Some Questions for you racers

[Des]

I was out in my shed today flipping through all the garbage I have in there and came across a magazine I bought in 1998, 50th anniversary of the Holden, I know back when I was an idiot and thought Holdens were "cool"

Something I noticed that was interesting, an FX Holden racing, which the caption mentioned had 6 carburetors, now thats on a 6 cyclinder engine.

Now I have heard of Torana's with triple SU's or Webber's mounted side draftly but never 6 carby's on one engine.

I just wonder would that be possible on a Benz, for our racers, and would that achieve noticeable improvements,

Is it just a matter of pumping more fuel into the motor? Or what is achieved by so many carby's?



Lets say Oscar on his Povo Benz could get 6 carby's working, would there really be any benefit over 3?

 

[BenzBoy]

More equal distribution of the air/fuel mix and more accurate petrol to air ratio. One carburettor may feed the closest cylinder better than it feeds the others at the end of the inlet manifold. Fuel injection solves both problems and gives an accurate dose of the good gas. Normally it is one carburettor per two cylinders for good distribution - and then you have to balance the buggers...an exact science and a good ear required.
Regards,
BenzBoy

 

[WGB]

In the 70's I owned a Datsun 260Z with an engine built for rallying.

It had 3 double barrel side draft Dellorto Carburetors which was effectively one carburetor barrel per cylinder.

My then wife drove it to school (she was a teacher) with the choke out most days.

I tuned it every two months with a "Colour-tune" plug to set the idle mixture after balancing the barrels with my Stethoscope. I also had a "Carbalancer" Gauge but the stethoscope was just as good and I used it on a mini-cooper S and a Daimler Sovereign Coupe I owned around that time.

In 1977 the 260Z (Chassis No 112) was timed through a flying Mile at 136.6mph which if you know how unstable at speed the early Z-cars were is a considerable feat.

Bill

 

[oscar]

Lets say Oscar on his Povo Benz could get 6 carby's working, would there really be any benefit over 3?

Yes. Looks! Imagine with the bonnet up watching six carbs without filters opening up with all those linkages moving back and forth

GrantV has got three carbs on his 230S. For the m110 I think going from one big solex or holley to three smaller carbs would make the biggest difference. Don't think there'd be such a noticeable gain between 3 and 6 carbs though. Like 6 carbs the route from carb to cylinder is very direct for 3 carbs.

Comparing the stock setup, it's such a long way in the plenum for cylinders 1 and 6 compared to cylinders 3 and 4. To my mind you're not only getting less fuel into cylinders 1 and 6 whilst the plenum is cold because of condensation of the fuel inside the plenum, but any resonant affect is lost or uneven between the cylinders.

In a 3 or 6 carb setup, every cylinder draws its fuel/air mix through the same amount of space between venturi and intake valve. Coupled with a tuned exhaust system with custom extractors the same length for each cylinder, this would be a marked improvement over the stock setup

 

[Des]

Thanks guys for your responses, very interesting!

 

[Michel]

The most successful 6 carb set up was done on big American V8s such as the Dodge Hemi and regular 440.
But there were others.
Have a look:

409 Chev engine with 6 carbies


Early cadillac 429 engine with a sixpack manifold and carbies


E-Type Jag with a V12 and 6 carbs


Triumph TR6 with six carbs


Chrysler's famed 440 with a six pack set-up


A six-pack manifold/carby set-up for an early Chrysler hemi


Whatta....


My all time favourite a 1970 Dodge Charger R/T 440-six pack


A car very similar to one I owned back in the 70s (Dodge Charger R/T 440-six pack)

 

[GreaseMonkey]

I used to have a 1966 Pontiac GTO with the 389 and the triple carb set-up.
It was a crude design where the two outer ones only kicked in at high RPM, and in top gear this would have been at a speed where the whole car was unstable, so irrelevant anyway. Funny, they didn't see the need to invest in brake technology though.
Being a big lazy American V8 I think it would have run the same whatever was on there. The Americans went through a phase of multi-carb set-ups probably thought up by marketing guys rather than engineers. Then they got to make up HP numbers too.
Good fun!
Chris

 

[SELfor50]

Quick question Michel, is that Yellow beast 2 x V6's side by side???

 

[Michel]

Quick question Michel, is that Yellow beast 2 x V6's side by side???

They look too big for V6s I would say they are Vee eights

 

[SELfor50]

I'm a peanut!! I didn't even count the leads...

I assumed cause there were 3 carbys on each block that they would be 6's..

Damn, that'd be one fast (but heavy) weapon..

 

[Michel]

Hehehehe.. that's ok

How about 8 carbies on an engine?

 

[SELfor50]

Now... that's just too far!!



























NOT!

 

[Michel]

How about two engines in a car?

 

[Michel]

Or if you want to go faster....

How about a jet engine?

 

[Michel]

How about TWO jet engines

 

[oscar]

1 jet, 2 jets Stop it Michel, you had me at "how about 8 carbies"

 

[SELfor50]

Hahaha...

IS that an NSX??

 

[Michel]

Hahaha...

IS that an NSX??

It is... and was for sale on US eBay a while back....