Fuel useage

[fmarshall]

Here is a two-for-one question.

First, I ran out of gas today - mostly I don't recall how many miles I had driven, as my speedo is kaput. I need a new casing and cable.

1. Anyone know where to obtain one? 63 Avanti R2 4-speed P/N 1557262

So, I flame out and coast into a gas station. Good Avanti!

And after filling, startinge, and driving home, I notice that a stram of fuel stain residue is on the fender. So, I will replace the cap.

2. Is it possible that the return fuel pressure, and the bad seal on the cap can cause tank venting, which could be reducing the mileage significantly?

(a side note - Avanti may be the best car to run out of gas in, as the tank sits above the fuel pump, so the supply is easily restred by gravity ...)

[StudeRich]

Well you better hope there is "tank venting", or you will suck the bottom of the tank in! The tank has to be vented, they are not sealed like new cars.

Original Avanti caps had a small hole drilled in the center of the rivet in the center.


StudeRich
Studebakers Northwest
Ferndale, WA

[fmarshall]

Perhaps a vent hole is okay, But I believe the gasket is dried and not sealing, so that more than vapor leaves - I'm guessing this due to the contrail on the rear fender.

[wagone]

I believe (and others, feel free to tell me I'm wrong) that there are two reasons why R2, 3.73 geared cars (not just Avantis but other Studes as well) get such poor gas mileage. Mine, for instance, has never seen better than about 13.5 mph; corected for the inaccurate speedo. At the takeoff on the AFB for the vacuum advance mine only delivers about 11 inches of mercury vacuum--that is BARELY able to opearate the advance in the distributor, at best. Now in my case, worn throttle shaft bushings MAY be contributing to this. And the second reason is that the spring tension on the primary rods is incorrect and hence with the limited vacuum the rods do not drop down to lean out the mixture and improve the mileage. I need to investigate both of these issues further. A proper 3.73 geared car driven reasonably ought to do 17-18 mph in mho. Course this comment may be off topic and if so I apologize.

wagone and the Old R2 Avanti

[StudeRich]

18 MPG with 3.73 gears and over 3400 LBS? Are you kidding? Sure you could improve it some with the mentioned Carb. fixes, but with four speed and 3.31 gears maybe! If you have Powershift and 3.73 or even 4 speed it will not happen! Way too many R's even with a 3.54! [:0]

quote:Originally posted by wagone

A proper 3.73 geared car driven reasonably ought to do 17-18 mph in mho.

StudeRich
Studebakers Northwest
Ferndale, WA

[DEEPNHOCK]

Mentioning the serial number will seriously affect your mileage[}]
(It's a Corvette and Avanti thing, fer sure)....
Jeff[8D]
[/quote]

[Karl]

Did see 14mpg with the Twin once.But the speed limit was 55.

63 Twin Supercharged Avanti
64 Avanti R3w/NOS
88LSC Avanti 350 Supercharged w/NOS

[Laemmle]

My R-1 with 3.54 and 4-speed never gave over 17mpg even when almost new (purchased the car with 30k on the clock and two years old).

quote:Originally posted by StudeRich

18 MPG with 3.73 gears and over 3400 LBS? Are you kidding? Sure you could improve it some with the mentioned Carb. fixes, but with four speed and 3.31 gears maybe! If you have Powershift and 3.73 or even 4 speed it will not happen! Way too many R's even with a 3.54! [:0]

quote:Originally posted by wagone

A proper 3.73 geared car driven reasonably ought to do 17-18 mph in mho.

StudeRich
Studebakers Northwest
Ferndale, WA

[wagone]

My comments come from an experience (18 years worth) with a Corvette with 3.73 gears and a 4-speed and it would rack up 17.5 mph (corrected for speedo error) all day, any day! But if 14 is the norm with an R2, so be it;just disappointed that it can't equal a Chevy.

wagone and the Old R2 Avanti

[Mr Mike]

My '60 Hawk has a 4 bbl carb, 3-speed w/OD, 3.73 gears and P205/75/15 tires. The OD didn't work until last week. I have monitored the MPG since purchasing it in Jan 07 and averaged 15.19 MPG over the 4100 miles accumulated since then. Allowing for a 5% speedo error that should make it about 14.4 MPG. I don't baby the car by any means and usually run 70 MPH on the interstates which would be about 3240 RPM. All things being equal, that should equate to upper 18's now that the OD is working. I can post the actual figures once I run a couple of tankfuls if anyone is interested.
Mr Mike

[ivorydan]

I replaced the 3.54 in my 64 R1 GT Hawk with a 3.07. I get app 17 mpg on highway driving.