Webers the right way!

[BruceLambo]

Ive just re-read what Jack has been on about. Let me get this right, you're saying that the air flow past the butterfly in the carbs will hit the inside of the intake runner at a different point - eg: one more biased directly at the valve and when the carb turned around, moreso have the air/fuel mix bounce off the top of the runner curve??
Hmmm is this why the orginal intake manifolds had the carbys 'tilted' inwards? A better 'look' at the valve to cylinder entry?

[Jac Mac]

Rambo Lambo,
Here is a way to visualise what Im on about, Lets say we are looking at a 4cyl inline motor with 2 side draughts. For the purpose of explanation the front carb is mounted right way up, the rear carb is mounted upside down. At part throttle the front carb will bias flow to the bottom of the port runner and the rear carb will bias flow to the top of the port runner. Now in the manifold change made here the difference takes place from bank to bank. I reckon the carbs were tilted to get both a straighter shot at the valve plus reduce the height and bulk of the carbs or bonnet scoop. Jac Mac.

[Peter D]

A post forwarded on by a mate of mine here in Oz - Chris C :

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Canuk 40 may have saved a lot of time and money using what is fitted to RF054.See attached pics which were posted some 2 years ago on this site. Only 1 member ever commented. Manifold is a DCO&E (Sydney Aust.) typically used on their superb 8 barrel fuel injection system. Was the standard 8 barrel system on a RF. The manifold incorporates a vacuum chamber with 2 ports - 1 for the ECU and the other for power brakes etc. A little Ozzie ingenuity with cast Weber adaptors-again off the shelf items- has the Webers sitting correctly as per original and no one can really tell the difference at first glance. I prefer a perspex back fire plate so the Webers are still quite visible through the rear window. The manifold - adaptors- studs-gaskets etc cost Aus.$900. A lot cheaper and superior to some of the Weber manifolds that are currently available.

Cheers.

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[Ron Earp]

I never caught that, neat idea and nice work!!!

I think, not sure, but I think either Jerry or Hershal had some dyno data with that manifold (RF supplied but from DCO&E) in EFI form and it was severely choking the 331 inch motor they were using it on above about 5500RPM. Isn't it a 38 or 40mm throttle plate in the standard DCO&E injection manifold?

However, I suppose that does not affect the setup you posted since the lower manifold from DCO&E is just a place to bolt the webers and get flow to the head.

[Peter D]

Hi Ron,

I am using the same DC&O manifold as Chris, but with the stock DC&O EFI throttle bodies/plates which are 45mm (about 2-3 years old).

Maybe there was an earlier version with smaller bodies/plates ?

(I hope so, because I am half way thru the big engine rebuild to a 331 & plan to keep the ARF 165's & DC&O setup ) !

Even with my old clunker engine, there was enough suction happening back there to make you think twice about wearing a neck-tie with the driver's window open - another Isadora Duncan moment !!

Kind Regards,

Peter D.

[JCoop]

Finally, after a few snags and stupid things like loose heater hose clamps and loose fuel line fittings, finally buttoned up and test drove her. I'd say at least 15 HP more and more grunt in the low end. I have to work on the timing yet.

[JCoop]

From the other side...

[Ron Earp]

Originally Posted by delaneyp

Hi Ron,

I am using the same DC&O manifold as Chris, but with the stock DC&O EFI throttle bodies/plates which are 45mm (about 2-3 years old).


Peter D.

I think you'll be okay. Look at that thread around Christmas 2005 I was posting on some time about that had the weber venturi size for engine size versus RPM. If you've a 331 and 45mm tbody size then your peak power supported is up to 7400RPM. Use a 40mm body and it is 5897 on a 331, and I want to say they had 40mm size and it fell over.

The problem with the webers is you get 48mm webers but then folks fit them with a 40mm choke, or whatever, and you definitely don't get a situation where the high RPM is supported as well as it can. Get too crazy with your motor and the webers won't support the RPM you want to pull. That is what I ran into with the 342, if I wanted 7500-7800 RPM the 48 IDA would not work since the largest choke size you could fit limited power to around 6900 RPM. Why spend the money for a revver if you can't feed it?

