A pair of dual HS2's isn't bad though. Especially when compared with a single
ZS,
double especially when looking at the runners on the late ZS manifold (very
small).
I can't say how much better a set of dual HS4's would be over a set of dual
HS2's
(1-1/2 vs 1-1/4, in case I've got my HS numbers wrong). But I can say that
those dual
HS2's run circles around the single ZS.
I have an '80 Spitfire. With the single ZS, the car was not happy above 40
mph. It
strained its guts out. Interstate highway's were a writeoff, I just wouldn't
venture
out onto them. It felt like the car was going to explode from the strain of
trying to
run at highway speeds. So much so that when I moved, I simply towed the car
here.
With the dual HS2's, the car is just fine on the interstate. I've had it
cruising
along at over 80 mph. It's wound up like a top at that speed (I've only the 4
speed
gearbox), but it's quite relaxed. It's a completely different car with the dual
SU's. Probably the best single performance mod a guy can make for a 1500.
Trevor Boicey wrote:
> Nolan Penney wrote:
> > > I was thinking of trying that with my 1500, but the stock manifold for a
>1500
> > > was for the Zenith Stromberg carb. What kind of manifold can you use on
>the
> > > 1500 to fit SUs onto it?
> >
> > Get the intake manifold of an earlier Spitfire engine. If I remember
>right, you
> > can go all the way back to a Mk II Spitfire manifold, and have it bolt up
>to a
> > 1500. The earlier engines ran dual SU's, as did 1500's from countries
>other then
> > the US. The 1500 SU's are the bigger ones.
>
> While the above would work, for the 1500 you probably should
> get the real carb set for the 1500, which is dual HS4s on
> a larger manifold. (compared to dual HS2s on a smaller manifold)
>
> The carbs are not hard to get, use the internet to find
> a UK junkyard.
>
> Consider you are probably seeking more performance, this
> is the only way to go.
>
> --
> Trevor Boicey, P. Eng.
> Ottawa, Canada, tboicey@brit.ca
> ICQ #17432933 http://www.brit.ca/~tboicey/
> "Clown college.... pfffft... can't eat that..." - Homer Simpson
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