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MG MGB GT V8 Factory Originals Technical - Remotely situated carb?!?
|Hey, I saw an old Jag that somebody'd plopped a SBC V8 into today. The way they solved the hood clearance issue was something I wouldn't have thought of in a million years: the 4-bbl carb was not on top of the manifold!!! ... it was located off to the side of the motor, well below the intake manifold, and there was a thick tube up to the top of the manifold. Anyone have a view as to the viability of such a scheme? Can the gas and air really stay evenly emulsified all the way up the tube? Does the carb feel an accurate vacuum signal that way?|
I mean, some of the old Ramcharger Mopar motors had a pair of 4-bbls spaced far apart, on either side of the motor, and the point of those motors was to use the weight of a long, moving column of air to force air into the combustion chambers ... but this "Jagolet" rig took that to the extreme; the tube was at least two feet long. My jaw was on the ground, as I've never seen anything remotely like it ... they said the car ran great though. Anyhow, it does solve the hood clearance problem once and for all, and I wonder if any MG-ers have taken this route.
I've "lumped" a 76 XJC with a LPG fueled, 350 SBC engine and TH 700R4 transmission, a conversion that's very common these days for older Jags although the LPG fueled version is not so popular on this continent as it is in Australia.
I didn't have any real underhood clearance problems with this conversion but during the process, I found that "Impco" (the manufacturers of LPG and natural gas fuel conversion equipment) offer several types of cast aluminum alloy induction connectors for vehicles requiring remote mounting of the propane mixer (carburetor).
LPG and natural gas fuels are easier to deal with than gasoline under these circumstances and there may be some opportunities to adapt their products to a gasoline fueled engine for remote carburetor mounting although the operating temperature required for the carburetor might raise some issues.
You might also be interested in the remote air filter ducting options available at <www.turbocity.com>.
They're designed to incorporate dual K&N air filters in a remotely located arrangement for V-8 engines.
My son is working on his '70 MGB with a 215 Buick engine in it, we've been looking at options for air vents through the hood. Haven't found the ideal solution yet but so far we've found that the hood grilles from the Datsun 240Z offer a racy looking solution but the "slots" have to be opened out to pass more air.
I also tried taking a couple of the MGB's own fresh air intake grilles from the scuttle before the windshield and adapting those lengthwise to the hood over each exhaust manifold. They looked reasonably nice except for the excess of chrome plating, painting them body colour or some contrasting colour would help of course. I like those better and will probably adapt them into a spare hood I have for my XJC project too.
I mentioned trying out the cold air grilles from the Datsun 240Z hood on the MGB hood- sorry, wrong model. That should have read "from the Datsun 280Z hood"
|Remote mounted carbs are nothing new since many early turbo conversions, before the days of engine managment, involved the mouting of the carb upstream of the turbo, and also away from the heat of that unit.|
The problem with any remote mounting for an engine that deals in liquid fuel (rather than in a gasseous form) is that there is often significant fuel dropout of the airstream, especially in light throttle and low engine speed conditions. This can be countered by careful attention to many details, but it will always remain a problem. Countering the low gas speed by designing in small intake ports to ensure higher gas speeds of course leads to clear restrictions in top end power.
The other more pronounced issue is that the further the throttle is away from the inlet valves, the slower the engine response. This is something that you are very likely to feel to some degree.
This thread was discussed between 22/08/2001 and 02/09/2001
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