Allan & others,
I was in charge of the rally at this year's Tigers United. As one of the tie
breakers, I used gas mileage. The MPG results I saw were bizarre.
I had every Tiger "top off" at the same station on the way to the start of
the rally. Then they ran the route, which totaled a bit over 70 miles. At
the end of the rally we dipped the tanks with a calibrated stick. (We also
tracked total miles and a few were "lost" costing them an extra mile or so
but nothing major.)
The range of gas usage shocked me. Our most efficient Tiger had 9.2 gallons
of gas left in his tanks at the end of the rally. Most had 7 to 8. A few
were in the 5s but one car had a bit over 3 gallons left. The guy with the
worst mileage used two to three times the gas used by our best performer.
I think Rob has a very valid point about mixture. Like Rob, I set the main
jets for a slightly lean freeway cruise. I shoot for 15.5 to one. I'm sure
our last place guy could have used some jet changes. Recently a club member
asked me to take a quick look at his Tiger which wouldn't run. It was a
stock 260 and someone had put a 600 CFM vacuum secondary Holley on it and
had installed 67 mains. I took a wild guess and replaced them with 62s. Now
he says his Tiger has never run better. One of these days we'll refine his
jetting but the idea is that once all the oxygen in the cylinder is burnt,
pouring more gasoline in is not only wasting the gas but it's sure not going
to help the oil with lubrication.
Two summers ago, my wife & I drove our "beater" Tiger 3500 miles in ten
days, to and from SUNI. Our mileage for the entire trip was a little under
24 MPG. This was with a 5 speed so its not fair to compare it to a stock
Tiger with a 4 speed. We have over a 300 mile range on a tank. For the trip
we borrowed a piece of hardware from our race program, an LM-1 fuel meter.
It reads your mixture (accurate to 1/10 from 10:1 to 20:1 while you're
driving. On that trip I learned that the typical Holley 600 CFM vac
secondary carb that many Tigers run was too big for a real Hi-PO 289 when we
got above 5-thousand feet. We started at sea level and almost hit
11-thousand feet at the top of the Bear Tooth Highway in Montana so we put
it through a good workout. We never changed jets the entire trip and the car
actually ran good the entire time. However it would have run better with a
smaller carb. There simply was not enough vacuum at altitude for the carb to
work with precision. The problem finding a better carb is most smaller
Holleys delete the PCV port which I insist on having. There are various
plates that insert between the manifold and the carb but then the air
cleaner may hit the hood. Hopefully, one of these days I'll figure it out.
Before I'd think about a bigger tank I'd find a 450 CFM vac secondary Holley
and jet it correctly. Even with a 4 speed you should get 18-20 MPG which
gives a range in the low to mid 200s.
good luck,
bt
--------------------------------------------------
From: "Rob Bernardino" <crbernardino@mac.com>
Sent: Friday, July 08, 2011 3:49 PM
To: "Allan Ballard" <allanballard@att.net>
Cc: "Tiger Talk List Tiger" <tigers@autox.team.net>
Subject: Re: [Tigers] Extending driving range
> I would err on the side of safety and say no. I commute 25 miles each day
> in my Tiger and have recently found the best fix is increase you mpg.
> Inflate the tires higher, run a hardtop. Actually the best fix was
> fortuitous. Car was recently stalling and had the MDS system switched out
> for petronix. That and perhaps running the car on the lean side gives me
> 17-18 mpg.
> Rob in Carmel
>
> C. Robert Bernardino MD FACS
> Oculoplastics and Aesthetic Surgery
> Vantage Eye Center
> Monterey, CA
> www.vantageeye.com
>
> Sent from my iPhone 4
>
> On Jul 8, 2011, at 1:54 PM, Allan Ballard <allanballard@att.net> wrote:
>
>> Temporarily I'd like to extend the driving range of my Tiger beyond the
>> limits
>> of the 13 gallon tanks.
>>
>> Obviously a fuel cell or bladder is an option although expensive and
>> permanent.
>>
>> So I wondered about a 10 gallon can of gas placed in the trunk and used
>> when
>> needed.
>>
>> I've traveled with gas in a storage container in the trunk of my Alpine
>> out
>> west but the Alpine doesn't have a battery in the trunk.
>>
>> Is travel with a storage container of gasoline in the trunk of a Tiger
>> safe?
>>
>> Allan Ballard
>> Mk1a Tiger
>> _______________________________________________
>>
>> tigers@autox.team.net
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