2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Boost Control

Thread Tools
 
Search this Thread
 
Old Sep 11, 2002 | 12:52 AM
  #1  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
Boost Control

I want to keep boost just below the cut-off mark.
What would be the best way to do this?

Is there any way to control boost with a "home depot" style controller?

I want to avoid fuel cut-which I'm getting -but I also want to avoid having to install a FCD.



87 TII
Mods: TT, MP, silencer, no muffler
Itsa loud *** *****!
Reply
Old Sep 11, 2002 | 12:53 AM
  #2  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
Oh BTW I did do the searches and couldn't find exactly what I wanted to do.
Reply
Old Sep 11, 2002 | 01:04 AM
  #3  
NRA T2's Avatar
Senior Member
Tenured Member 05 Years
 
Joined: Sep 2002
Posts: 420
Likes: 0
From: wa
why no fcd?
Reply
Old Sep 11, 2002 | 01:08 AM
  #4  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
I just want to keep things safe. But lets say I did do a FCD. WOuld there be anything I could use to control the boost from going to a unsafe level?
Reply
Old Sep 11, 2002 | 01:11 AM
  #5  
Rpeck's Avatar
What R U thinking self?
Tenured Member 05 Years
 
Joined: Mar 2002
Posts: 2,333
Likes: 0
From: Stockton, CA
A boost controller will not lower boost, only raise it. You need to port your wastegate, or get a external wastegate setup to turley avoid boost creep & spikes.
Reply
Old Sep 11, 2002 | 06:17 AM
  #6  
NZConvertible's Avatar
I'm a boost creep...
Tenured Member 05 Years
 
Joined: Jan 2002
Posts: 15,608
Likes: 8
From: Auckland, New Zealand
Re: Boost Control

Originally posted by TheBigOne
I want to keep boost just below the cut-off mark. What would be the best way to do this?
Remove your modifications.
Is there any way to control boost with a "home depot" style controller?
No.
I want to avoid fuel cut-which I'm getting but I also want to avoid having to install a FCD.
Not possible.

If you want to exceed 8.6psi on the stock ECU, you need an FCD. There's no way around it. If you want to keep below 8.6psi, stop installing things that increase boost!
Reply
Old Sep 11, 2002 | 08:15 PM
  #7  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
Re: Re: Boost Control

Originally posted by NZConvertible
Not possible.

If you want to exceed 8.6psi on the stock ECU, you need an FCD. There's no way around it. If you want to keep below 8.6psi, stop installing things that increase boost!
Maybe I'm asking the wrong question?!

So what is the point of the Home Depot Boost Controler?

I understand that you can't lower boost. I'm interested in controling it. But controling to the point below Fuel Cut if possible.

So if I install the FCD how do I control a safe level of boost. People say "you cant lower boost" OK I understand that. I want to CONTROL IT! If I cant then what is the point of a Boost "Controler"
Reply
Old Sep 11, 2002 | 08:23 PM
  #8  
RestoTII's Avatar
Senior Member
Tenured Member 10 Years
 
Joined: Jul 2001
Posts: 576
Likes: 0
From: Havre de Grace, MD
the home depot boost controller works like this... the wastegate opens at a certain pressure. If you put a restriction in it (closed valve), it'll see a lower pressure and not open. So if you tee into the line that gives the wastegate it's pressure and totally close the valve, it'll never open. If you totally open the valve (which will still make some restriction), it'll open just above where it normally does. So basically, you aren't going to limit it to less than fuel cut if you're already hitting it without restricing your exhaust or intake. And by doing that, you've just backstepped all the mods you've done. I suggest going with a better quality boost controller if you don't know FOR SURE what you're doing with a DIY MBC ahead of time. Also, get an FCD cause fuel cut SUCKS.
Reply
Old Sep 11, 2002 | 09:58 PM
  #9  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707


Thank you! Thank you! Thank you!

My question is answered. Complete and Intellectually.

Reply
Old Sep 11, 2002 | 10:03 PM
  #10  
BlackRx7's Avatar
Daily Domestic Killer
Tenured Member 10 Years
 
Joined: Mar 2001
Posts: 2,425
Likes: 0
From: San Antonio, Tx, USA
okay if you want to lower boost, it is the simplest boost mod. Simply put the STOCK AIR BOX back on or take that mid pipe off and put the cat back on, A restriction in the intake or exhaust will suit your needs just fine
Reply
Old Sep 11, 2002 | 11:00 PM
  #11  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
I just installed a Sunpro vacume gauge to see where I'm at when I get a fuel cut. It's not cutting at 8.6

More like 6.5-7.0. Strange?

