Bestow unto me: Your knowledge on the most basic of vacuum setups - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 10-26-2012, 06:02 PM   #1
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default Bestow unto me: Your knowledge on the most basic of vacuum setups

I have a car i'm working on that i literally only have two things that need vacuum.

1) MAP sensor.
2) Brake booster.


What i have:

1) Vacuum rails on each cylinder bank.

What i don't have:

1) Intake manifold.


What's the cheapest, yet elegant way to do this while keeping the brake booster and the MAP happy? I'm a little worried about volume, don't want the MAP freaking out when i'm on the brakes, and i HAVE to tie both of the rails together somehow before the MAP sensor is in the system.

Elegant and correct takes precedent over "cheapest."

What i'm initially thinking:

Tie rails together, run to distribution block. Run MAP off of block. Run another line to an aftermarket reservoir with check valve, which then runs to brake booster. Is this overkill and needlessly complicated?
concealer404 is offline   Reply With Quote
Old 10-26-2012, 07:41 PM   #2
Elite Member
 
Join Date: Mar 2010
Location: Detroit
Posts: 1,524
Total Cats: 27
Default

pics? I'm assuming its ITB, if so, I think the throttlebodies will have a vacuum nipple you can use on each one.
flounder is offline   Reply With Quote
Old 10-27-2012, 02:32 PM   #3
Junior Member
 
Join Date: Sep 2011
Location: finger lakes NY
Posts: 444
Total Cats: 17
Default

How many cylinder banks you got?
DaveC is offline   Reply With Quote
Old 10-29-2012, 11:36 AM   #4
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by flounder View Post
pics? I'm assuming its ITB, if so, I think the throttlebodies will have a vacuum nipple you can use on each one.
They do, but they're plugged, and will remain that way, since i have nice big vacuum rails fabbed up to use. Plus i don't really want to either:

1) Run a rats nest of vacuum lines to a block from each cylinder
2) Run a map off of one cylinder. Impossible to tune.

Quote:
Originally Posted by DaveC View Post
How many cylinder banks you got?

Two.




Here's a better picture that you should be able to see the rails in. (Bottom brass nipples)


IMGP4387 by concealer404, on Flickr
Attached Thumbnails
Bestow unto me: Your knowledge on the most basic of vacuum setups-20120908_224616.jpg   Bestow unto me: Your knowledge on the most basic of vacuum setups-6768937635_ec9f4c678b_b.jpg  
concealer404 is offline   Reply With Quote
Old 10-29-2012, 02:03 PM   #5
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Quote:
Originally Posted by concealer404 View Post

Tie rails together, run to distribution block. Run MAP off of block. Run another line to an aftermarket reservoir with check valve, which then runs to brake booster. Is this overkill and needlessly complicated?
The brake booster has its own check valve, no? What does adding a second one do?

--Ian
codrus is offline   Reply With Quote
Old 10-29-2012, 02:08 PM   #6
Elite Member
iTrader: (1)
 
Join Date: May 2009
Location: Jacksonville, FL
Posts: 4,682
Total Cats: 216
Default

My experience with ITBs leads me to believe that the MAP sensor is borderline useless.
Assuming your ECU has a baro in it and doesnt need the MAP for taking a pre-cranking baro reading like some do.
Full_Tilt_Boogie is offline   Reply With Quote
Old 10-29-2012, 02:09 PM   #7
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by codrus View Post
The brake booster has its own check valve, no? What does adding a second one do?

--Ian
I BELIEVE (if i believe what the internet tells me) that the check valve was in-line, not in the booster itself. None of the factory lines exist anymore in any way, so i have to build everything from scratch.

I will double check that the boost has a check, though.

I think the ticket here is to tie the two vacuum rails together before the MAP, then go from MAP to one of these: Steel Black Finish Vacuum System Reservoir Tank Universal Fit Hot Rat Rod | eBay

And then to booster.
concealer404 is offline   Reply With Quote
Old 10-29-2012, 02:10 PM   #8
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by Full_Tilt_Boogie View Post
My experience with ITBs leads me to believe that the MAP sensor is borderline useless.
Assuming your ECU has a baro in it and doesnt need the MAP for taking a pre-cranking baro reading like some do.
The plan is to tune in "blended" mode.
concealer404 is offline   Reply With Quote
Old 10-29-2012, 07:13 PM   #9
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Quote:
Originally Posted by concealer404 View Post
I BELIEVE (if i believe what the internet tells me) that the check valve was in-line, not in the booster itself. None of the factory lines exist anymore in any way, so i have to build everything from scratch.

The one I was thinking of is in the factory line, yes. It's in the ~ 6 inch long rubber hose that connects the factory booster to the hard line that crosses over the firewall. It's inside the line, not visible.

--Ian
codrus is offline   Reply With Quote
Old 10-29-2012, 07:16 PM   #10
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by codrus View Post
The one I was thinking of is in the factory line, yes. It's in the ~ 6 inch long rubber hose that connects the factory booster to the hard line that crosses over the firewall. It's inside the line, not visible.

--Ian
At this point, i should clarify that i'm not working on a Miata in this case.

