Fuel System: Anyone ever tried a Paxton Powerhat on an Avanti?

[PackardV8]

Yes, everyone knows the R2 air horn is a bottleneck for getting boost into the carb.
No, not many of us want to cut a hole and run a hood scoop.
Maybe, there's a way, similar to this, but lower profile.

"it's unique low-profile design measures only 3.2" tall (overall height) and permits near-360 degree rotation for universal fitment.
At first sight the PowerHat looks like a giant, polished air cleaner that is sealed off, minus a single three-inch inlet (though they also have dual inlets available). Flip the PowerHat on its belly and now it looks like a giant compressor housing. Remove the two pieces of cast aluminum from each other and inside is an air diverter that resembles an air filter, just without the cotton. It resembles that for good reason; because that’s basically what it is. To properly encompass the carburetor with even airflow, a bit of restriction is needed to fill the hat completely. Without that restriction, the air would rush over the carburetor at whatever direction the hat was pointing, some being sucked in and some just bouncing around aimlessly inside the hat.

Anyone have an R2 convenient to measure the clearance between the carb air horn mounting flange and the bottom of the hood? Or maybe just measure the height of the R2 carb air horn? IIRC, we don't have even the 3.2".

jack vines

[karterfred88]

The carb mount ring to the tallest part of the bonnet is 2 1/2 inches +/-, the "hat" clears the underside of the hood by approximately 3/4", but the hose to the blower hits the hood brace on a 63 Avanti. The design of the original "hat" drops the inlet immediately off the hat so that the inlet circle is below the highest part of the hat. I have been looking for something that will clear the hood, have a 2.75 intake and fit 5.125 carb. Nothing currently exists that does both--at least not that I can find, all need "modification" of the inlet size, angle or height, as the smallest is 3 inch and most 4 that fit the 5.125 carbs. The Paxton unit "may" bolt on and just clear the hood, but then getting a hose to fit and clear might be a challenge.
Also- there would be two air cleaners, before the blower and after might limit airflow even more than the original design.

[j.byrd]

Hey guys, we no longer have our Avanti, but I was wondering after reading this if there is a way to drop the engine just a bit without messing up other things ? Tranny, driveshaft, and rear end angle taken into consideration would be necessary I would think, but ..... ????

[karterfred88]

Hey guys, we no longer have our Avanti, but I was wondering after reading this if there is a way to drop the engine just a bit without messing up other things ? Tranny, driveshaft, and rear end angle taken into consideration would be necessary I would think, but ..... ????

If you get rid of the steering bell crank you could easily drop it, but couldn't drive it. The crank pulley is already a clearance issue with the power steering ram ball end with the "short" motor mounts and not a lot of clearance to the pan from the top of the bell crank. You can "raise" the body with shims, but at some point, it begins to get "funny looking" as the front bumper position drops in relation to the body.

[j.byrd]

OK, thanks...I just couldn't remember much about the underneath spaces and since mine left the house in 09 and I am even older now, well, was just thinking, ha !.

[(S)]

Avanti engine mounts...

The R3 Avanti engine used a thinner front engine mount, any hood issues can be fixed a bit by using them....

[Milaca]

You can "raise" the body with shims, but at some point, it begins to get "funny looking" as the front bumper position drops in relation to the body.

The Avanti II was basically built this way, was it not? Did they raise the front of the body for powertrain clearance or just for appearance purposes?

[Gunslinger]

It was supposedly for engine clearance but Nate Altman had also said he never liked the Avanti's forward rake.

[karterfred88]

The R3 Avanti engine used a thinner front engine mount, any hood issues can be fixed a bit by using them....

True, but then you fight the power steering ram's touching the crank pulley. I got around that by substituting an aircraft Heim joint for the ball end and picked up 3/8" inch clearance.

[64V-K7]

I dropped my 70 Avanti II body down 1.5" by removing shims from the body, resulting in a tight fit under the hood.. The the R3 airbox was added, etc. More hood problems .... So I took the R3 Airbox to a machine shop and had them remove 3/16" from each half. I won't reveal what the bill was, but it was probably the MOST cost INeffective thing ever done on this car... but the hood closes nicely now.....

[karterfred88]

Speaking of blower hats etc., does anyone still have a repro R3 box they won't be using. I know all the pitfalls of them, but would a nice way to hide a TBI unit.