Cannot hold boost as rpm raise - 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 05-18-2010, 03:37 PM   #1
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default Cannot hold boost as rpm raise



Uploaded with ImageShack.us

It's not pretty clear but I lose boost after 6.000.
I pressurized air in the system and the pipes hold steady without leaks.
Also I can't find any leaks in the manifold.

The external wg right now is hooked directly to the compressor nipple and I am using a 0.8bar spring.. With or without boost controller even at 1.5bar or 0.7bar boost drops at 0.5 at high rpm.

Also when boost drop occur the external is shutting (I can't hear it)
gianic is offline   Reply With Quote
Old 05-19-2010, 02:50 AM   #2
Junior Member
 
Join Date: Dec 2006
Location: Vancouver, BC
Posts: 131
Total Cats: 6
Default

I would almost think this is a joke, but you posted this before the thread linked below.

Tried this? https://www.miataturbo.net/diy-turbo-discussion-14/boost-sag-no-you-dont-need-ebc-47532/

You say you can't hear your external wg open when the boost is dropping but maybe it's only slightly cracked open?
VanMSM is offline   Reply With Quote
Old 05-19-2010, 06:42 AM   #3
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default

Yes I can't hear it releasing the exhaust gases because she tries to hold boost at a steady level and at this point she is wide shut. So the system tries to build pressure.
gianic is offline   Reply With Quote
Old 05-19-2010, 12:52 PM   #4
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,315
Total Cats: 1,913
Default

Quote:
Originally Posted by gianic View Post
Yes I can't hear it releasing the exhaust gases because she tries to hold boost at a steady level and at this point she is wide shut.
Yeah...

Tell ya what. Try moving the feed from the compressor outlet over to the other side of the IC, and see what happens. It's cheap, it's easy, and it'll save you a lot of arguing.
Joe Perez is offline   Reply With Quote
Old 05-19-2010, 01:13 PM   #5
Elite Member
iTrader: (8)
 
Join Date: Dec 2008
Location: Kingston, Ontario
Posts: 2,791
Total Cats: 71
Default

try this... turn overboost protection on, and just unhook the WG.

Should tell you pretty fast if you can make boost or not....

Cruise up to the rpm that you dont have any boost and then mat it...you will hit overboost, or you have something else wrong.
shlammed is offline   Reply With Quote
Old 05-19-2010, 01:58 PM   #6
Elite Member
 
Join Date: Dec 2008
Location: Colorado
Posts: 1,669
Total Cats: 36
Default

Quote:
Originally Posted by Joe Perez View Post
Yeah...

Tell ya what. Try moving the feed from the compressor outlet over to the other side of the IC, and see what happens. It's cheap, it's easy, and it'll save you a lot of arguing.
Dude, just put it in your sig. Seriously.
Sparetire is offline   Reply With Quote
Old 05-19-2010, 03:18 PM   #7
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,633
Total Cats: 1,559
Default

Quote:
Originally Posted by VanMSM View Post
I would almost think this is a joke, but you posted this before the thread linked below.

Tried this? https://www.miataturbo.net/showthread.php?t=47532
Gianic,


Read this thread https://www.miataturbo.net/showthread.php?t=47532

We know what the problem is and we are trying to help you.

Last edited by sixshooter; 05-20-2010 at 11:16 AM.
sixshooter is offline   Reply With Quote
Old 05-19-2010, 04:52 PM   #8
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default

I read the topic guys, thanks for the reference.
But I don't think it will do the trick for my situation, because a week before I was holding 1.5bar steady as hell.

Something for discussion. I disconnected the servo brake pipe and tapped the hole on the manifold with my finger. The engine stalled. Is it normal ? Should it stall or should keep running?

EDIT: I am not missing 2-3 psi of boost. I am loosing 15 psi of boost geometrically as rpm raise.
gianic is offline   Reply With Quote
Old 05-19-2010, 05:24 PM   #9
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,315
Total Cats: 1,913
Default

This is what you said at first:
Quote:
Originally Posted by gianic View Post
With or without boost controller even at 1.5bar or 0.7bar boost drops at 0.5 at high rpm.
And frankly, I have no idea what "boost drops at 0.5 at high rpm" means. It's cryptic as hell

However, you also posted a screen-shot of a log which shows a boosted run in which, from maybe 5,000 to 7,000 RPM, MAP decreases gradually from ~170 kPa to ~150 kPa. And given that this was the only part about your message that was even remotely comprehensible, that's basically the part that I took as actually being meaningful.


Various people offered advice based on this rather limited data. You choose to ignore it, and then wrote the following:
Quote:
Originally Posted by gianic View Post
a week before I was holding 1.5bar steady as hell.
(...) I am not missing 2-3 psi of boost. I am loosing 15 psi of boost geometrically as rpm raise.
So, I understand that English isn't your first language, and believe me, you speak English better than I speak Greek. But I'm very confused by all of this.

