Severe boost creep and ECU not hitting overboost protection? FML - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 12-23-2010, 12:09 AM   #1
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default Severe boost creep and ECU not hitting overboost protection? FML

So since I replaced the turbo, I haven't really had the opportunity to get on it very much. Well tonight I was out on the highway and was playing around a bit and rolled into 4th. Everything felt fine but up on the top end of the revvs, the car felt "flat" so I looked at the boost gauge and saw 20psi! WTF? I had just moved boost signal to after the intercooler and turned down the MBC a bit. So I pulled over and routed the boost signal back to how it was, off the compressor housing to the MBC to the wastegate. Jumped in the car and saw boost creep up past 15psi and backed out of it. So I pull over again and turn the MBC down even more.. 3/4 of a turn. Same thing. Pull over...again... and actually uninstall the MBC and run straight wastegate. Now the throttle response feels a bit more numb, but I get back on it. Boost runs up to 6-7psi at first...at above 5,500 rpm boost starts going up to 13-14psi (the MBC was set to 13psi). OK, so now I'm getting boost creep...great. Never had a problem with this before...even in cold weather.

The thing that scared me is that the Hydra didn't activate the 15.5psi boost cut that I have set. Why? What the hell? Great way to blow my new engine. Is there a specific setting I need to go check?

The ONLY thing I can think of that might cause the creep is that when the turbo was put back together (by a professional shop) that the compressor housing wasn't perfectly back in it's location..it was a few degees off. I realized this when I was putting it back in and noticed the charge pipe didn't want to slip right back on as I have done before. The only thing I can think to do is unhook the actuator arm and make sure it's in correct alignment and isn't binding up...other than that...I'm stumped. A 2560R shouldn't have any problems with creep on the internal wastegate..it's never been an issue before. When I took the CHRA out and inspected the exhaust housing, I did find some very fine cracks around the wastegate port..and they were on the side facing out...which shouldn't be a problem.

Ideas?
Doppelgänger is offline   Reply With Quote
Old 12-23-2010, 01:10 AM   #2
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

unhook the gate, see if it over-boosts. Make sure there is a hard-cut on fuel or spark for overboost protection.
hustler is offline   Reply With Quote
Old 12-23-2010, 01:11 AM   #3
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,207
Total Cats: 2,587
Default

Definitely check the wga 1st. probably the easiest thing to start with.
Also I'd figure out the lack of overboost protection. That is extremely bad to not have.
When dialing in my boost my ms would cut so hard I thought I'd break engine mounts lol.

good luck
18psi is offline   Reply With Quote
Old 12-23-2010, 09:15 AM   #4
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Yeah, I probably saved my motor with overboost protection on a couple occasions.
hustler is offline   Reply With Quote
Old 12-23-2010, 10:23 AM   #5
Elite Member
iTrader: (10)
 
leatherface24's Avatar
 
Join Date: Dec 2006
Location: Pembroke Pines
Posts: 4,033
Total Cats: 2
Default

BAH let that **** creep. Im doing 23psi on my stock **** and its held together through rough *** abuse so far
C'mon be a man and get blow'd up again

leatherface24 is offline   Reply With Quote
Old 12-23-2010, 10:39 AM   #6
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

I wouldn't care for the high boost....if it were tuned to handle it.
Doppelgänger is offline   Reply With Quote
Old 12-23-2010, 11:11 AM   #7
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

My current Hydra + 2560 overboost protection = spark blowout winter project is porting the turbine housing through BEGi before I get a set of Savs COPs. After the 3" exhaust it would creep to 14-15psi on wastegate. Then I rebuilt the engine and overboost now tries to go through the roof at like 4500 rpms - the ECU is supposed to have its own overboost protection, but the spark blows out first
fooger03 is offline   Reply With Quote
Old 12-23-2010, 11:46 AM   #8
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,110
Total Cats: 518
Default

If I recall correctly, for any rev or boost limit it's safest to run both fuel and spark cut, especially with a turbo. Just an FYI tidbit for you.

Keep in mind your MBC has nothing to do with the PSI you see on the boost gauge. If your flapper valve is bound up just a little bit, it could take 20psi through the MBC to make the wastegate force the flapper valve open. Vise versa if your flapper valve is looser than a previous setup, although it doesn't sound like that's your problem. Ideally you shouldn't have much bind at all in your wastegate system, although you wouldn't know until you disconnected it and felt it by hand.

