home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > performance & modifications

Reply
 
Thread Tools Display Modes
Old 10-03-2020, 01:57 PM   #1
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default Boost Gone Wild

The essence of the problem is that I'm unable to control boost.

The motor is a 94 b230ft. It's been converted to microsquirt. It has LS2 truck coils, Red fuel injectors, 3 in custom downpipe, Open 3in Exhaust, oversize Pistons, new valve job, Red fuel injectors, walbro in tank pump.

My ambition was to raise boost to approximately 12 PSI. My first attempt included an electronic boost controller. I never was able to get that to work and boost levels remained at factory settings. Roughly 7.5 PSI. I then introduced a manual boost controller. Immediately it became clear that the Boost was increasing unchecked. I double-checked the plumbing for the manual boost controller and determined that it was plumbed properly but even with the manual boost controller essentially open presenting no restriction or resistance to the Boost signal the wastegate was not effective in limiting the amount of boost. I suspected a bad wastegate but it seems to test okay on the bench. I replaced it anyway with an aftermarket type from Kinugawa. I started with a 0.8 bar Spring yet still the Boost climbed 2 in excess of 14 PSI 4500 RPM. I switched out the spring to a 0.6 bar and while boost was equally uncontrollable the Boost curve did change in that at any given RPM the Boost was lower with the 0.6 spring than it was with the 0.8 spring although with both Springs the Boost was headed to catastrophic levels.

At this point I suspected some mechanical issue so why tested the wastegate with a hand pump while fitted to the turbocharger on the motor in the car. The external actuation observed seemed appropriate. I've then suspected that perhaps there was some mechanical problem with the wastegate itself inside the turbo housing. But after removing the downpipe and again observing the wastegate Actuator, it seems to be consistent with normal operation.

The wastegate actuator is connected to the turbo housing nipple with a short piece of new silicone hose. I've checked to be sure that the turbo housing Port is not clogged or blocked in any way.

If anyone has any ideas as to what's going on here, I would sincerely appreciate hearing them. I'm really at a loss for what's happening. Complicating matters is that this is a track only car without registration so my only opportunity to identify these issues is at the dyno and that is a bit of a hassle never mind the expense.
SwedishKnievel is offline   Reply With Quote
Old 10-03-2020, 03:22 PM   #2
VB242
F*ck 12
 
VB242's Avatar
 
Join Date: Sep 2011
Location: In my 15x20 Corona cell
Default

What turbo?
__________________
"i will destroy all of you!"
-Sheldon Plankton

Booty Scooty
https://youtu.be/i4oAOZ8nbq4
VB242 is offline   Reply With Quote
Old 10-03-2020, 04:16 PM   #3
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

Td04h 13c
SwedishKnievel is offline   Reply With Quote
Old 10-03-2020, 04:26 PM   #4
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

WG operation video with psi callouts

https://youtu.be/cmBeJMUa1NY
SwedishKnievel is offline   Reply With Quote
Old 10-04-2020, 08:42 AM   #5
MadDog_945
Våga Vägra 8V
 
MadDog_945's Avatar
 
Join Date: Apr 2006
Location: Lower Saxony
Default

that turbo is way too small for a open dp in 3inch.. what you have is a perfect example of boostspiking / creeping

get a proper 15g with at least a straight flange.. that conical housing ist scheisse
MadDog_945 is online now   Reply With Quote
Old 10-04-2020, 05:06 PM   #6
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

Thanks for the reply.

So you believe that's my only/best option?

Can you help me understand what is happening that the 15g will solve?



Quote:
Originally Posted by MadDog_945 View Post
that turbo is way too small for a open dp in 3inch.. what you have is a perfect example of boostspiking / creeping

get a proper 15g with at least a straight flange.. that conical housing ist scheisse
SwedishKnievel is offline   Reply With Quote
Old 10-05-2020, 03:34 AM   #7
MadDog_945
Våga Vägra 8V
 
MadDog_945's Avatar
 
Join Date: Apr 2006
Location: Lower Saxony
Default

the backpressure will push through the wastegate so for the flow it seems like the gate is closed. test it!

unhook the wastegate lever.. you will have max bosst at around 4500rpm even the wg is set to fully open all the time...
MadDog_945 is online now   Reply With Quote
Old 10-05-2020, 09:53 AM   #8
rb92673
Board Member
 
Join Date: Jan 2017
Location: San Clemente
Default

Have you done a compression and leak down test? I had similar issues on my lemons car and it turned out to be a burnt exhaust valve. Unburnt fuel was burning in the exhaust manifold producing lots of boost. I was at 20 PSI at 4500 rpm with the wastegate wired open.

