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View Full Version : Wedge Dual Webbers on a TR7?



KLUTZ
11-07-2004, 03:15 PM
I noticed on Ebay this morning, a 1979 TR7, normal 2L engine, with dual Webber Carbs on it. Is this not some kind of "Overkill?" I have read about one Webber being a lot for a Spitfire, so what would two do this engine? Can't think it would make it go much faster, and would they have to be Syncronized like my ZS's? I realy don't know a lot about them. /ubbthreads/images/graemlins/thumbsup.gif
Thanks
Paul /ubbthreads/images/graemlins/canpatriot.GIF

piman
11-08-2004, 05:09 AM
Hello Paul,
their fitting to a standard 2 litre engine will make little difference to performance, if they have been set up correctly and an adverse effect if they haven't, impressive to look at however. And, yes, they need to be synchronised.

Alec

DHTR4A
11-02-2005, 01:05 PM
hello ,
anybody put dual webbers on a 1966 tr4a ?
need pics .......

CraigFL
11-02-2005, 02:11 PM
Dual Webers are possible on any engine but you may end up with something you didn't ask for. When you size a carb for an engine, there is an optimum venturi/choke size. The more venturis you put on for any given engine, the smaller they need to be so that total area/air flow remains roughly the same. You could probably make any venturi work at idle with all the different jets available for a Weber but each carb is optimized for a certain airflow. If you have to put smaller venturis in, you are going to end up with a carb that's very difficult to tune over its entire operating range and would probably be better off going to the next size smaller carb. Transitioning from idle to WOT with very large venturis would probably kill the engine. Of course the big benefit of multiple carbs is when you have a modified engine. one bbl per cylinder makes it much easier to tune and optimize for producing the most HP.

michalotti_tr
11-02-2005, 02:14 PM
[ QUOTE ]
hello ,
anybody put dual webbers on a 1966 tr4a ?
need pics .......

[/ QUOTE ]

Same setup as on the '3 - considering the cost and rarity of Webers, I think I'd go with a quad PRI carb setup - I've spoke with them and if you'll send them a stock intake they'll set you up.

NFI, just impressed with their products.

philman
11-02-2005, 09:46 PM
i have dual webers on my '76 fch. slightly better acceleration. lower gas mileage. but maybe that has something to do with my driving style and the "hot" cam. Anyway, I think I'll be pulling that engine out for a 3.5 liter v8 soon and selling off my 2liter engine parts next spring.

Bugeye58
11-02-2005, 10:21 PM
Years ago, I had a set of DCOE 45's on a '67 TR4A, and it seems I wound up using 32 or 33 mm choke tubes on the thing.
Lots of choices of emulsion tubes, air correction jets, etc, coupled with a lot of dyno time to get it to run to my satisfaction.
In the grand scheme of things, although it looked impressive as ****, not worth the time, cost and effort as far as performance was concerned.
For a full blown race car, maybe, but not a street ride.
Jeff

Dave Russell
11-02-2005, 11:55 PM
[ QUOTE ]
Years ago, I had a set of DCOE 45's on a '67 TR4A, and it seems I wound up using 32 or 33 mm choke tubes on the thing. Jeff

[/ QUOTE ]
Yeah - Once you get the choke tubes on those big impressive carbs sized down to where they will run well on the street, they look impressive but actually don't have much more breathing than a pair of 1 3/4" (44 mm) SU's. Just feels snappier because the can be dumped wide open all at once, which the SU's won't do.
D

Bugeye58
11-03-2005, 12:05 AM
[ QUOTE ]
Just feels snappier because they can be dumped wide open all at once, which the SU's won't do. D

[/ QUOTE ]
Exactly, Dave. Accelerator pumps are wonderful things, at times.
Jeff