Inliners International Forums General Discussion Blown and Injected OK guys You got me!!!

I give up,leaning more and more towards turbo-charging a 4.0 liter Jeep-engine instead of the 4 barrel Holley setup I was aiming for.

I also had my mind on trippel Webers,but after looking at pic's of the Brazilian turbo-cars it's just surrender left to do.

And now all my calculations is blown to pieces,and it's back to the drawing-board again.

My goal is not to compete with the big dogs,I'm more into building a engine with most of the parts I got already,I've found a turbo,got the cam,will build a new exhaust-manifold...

But now to a question that came up : I want to build a blow-trough setup and would like to use a Holley since I already have a intake-manifold for the engine,but what to do to the carb to make it work as a blow-trough carb and what size of carb is best to use to a 4.0 and 6-14 psi pressure of boost.

Regards : Speed-Swede

i don't know how to do the carbs, but since those motors came with EFI, why not use it. the fuel control is the best. tom

Hi Tom!

I have had my mind on Fuel-injection but I don't think it fits the overall style of the car,my friends in the club says it looks a little bit kind of an old Bonneville-racer and I'm trying to build it more and more in that direction so therefor I think it's kind of to much Hi-Tech.
"And a turbo is not...Ooooops"

So I think I have to make a small sacrifice and end up with a smaller amount of power but since the car has a weight of aprox. 850 kg (1800-1900 pounds,not really shure but something like that)
It probably will have the power to get me out on Sunday Picnics and to the grocery-store on occation.

And amother aspect is where to put all the stuff that comes with a EFI-system,boxes and wires and such things. A T-bucket is not that big and there are other things to fit in that tiny body,such as a chubby Swede and then the picnic-basket of course...

Yet another thing to consider is that the engine I got is a -89 and they have the Bendix-systerm and I've heard that's not so good,so I think it's better to stick with an "good" old Holley 4 barrel on top of a Offenhauser intake if I dont get lucky and stumbles upon 3 Dell'Orto 48 turbo-carbs but that is not something You will find laying around.

Bets regards : Hans "Speed-Swede"

There is a Co. that makes a four barrel FI throttle body.
It looks like a four barrel Holly carb(to keep that old school look)
I believe it has four injectors.
Just a thought.
MBHD

If you have to use a Holley 4 epoxy over all the cup plugs on the outside of the metering blocks so they can't back out under boost. Get Nitrophyl floats so they won't crush under boost (won't always happen with the metal floats, but it can). Holley makes boost referenced power valves, what to reccomend for which to use for your application, I have no idea.

However if you want to use a vintage looking 4 barrel carb, that has a history of use in a blow through application think about a Carter, they were used blow through by the factory on Studes with the McCullogh blower. It has been fairly well scienced out by the Stude nuts (I mean that with respect) and has been adapted to blow through turbo (with boat loads of boost too) on the Stude V8 by more than one person. I bought a booklet off Ebay that had alot of info on that kind of stuff. IIRC it was by Dick Datsun (sp?) and it was titled 21'st Century Turbo. It's the same guy behind the Gator Spercarger site: http://www.gatorsuperchargers.net

Nexxussian: Thanks for the info,that helps a lot,now I do know a bit more.

About the "Carter-solution" : What is there to do to get them functional for blow-trough,it seems to me that a Carter could be an option since a friend of me have a pair of 625 Competition carbs laying around since ages that he don't use for anything,but I don't know if they are suitable for my needs considering carb-size for my engine-size and boost/power-level,they could be to big or to small I don't have a clue about that,but some research can be a cure for that maybe "learn an old dog to sit".

I think I have to make a call to a Swedish book-store that carries almost any book that been released in this area and see if they got some books in the topic.

Best regards : Hans "Speed-Swede"

There is a seal (IIRC) installed on the accelerator pump shaft and there is an actual tuning chart for the carter in a blow through application (jetting Vs boost) I have yet to find the book I have (form Dick Datsun). It's more of a compilation of stuff, and is not really a 'book' but I remember seeing a section on the Carter used on the 289 CID Stude V8 with the tuning charts and a slick way to adapt the fuel pump (on a Stude) to make it self compensating (because if you are planning on blowing through the carb you will have to boost reference the fuel pressure, as the boost goes up, the fuel pressure must increase by the same amount.

Not sure what carb you want to blow through?
As far as increasing fuel pressure as boost pressure increases,you just need a regulator that uses a boost reference hose.

MBHD

The modifications done to the Carter AFB for blow-through type blowers:

(A) Idle mixture control screw seal (2). This may be done by removing the idle mixture control screws, and milling a small recess (1/4 to 5/16 inch diameter, 1/8 inch depth) using the threaded hole for the idle mixture control screw as a pilot. Now obtain an O-ring with an I.D. that will seal the idle mixture control screw and and O.D. that will seal the recess. Install the spring on the screw, then a flat washer, then the O-Ring, and install in the housing.

(B) Pump shaft seal. This may be accomplished by machining a brass plug to fit in the underside of the airhorn in the pump recess. Obtain 2 thin teflon or neopreme washers and a thin conical spring. The components are assembled as top of airhorn, teflon or neopreme washer, spring, teflon or neopreme washer, plug. The accelerator pump shaft is inserted through the center. the washers I.D. should seal the pump shaft.

(C) Thottle shaft seal. This is a vacuum seal, and is accomplished by milling a groove on each side of each throttle shaft, and milling a corresponing groove in the lower portion of the throttle body from the groove in the throttle shafts back to the area just below the side area of the auxilliary air valve. A quarter inch hole is drilled on each side connected the groove with the side area beside the air valve.

(D) Thicker airhorn gasket. Carter did this the easy way, by stapling two airhorn gaskets together.

(E) Float baffles. Carter disassembled the standard AFB floats, inserted a baffle made from expanded aluminum (side to side), and reassembled the float. This works MUCH better than the foam floats. While the foam will not normally crush (it can, and I have seen foam failures from crushing), the pressure can, and does, cause the foam to absorb fuel, thus becoming heavy. Carter did not use foam floats, not will we when modifying these units.

Jon.