As far as 12 pounds of boost, why not just get a 12# actuator.
rb92673 is offline   Reply With Quote
Old 10-05-2020, 10:11 AM   #9
linuxman51
BRANDSCHUTZVORSCHRIFTEN!
 
linuxman51's Avatar
 
Join Date: Dec 2002
Location: mont, AL
Default

did you take the boost controller off? some of the cheap boost controllers... well, don't.
__________________
"They bum rushed them in their own crib, they drank all their beer, they partied with their ladies and they left with the trophy"

Now with in-house Dyno tuning!

Megasquirt Tuning!
Plug and play LH 2.4 Megasquirt, now with stealth mode!
linuxman51 is offline   Reply With Quote
Old 10-05-2020, 01:19 PM   #10
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

Quote:
Originally Posted by linuxman51 View Post
did you take the boost controller off? some of the cheap boost controllers... well, don't.
I did. MBC is off the car. It really does seem that MadDog_945's assessment is correct. I've had the same issue with both the factory and aftermarket WG actuator.

I don't believe we have a burnt valve, yet. I just refreshed the head.

What is interesting is that this condition did not occur when the motor was tired but it did after I rebuilt the motor. Makes sense that with a fresh motor it's a more efficient airpump and therefore more likely to cause the issues I am experiencing.

Assuming my problem is boost creep, how does the 15G solve the problem? Are there any other solutions that retain the 13C? The dyno tuner suggested a sandwich adapter with a proper wastegate.
SwedishKnievel is offline   Reply With Quote
Old 10-05-2020, 02:16 PM   #11
culberro
Ronald Culberbone III
 
culberro's Avatar
 
Join Date: Feb 2010
Location: Portland, OR
Default

Quote:
Originally Posted by SwedishKnievel View Post
Assuming my problem is boost creep, how does the 15G solve the problem? Are there any other solutions that retain the 13C? The dyno tuner suggested a sandwich adapter with a proper wastegate.
The 13c and 15g are hilariously undersized turbos if you're using the car for anything other than daily driving it. Adding an external WG sandwhich plate could work (if there's room), as will porting the wg opening on the 13c hotside. I have a good ported 13c hotside that I would sell for cheap.

If you're using the car for crap can racing (guessing from your avatar), grab a t3/t4 60 trim or TO4E turbo from ebay. Slap the ATP ultimate wastegate on it. Have more fun and more reliability.
__________________
Cult Person. Pissing in your Kool-Aid.
culberro is offline   Reply With Quote
Old 10-05-2020, 04:01 PM   #12
iHateVolvoPeople
Board Member
 
Join Date: Feb 2014
Location: Midwest
Default

Quote:
Originally Posted by SwedishKnievel View Post
Thanks for the reply.

So you believe that's my only/best option?

Can you help me understand what is happening that the 15g will solve?
What happens is your free flowing downpipe becomes the path of least resistance for the exhaust gasses. That is to say, even with the wastegate puck fully open, the exhaust gasses will spin the turbine, increasing boost pressure, rather than flowing through the wastegate hole under the puck and regulating boost pressure effectively.

Your downpipe is more efficient than the tiny wastegate hole. A fun experiment to further support this idea is to fully remove the actuator arm from the wastegate. This will allow the flapper/puck to move freely. Now go for a drive like this and I bet the vehicle will still make boost. In a proper sized wastegate capable of regulating turbine speed, and thus boost pressure, you would expect to see little to no boost pressure with the puck wide open, because the exhaust gasses would ideally bypass the turbine and exit through the wastegate hole.

A bandaid solution (though I don't even think I'd call it that, as it has proven to be long term effective) is to port the area underneath the wastegate puck. You will notice that on the 13c, the hole is extremely small. Now compare that size hole to a 15g. I ported a healthy 13c and it helped with a few psi at least, but I was conservative with my porting as I did not want to do any irreversible damage.
__________________
Feedback Thread
I have a mental disorder.

Last edited by iHateVolvoPeople; 10-05-2020 at 04:08 PM..
iHateVolvoPeople is offline   Reply With Quote
Old 10-06-2020, 06:40 AM   #13
MadDog_945
Våga Vägra 8V
 
MadDog_945's Avatar
 
Join Date: Apr 2006
Location: Lower Saxony
Default

unfortunately it is not only the size of the wg port, it is also the arrangement in the conical housing.. i believe the two flows interact somehow..

believe me.. you wont get rid of this as long as you use the conical housing
MadDog_945 is online now   Reply With Quote
Old 10-06-2020, 11:32 AM   #14
blkaplan
50 shades of beige
 
blkaplan's Avatar
 
Join Date: Jul 2002
Location: Rockville, MD
Default

conical housing is hot garbage.

