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-   -   Blow through carburetor turbo setup? (https://www.homemadeturbo.com/forced-induction-7/blow-through-carburetor-turbo-setup-95522/)

bitchM0VE 09-20-2008 06:37 PM

Blow through carburetor turbo setup?
 
I want to turbo my 86 Isuzu Trooper II. I'm looking for information on blow through carburetor setups. Not interested in a suck through setup. It's a 2.3L 8 valve I4 70HP stock. Truck has 225K, drivetrain in it has 40K. Motor runs perfect w/new everything. I have a weber 32/32 conversion on it, so around 85HP. :1 Truck has 3" suspension lift, new 33x12.50's, disk brake conversion, winch, brush guard, roof rack, vinyl flooring, electric fans, and cold A/C. ;D It's awesome, but has no power. Motor is completely out of steam after 5K. 4.5K is probably peak HP. It's not a high RPM machine.

Anyone have any info or good links to adapting a carburetor for a blow through turbo setup? I've done some research and I'm reading that any carburetor can be modded to accommodate boost. That sounds great. I want to turbo it for cheap next summer. Something like 100-200 dollars tops. I'll probably use a t25 off a volvo from the local junkyard unless I find an old turbo impulse as the entire manifold/turbo/downpipe setup bolts up to the troopers 2.3L. I have two tiny IC's off a mazda millenia I'll probably use. I read that Turbocharging by Hugh MacInnes has some info on blow through setups. Guess I should probably buy it. Anyone have a copy of it?

Smith-02 09-20-2008 10:13 PM

Re: Blow through carburetor turbo setup?
 
google for 'weber blowthrough mods'

1:1 fpr or a boost referenced low pressure fuel regulator.


carbs are ------- easy, theyre mechanical management

bitchM0VE 09-20-2008 11:57 PM

Re: Blow through carburetor turbo setup?
 
Hmm. Searched and ain't coming up with much. I have read you have to pressurize the bowls to keep the carb working and that it's easy on a Weber, but no details. I know there's a vent on the bowls so it couldn't be too hard to hook that to the intake manifold. Maybe have a 1 way valve so it can't put vacuum on it or something. I've also read some people build a box around the carb and pressurize the entire thing, but that sounds like a pain.


Smith-02 09-21-2008 12:02 AM

Re: Blow through carburetor turbo setup?
 
---- carb boxes, theyre for people who cant figure out how to make a carb work with boost.


every lb of boost is +1lb of fuel pressure. 1:1 fmu.

gotta keep the static psi of fuel (like 4-7) in the carb to keep venturi function and internal passages still working as they should.

its an easy concept, just keep the 1:1 and use a carb like a weber or a holley that can handle the boost.

best bet, adapt to a holley 350cfm 2bbl and just do holley boost mods. more bang for the $

onlyflash944 09-21-2008 12:09 AM

Re: Blow through carburetor turbo setup?
 
i don't know about webbers, but q-jets are simple as solid float that won't be crushed under boost, bigger primary jets, shorter secondary meetering rods. learn how they work, then make your own informed decisions on what you need to do to use boost. its not rocket science

Smith-02 09-21-2008 12:13 AM

Re: Blow through carburetor turbo setup?
 
q-jet on a ------ 2.3? damn

onlyflash944 09-21-2008 12:22 AM

Re: Blow through carburetor turbo setup?
 

Originally Posted by c0mpl3x
q-jet on a ------ 2.3? damn

the rochester was on a pontiac 455, I'm clueless on the webber, never had one apart. hell i've never even owned one of those. i can't imagine that they would be too different in the way their made.

enikolayev 09-21-2008 12:26 AM

Re: Blow through carburetor turbo setup?
 
i was boosting a bug back when i was 16 and i remember reading about drilling the holes for the shafts out slightly larger, and sticking o rings in there.

bitchM0VE 09-21-2008 12:28 AM

Re: Blow through carburetor turbo setup?
 

Originally Posted by c0mpl3x
---- carb boxes, theyre for people who cant figure out how to make a carb work with boost.


every lb of boost is +1lb of fuel pressure. 1:1 fmu.

gotta keep the static psi of fuel (like 4-7) in the carb to keep venturi function and internal passages still working as they should.

its an easy concept, just keep the 1:1 and use a carb like a weber or a holley that can handle the boost.

best bet, adapt to a holley 350cfm 2bbl and just do holley boost mods. more bang for the $

Ok, see I'm reading you have to also pressurize the bowls themselves. I read most use a 1:1 FMU to keep the fuel pressure at say 3-5 PSI. Read others just set base pressure high and if it doesn't flood out, then you don't need an FMU. I'm running 8 PSI base right now on my Weber, so I could probably run say 5 lbs boost without a 1:1 regulator. Just have to pressurize the bowls I read and hope the floats are not crushed.

Anyways this weber is new and bolts up to my intake manifold, so I don't want to have to change it. I just wanna mod it to compensate for boost.

Smith-02 09-21-2008 12:52 AM

Re: Blow through carburetor turbo setup?
 
thats what i just told you to do. find out what needs done, and mod it.

my weber 32/36 is nitrophyl floats so im good... find an old carb'd jag, grab the float. weber 32/36 came stock


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