Isn't this a brand new turbo from ebay? If so I'd do what Hustler says and disconnect it, making sure it isn't bound up somewhere. And than start from the bottom going up, compared to what you're doing now, which is starting above your boost level and going down. Unscrew your MBC until it falls apart, but it back together with a single thread, and work your way up to your boost target. Start with your boost signal coming from the pre-TB position, because it will change compared to the compressor housing source.
curly is offline   Reply With Quote
Old 12-23-2010, 01:47 PM   #9
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

Well, I did what I could while I was out on the road. I'll convert to the post intercooler signal once I stabilize boost using the compressor as the source. I'm thinking it HAS TO BE bind in the actuator arm. I mean, running off just the WG can I shouldn't get more than 6psi at all...no boostcontroller to throw things off. WG boost is WG boost.

No, no eBay turbo...genuine Garett.

And for the record, when I switched the boost signal to post-intercooler, I noticed throttle response went down. It took more throttle to get into boost then before. As soon as I went back to comppressor-sourced signal, the car felt much more 'egar' when throttle was applied.
Doppelgänger is offline   Reply With Quote
Old 12-23-2010, 07:08 PM   #10
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

OK, so I got under there and played with the actuator and junk. I disconnected it and opened the wastegate flapper and pressureized the actuator to see how far off/how much bind it had when open and was surprised to see the arm about 7/8" of an inch to the side.

My test rig consisting of a small air compressor and some hose. This allowed my to actuate the wastegate.



The misalignment-



So I adjust the actuator for a closer alignment when open-





Guess I'll be hitting the road soon to see if it works.
Doppelgänger is offline   Reply With Quote
Old 12-24-2010, 12:22 AM   #11
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

FM upgraded their wastegate actuators sometime before June '08 from that adjustable actuator to a fixed length "bent arm" design. I think there was something about it working better. Also make sure that your actuator mount is stiff, it sounds like FM had a flimsy mount years back, and upgraded it (also sometime before June '08)

Also, did you do anything that could have changed the timing? Retarded timing will easily cause your overboost. Regardless of how far open the wastegate is.
fooger03 is offline   Reply With Quote
Old 12-24-2010, 01:48 AM   #12
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

Yeah I saw that FM did that with the WG, but when I was at FM's Summer Camp last year, Jeremy and Keith looked at that and we discussed it. They said if it wasn't causing problems that it should be OK, esp. with the spacers on the WG mount that were aligning it properly. The mount itself is pretty damn stuff too....soooooo I dunno. I did notice when I was playing with the actuator that it was impossible for it to move the entire sweep of the wastegate flapper...which I found strange. Almost like if I wanted it to open and fully open the flapper that the flapper wouldn't be fully closed out of boost...or if I wanted it fully closed out of boost that it didn't have the reach to open all the way. I adjust it it to about the middle of this as best as I could.

However, I went back out tonight and had my hopes up...but they were shot down pretty quickly. On the MBC, it was set to about 11psi...and that was reached, but boost quickly started creeping past 15 and I let off. Once again, I reverted back to just the WG with no MBC and boost is much slower to reach 6-7psi..and keeps creeping up to 15-16psi (on the gauge). It feels like a big turbo now...slow to get into boost and a steady climb to 15psi+. I don't knwo what I am going to do*. My next logical step is to get a new exhaust hausing, have the WG ported and drill out the holes for 10mm hardware.

* I did not know that timing can cause boost to creep. I have not made any changes to the map, but tomorrow I will re-load a map and do some datalogging. How can retarded timing cause creep?
Doppelgänger is offline   Reply With Quote
Old 12-24-2010, 03:23 AM   #13
Elite Member
 
Join Date: Jul 2005
Location: Anacortes, WA
Posts: 2,479
Total Cats: 116
Default

Did you change your timing belt recently?

I’ve seen weird sudden boost creep issues with a cams off. Like it Makes a bunch of uncontorollable boost but doesn’t make more power.

