[Saloon-lovers] reply to posts on airflow, lumping, owning a mega tow-vehicle


I’ve got a convertible, a two door fixed head and a couple of four door hard
tops, but more than anything else I’m most envious of your six wheel drive

In regards to over carburetion with SU’s. The SU is a variable venturi
carburetor. At any throttle position, fuel pickup is good from the jet
because of how the piston moves relative to air flow. In contrast, a good
old fashion Holly Double Pumper sucks (pardon the pun!) at low throttle
opening because air velocity around its venturi is slow. That’s why your
standard V8 style carburetor requires gizmos like accelerator pumps to get
things going when you punch the gas, don’t need one on an SU.

One could certainly put more SU carb capacity than required, but it will
still run well at light throttle, and real good wide open.


Mike Waldron
Oklahoma, USA

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reply…sorry Stephen, i cant find it yet, however it is a US article and
refers to Holley carbs. It includes a bunch of formulae that allow one to
calculate the optimun CFM with regard to engine capacity,rpm etc etc.

It stresses that too large a carbie throat area is most unsuitable at

lower rpm especially, therfore my interser in 3 smaller carbs. My knowledge

It does lead me into the area of US V8 engines as one of my other interests

is building and modifying 4wds…as i live in Australia and both Jaguar and
US V8s
are foreign imports, my feeling is if u want to modify your car, that is
up to yourself, BUT if people end up making negative comments cause u spent
time and
money and love doing it and now the finished product is just as costly, but
valuable than an original (in thier opinion), then learn not to be cranky!

Engines in particular, i like to keep fairly original. In Oz it costs the
to convert to V8, as to repair a 6, the V12 is a differnt story.

if u do the work youself u can change back i suppose but i dont think many
The V8 conversions are generally worth 10% less at least…more for the V12.
i have spare car S11 that had a Chevy in place of the V12…only minus the
actual engine
the dude who sold it to me was most uncomplimentary abot all Jag motors…I
hated him,
but he did point out the Chev 350 is somewhat lighter than even the
much better handling.

Also there is no real denying the V8 can be made to produce 300hp very
and cheaply, especially if u live in USA…i think most “lumpers” live there
bet there aint many in England!..in Oz a common conversion is the GM
a bit of a waste of time in my opinion.

90% of people cannot understand why i put a Supa 5-speed gearbox in my
Daimler Vandenplas…apart from the fact the auto was stuffed and i got the
conversion for half price, i reply by asking if V12 Ferraris have autos.
the other 10% dont need to ask ( i STILL ask myself sometimes).

We could go on, especially about interiors, even sound systems…but i wont

A poster was email-dreaming about owning a mega tow vehicle…DO IT!

I have a GMC 6WD…it will carry 2.5 tonne on the back and also tow a 2.5
tonne trailer
that is any conditions!!
i had waited 4 years to buy a vehicle, and missed out on the exact one i
even though i was prepared to put the money in the mans account immediately
sight unseen.
A truckie was offloading his load to pick it up!! and the man said he wanted
to give him
first go…so i missed out ( it was an Inter D1610 4wd,5 tonner, with
winch,26000 miles
excellent nick…$2000)…but i got the GMC instead…i also tow dead jags on
a car
trailer behind my Scout. The club has scored some paddock wrecks for

					regards tony--------------

Date: Mon, 8 Jan 2001 07:59:01 -0000
From: “Stephan Kassner” kassner@myisp.co.uk
Subject: Re: [Saloon-lovers] SU Airflow Data


triple carbs…manifold from 420G…have choice of HD8 or old H6…
in light of your post re 3 smaller HD6, i dug about for my airflow
formula book…would u use H6(ex-MK7) or HD8

I’m thinking along the same lines - do you have the formula/figures
handy for the various carbs HD, HS, HIF? I’m sure I’m not the only
one interested!

I’m considering 3 HIF6’s . . . . Cos they’re very easy to get, and CHEAP!

    • around 15 pounds English each s/hand.

Maybe you can tell me the title of the formula book to which you refer?


Stephan K.
67 Mk2 340 with 4.2l engine 2x HD8’s - no air cleaner - Love that induction

Happy to correspond off list if you feel this is more appropriate.

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