Webers and a hot cam - idle?

[Zoom This]

During my engine build I toyed and wrestled with the decision to use Webers on my 418 stroker. But after much discussion I decided not to and stuck with the Edelbrock Victor Jr. and an 850 Holley. Why? Because of those that I spoke to said that my terrific sounding lumpy idle would all but disappear using a Weber setup. Is this true? Gotta have that distinctive idle. I am using a dual pattern camshaft grind. Will Webers work good with this cam AND will I loose my lumpy sound? I gotta know.

[G.R.]

If you want that "bada$$" lumpy sound @ idle keep your setup--If you want the sound and performance when you put your foot to the pedal go with the Webers--my limited understanding is that the Weber system will smooth a "lumpy" idle because it is more efficient when properly setup

[427Aggie]

lumpy idle and webers don't go together...main problem is that because of the individual runners you can't go with alot of cam or you get popping back out the top of the carbs

Matt

[Cal Metal]

Lumpy idle is caused by excessive cam duration. 427 Aggie is right, you will experience reversion due to the inidividual runner system with Webers if you use a cam that has duration much beyond 280 degrees.

[Chaplin]

Cal-
Are you talking about 280 advertised duration or 280 @ .050? I assume the later, but just want to clarify. Webers are on my list of future upgrades. Right now my cam is 244 I/E @ .050 and with a single 4- barrell I have a very lumpy idle and was wondering if I'd have to swap cams to use Webers.

Mike

[BB427]

We run a Ford 300 6 cyl with 3-48 IDAs on an indivigual runner intake and a Jerico 4 speed. The camshaft is a Ultradyne roller with over .725 lift and a ton of overlap. We have never had a problem with reversion or idle. This car is not street driven so I can not speak for cruising speed but it idles well and runs awesome.

brent

[RICK LAKE]

Zoom This I know of 1 person with over 700" cam running a set of webers. in the mid range this motor will put out 40-60 hp more power than a carb. In the upper rpm the carb wins out. A set of 48 IDA are a little small for flow on a 427 built for 600 hp The webers run out of flow at about 65-6800 rpms 58's runout of flow at 7200 rpm. When tuned right any weber motor sings. Only a couple of people know what I am talking about. It takes alot of work to get them right. If you want that look you may want to check out the TWM fuel injection system. They look like webers and flow better plus you can get them up to 58mm. You will need to convert over to FI. In the long run you might be alot happier. Zoom sent me a private e-mail if you want to talk more about this. Rick Lake


Chaplin Mikey get back to work, and which Rick???? You better not tell the wife out thoses webers. No Blue stick YET?

[Mike I]

Mike (Chaplin),

You should be okay with 244 I/E @ .050. My cam specs are 336 I/E advertised, but only 235 I/E @ .050. I was told emphatically by someone at Inglese (no names) that my cam would not work with Webers and I could either buy a new cam from them, or have my cam reground (also by them). I stuck with my cam and can tell you it works well with the Webers, although it no longer has a lumpy idle. With Webers, most cams (even mild ones) will always have some reversion at WOT, it just gets worse as the duration number goes up.

Zoom, the thing Webers really hate are split duration cams. Hope this helps.

Mike

[427Aggie]

Ok I am running a Comp Cams 33-246-4 which is 294/294 and 248/248@ .50 with a .605 lift at 110deg.

I can tell you that I really should go down 1 level because I get reverb at about 3500-4500 or so...if you are racing then you won't get alot of the problems that street use gets. I love the webers and wouldn't do anything else anymore but I have had them a year and am still tweaking them a bit here and there.

Matt

[Mike I]

Matt,

I just have to say, your engine bay is truly a sight to behold!! An ERA with a 427SO and 48IDAs.....outstanding!!

My little mouse motor pulls like a mild BB with the Webers, that 427 of yours must cause blackouts on hard acceleration!!

On the topic of Webers with mild to wild cams, I happened to be standing near the SAI pit area at last year's Daytona Historic races as they were prepping the two GT40 Mark I cars for the next heat. Both cars had very highly tuned SBFs with 48IDAs. They started both cars within minutes of each other and I would guess by the sounds that both had very high compression and very agressive cams. The sound that came out of those two motors was nothing short of unearthly.....the snap and revving ability was astonishing, like a blown alky motor......I'm gettin' a chubby just thinking about it!!!

Mike

Btw, at this years Daytona historic races, I finally got to witness their full comp 427SC take hot laps.....even more impressive than the two 40s......my buddies and I thought there must be two of them out on the track the way it came around so quickly each lap!!

[tommyboy]

Hello Zoom This,
With an isolated runner type intake system such as used with the Weber 48IDA carbs, you need to run a single profile cam with around 110 degree lobe sepration. I have a 427 stroker small block with 48IDA's and I am running a Cam Techniques cam designed for an isolated runner system. I went with a complete roller cam and valvetrain which allowed me to run more lift but not sacrifice my idle quality and driveability. As for a lumpy idle, lets just say that when I'm at a stop light the car rocks side to side and sounds great. People pull along side and say "looks and sound great What the hell do you have under the hood !!"
Although there is absolutely nothing wrong with a single 4 barrel carb/single plane manifold induction system, they are capable of serious horsepower and generaly easier to tune and definitely easier on the wallet, I still can't get over how nice a Weber setup looks and how the Webers add a little more interest under the hood. People always seem to make a nice comment and walk away with a smile !! No right no wrong all fun.

[thundercat]

I'm running the Comp Cam 33-245 ..282S ..282 adv. ..236@ .050 NO PROBLEMS Runs real well...SteveMcD

[Snakebit]

I'm running a 68 Ford 302 block stroked to 331.
Air Flo Reasearch 185cc heads 58cc 10.5 cr
Comp Cams 282S cam with 236/236 @.50 duration 110.

What size choke , jets and emulsion tubes are you running?
Mechanical pump or electric pump?

[thundercat]

My engine is a 428CJ FE. Not a small block ..I used 37mm chokes 150 mains ..200 air..65 idle..F7 etubes ..65idle .. 2.5 psi fuel press .. mechanical pump .. .050 bleed line back to tank.. Hope this helps .. Steve McD