carb enclosures??? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-19-2002, 06:11 PM
chevyelc81's Avatar
Member
 
Last photo:
Join Date: Apr 2002
Location: Connecticut/Florida
Age: 31
Posts: 256
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post carb enclosures???

When you run a supercharger(blow through type), do you have to run a carb enclosure that encloses the entire carb, or can you run hosing that bolts in place of where the air filter would normally go? I thought you had to run an enclosure, but I saw a supercharged car in a magazine with the carb exposed. Is there a special carb??? any info will help. thanx <img src="graemlins/drool.gif" border="0" alt="[drool]" />

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-19-2002, 06:14 PM
BOBCRMAN@aol.com's Avatar
Member
 
Last photo:
Join Date: May 2002
Location: Holly, michigan
Posts: 8,130
Wiki Edits: 0

Thanks: 25
Thanked 267 Times in 250 Posts
Post

you can run them either way ,its easier to use an enclosure. you have to seal the throttle shafts and minor mods if you blow thru.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-19-2002, 06:16 PM
woodz428's Avatar
Troll Hunter
 
Last photo:
Join Date: Sep 2002
Location: Philo,Il
Posts: 2,702
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Yes you do , there are more complex ways around it but the enclosure is the most effective solution. What you are doing is pressurizing all the circuits in the carb, without some sort of pressurization when the blower gets up on boost it will blow the fuel back through the jets because the fuel bowls aren't pressurized. That's the short explanation. Ford used the blow through without the bonnet in the mid fifties, the difference was the fuel bowls were on top of the carb thereby getting pressurized.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-20-2002, 05:52 AM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 37
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
Post

[quote]Originally posted by woodz428:
<strong>Yes you do , there are more complex ways around it but the enclosure is the most effective solution. What you are doing is pressurizing all the circuits in the carb, without some sort of pressurization when the blower gets up on boost it will blow the fuel back through the jets because the fuel bowls aren't pressurized. That's the short explanation. Ford used the blow through without the bonnet in the mid fifties, the difference was the fuel bowls were on top of the carb thereby getting pressurized.</strong><hr></blockquote>

NO, this is not correct! You do not have to run an enclosure and the modifications are the same to the carb with the exception of sealing the throttle shafts if you just use a bonnet. This is not even an absolute. Alot of turbo guys just use a bonnet with no throttle shaft seals. On a new holley there is little leakage.

Additionally, whether in an enclosure or not the fuel can be pushed back out of the bowls if boost pressure exceeds fuel pressure. This is why a boost referenced fuel regulator is manditory. You set it at the normal 7 psi and it raise the fuel pressure at the rate of the boost increase. This means you must run a high pressure pump. If you are going over 10 psi, a fuel injection pump is necessary to make enough pressure.

For more information on this stuff check out <a href="http://groups.yahoo.com/group/blowthruturbo" target="_blank">this</a>list on yahoo. There is a wealth of information on this stuff.

Chris
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-20-2002, 07:26 AM
chevyelc81's Avatar
Member
 
Last photo:
Join Date: Apr 2002
Location: Connecticut/Florida
Age: 31
Posts: 256
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Thanx alot for the info, this really helps. So if I buy a brand new holley carburator, I will be safe with just the bonnet, and no carb enclosure??
What about your power brakes, and vacuum advance, etc?? Where do you put these?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 11-20-2002, 10:20 AM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 37
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Power brakes can be a bit of a problem. They will work under normal driving conditions, but under boost you could use a check valve to keep the brake booster from working backwards. Best bet is a manual setup.

Vacuum advance, kindof the same issue. Most guys just eliminate it. Usually on a boost application timing retard is more important than advance. Make sure you get a BTM module.

Chris
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 11-21-2002, 02:21 PM
woodz428's Avatar
Troll Hunter
 
Last photo:
Join Date: Sep 2002
Location: Philo,Il
Posts: 2,702
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

The Paxton conversion that was offered in the '60's( by Shelby as well as Paxton) used the enclosure and it is much simpler than sealing the throttle shafts since they are in the box they don't require sealing. Yes if you get too much boost the fuel will blow back through the jets even with the enclosure if a pressure sensor line isn't used. Another way is to have a pressure switch to activate an electric pump to keep the pressure up, anything over 8-10 pounds boost is really unneccesary for a street engine.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 11-21-2002, 07:52 PM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 37
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Quite a few ford guys are running 18 psi turbocharged street engines on pump gas. Nasty little buggers....You dont want to challenge one of them to a street competition.

Chris
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 11-22-2002, 08:29 AM
chevyelc81's Avatar
Member
 
Last photo:
Join Date: Apr 2002
Location: Connecticut/Florida
Age: 31
Posts: 256
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

I bet useing an enclosure is fun to tune...you have to remove it everytime you want to make an adjustment... Would I be safe with a new holley and a bonnet?? Ill probably use a max of 8psi boost. Or should I just be safe and get an enclosure?
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 11-22-2002, 02:49 PM
woodz428's Avatar
Troll Hunter
 
Last photo:
Join Date: Sep 2002
Location: Philo,Il
Posts: 2,702
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Jusr because you run 20 lbs boost ( I know it's done)on the street doesn't, for me, make it a street car. I've run many unstreetable cars on the street in my life, but would never reccomend someone else build them, a 5:14 gear on the street is quick but makes a crappy street car. The adjustments aren't that bad ,most enclosures I've used are 2 parts, the top comes off for adjustments and if I recall correctly they have holes for idle mixture and such.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 04:20 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.