Webbers v12 setup

johnj · Post by **johnj** » Mon Sep 08, 2014 12:48 am

Looking at putting a set of 6 twin choke webbers on my etype just wondering if its worth the effort any tips :o

Woolfi · Post by **Woolfi** » Mon Sep 08, 2014 7:49 am

Shure NOT !
Weber carbs give each cylinder one "succing pipeline". Because of this the gas is "swinging" inside the cylinder, at a special rev range.
To yuse this effect at lets say rondabout 4500 - 6000 rpm for a goog cylinder-filling, the lenth of the swining-pipeline is important. It is spossible, to calculate the length. The length is roundabout 15 - 20 cm longer, than the length of this swining-pipeline at a real EV12 with Webers upon the motor. The motor can't reach the rev range, where the effect is happening, if the pipeline is too short.
I had a EV 12 5,3 with the original Stromberg carbs. Now I have a 6,0 l motor in the car , still with 4 Strombies. If you change the trumpet at the front of the air-filter to a 40 - 55 mm wide pipeline, drill a hole of 50 mm longline through the 2 mufflers and change the shape of the carbs needles (this is important), the motor will produce roundabout 20 - 25 more horsepower und feels more sporty. With 6 Weber you are wasting time, money and loose torque below 4000 rpm. Torque between 2000 and 4000 rps is important for fun at daily driving. Because of the too short complete length of the runners, maybe the motor is producing over 4000 rps also less power, than the original motor.
Don't believe the rumors about Weber and hope for a gain in power. IF the length is correct , you will have more ponies over 4000 rps. With Weber it is very difircult, to reach the length, the motor needs for more power.
In the internet you can find pictures of EV12 motors with injection systems for more power. The complete lenth of the runners is surprisingly long. Regards Wolfgang Gatza

JIM BAUMANN · Post by **JIM BAUMANN** » Thu Sep 11, 2014 9:55 pm

Do also have a look here:

viewtopic.php?t=3838

I too was initially seduced by the look of the things-and the thought of punting in more fuel ==> would give more bhp and consequent ooommmphhh! Not so it seems! -but the helpful chaps here explained it chapter and verse. Hope its of interest and use!

cheers

Jim B

abowie · Post by **abowie** » Fri Sep 12, 2014 9:17 am

But they look cool!

Woolfi · Post by **Woolfi** » Fri Sep 12, 2014 10:44 am

Hello Jim !
Would you like to see, what happens , when you "punting in more fuel" with Weber carbs ? More ooomp or more cost and bad smell ?

Regards Wolfgang Gatza

JEP41 · Post by **JEP41** » Sat Sep 13, 2014 7:03 am

In defence of the weber carb setup and having three on my series 1 OTS and three on my C-Type replica. The youtube clip shows how webers perform when not set up correctly. Initial firing of my C-type engine after building the engine gave similar results, including flames out of the carb inlets. But once the timing was set correctly and the jetting adjusted the webers performed perfectly with no noticeable smell and no excessive fuel consumption. Checkout: Jaguar C-Type engine 1st run its also on youtube.

PeterCrespin · Post by **PeterCrespin** » Sat Sep 13, 2014 9:29 am

Agreed John, Webers can be set up to do whatever you want, but side draughts on a six are a whole lot easier than down draughts on a twelve because there's simply no room for a decent manifold runner length and none at all for a proper ram pipe. It's the physical constraints that prevent optimal installation, not any failing of the IDF version.

Nothing to stop people putting DCOEs on a V12 if the make over head manifolds and can find space. Hardest on the E, easier on XJ/XJ-S.

Pete

Mountain King · Post by **Mountain King** » Sat Sep 13, 2014 10:32 am

Not sure if this would actually work on an e as an important piece of the V12 engine may not fit...
http://www.jenvey.co.uk/home/throttle-b ... f45-ckjr04

but the tract length of 201mm would assist greatly

or http://www.jenvey.co.uk/home/throttle-b ... f45-ckjr04

i give up, i cant post url's

PeterCrespin · Post by **PeterCrespin** » Sat Sep 13, 2014 12:24 pm

Just drop URLs into www.tinyurl.com

The first one worked and you notice they refer to the Ford Jaguar V12 which is the 6.0L distributorless variant ONLY used in the X305 saloon from 94-96. no no dizzy to get in the way.

Surprised they bothered with such tiny market of a few thousand cars, most of which will stay standard luxury cars, not sporting conversions with no air filter. Besides which, the NipponDenso sequential injection and menifold proportions were already the best of any Jag V12! Sure looks pretty though and could probably be used on any V12 with EDIS.

210mm isn't all that great a tract length mind you - typically you'd want nearer 300 for a street car but I suppose for racing...

Pete

Pete

Mountain King · Post by **Mountain King** » Sat Sep 13, 2014 12:30 pm

thanks for the tiny URL link

I missed the word "ford", yep the dizzy is kind of important..

is a nice piece of engineering though and I had not heard of Jenvey before, looks like they focus more on the 80's and later cars.

Andy

Post by **Heuer** » Sat Sep 13, 2014 12:32 pm

The second link now works as I edited it. You used the URL button on the Forum editor - no need just put in the http//xxxxx link directly as you did on the first one.

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