Notices
Evo General Discuss any generalized technical Evo related topics that may not fit into the other forums. Please do not post tech and rumor threads here.
Sponsored by: RavSpec - JDM Wheels Central

Boost sweet spot

Thread Tools
 
Search this Thread
 
Old May 26, 2004, 06:26 AM
  #1  
Evolving Member
Thread Starter
 
xstang's Avatar
 
Join Date: Feb 2004
Posts: 139
Likes: 0
Received 0 Likes on 0 Posts
Boost sweet spot

Just curious as to where the boost sweet spot is. I know the characteristic of the stock turbo causes boost to taper towards redline.... What I've noticed is the closer to 19psi the less it tapers. If I set it to 21 it seems to hold real good and taper to 19ish redline. However, If I bump it to 23-24psi on race gas, it really tapers bad at redline 16-17psi. Is this what everyone else is seeing? Thinking I may need a new boost controller.
Old May 26, 2004, 08:07 AM
  #2  
Evolving Member
 
Reignman's Avatar
 
Join Date: Nov 2003
Location: Apex, NC
Posts: 167
Likes: 0
Received 0 Likes on 0 Posts
I think the stock turbo just runs out of efficiency with the higher boost levels and higher RPMs
Old May 26, 2004, 08:17 AM
  #3  
Evolved Member
iTrader: (2)
 
EVOSTEVO's Avatar
 
Join Date: Jul 2003
Location: Sub-Chi-Town
Posts: 558
Likes: 0
Received 0 Likes on 0 Posts
do you have a full exhaust and bov if you are running a stock bov it could start to maybe leak pushing that much boost. i think 23-24 is a little high even for race gas
Old May 26, 2004, 09:14 AM
  #4  
Evolving Member
Thread Starter
 
xstang's Avatar
 
Join Date: Feb 2004
Posts: 139
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by EVOSTEVO
do you have a full exhaust and bov if you are running a stock bov it could start to maybe leak pushing that much boost. i think 23-24 is a little high even for race gas
Yeah.. It spikes at 23 or so and tapers quick... It is a full exhaust and stock BOV...
Old May 26, 2004, 09:22 AM
  #5  
Evolved Member
iTrader: (22)
 
GTVEVO's Avatar
 
Join Date: May 2003
Location: Ozark, MO
Posts: 1,689
Likes: 0
Received 0 Likes on 0 Posts
My opinion is from 19 to 21 is where the sweet spot is, on your mods I would say yours would be at the 19-20 psi range. Just my .02. ENJOY
Old May 26, 2004, 09:29 AM
  #6  
Evolved Member
iTrader: (2)
 
EVOSTEVO's Avatar
 
Join Date: Jul 2003
Location: Sub-Chi-Town
Posts: 558
Likes: 0
Received 0 Likes on 0 Posts
wait do you have a controller cause i dont and i can get the boost to kick up to around 22-23psi then it will drop to 17ish. and like gtvevo said keep it around 19-20psi if you do have a controller
Old May 26, 2004, 09:35 AM
  #7  
Newbie
 
TYRONEBIGGUM's Avatar
 
Join Date: Apr 2004
Location: LA
Posts: 54
Likes: 0
Received 0 Likes on 0 Posts
sweet spot is between the legs
Old May 26, 2004, 11:49 AM
  #8  
Evolving Member
Thread Starter
 
xstang's Avatar
 
Join Date: Feb 2004
Posts: 139
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by GTVEVO
My opinion is from 19 to 21 is where the sweet spot is, on your mods I would say yours would be at the 19-20 psi range. Just my .02. ENJOY
Well.. I installed bigger injectors/walbro255/ARP bolts hoping I could turn up the boost a notch... I guess it is impossible though to maintain 21 to redline,,,, The best I can get is 19.5 or so at 7000rpms...
Old May 26, 2004, 11:53 AM
  #9  
Evolved Member
iTrader: (15)
 
WannaRace's Avatar
 
Join Date: Mar 2002
Location: Midwest
Posts: 810
Likes: 0
Received 0 Likes on 0 Posts
Get a good boost controller that will hold boost steady. I have rock solid boost at 20.5psi exactly without a change across the powerband.
Old May 26, 2004, 11:57 AM
  #10  
Evolving Member
iTrader: (6)
 
2literv8eater's Avatar
 
Join Date: Dec 2002
Location: Sparta NJ
Posts: 159
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by WannaRace
Get a good boost controller that will hold boost steady. I have rock solid boost at 20.5psi exactly without a change across the powerband.
What boost controller are you using?
Old May 26, 2004, 11:57 AM
  #11  
Evolving Member
Thread Starter
 
xstang's Avatar
 
Join Date: Feb 2004
Posts: 139
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by WannaRace
Get a good boost controller that will hold boost steady. I have rock solid boost at 20.5psi exactly without a change across the powerband.
Which controller do you have? I have the BR MBC,,,
Old May 26, 2004, 11:58 AM
  #12  
Evolved Member
iTrader: (1)
 
leonard_shelby's Avatar
 
Join Date: Jan 2003
Location: summerland
Posts: 578
Likes: 0
Received 0 Likes on 0 Posts
sounds like he must have an EBC of some kind
Old May 26, 2004, 11:59 AM
  #13  
Evolved Member
iTrader: (15)
 
WannaRace's Avatar
 
Join Date: Mar 2002
Location: Midwest
Posts: 810
Likes: 0
Received 0 Likes on 0 Posts
The cheapest probably out there: Joe P.
Old May 26, 2004, 12:08 PM
  #14  
Evolved Member
iTrader: (1)
 
leonard_shelby's Avatar
 
Join Date: Jan 2003
Location: summerland
Posts: 578
Likes: 0
Received 0 Likes on 0 Posts
an MBC holding exactly 20.5 ? Wow .. what sort of boost gauge, sure it is accurate ?

I've never heard of a MBC that could do this, then again, what the hell do I know
Old May 26, 2004, 12:10 PM
  #15  
Evolved Member
iTrader: (2)
 
siantjab's Avatar
 
Join Date: Mar 2004
Location: TPA
Posts: 664
Likes: 0
Received 0 Likes on 0 Posts
WannaRace, would you recommend the Joe P MBC? I was just about to order mine and was looking at the Hallman Pro RX kit (with both springs), but the Joe P is quite a big cheaper. How long have you had it and have you had any issues with it? Do you have some overhead with it, or is it maxed out to hit 20.5 PSI?

Sorry for all the questions. I just hate to waste money testing products. I KNOW the Hallman will work OK, but have had no feed back on the Joe P.

Thank You!



All times are GMT -7. The time now is 04:53 PM.