Atleast the straight or angled setup gives it a chance to breath a little bit.
__________________
www.BEIGEPOWER.com
Kaplhenke Racing Facebook
Quote:
Originally Posted by DarkKratoz View Post
The only safe bet is Ben.©
blkaplan is offline   Reply With Quote
Old 10-06-2020, 12:01 PM   #15
thelostartof
unbalanced chemical
 
thelostartof's Avatar
 
Join Date: Jun 2002
Location: Apache Junction, AZ
Default

Seems like we are missing something, Many of us have run a 13c with a 3" downpipe/exhaust with a cam upgrade and had zero issues holding 8psi of boost to redline.

Are you using the stock 13c WG actuator? Threaded or unthreaed?
__________________
Chip Feedback Thread / PM LH 2.4 Chip Prices

Last edited by thelostartof; 10-06-2020 at 12:06 PM..
thelostartof is offline   Reply With Quote
Old 10-06-2020, 01:41 PM   #16
iHateVolvoPeople
Board Member
 
Join Date: Feb 2014
Location: Midwest
Default

Quote:
Originally Posted by MadDog_945 View Post
unfortunately it is not only the size of the wg port, it is also the arrangement in the conical housing.. i believe the two flows interact somehow..

believe me.. you wont get rid of this as long as you use the conical housing
Yeah it is tiny and flows like crap. Though I had good luck porting mine.

At the end of the day it makes more sense to upgrade to something that flows better.
iHateVolvoPeople is offline   Reply With Quote
Old 10-07-2020, 04:47 PM   #17
JE Jr
Board Member
 
JE Jr's Avatar
 
Join Date: Nov 2002
Location: Sweden
Default

Whats the smallest inner diameter of the 3inch downpipe at the connection to the conical housing? Stock downpipe is 56mm.

I measured the smallest diameter of conical turbine housing outlet is 54.5mm. Maybe its possible to open it up slightly to get less flow interference?
__________________

White car: --744 GLE ´88-- Polishing object
Black car: --S80 V8 ´07-- Daily driver
www.garaget.org/JE_Jr
JE Jr is offline   Reply With Quote
Old 10-07-2020, 05:31 PM   #18
iHateVolvoPeople
Board Member
 
Join Date: Feb 2014
Location: Midwest
Default

Quote:
Originally Posted by JE Jr View Post
Whats the smallest inner diameter of the 3inch downpipe at the connection to the conical housing? Stock downpipe is 56mm.

I measured the smallest diameter of conical turbine housing outlet is 54.5mm. Maybe its possible to open it up slightly to get less flow interference?
Perhaps, but I think the actual flow section of the hot side itself is tiny tiny. Places where we can not reach easily.
iHateVolvoPeople is offline   Reply With Quote
Old 10-08-2020, 03:47 AM   #19
MadDog_945
Våga Vägra 8V
 
MadDog_945's Avatar
 
Join Date: Apr 2006
Location: Lower Saxony
Default

Quote:
Originally Posted by JE Jr View Post
Whats the smallest inner diameter of the 3inch downpipe at the connection to the conical housing? Stock downpipe is 56mm.

I measured the smallest diameter of conical turbine housing outlet is 54.5mm. Maybe its possible to open it up slightly to get less flow interference?
but you can get a shot 16t for 50 bucks to use the hotside??
MadDog_945 is online now   Reply With Quote
Old 10-23-2020, 06:15 PM   #20
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

Quote:
Originally Posted by thelostartof View Post
Seems like we are missing something, Many of us have run a 13c with a 3" downpipe/exhaust with a cam upgrade and had zero issues holding 8psi of boost to redline.

