blow thru carb crutch mods!!!

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srixon4406

srixon4406

TURBO TOAD
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Does anybody have a any pics of the Mods that are made to the carb for running a air assisted brvp I searched the turbo forums and can only find bits and pieces of what's needed to be done I was hoping somebody may have sent there carb off to one of the well know carb guys and may have taken some pics of the Mods that where made to the metering blocks and also there brpv any and all help is appreciated
 
I remember seeing a thread on the turbo forums that either had the directions and pictures on how they modified the carb for a boost reference power valve or there was a link to a site that had it.

Looking for it now. Wish me luck, this could be a wild goose chase since its been a couple years.
 
CUUDAK said:
Lots of pics in this thread,

http://www.theturboforums.com/smf/t...section/the-'crutch'-carburetor-tech-section/
Click to expand...

Yah AnotherA the link that CUUDAK posted didn't have the pics posted till around two or three days ago Brent posted them after I requested some info
I've searched the forums till my head hurts and its hard to get any complete write ups
Here's a good one for making a HOME MADE BRPV

http://www.theturboforums.com/smf/c...-make-your-own-brpv's-at-home-dialup-beware!/

I made one last night it only took me about a half hour I think I'm going to try it first with the extension tubes before I go full blown crutch but I'd like to have everything in place if I have to go that direction
 
It looks like most people are recommending that Crutch system that CuudaK posted.

Isn't tuning such a blast!
 
AnotherA said:
It looks like most people are recommending that Crutch system that CuudaK posted.

Isn't tuning such a blast!
Click to expand...

Yah its the real deal I found a air pump on eBay the other day I paid 17 bucks for it and it gave me the bug
The only thing there using a different style brvp with a copper cap that holds the spring closed till the air is applied
Also I'm looking for the metering block and the main body Mods

Here's a good one I my try this one
http://www.theturboforums.com/smf/c...ch-carb-main-body-pics/msg1333974/#msg1333974
 
Here is another way to boost reference the powervalve without the airpump. Seems to be a bit easier and it does work. This will reference the powervalve through the vacuum port on the metering block. I know it is for blower application but it is all the same theory as far as boost is concerned.

http://www.motorsportsvillage.com/modifycarb.html

Just curious, Is the engine already running? Are you having problems with the fuel curve? Do you have an AFR gauge? I do believe that in some instances you won't need to reference the powervalve unless your power levels are really high. I have seen several boosted applications work fine without this modification.
 
CUUDAK the car is in pieces right now I'm making some necessary changes to my setup I do have a afr gauge hooked up I've red post after post of people having problems and I'm new to the whole turbo seen and I'm trying to weigh all my options and gather all the information that I can on tuning a blow through setup so when the time comes I can get the most out of my setup
 
I recently read something VERY interesting.

On the 4150 based double pumper carb......if you EXTEND the vent tubes UP and into the throat of the Carb Hat,.....it dramatically influences the A/F ratios and you can effectively reduce the jets 8-10 sizes down.

It still means that to Blow through mod a carb, you need solid floats, plug the choke rod hole, epoxy the air bleeds, and mill the choke tower off (unless using a later HP Holley or Proform center).

I am soooo looking forward to Boost on my Single Turbo 360 Duster project.
I just Hangar18 modd'd my carb last weekend.

Read it here:
http://www.theturboforums.com/smf/carburetor-boost-tech-questions/vent-tube-extensions-wow!/

View it here:
ventextentions.png
 
Yah prine if you use the vent extension and one of these
http://www.theturboforums.com/smf/c...-make-your-own-brpv's-at-home-dialup-beware!/

All the research I've done they say
Step one the hanger Mods
Step two the modified pv and the vent extension
Step three full blown crutch setup

These are the three main Mods that I've researched of course you want to try tuning the carb before you moving on to the next modification
This is just my opinion from the count less hours of research that I've come up with I have next to no experiencewith blow thru setup
Thanks Aaron
 
Prine said:
I recently read something VERY interesting.

On the 4150 based double pumper carb......if you EXTEND the vent tubes UP and into the throat of the Carb Hat,.....it dramatically influences the A/F ratios and you can effectively reduce the jets 8-10 sizes down.

It still means that to Blow through mod a carb, you need solid floats, plug the choke rod hole, epoxy the air bleeds, and mill the choke tower off (unless using a later HP Holley or Proform center).

I am soooo looking forward to Boost on my Single Turbo 360 Duster project.
I just Hangar18 modd'd my carb last weekend.

Read it here:
http://www.theturboforums.com/smf/carburetor-boost-tech-questions/vent-tube-extensions-wow!/

View it here:
http://i40.photobucket.com/albums/e237/kpgsx/ventextentions.png
Click to expand...



Yep, I can second that the vent tube extensions make a big difference.
I was surprised how much i had to downsize the jets the first time I put it on.
 
I've had sometime to mess around in the last couple nights at work and I've been trying to figure out just what's intailed in the crutch mods
Here's what I ended up doing
1. I modified a stock pv by taking the spring off then unscrewing the spring hold down and flipping it over then a epoxied the spring to the hold down
2. I made up a cover to put pressure on the spring I used a 1/2 copper coupling and modified it with a couple tabs so I could screw my jets into it and placed a 7/16 brass washer in the end of the coupling its a very tight fit and ran a bead of soldier along the top edge of the coupling and the soldier locked the washer into place
3. Then I did some metering block mods
4. I'm still working on the main body and base plate modifications but ill post some pics when I get them done
IMAG0032.jpg

IMAG0029.jpg
 
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