Another issue I have seen with slow to rise boost is the door inside catching on the edge of the hole and not closing all the way. A piece of safety wire on the post on the door inside the outlet housing made it so it wasn't so loose and it stopped catching.

Bob
bbundy is offline   Reply With Quote
Old 12-24-2010, 03:26 AM   #14
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,207
Total Cats: 2,587
Default

Quote:
* I did not know that timing can cause boost to creep. I have not made any changes to the map, but tomorrow I will re-load a map and do some datalogging. How can retarded timing cause creep?
By creating more exhaust gasses from unburnt fuel.
But I really doubt that that is your issue. Very unlikely IMHO.

I would port iwg hole and make sure its barely smaller than the flapper (be careful not to get carried away or your hotside is ruined).

I ported mine before putting it on, and although everyone and their mother was claiming that I'm insane to run IWG on a 30r I barely get creep. Like 1psi from 5500-6. Nothing drastic at all.

Did you change the hotsides when swapping in this turbo?
From your previous thread I got the feeling that you were going to keep your old hotside (and left it still bolted up) and just swap chra and comp.
18psi is offline   Reply With Quote
Old 12-24-2010, 11:43 AM   #15
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

Correct..just changed the CHRA...retained my compressor and hotside. I had an issue one time long ago where I was tweaking something about put the car back together and took it for a spin and saw the boost spike like crazy...just one time...a long time ago. I remember pulling over, turning the MBC down a touch...like 1/64 of a turn and boost retrned to normal. Not that I think it has to do with this, but I just remembered that because it scared the **** out of me and was really out of the blue. That was like 2 years ago.
Doppelgänger is offline   Reply With Quote
Old 12-26-2010, 10:44 PM   #16
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

OK. So I managed to some datalogging. This was done on just the WG. Boost crept up to 16psi and I noticed that injector duty cycle was in the 90's!!! Anyway, here is the .CSV file so anyone interested can look for yourself.

The run was from a stand..so 1 & 2 weren't WOT as I would have ended up off the road . I go into 4 & 5....give it a rest and go WOT in 5th. It's clear the longer WOT is held, the more boost creep. In 3rd gear, I barely get 11psi, 4th I get 13 and on the 5th gear run it goes just over 16psi. It's also in the mid-20's *F outside.

I don't know what to do. I guess the next step would be to attain a WG can to compare to mine. Maybe it's not opening all the way? See post #12 above about actuator not able to cover the same range of the flapper. If it's not that, I guess I'll have to buy a new exhaust housing...but this should have to be done as I had YEARS of driving with no boost issues at all...it's not like the CHRA has different blades that would flow significantly more and cause an issue, it's the same specs, same turbo...the WG hole should be able to flow just fine.


Anyone have a WG actuator like what is pictured above that I can borrow?
Attached Files
File Type: zip overboostgeares12345.zip (10.3 KB, 73 views)
Doppelgänger is offline   Reply With Quote
Old 12-27-2010, 08:47 AM   #17
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

For the record, I found overboost protection on my way to work. I tinkered with everything again...put it all back the way it was before and put larger signal hoses on the turbo/MBC. Boost builds retarded fast but quickly pisses the Hydra off and it shuts down the party. I didn't have too much time on the way to work to kee padjusting it, but I will later to see if I can get into boost without the Hydra trying to make a Civil War reinactment behind me.
Doppelgänger is offline   Reply With Quote
Old 12-27-2010, 09:42 PM   #18
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

Well, I wired the WG flapper fully open and went for a drive..........




















...and achieved 15psi! FML
Doppelgänger is offline   Reply With Quote
Old 12-27-2010, 11:48 PM   #19
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,110
Total Cats: 518
Default

Dude, something is seriously wrong. I was getting 3-4ish psi between 6 and 7k with my shitty greddy wastegate flapper just dangling. You musta left a beer can inside the down pipe or something.
curly is offline   Reply With Quote
Old 12-28-2010, 12:04 AM   #20
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Sep 2007
Location: Charlotte, NC
Posts: 6,868
Total Cats: 66
Default

Nothing in the exhaust...nada....zip....zilch....zero.
Doppelgänger is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 12-15-2017 09:00 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Going back to stock. Need some 1.6 parts. Trent WTB 2 10-01-2015 01:15 PM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:45 PM.