But i would guess that the Escort had the same sort of thing going on. There were no outwardly-visible signs of a check valve.
concealer404 is offline   Reply With Quote
Old 10-29-2012, 10:38 PM   #11
Elite Member
 
Join Date: Mar 2010
Location: Detroit
Posts: 1,524
Total Cats: 27
Default

KL in an escort?
Attached Thumbnails
Bestow unto me: Your knowledge on the most basic of vacuum setups-91-94_%2526_95-96_ford_escort_3-door_hatchback_%2526_wagon.jpg  
flounder is offline   Reply With Quote
Old 10-29-2012, 11:23 PM   #12
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Yep in a 93 GT. SCCA Solo SMF assault.
concealer404 is offline   Reply With Quote
Old 10-30-2012, 09:56 AM   #13
Elite Member
iTrader: (1)
 
Leafy's Avatar
 
Join Date: Jun 2012
Location: NH
Posts: 9,091
Total Cats: 90
Default

Run a vac pump for the brake booster? Hell if its not a street driven car, see if its reasonable to just make a vac reservoir and charge it between runs for the brake booster, that will be lighter.

The true correct way to run map sensors on itbs is to put a map on each cylinder and use an ecu that supports that many map sensors, or make a circuit to blend all the map signals together (just connecting all the cylinders in a vac manifold and running a map off there doesnt work right). Alternatively you could just tune the thing straight alpha-n including timing and just use the map for baro correction. As much as I hate alpha-n, if I was tuning a naturally aspirated auto-x car it comes with a lot of benefits like instantly responding to throttle changes with minimal transient corrections.
Leafy is offline   Reply With Quote
Old 10-30-2012, 10:43 AM   #14
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by Leafy View Post
Run a vac pump for the brake booster? Hell if its not a street driven car, see if its reasonable to just make a vac reservoir and charge it between runs for the brake booster, that will be lighter.
Let's keep this as simple as possible. That sounds dumb. Both of them. The first one because it's more complicated and heavier. The second one because it's a pain in the *** and MIGHT save an ounce of vacuum line.

Either way, the car is plated, registered, and insured, and will stay that way since i'm not going to trailer it to local events.

Quote:
The true correct way to run map sensors on itbs is to put a map on each cylinder and use an ecu that supports that many map sensors, or make a circuit to blend all the map signals together (just connecting all the cylinders in a vac manifold and running a map off there doesnt work right). Alternatively you could just tune the thing straight alpha-n including timing and just use the map for baro correction. As much as I hate alpha-n, if I was tuning a naturally aspirated auto-x car it comes with a lot of benefits like instantly responding to throttle changes with minimal transient corrections.
I said "Blended Mode" earlier. It where you use both MAP and Alpha-N. This thread isn't about how i should tune my car, it's about the simplest and easiest way to run what little vacuum system i need.
concealer404 is offline   Reply With Quote
Old 10-30-2012, 10:53 AM   #15
Elite Member
iTrader: (1)
 
Leafy's Avatar
 
Join Date: Jun 2012
Location: NH
Posts: 9,091
Total Cats: 90
Default

So you basically just want my first sentence of my 2nd paragraph.
Leafy is offline   Reply With Quote
Old 10-30-2012, 11:05 AM   #16
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by Leafy View Post
So you basically just want my first sentence of my 2nd paragraph.
No, not really.

I know how the car is being tuned. That's not open for discussion, and wasn't a topic in this thread.


Just so we're clear, i'm more concerned with brakes, which is why i specifically posted a reservoir with a built in check valve earlier.
concealer404 is offline   Reply With Quote
Old 10-31-2012, 09:12 AM   #17
Junior Member
 
Join Date: Apr 2010
Posts: 60
Total Cats: 0
Default

You are no doing anything crazy here. Run the vacuum reservoir with a check valve, plumb it to both rails. They work and have been around for ever. Problem solved.
ChrisGriffin is offline   Reply With Quote
Old 10-31-2012, 10:27 AM   #18
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Quote:
Originally Posted by ChrisGriffin View Post
You are no doing anything crazy here. Run the vacuum reservoir with a check valve, plumb it to both rails. They work and have been around for ever. Problem solved.
I didn't think so, but i just wanted to make sure before i set myself up for failure again. This entire build has been one step forward, three steps back for the last 2 years, and i'm pretty burnt out on it.

I appreciate the reinforcement.
concealer404 is offline   Reply With Quote
Old 11-02-2012, 01:10 PM   #19
Junior Member
iTrader: (1)
 
Join Date: Sep 2006
Posts: 201
Total Cats: 12
Default

You have nothing to worry about. Sourcing vacuum for your brake booster and MAP signal from the same junction won't cause any problems.

Here's my common rail IRTB vacuum setup, and what you could do with yours.

FWIW, unless you have insane amounts of lift and duration, running a purely MAP setup will be absolutely fine - I do. Even with crazy cams, it should still run fine.

Here's a nifty small vacuum distribution block from BEGI:
Signal Source Fitting - Two Vacuum Sources BEGi

Attached Thumbnails
Bestow unto me: Your knowledge on the most basic of vacuum setups-throttles_and_vac.gif  
wildo is offline   Reply With Quote
Old 11-02-2012, 01:48 PM   #20
Elite Member
Thread Starter
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,460
Total Cats: 782
Default

Neat thank you!
concealer404 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
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM
3rd Time's a Charm...hopefully. zephyrusaurai Meet and Greet 2 09-28-2015 11:59 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 12:40 PM.