Stromberg BIG97 dyno thrash

Norm Schenck at Competition Fuel Systems has been dyno testing Stromberg 97 and BIG97 carburetors for us for year. In fact he had a major hand in developing the BIG97 from scratch.

We set up a dedicated dyno motor at Norm’s facility in Vassar, Michigan and we’ve been watching intently as horsepower has grown with small tweaks to the carburetion and heads. This set up is with the cast iron vortec heads, that Norm ported himself. We have a set of AFR CNC ported heads waiting in the wings and they would probably make more power, but Norm suspects that the limitations of the Edelbrock tri-power intake would not have allowed for much more flow than was achieved with the vortec heads.

Want to know the numbers? This is a GM 330 horse crate motor and the best we got this time (by taking off the mufflers) was 404 ft-lbs of torque at 4300rpm and 386HP at 5400rpm. We still made over 400/380 with the mufflers on. This was on 89 octane gas with top end A/F ratios all in the 13s ! The dyno can now read separate A/F ratios per cylinder.

What this motor will do once someone (ie us) develops a new intake for the BIG97s is anyone’s guess. But it will be impressive, you can be sure of that…

BIG97 Tri-Power Installation video

Want to know more about BIG97 Tri-Power installation? Watch Bob ‘Bleed’ Merkt modify his Chevy intake manifold and install the carburetors, linkage and fuel line on his 1932 Ford Panel. The Stromberg BIG97 Tri-Power base castings may have the same external dimensions as a regular 97, but on the inside you’ll find bigger, offset throttle bores with flared exit cones to increase airflow capability and improve air pressure recovery. The intake manifold modifications recommended here (click this link for a print-out) enhance that effect, adding even more potential to your BIG97 Tri-power.  Another great video, awesomely directed and filmed by Piero DeLuca.

 

Stromberg BIG97 Installation Guide

The Installation Guide for the All-New Stromberg BIG97 can be found on the Stromberg Tech Center at www.stromberg-97.com, along with a lot of other tech information. So if you want to read up before you make a purchase, it’s the ideal opportunity. It covers not just the carb installation but tuning tips for the BIG97 Tri-Power.  If you click on this link, it will take you straight there.  BIG 97 Installation Guide

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ALL-NEW 250cfm Stromberg BIG97 available now!

We’ve been talking about our new BIG97 for far too long already. But now they’re available. Here’s the press release to start with. And we’ll be posting far more (i.e. everything we’ve got!) in the coming days and weeks. Please stay tuned!

May 2015. New BIG97 makes traditional carburetion available to a new performance audience.

Stromberg Carburetor is excited to announce the all-new BIG97 Tri-Power. On the outside, it’s all Genuine 97 – the original hot rod 3×2. But on the inside, an incredible 750cfm air flow makes traditional hot rod carburetion available to a whole new performance audience. Designed on the classic Primary/Secondary format with many new and exclusive features, the all-new BIG97 Tri-Power is the perfect bolt-on for your performance small block Chevy or Ford.

with fuel

  • BIG 750cfm airflow – 55% more air than regular 97s
  • Signature 97 outside shape – No change!
  • New power valve circuits improve fuel conditioning
  • New ‘early plenum effect’ boosts top end power
  • Ported distributor vacuum adds mid range torque
  • Progressive linkages and classic 3-into-1 fuel line available
  • Runs out of the box. Pre-jetted for typical SBC/SBF

Stromberg owner, Clive Prew said: “With 750cfm in a three-carb package on a progressive linkage, you can cruise economically on the single Primary, then punch in the Secondaries when you step on the gas. BIG97s reduce the level of vacuum the engine has to pull to get the air it needs, which promotes higher air/fuel density. They also reduce mixture velocity which allows that denser, fuel-heavy air an easier, less turbulent, turn into the inlet manifold. Coupled with improved fuel conditioning, it all adds up to more power for your rear wheels.”

From the outset, Stromberg’s aim was to re-engineer the 97 venturi and throttle body to maximize airflow without changing the signature outside shape. But achieving as much as 250cfm per carburetor – some 55% more than a regular new 97 (at 162cfm) is only part of the story.

The BIG97 Primary carburetor has a new power valve, located in the fuel bowl. Feeding top end enrichment directly into the emulsion tubes, it significantly improves fuel conditioning for more horsepower on less fuel. How? Because the more it emulsifies the fuel, especially at high rpm when manifold pressure is low, the easier it is to atomize, distribute and burn. At the same time, an oval cut-out, just under the throttle plates (Stromberg’s ‘early plenum effect’ ) coupled with our recommended intake manifold modifications, boosts top end power by slowing the mixture down and allowing any cylinder to draw from both barrels.

BIG97 Primaries also come with a swap-in fitting to provide ported vacuum for your aftermarket distributor, improving combustion efficiency in cruising mode for more torque and improvements in fuel mileage too.

Finally, everything that’s made the Genuine Stromberg 97 so popular over the past ten years is built into the all-new BIG97: An early style cast iron base for low heat transfer. A reinforced air horn casting to eliminate warping and leaks. High tech gaskets. Stainless steel levers, linkage and springs. Original-style riveted throttle and choke shafts. And more.

Stromberg BIG97 Primary and Secondary carburetors are available separately or as a ready-to-run Tri-Power (one Primary and two Secondaries), with extra savings available on packages with Stromberg’s exclusive Small Block Chevy linkage and fuel line.

Further reading on all of the new BIG97 features and benefits is available on the Stromberg Tech Center at www.stromberg-97.com:

The new Genuine Stromberg BIG97 Tri-Power is available through the worldwide Stromberg dealer network. Further details and help with installation is available at www.stromberg-97.com.

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