The vacume line is T off a vacume line that comes directly from the intake manifold.

So I hooked up a volt meter directly to the battery with the engine running. 12 volts - 13.5 volts.

With the engine off I got12.5 volts. As I start the car it drops to 7-6.5 volts

It still starts. Kinda slow though.

Hopefully its not a connected problem.
Reply
Old Sep 11, 2002 | 11:23 PM
  #12  
600HP CLUB's Avatar
Senior Member
Tenured Member 20 Years
 
Joined: Jan 2002
Posts: 725
Likes: 14
From: Northern California
how does fuel cut feel? i think i'm getting that or am i? i'm stock, but i don't have air pump nor acv, and the car HAD fcd, intake, and full exhaust.

my car does weak boost on second and pause for a half a sec on 5k rpm and then boost back hard in 5.5k rpm.


-mike
Reply
Old Sep 11, 2002 | 11:27 PM
  #13  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
the car lurches hard.

Its like driving in 1st gear at around 10mph then
tap-dance the gas pedal.
Reply
Old Sep 11, 2002 | 11:30 PM
  #14  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
Originally posted by 600HP CLUB
how does fuel cut feel?...........the car HAD fcd, intake, and full exhaust.

-mike
do you still have the FCD????
Reply
Old Sep 11, 2002 | 11:39 PM
  #15  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
Originally posted by 600HP CLUB
how does fuel cut feel? i think i'm getting that or am i? i'm stock, but i don't have air pump nor acv, and the car HAD fcd, intake, and full exhaust.

my car does weak boost on second and pause for a half a sec on 5k rpm and then boost back hard in 5.5k rpm.


-mike
Reply
Old Sep 11, 2002 | 11:44 PM
  #16  
jreynish's Avatar
New Project on the Way...
Tenured Member: 20 Years
iTrader: (2)
 
Joined: Apr 2002
Posts: 3,764
Likes: 6
From: Yellowknife, NT
Ok.. these problems YOU SHOULD fix ASAP without cutting corners... because trust me these little things turn out to be big problems if you don't have the money for a FCD or a S-AFC or something you should avoid from stepping on it. cause Feul Cut seems to DESTROY engines FAST don't know why but it does. so i suggest that you eithe invest in an FCD or S-AFC because that way you are sure that you won't pop your engine as for the other problems keep searching i know what it is like i have a blown engine and little probs kept adding up. so take my advice. And fix the proplem properly. otherwise you will be hurting in the long term.
Just me $0.02
Good Luck
Reply
Old Sep 12, 2002 | 02:47 AM
  #17  
TheBigOne's Avatar
Thread Starter
Full Member
Tenured Member 15 Years
 
Joined: Mar 2002
Posts: 174
Likes: 0
From: 415 -> 707
S-AFC???????
dont know what is it???
Reply
Old Sep 12, 2002 | 03:46 AM
  #18  
NZConvertible's Avatar
I'm a boost creep...
Tenured Member 05 Years
 
Joined: Jan 2002
Posts: 15,608
Likes: 8
From: Auckland, New Zealand
Re: Re: Re: Boost Control

Originally posted by TheBigOne
So what is the point of the Home Depot Boost Controler?
The first thing you need to do is stop thinking of a bleeder valve as a controller, because they are not. All they do is raise boost, that's it.
I understand that you can't lower boost. I'm interested in controling it. But controling to the point below Fuel Cut if possible.
Again, that word "control" is confusing you. Whether you're taking about a $10 bleeder or a $1000 electronic boost controller, all they can do is raise boost. What you want to do is limit boost, which is just lowering it from where it normally would be. Which you can't do.
So if I install the FCD how do I control a safe level of boost. People say "you cant lower boost" OK I understand that. I want to CONTROL IT! If I cant then what is the point of a Boost "Controler"
The only way you can limit the amount of boost your turbo can make is to restrict airflow. If you want to keep the boost down, stop modifying!

To learn how bleeders work, read this.

