I am curious as to what different amounts of fuel these cars are consuming. I'd like to post jet sizes and total jet area comparisons between the different engines. I hope everyone will post theirs- this shouldn't be a secret as each engine is different and it isn't something that anyone can "steal" and gain performance with their particular engine combo I will start. We have three Holley 94s. Each has 2 - 051 jets in it. I was told these are the largest jets available for these carbs and you have to start drilling them out from there. True? Area = pi x R squared Area = 3.14 x (.0255 x .0255) x 6(number of jets) Area = .002 sq in x 6 Area = .012 square inches My total jet area is .012 sq in? seems small to me By reading the plugs our motor after last race they are a bit lean. We think it is a restriction between the tank and pump causing the lean condition at high rpms late in the run. We will have that fixed next time out and see for sure. I hope I did my math correctly. Somebody correct me if I am wrong. I made the ***umption that jets stamped .051 are .051" diameter Brad I edited this post because I forgot to multiply my total area by the number of jets the first time I posted.
I am not sure that you will get any relevant information by comparing what I am running with what you are running...our engine combinations are so different. I have (8) .062s in 4 Rochesters 2 bbls. As for performance...I have run my engine at fast ldle for a little over 15 mintues in three heat cycles and to break in the cam. It is slightly on the lean side...so I will go up two steps. In that 15 minutes it consumed 6 gallons of fuel. I though I better add...I am running a little over 235 ci. (1954 chevy 6). Ron.
Godzilla, by my calculations you currently have .024 square inches of jet area. Twice as much as our flathead which is 286 cid. If you can burn that efficiently that gives a good indication of overhead valve versus side valve efficiency. On a very basic level fuel burned should equal power produced. Of course that doesn't take into account the hundreds of factors that come into play on efficiency of the engine, parasitic losses etc etc. I realize we are comparing apples to oranges but its interesting to me to see the differences in the wide variety of engines produced that end up with similar results in a given cl*** such as HA/GR. When is someone going to build a straight eight so we can throw it in the mix???????? Brad
the cam will play a part here comp tells our cam wil only flow 600 cfm we 585 cfm worth of carbs I have run as small as 40s up to 75s depending on condtions did you factor in the power valve
Hey Brad, we've got one down here.......still running stock configuration, but next time it hits the track it will be a little bit crankier.... Cheers, Drewfus
Info from the owner.... was built from start to finish in 5 weeks,That was non stop for them 5 weeks and no sleep! Running 39' Buick str8 248 ci, v8 GM 3 speed gearbox,mits l300 diff,38 chev front end.Every thing else hand fabricated in the back bay of the owners old service station. Unfortunitly they had a minor mechanical problem at the april nostalgia meet but all sorted and test driven around the back streets of Yanderra at full noise and lovein it. Special thanks to Good mates Paul Schembri (tigger), Jb, Muppett, Boss Spruggle, Joseph Rodriguez and all the original hambers.
I love it! Some of those old straight 8s had some serious torque. I would be interested in knowing what it weighs.
I made my manifold so that it could be changed easily. I am going to build one for a single holley 4 bbl...and one for two holley two bbls. If I continue to run it with the rochesters I am going to have to go up two steps in jet sizes and make block-offs for the power valves. I was reading an article the other day on Fords new inline carb...if I can get my hands on it I will make a top for it too. That is about all my news. Ron.
Recycler, Both your calculations are correct. However, the fact that Ron's total jet area is twice what yours is can be partially attributed to the different designs of the boost ventura's in the carbs. This last weekend I was doing some flow bench testing of the vacuum signal at the boost ventura on a stock 750 cfm Holley vs a 750 cfm Pro Form. The Pro Form vacuum signal was 53% greater than the Holley. Although this sounds significant other factors have to be taken in consideration ie, air bleed sizes, emulsion tubes, etc. Thats why I go to Bo Laws (BLP carbs) for the serious engines we build. Recently I dynoed a 468 BB Chevy and saw a 110 lb/ft torque increase between a Holley Street Avenger carb and a BLP carb from 3000-4500 RPM. Thats the 4th Street Avenger Holley I've had on the dyno and I'm convincet they are a piece of ****. The best way to tune carbs are on the dyno, then fine tune them at the track under race conditions. Ron
All HA/GR owners, If any of you feel you could use help with your carb or ignition setups feel free to contact me. There are several things you can do to eliminate problems before they show up. Even the way your carb is orientated relating to the direction the car is accelerating can be a major problem. Ron
I bought some material for a second top Wednesday and then I started thinking...since I have decided to leave the current trans in my car...I might as well give up a little more nostalgia and run a single 4 bbl carb as well. My car is running very well with the 4 Rochesters on it now...but I have raced cars with a single 4 bbl for more years than I can count... and like the fine tuning that can be done at the track. I bought a killer intake last night...by wednesday of next week I should start wringing it out. My next trip is going to be to Lawton with the Central State G***ers to run the 1/8th mile. It will give me a chance to evaluate the car. If I can get a good plug there I will be ready for my debut at Tulsa's 1/4 mile very soon.
Godzilla, I figured you were making the switch to a 4bl. Mudflap, I didn't take into account the power valves. We have an 8.5 in the center carb and 4.5s in the outside 2 carbs. I think those numbers determine the vacuum opening point. How do you know how much extra fuel they flow? Brad
If my memory is working I belive that is 36 thousands orfice the onein our rochchester is 44 thou but it has been 40 years since Iworked on a ford carb the HORNET burns a quart a run
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