel and flows better than the OE one, so I went for it.

 

[No_Skillz]

Tap a nipple for the MBC as close to the compressor as you can. On the J-pipe is a popular spot. You definitely do not want to keep it hooked in your BOV line.

Then do a BLT to make sure there are no leaks.

Are these symptoms with the MBC set on the lowest setting?

 

[atlguyinbama]

They are with the MBC set on any setting.

 

[gofer]

damn man... i came back to see how your spike problem was playing out and it doesn't look good, yet.
its spiking because something is "delaying" your wga to see that much boost and open the flapper completely up to maintain 12-13psi... this can only be a few things.

1. the pressure source you have your wga connected to sucks (take that vacuum line off the bov and run it off one of the licp) causing your wga not to see the actual psi your running until your boost gauge is pegged to 30lbs. http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/237982-best-way-install-mbc.html

AND/OR

2. your wga isnt working properly (you mentioned it yourself, the wga is just a diaphram... maybe the spring on the diaphram is getting stuck and its taking 30psi to pop it open)http://www.dsmtuners.com/forums/newbie-forum/274251-video-how-test-wastegate-actuator-wastegate-functionality.html

im sure you have friends with dsm's that have 14b's/16g's laying around with a wga collecting dust on it. see if you can't borrow one, it only takes a second to put one on... use the process of elimination and you'll find your problem.

good luck

 

[sd_ff22]

^^^^Outstanding answer and advice.

 

[gofer]

bump to see if you got the prob fixed... what was it?

 

[atlguyinbama]

Still working on it. I have found a boost leak (notorious throttle body seals), and am waiting for the seals to show up to fix that. I shimmed the actuator again to make sure the flapper stayed shut. I will keep you guys updated.

 

[gofer]

problem solved?

 

[ZenkaiRacerDsM]

Just thought Id bring this back. I have an FP 18g and have been running the same turbine housing from bullseye for years now and have been stuck at stock boost. If I turned the MBC up, it would raise spike not boost. Before the 18g I had the housing in a 14b and it did the exact same thing.

I didnt really care for the longest time because I didnt have the fuel mods to run high boost anyways. But now that I have fuel mods for 20psi or so its pissing me off.

I also had problems with the 14b actuator not fitting correctly with the bullseye housing. Except mine was the opposite. I had to put the arm on the flapper then tighen the bolts down as it pulled on the arm. Im sure this created too much preload on the flapper causing my spike.

Anyways Im tired of messing with it and just ordered an evo 3 housing. As soon as its in Ill throw it on and post the results of happy boosting. Hopefully.

 

[sd_ff22]

the wastgate flapper arm is adjustable. havent heard anyone mentioning that to bring their flappers into spec. i had the housing that gofer now has. it was rock solid and you could set it up for preload with out having to have an adjustable actuator arm.

 

[ZenkaiRacerDsM]

I said screw it and am going with a fully external setup. The fluctuatiing boost is pissing me off. No mattter what I set the preload to it bounces all over the place making it hell to tune.

I want rock solid boost at about 20 psi, so external here I come.