Last edited by NZConvertible; Sep 12, 2002 at 03:50 AM.
Reply
Old Sep 12, 2002 | 09:59 AM
  #19  
Ryde _Or_Die's Avatar
...
Tenured Member 10 Years
 
Joined: Aug 2001
Posts: 7,539
Likes: 0
From: Tampa, FL
Originally posted by TheBigOne
S-AFC???????
dont know what is it???
http://www.apexi-usa.com/electronics_safc.asp
Reply
Old Sep 12, 2002 | 10:39 AM
  #20  
Josepi's Avatar
Despise Enmity
Tenured Member 20 Years
 
Joined: May 2001
Posts: 2,420
Likes: 0
From: Richmond, VA
Re: Re: Re: Re: Boost Control

Originally posted by NZConvertible
The only way you can limit the amount of boost your turbo can make is to restrict airflow. If you want to keep the boost down, stop modifying!
Couldn't you modify a restrictor plate in the exhaust or intake track thus reducing boost?

Sorry, had to be a smartass today!
Reply
Old Sep 16, 2002 | 05:41 PM
  #21  
jreynish's Avatar
New Project on the Way...
Tenured Member: 20 Years
iTrader: (2)
 
Joined: Apr 2002
Posts: 3,764
Likes: 6
From: Yellowknife, NT
Ok I am going to make this really simply if you want to stop your feul cut you MUST buy:
Option:

a) Feul Cut Defenser = $105.00 US

b) S-AFC (will allow you to have more boost by allowing more feul and air to enter the engine by controlling the air to feul mixture with more feul) = $315.00 US

c) Don't step on it to keep from hitting Feul Cut $0.00

d) You can replace all moded part with the stock ones and you will not hit Feul Cut = $whatever parts you didn't keep

Now to reinerate that IF you are hitting feul cut you can't regulate lower boost as it makes more problems than you already have. from what i have read you would do fine for the amount of PRESENT problems that you have to buy a Feul Cut Defenser (FCD) that will stop the feul cut by fooling the computer but if you do this your factory boost guage will not work and you will have to buy and after market one to keep track of your boost.
Good Luck
Reply
Old Oct 7, 2003 | 01:21 AM
  #22  
89t295k's Avatar
Senior Member
Tenured Member 20 Years
 
Joined: Sep 2003
Posts: 342
Likes: 1
From: Boise, Idaho
What are pop off valves...don't they pop off at certain addjustable psi..could this be installed at the intake to set max boost?? this is what I'm looking 4 because I'm happy with 10 psi forced induction but wish to add more mods to exhaust for more power/not boost. Thx
Reply
Old Oct 7, 2003 | 01:44 AM
  #23  
Scott 89t2's Avatar
SOLD THE RX-7!
Tenured Member 10 Years
 
Joined: Mar 2001
Posts: 7,451
Likes: 0
From: Vancouver, BC, Canada
Originally posted by 89t295k
What are pop off valves...don't they pop off at certain addjustable psi..could this be installed at the intake to set max boost?? this is what I'm looking 4 because I'm happy with 10 psi forced induction but wish to add more mods to exhaust for more power/not boost. Thx
no they are an "emergency" back up device for if something goes wrong. hose pops off etc. think of them as a fuse. they are not ment to be used to control boost.
Reply
Old Oct 7, 2003 | 10:11 AM
  #24  
89t295k's Avatar
Senior Member
Tenured Member 20 Years
 
Joined: Sep 2003
Posts: 342
Likes: 1
From: Boise, Idaho
Exactly..sounds good to me, f the turbo-save the engine.
I'm seeing 9-10.5 psi and think a pop off at 12 or so would be grand since I have stock fuel...sucks that I can't do more power mods with being at 10psi....would like to drive her for a while with no "BOOM"
Reply
Old Oct 7, 2003 | 01:13 PM
  #25  
Fitness Stain's Avatar
Yar-Har-Har
Tenured Member 05 Years
 
Joined: Sep 2002
Posts: 1,954
Likes: 0
From: Nashville, 37217
im gonna have a s5 turbo, no emissions, full RB turboback exhaust, and an fcd...everything fuel related is stock....


will i be safe as long as i keep my eye on my boost guage and keep it around 9psi?

should iport my wastegate?
Reply



All times are GMT -5. The time now is 06:11 AM.