Are you using the stock 13c WG actuator? Threaded or unthreaed?
I have the boost creep issue with the stock unthreaded WG actuator. Two different actuators in fact, both bench tested.
SwedishKnievel is offline   Reply With Quote
Old 10-23-2020, 06:16 PM   #21
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

Quote:
Originally Posted by MadDog_945 View Post
but you can get a shot 16t for 50 bucks to use the hotside??
A 16T hotside will snap onto a 13c without modification of the turbo? Obviously the downpipe will have to be modified.
SwedishKnievel is offline   Reply With Quote
Old 10-23-2020, 06:19 PM   #22
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

I have the turbo off and the hotside housing off. I am going to try to port the wastegate opening by about 5mm. My very rough cowboy/internet CFD calcs tell me that will increase flow by almost 100%. I also intend to knock down some of the very thick part of the casting on the ex manifold side that seems to direct flow past the wastegate port. I will post before/after pictures of the work and report if it works.
SwedishKnievel is offline   Reply With Quote
Old 10-23-2020, 08:32 PM   #23
Duder
Comes with a free Frogurt
 
Duder's Avatar
 
Join Date: Dec 2009
Location: Torrance, CA
Default

You guys are pretty close concerning the open 3" exhaust being the culprit. It is indeed part of the problem here.

"The best exhaust for a turbo is no exhaust" (well, almost)...we've probably all heard this. It is mostly true. A diverging nozzle, basically a long shallow cone, would ideally be the best exhaust straight out of the turbine.

But your tiny turbine with tiny wastegate port and large open exhaust system are effectively acting like "no exhaust" (system) is present. What this does is reduce the turbine pressure ratio needed to produce the shaft power required to drive the compressor. Which is great, as long as you can control boost. By reducing post-turbine restriction we are actually asking the turbine wheel to flow more. If you look at a turbine map, we are above the choke flow curve the whole time here since the wastegate is open. Power required by the compressor hasn't changed, and lines of constant power are diagonally arranged on the turbine map, going up as you move left.

The turbine operating point went from a high pressure ratio, above the choke curve on the flow axis, to a lower pressure ratio (lower on x-axis) but to a higher flow condition, even higher above the choke curve on the y-axis.

Increasing your corrected turbine flow means that a small wastegate port might reach choke, and therefore even if the wastegate valve is wide open, turbine power won't be reigned in enough to control turbo speed (hence boost). This is known as boost creep.

At low engine speeds & lower loads, before you hit peak boost, you would likely notice a difference in power & response if you drove the car with the wastegate valve wired shut vs. flapping in the breeze. If you removed the actuator and left the valve crank arm free, the valve would open way early and you'd reduce your available turbine energy and feel a difference in both power and response.

The key is that once you reach full boost in this case, even with the wastegate valve in the turbine housing completely open, that opening can't flow enough.

Potential solutions:
  • Upgrade to a larger turbocharger or bigger turbine housing that flows more. Either way, more turbine flow capacity.
  • Port the ever-loving crap out of the wastegate, opening the port hole diameter, adding a radius at any sharp corners. This may not ever be enough however.
  • Add restriction to your exhaust system. Smaller tubing diameter, or add a cat or a muffler. That will increase turbine pressure ratio and bring overall flow back down, to a point.
Duder is offline   Reply With Quote
Old 10-26-2020, 01:26 PM   #24
MadDog_945
Våga Vägra 8V
 
MadDog_945's Avatar
 
Join Date: Apr 2006
Location: Lower Saxony
Default

on point, thx!
MadDog_945 is online now   Reply With Quote
Old 10-27-2020, 04:27 PM   #25
SwedishKnievel
Board Member
 
SwedishKnievel's Avatar
 
Join Date: Sep 2013
Location: Los Angeles
Default

Quote:
Originally Posted by culberro View Post
If you're using the car for crap can racing (guessing from your avatar), grab a t3/t4 60 trim or TO4E turbo from ebay. Slap the ATP ultimate wastegate on it. Have more fun and more reliability.
After a lot of mental masturbation on this topic, it seems that the T3/T4 is the least effort / best chance for success approach. Help me understand some things if you will:

1. Advantages of the ATP waste gate vs. some other waste gate that might come on a complete turbo on ebay? If I use the ATP WG, can I use the actuator off my 13c (I have 3 of those now)?

That is, this: https://www.ebay.com/itm/T04E-T3-T4-....c100677.m4598

vs this: https://www.ebay.com/itm/T04E-T3-T4-....c100677.m4598

2. The term "60 trim" I think refers to the exhaust manifold interface? Is that right? Does it relate to a specific measurement?

3. A/R ratio. What should I look for?

4. Does a T3/T4 use the coolant lines that the 13c does or do I cap them off?

5. What should I expect to have to modify for the oil lines?

I really appreciate your help. Thank you in advance.
SwedishKnievel is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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 On

Forum Jump


All times are GMT -4. The time now is 04:15 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.