Not Ranked
I am so onboard with you race-it. I had Webers on my 428-powered ERA Cobra back in the 1980's and that made a true believer out of me. So many people told me I was crazy to go with the Webers and, yes, it wasn't simply a plug-and-play situation, but the benefits far outweigh the frustrations of dialing them in. Now I have them on my side-oiler and the payoffs are:
1. Stunning throttle response. A friend who drag races motorcycles went for a ride with me and after two gears said, "That's the closest thing I've ever felt to what it feels like launching on my Suzuki."
2. Developing a great "tactile relationship" with your engine. You listen to your engine much more closely, developing an ear for what each cylinder is doing, how the exhaust pipes "talk" to you, the cadence of each cylinder firing, even how black the pipes are getting (or not getting), the smell--too rich? Too lean? More timing? You will learn more about your engine and what it likes and doesn't like as you find the proper tuning for the Webers.
3. The sound of four 48IDA's at full throttle is decadent.
4. The "Oh Wow!" factor when you open the hood at a show or cruise night. A set of dual quads is pretty tasty looking to anybody, but when you open the hood and people see those 48's poking up, it's an instant crowd.
So as race-it says, if you're thinking about going with the Webers, and you don't mind spending some time dialing them in, go ahead and do it. They're not cheap, you won't find many people in the neighborhood who can help you get them tuned, and the various combinations of venturis, jets, holders, air correctors, linkages, and adjustments might make you crazy. I'm not a mechanical whiz but I took my time, read the Pat Braden book and a few more, and now I can understand what my engine is saying to me. I rarely have to touch the Webers now that they're in the sweet spot and I sometimes just diddle with them simply to learn more about them.
A few tips on getting them right which I learned from my own experiences--
1. Don't overthink your setup if there's something amiss. Many times, a simple adjustment of the idle mixture screws will make a huge difference. They are rather sensitive to adjustment and just a slight turn to lean the mixture or fatten it up can cure backfiring under acceleration (too rich) or backfiring when backed off the throttle (too lean). That notorious "lean stumble" around 2000-2800 RPM's can also be minimized or eliminated by an idle mixture adjustment. But remember, being happy with Webers often means choosing a compromise. If the stumble is very minor and the engine really gets it on across the rev range, decide just how fussy you should be.
2. Clean plugs are critical! Read them every time you make a change to your setup. They are your most valuable tattletails as to what's happening inside your combustion chambers. Have a couple of sets of plugs on hand. Pull the plugs out and look at them after every test drive, and put clean ones back in.
3. Not all Webers are created equal. An old racer friend of mine told me that he has dialed in many a set of Webers by using different size idle jets in one or two of the carburetors to get the correct setup. I have 60's in three of my 48's and 65's in one. That may fly in the face of what some experts will tell you but my engine was recently freshened up, dynoed, and all is well inside. The different size jets give each cylinder what it wants and the performance speaks for itself. I've learned that just like two identical engines built on the same day in the same shop by the same guys, there are small differences. Webers are the same. Sometimes, you need to think outside the box when everything you've tried doesn't seem to work.
4. Air cleaners effect the flow and therefore effect the mixture. I've run nylon "booties" on my Webers and run them without and there's a noticeable difference in how the engine behaves. Don't overlook the possibility that your air cleaners (or lack of them) impacts the tuning.
5. A rich mixture is a big no-no. Crap fuel mileage, black smoke out the pipes that makes even the hottest-looking Cobra look like a crapcan, and extra fuel washing the cylinder walls, not to mention fouled plugs and crumby low-end performance. I've always gone with the leanest setup I can which still gives me the best across-the-board performance. I always use a little octane boost to help prevent detonation and when I can get my hands on ultra-high octane gasoline, the engine loves it. I've heard knowledgable tuners say really big jets just pour fuel over the problems and they're right. A big-block will probably run without stumbles or big lean skips with 70 idles, but you're just hiding the symptoms of an improper setup.
Webers rock. They just need a little love. You won't be sorry.
|