Last edited by Joe Perez; 05-19-2010 at 05:39 PM.
Joe Perez is offline   Reply With Quote
Old 05-19-2010, 05:51 PM   #10
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default

I'm talking about boost drop at high rpm. Isn't this sentence clear enough to understand?

DATA:
1st run at 10 psi:
3.000 - 9 psi
4.000 - 10 psi
5.000 - 8 psi
7.000 - 5 psi

2nd run at 21 psi

4.500 - 22 psi
5.000 - 15 psi
7.000 - 7 psi

When boost drops I cannot hear the wastegate bypassing exhaust gases(VTA) and seems that the wastegate is sitting shut trying to build the requested boost target.

I ensure you that the boost reference point is not the deal, because I am using wastegate boost reference from the compressor's nipple 6 months with great success.
This started now, all of a sudden.

My english are bad and I am using a greek style of syntax, forgive me for this.
gianic is offline   Reply With Quote
Old 05-19-2010, 05:54 PM   #11
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default

Haha you've just edit bad words
gianic is offline   Reply With Quote
Old 05-19-2010, 06:23 PM   #12
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,633
Total Cats: 1,559
Default

Ok, so it worked before, but not now? Have you changed anything? Timing?

Have you checked the turbo to see if it spins freely or is damaged?
sixshooter is offline   Reply With Quote
Old 05-19-2010, 06:48 PM   #13
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,315
Total Cats: 1,913
Default

Quote:
Originally Posted by gianic View Post
Haha you've just edit bad words
I felt some remorse after I saw that you were from Greece. The language barrier is a hell of a thing to overcome sometimes.

Wait a minute- the EU is convinced that your country is going to cause the total collapse of all banking and commerce everywhere, and yet you have money to be turbocharging a Miata? I may have to write a letter to Mr. Papandreou. Clearly your taxes are too low.
Joe Perez is offline   Reply With Quote
Old 05-19-2010, 06:52 PM   #14
Junior Member
 
Join Date: Dec 2006
Location: Vancouver, BC
Posts: 131
Total Cats: 6
Default

How about you put a T on your compressor outlet where the external wastegate hooks up and put a boost gauge there? You could see what the wastegate thinks it's doing.

Maybe you sucked a small child into your intake and it's plugging your intercooler?
VanMSM is offline   Reply With Quote
Old 05-19-2010, 07:46 PM   #15
Senior Member
iTrader: (2)
 
Join Date: Oct 2007
Location: Northeastern CT
Posts: 547
Total Cats: 2
Default

Quote:
Originally Posted by VanMSM View Post
Maybe you sucked a small child into your intake and it's plugging your intercooler?
god, i hate it when that happens!
therieldeal is offline   Reply With Quote
Old 05-19-2010, 07:59 PM   #16
Elite Member
iTrader: (8)
 
Join Date: Dec 2008
Location: Kingston, Ontario
Posts: 2,791
Total Cats: 71
Default

your turbo making any noise?

My turbo did this just before it stopped spinning entirely.
shlammed is offline   Reply With Quote
Old 05-20-2010, 04:52 PM   #17
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default

Quote:
Originally Posted by Joe Perez View Post
Wait a minute- the EU is convinced that your country is going to cause the total collapse of all banking and commerce everywhere, and yet you have money to be turbocharging a Miata? I may have to write a letter to Mr. Papandreou. Clearly your taxes are too low.
Hahahaha! It's weird that you have all that knowledge for a little country like Greece . Our taxes are already huge. Trust me. I have a small tv production company and I am paying 40% of my pure income to taxes. Fair enough huh?
Consider also the vat taxes 21% and the gas 7.2$ per gallon.

Anyway. The turbo seems to be ok spins freely without any noise (5.000miles on it) although I found some oil on the compressor side, don't know why maybe I need a restrictor.
gianic is offline   Reply With Quote
Old 05-20-2010, 05:13 PM   #18
Senior Member
iTrader: (14)
 
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0
Default

Are you sure your wastegate isn't sticking? If it's a subtle leak, it may not sound like anything at all but may be enough to cause you to loose some boost.
lordrigamus is offline   Reply With Quote
Old 05-20-2010, 05:35 PM   #19
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Mar 2007
Location: Greece
Posts: 290
Total Cats: 4
Default

Quote:
Originally Posted by lordrigamus View Post
Are you sure your wastegate isn't sticking? If it's a subtle leak, it may not sound like anything at all but may be enough to cause you to loose some boost.
If it was stuck open I would here it because is is vented to air. So it's not stucked.
gianic is offline   Reply With Quote
Old 05-20-2010, 06:03 PM   #20
Senior Member
iTrader: (14)
 
Join Date: Aug 2008
Location: Tinley Park, IL
Posts: 1,488
Total Cats: 0
Default

Quote:
Originally Posted by gianic View Post
If it was stuck open I would here it because is is vented to air. So it's not stucked.
Probably not then.
lordrigamus 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 57 07-19-2017 05:11 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
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 05:22 AM.