Looks like yours will be good though and I bet ultra reponsive!

R

[Peter D]

Thanks Ron - that info gells with what I am hearing from lots of experts - 45mm chokes/plates on a DC&O manifold + AFR 165's = good flow for a 331.

Stupid question - is it appropriate to compare choke sizes on Webers vs EFI ? The reason I ask is that it seems to me (who knows nothing about Webers) that there are lots of bits & pieces down the throats of Webers, whilst the only flow obstruction to EFI is effectively the spindle at WOT.

Kind Regards,

Peter D.

[Jac Mac]

Hi Peter,
It's not a stupid question, but an enlightened observation!
Jac Mac.

[Ron Earp]

I'd thought of that as well Peter. Obviously there would be less flow through the weber for all things considered when comparing X weber choke verus X EFI throtle body. But, the only equations I had were for the weber and I imagine it is good enough for government work. If you are okay with the weber I think you'd be more than okay with the EFI.

[John Fitzpatrick]

J Coop--
From your left side engine photo, it looks as though you've removed the return springs on your Webers and gone to an external tension spring on the side of your (very nice!) turkey pan.
If that's correct, would you comment on the advantage of doing it that way?
Thanks
John

[JCoop]

John, actually, I did not remove any of the stock springs. It was just that it was so soft at the pedal that I felt it needed additional tension. So, this works great and also serves as a good safety in addition to the MSD rev limiter. I plan to change to rod linkage eventually but I just started thinking about it...maybe a good winter project.

[Canuk40]

Hi Peter,

Thanks for reminding me about the DCO&E manifold. We've actually done a couple 347s with them fitted with 50mm throttle bodies (no problem with a/f ratios at high rpm - Ron

I haven't been able to source the manifold on it's own here, can you PM the contact info for the manufacturer,thanks.

There is some time to be saved with the vacumm chamber cast into the valley area, however the total cost of the setup with cold air box and blast plate, Webers and linkages is still hard to beat buying in the USA.

Our adapter spacers do give us the opportunity to ad more ports for things like PCV and even an idle air control to compensate for accessory drag like A/C and lights. So we can make it look original and pick up more functionality than can be gained from one common vacumm chamber.

By the way Ray, great pics and I'm glad the initial settings were close enough to give you an immediate seat of the pants response.

Here's our 347 EFI installation with the motor just about as low as you can go!

Cheers

[Jac Mac]

Hi Ian,

Is there a problem with #7 cyl, It doesnt seem to be running as hot as the other's.

Jac Mac.

[Peter D]

Hi Ian,

The last contact info I have for DC&O is :

Dave / Owen James (father / son)
D C & O Services & Products
12 Millwood Ave, Narellan. NSW. 2567. Aust.
Tel : +61 2 4647-2778
Fax : +61 2 4647-3418

I'll see if I can russle up an email address tomorrow.

Kind Regards,

Peter D.

[Peter D]

Hi Ian,

Owen James' email address at DC&O is :

dcosp@bigpond.com

He tells me that they now have a version of their manifold specifically designed for Webers (as well as the standard one for the 8-stack).

Also have the full setup for GenIII's - straight-up 8 stack, or crossover.

Kind Regards,

Peter D.

[Peter D]

Further news on DC&O :

DC&O manifolds to suit both injection and webers IDA & IDF (he now runs this pattern for both carb and injection) for 302 Windsor/302 Boss/351 Windsor/351 Cleveland/FE 427 / 428 Ford Modular 4.6 and 5.4ltr can be bought through Bullit Performance Email bullitt@optusnet.com.au
Butterfly or choke size is 50mm.

All of DCO&E manifolds and injection systems can be found on www.verycoolparts.com

Kind Regards,

Peter D.

[Canuk40]

Thanks Peter, Hi Jac

Yes #7 wasn't firing properly. The problem was eventually traced to a bad connection inside the multi-pin plug going into the onboard computer. Goes like a bat out of @#$ now!

Cheers