Twin 38 DGAS Carburettors on essex V6

[DavidY]

phillpot said:

as a little aside this looks interesting.....

Fitted to a Gilbern, and I believe works quite sussessfully ?




ETA any better Thomas?

If not try clicky

Edited by phillpot on Friday 21st December 18:22

The BIG problem with an Essex is the ability to get the exhaust gasses away, it's all very well putting on a great multiple carb setup, but it will only realise a fraction of it's potential with a standard exhaust (especially a TVR one). IME it is better to sort out the exhaust, and then start playing with carb setup's

[phillpot]

Don't shoot the messenger !

just posted the picture out of interest, no idea if it would fit or give worthwhile benefits but the rumble of a V6 with the induction roar of twin 45's has gotta be good.

(I would guess it wasn't bolted onto a bog standard engine)

[Cerberus90]

Still no luck with thumbsnap, can at least see it now it's bigger without clicking on it,

Looks interesting though, I think it'd be tight on an M, but it might fit, when you think of the height of a DGAS + the rubber spacer + air filter.
Sounds like it's a custom manifold someone's welded up themselves anyway so probably not going to find another one anywhere,

Can't imagine the bends that the airflow has to take will do much good though. The short swan-neck manifolds for the A-series with similar bends to that don't seem to be very well recommended due to flow issues, usually have to put a bulkhead box and a longer straighter manifold on.

[Slow M]

thegamekeeper said:

I am not convinced the answer is "out there somewhere". The internet is just a load of individuals sitting in their bedrooms typing. Who knows who they are and what they know but you are prepared to take their "opinions" and risk your engine.

Even the OP is vague. What does similar mean? Is your engine 3.4? is it a GA block or a South African ambulance or one of essexengines.com,s trick conversions? Does your cam have 276 degrees duration, .447" lift. Are your inlets 37mm, exhausts 43mm? What is your advance curve on "your" dizzy like?

Sitting in your garage trying things IMHO is pointless. At some point, and it may as well be the first point you need to get it on a Dynamometer and set it up properly in load conditions employing someone who as John said has the gear and also has the idea.

Not even remotely convinced by Adrians lambda sensor and electric drill at this point

rsh,

I agree with a lot of what thegamekeeper said. In particular, each engine build is slightly different. Chose a different piston, shave a head at a slight angle, slight difference in distributor curves, quench, all will affect each other. Flame propagation will differ, fuel needs will as well, and so on ad nauseam.

You are re-developing an engine, (a task to which major manufacturers devote huge budgets,) but seem to have an aversion to embracing the advise given to you, for free, by people with real world experience. Instead, you seem to only want hard numbers. If anybody gives them to you, without access to the engine, they are going to be a GUESS!

Rolling road is the laboratory version of the "old school" method of running @ steady RPM, shutting down, and doing a plug check. Try to do so at the middle of the three different circuits (estimate the RPM). Lambda sensors do the same thing. They read Air/Fuel ratio, and let you see where you are in relationship to stoichiometric mixture (14.7:1). Some come with LED gauges that make it easy for a passenger to record. Gunson's Colortune was a superb tool for setting the individual carbs mixture, but only through the lower RPM ranges, and (rumor has it) not with high compression engines.

I would strongly urge you to at least do some of your own testing to determine WHY you are unhappy with the current set-up. For a start, how certain are you that camshaft timing and ignition timing are close to being optimized?

Best of luck with getting the car to where you are happy with it,
B.

[rsh]

Thanks for all your well intentioned comments, I'm well aware of all the points raised above regarding differences between engines. I was just after some insight into whether the jetting went bigger or smaller on mains and a/c (on the Essex Engines combination I refer to above, mains = std, a/c = smaller which seems counter intuitive).

Responses to this thread remind me of the time I dared ask about spring rates ...

[Slow M]

rsh,

Sorry, all of my literature is buried in a storage unit.

Weber dealers used to keep the wall charts, showing calibrated parts, and how they relate each other in terms of lean/rich on a line diagram. Try finding it on line.

Carl @ Paeco is one of the worst people I've ever dealt with, but his catalogs were always good. http://www.paeco.com/Weber%20Calibrated%20Parts.ht...
Hope it helps.

Best,
B.

P.S. I always learn a little bit more, in those spring rate discussions.

[Erich Stahler]

phillpot said:

as a little aside this looks interesting.....

Fitted to a Gilbern, and I believe works quite sussessfully ?




ETA any better Thomas?

If not try clicky


Not yet another variation!!!

Edited by phillpot on Friday 21st December 18:22

[lockmonster1]

Did you ever sort out the size of jets, I changed mine and it is great now, little smoke from exhaust now and then, but runs great

[rsh]

no, never got them running satisfactorily, sitting on the work bench now, what jets worked for you ?