The other day, on the Jalopy Journal blog, Ryan posted some "teaser shots" for the Hot Rod Revolution, and in one of the photos there is a 283(no Assy. holes) with 4 Webber carbs.Has anybody out there built an engine like that? That motor looks bad ass!
Yes those are 48 IDA'S. There are 48 IDF'S also. If I'm remembering right 2 of those carbs are equal to an 850 carb.
Yep... The Roadster on the right had 48 IDAs on a Moon Racing manifold atop of a Snotty 355 SBC best run without VHT 12.40 at 119 and with the super glue VHT a 10.98 at 121! When you build it be sure to have a "Colortune" and an accurate flow meter and you'll do fine until there is a significant barometric change then expect completely different performance. I would highly recommend the IDFs for small engines for the street... they have smaller chokes and are better suited for the street rpms!
Some one else alluded to it above, but there are basically two types of Weber down draft carbs, The IDA and the IDF. Both are absolutely remarkable carbs in that they can be tuned to damn near any engine or combonation that you can think of. Part of the secret is replacable venturis called "chokes". Instead of having one carb that flows X amount of air and tuning around that, the Webers can be "choked" to the nessesary airflow needs and tuned to that. It is best to have a good selection of jets and things plus a really good tuning guide. The IDF is the better of the two carbs for street use, and by far less expensive. These are not nearly as pricy as people seem to think they are. Redline is another great source for Weber stuff.
I actually got really good at setting up Weber's, Delorto's, and SU's since I 've owned all combinations and raced them all. As I mentioned before it's important to get the right size for the application and yes they are very tune-able if you know what rpm to engine flow ratio... because that'll determine your "Air Meters" and choke sizes. Another factor is if your running Individual runners or a common plenum manifold. Individual Runners will require accurate flow meter as well as a British tool called a "Colour Tune" that'll indicate the mixture going to each individual cylinder is perfect and will greatly enhance the performance of your engine. Common Plenum Manifolds are like the old multi-carb logs and are more forgiving regarding mixture levels because you can shut the idle mixture screws off the end carbs entirely while running off the center carb's idle circuits... that way you can conserve fuel and not accidently load up the engine at low RPMs. I've tuned Countach's, Ferraris, AC Cobras, GT40's, Jaguars, Austin Healeys, Hot Rods and aircraft from what I learned from Webers and SU Carburetors! The Countach ran 6 DCOE side draft carbs and I developed a special tool to balance the air flow where you don't have to remove the quarter panels and that has kept me more than busy with a couple of fellas car collections in the past. Also helped me with OLD multi-carb set ups Such as Cadilackids coupe... I loved the Hudson Hornet set up!
IDF and IDA carbs are fine, and they also sound totally awesome, but imo the DCOE is the winner of them all. There used to be a T coupè from hotrod webers? w/ 4 side draft DCOEs and it looked awsome. Dell'Ortos are as good. Oh, the made in the UK ones are good too, but apparently theres many copies.
Dont forget the dellorto carbs, they are a clone of the weber idf's, and again less money. Check out CB performance in california. I too have some idf's 48's originaly from inglese. Would like to share info sometime on how to set them up on sbc's. Been reading the cobra forums for baseline jetting on similar cubic inch and cam setups. Keep this thread alive!
Be carefull with "older" ones, there are certain areas that if worn out, would cost more to repair than the carb is worth. Also the older ones dont have the third hole progression circut drilled, the new ones do. Stay away form EMPI, and at most take apart the new ones to make sure they are clean from original assembly. FLoat level settings are very important, along with max 3psi fuel pressure.
Agreed on the 3# pressure max.Also I've found,for street use.If you run a return line back to the tank,webers will love you for it.Hard starting issues if not. Fun setup.
Hope to learn from this post as I have an older unit that has never been installed Have valve covers from Inglesse & all the other parts to install but not sure about Have talked to Comp Cam & they were very helpful just haven't pulled the trigger yet
^^^ thats is what i was talkin about^^^ The T coup and its mate's rodster wore that set up. These carbs sound bad ass on 4 or 6 cylinder inline engines, and EVIL on V8. Plus, and its a BIG plus, you cant quite beat the looks.
Don't forget the DCNF 40's They have a bolt pattern very close to, if not the same as small 2GC's They came stock on Ferrari's, I ran a pair on an O.T. car and I was very happy with the results. Shawn
The "Teaser" pic is of my motor. Small journal 327 with 48 IDA's. They are good for 660 CFM per carb. Alot of consideration goes into the setup. # 1 and most important is the cam selection. Must be custom ground with almost zero overlap of intake and exhaust valves. Yes.they are costly. 3# fuel pressure MAX. They are awesome once you get them tuned !
I used 42DCNF carbs off a Maserati/ Citroen on mine. Lower intake is a Early Rochester FI intake. I made my own adapters and linkage. I have a thread about that somewhere...