begi and boost creep - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 07-31-2007, 10:46 PM   #1
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: May 2007
Location: chilliwack, bc
Posts: 93
Total Cats: 0
Default begi and boost creep

so on the weekend, i installed the begi downpipe for my greddy kit.
now, i get some scary boost creep. it'll hit 6psi, then creep up from there to about 8 or 10psi.
i've only got the 1.6l injectors, so this can spell disaster.

anyone else get this?
ideas?
reckless_abandon is offline   Reply With Quote
Old 07-31-2007, 11:06 PM   #2
Junior Member
 
Join Date: Nov 2005
Location: PA/DC
Posts: 468
Total Cats: 0
Default

yeh...it will be fun for a while but if you want to keep her safe you need tuning and more fuel.

trust me! just invest a little in some tuning and it will pay off in the long run!
Snowsurfer03 is offline   Reply With Quote
Old 07-31-2007, 11:18 PM   #3
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

that's a feature, not a problem. get yourself some injectors and/or a hp fuel pump and enjoy.

I have never heard of a boost creep problem with the greddy. It's always a boost droop. Perhaps some porting on the turbo's turbine out would get it flowing better. Where does your WG actuator reference boost signal?
Ben is offline   Reply With Quote
Old 08-01-2007, 02:35 AM   #4
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: May 2007
Location: chilliwack, bc
Posts: 93
Total Cats: 0
Default

the wastegate has a vacuum line to the turbo housing.
do you recommend just the injectors? or will i need a fuel pump to go with the injectors?
and if so, which fuel pump? i was thinking about getting the 7MGENA supra injectors to be safe. but i'm no expert.
reckless_abandon is offline   Reply With Quote
Old 08-01-2007, 02:44 AM   #5
Elite Member
iTrader: (24)
 
kotomile's Avatar
 
Join Date: Oct 2006
Location: Monterey, CA
Posts: 7,578
Total Cats: 40
Default

I would *think* the Begi would make the boost drop, not creep, since the WG gasses aren't nearly as choked as the "Stock" downpipe..

My Begi just arrived yesterday..

Are you sure you did nothing else to the car that might have caused this?
kotomile is offline   Reply With Quote
Old 08-01-2007, 08:50 AM   #6
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

yeah you'd probably be good with the 300cc injectors only. i'm thinking by the time your boost creeps, the ecu is at 90% duty cycle. be safe, get a wideband.

check to make sure that your actuator rod can move feely and the flapper door actually opens fully. like i said, I've never heard of creep on a greddy, only droop, and usually bad droop due to their shitty wg actuator.
Ben is offline   Reply With Quote
Old 08-01-2007, 10:06 AM   #7
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,838
Total Cats: 1,787
Default

haha, I was going to say the problem is!??!
Braineack is offline   Reply With Quote
Old 08-01-2007, 11:23 AM   #8
y8s
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
 
y8s's Avatar
 
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,038
Total Cats: 406
Default

you get boost creep because the WG is too small to pass that much gas. it's more apparent on low-boost setups because less exhaust is going through the turbo and more is diverted through the WG.

if you dont want to change the fuel system, port the wastegate.
y8s is offline   Reply With Quote
Old 08-01-2007, 11:50 AM   #9
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: May 2007
Location: chilliwack, bc
Posts: 93
Total Cats: 0
Default

i just checked the wastegate to see if it moves, but i cant get the wastegate flap to open manually. this may be my problem.
reckless_abandon is offline   Reply With Quote
Old 08-01-2007, 12:29 PM   #10
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: 26,317
Total Cats: 1,914
Default

Quote:
Originally Posted by reckless_abandon View Post
i just checked the wastegate to see if it moves, but i cant get the wastegate flap to open manually. this may be my problem.
If it is still connected to the WG canister it is *very* difficult to operate manually. For a device that's designed to actuate on only a few PSI, the diaphragm in that canister is surprisingly stiff. This is not indicative of a problem.
Joe Perez is offline   Reply With Quote
Old 08-01-2007, 09:17 PM   #11
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: May 2007
Location: chilliwack, bc
Posts: 93
Total Cats: 0
Default

that makes sense.
i havent tried to move it while disassembled.
reckless_abandon is offline   Reply With Quote
Old 08-01-2007, 11:44 PM   #12
Senior Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Outside of the Loop-ATL
Posts: 754
Total Cats: 0
Default

Quote:
Originally Posted by kotomile View Post
I would *think* the Begi would make the boost drop, not creep, since the WG gasses aren't nearly as choked as the "Stock" downpipe..

My Begi just arrived yesterday..

Are you sure you did nothing else to the car that might have caused this?
Like Y8s said, boost creep is caused because off opening the exhaust. Its normally only a problem on small turbo on larger engines running low boost. Supra have that problem really bad with stock turbos. Running just a full exhaust 3' on a 7mgte supra without any other mods will cause a boost creep of 9 psi before setting back to stock 6psi. DSM have the same issue hence the reason for the 34mm wastegate "mods".

The only cure for boost creep is to port the wastegate.... well that or just turn up the boost...but yea
wildfire0310 is offline   Reply With Quote
Old 08-02-2007, 12:24 AM   #13
Junior Member
 
Join Date: May 2006
Location: Portland, OR
Posts: 70
Total Cats: 0
Default

I've heard of the same problem on FDs when you get a downpipe or pull out the cat. Their solution is like y8s said, porting the wastegate.
Agent935 is offline   Reply With Quote
Old 08-02-2007, 12:40 AM   #14
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: 26,317
Total Cats: 1,914
Default

Quote:
Originally Posted by reckless_abandon View Post
that makes sense.
i havent tried to move it while disassembled.
If you have a hand-operated vacuum pump which has a port on the exhaust, you can connect the outlet of the pump to the inlet of the WG canister and make enough pressure by hand to actuate the diaphragm.
Joe Perez is offline   Reply With Quote
Old 08-02-2007, 09:18 PM   #15
Junior Member
Thread Starter
iTrader: (1)
 
Join Date: May 2007
Location: chilliwack, bc
Posts: 93
Total Cats: 0
Default

what is involved in porting the wastegate? and should i get a professional to do it?
reckless_abandon is offline   Reply With Quote
Old 08-02-2007, 10:11 PM   #16
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

I would say if you have to ask, let a pro do it.

I have always wanted to do this:
http://www.gpopshop.com/portpolish.html
(minus the exterior polish that is)

I'd bet the gains are as worthwhile as they claim.
Ben is offline   Reply With Quote
Old 08-03-2007, 03:01 AM   #17
Elite Member
iTrader: (24)
 
kotomile's Avatar
 
Join Date: Oct 2006
Location: Monterey, CA
Posts: 7,578
Total Cats: 40
Default

Is it just take off turbine housing, radius the corners, polish?
kotomile is offline   Reply With Quote
Old 08-08-2007, 03:56 PM   #18
Elite Member
iTrader: (24)
 
kotomile's Avatar
 
Join Date: Oct 2006
Location: Monterey, CA
Posts: 7,578
Total Cats: 40
Default

Another question: I have the stock 1.6 injectors on mine now, but with a 190HP. Vortech FMU is untouched, so 12:1 disc. If I bolt on my Begi DP and get boost creep to, say, 8 psi, will I run lean?

And another: If I bite the bullet and get the AEM EBC.. will it help to control the creep?
kotomile 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
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 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


Thread Tools

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 12:35 PM.