---------------- If you use V-belts on a 6-71 making 10 lbs. boost, you'll need more than "2 or 3" belts". More like 5, 6 or 7 V-belts....*minimum*. Even then, you'll have some slippage and running them tight enough to avoid a whole lot more slippage every time the engine suddenly changes speed, will put a lot of strain on the blower snout and drive bearings. That's why, 'back in the day' as soon as they became readily available, guys went to cogged Gilmer bets in the first place. Mart3406 ===========================
huh, I didn't think about that way... I just don't think a cog belt will look good, but, then again, performance>looks
A road warrior setup? like from Mad Max? Where do the make/sell those? I've never seen one out side of my TV. Or tell/show me how to make one and I'll do it, I've just never seen one. sorry if I sound like a smart a$$, I don't mean to... Is anyone running one?
------------------ No, no one is running one and you've never seen one, because outside of the minds sci-fi fiction writers and Hollywood movie makers who make pap aimed at the lowest common denominator of the generally already non-tech savvy public, the 'Mad Max-style' clutched roots blower set-up as shown in that movie doesn't exist and and mechanically, wouldn't and couldn't work. More bad news too. Believe it or not - and I've got this on very good authority - both "Star Trek-style" 'transporters' - along with dilithium crystals - as well as "Back To The Future" 'flux-capacitors' used in Delorian DMC-12 time machines don't really exist either!!! Mart3406 =============================
that's what I figured, I just didn't want to look like a Dumb A$$ if Porkn****** waved his magic wand and posted pics, tech articles and other stuff to show me again how I knew everything... yesterday...
Mart3406 is right. I am a millwright/industrial mechanic. The belts do have alot of slip and it takes alot of horsepower to turn over a 671 blower. If you really wanted to you could run an idler pulley system with it and whats called a double v-belt which is basically 2 v-belts glued back to back and idlers pushing inward. Modern cars, Grand Prix GTP, mustang cobra 5.4 L and ford lightning use a serpentine belt to run thier blowers but I beleive thaey are like 6PSI max. On alot of indusrtial machines they do use multi strand chain to drive blowers but again you would have to run an idler system and a cover. Try commercial Bearing or another industrial supply and they can provide access to anything you want that will fit the shaft of the blower snout, the bigger problem is coming up with something to fit on your front pulley to work with and may end up having to get something manufactured to work.
--------------------- 'Back in the day' -ie - "BGB" (before Gilmer belts!) a few drag racers did use chain drives for their blowers. Chain driven blowers were largely abandoned (and I think eventually. even banned altogether by most sanctioning bodies) because of the danger of broken and thrown chains. Also, compared to a Gilmer belt, chains are pretty inefficient and absorb a fair bit of power. On the street, a chain drive would be even less practical too, because besides the danger of a broken or thrown chain flying around and cutting up and through everything in it's path eek the chain would need to be lubed constantly and the excess oil would be thrown all around the engine compartment. Mart3406 ============================
in agreement with all except the lubrication. There is O-ringed chain available with sintered bronze bushings, largely used in motorcycle chains. I have seen 3 inch pitch chain get thrown and it cut through the guard, scary stuff..........
no need to worry with turbos about belt slip... going thru that with my McCulloch VS-57 on the Hudson 308. yea it slips, looses about 1lb of boost but is one excellent street driving set-up. I used the wide pulleys from Paradise Wheels, small blower pulley for a R2 Studebaker, Idler from a 55 Kaiser and a flat 7.5" diameter Chevy crank pulley. 61" long belt. I would rather build turbo engines, either blow-through or draw-through as they each have there good and bad points. I vote for twin turbos but that's what I am building on the present project. Twin Corvair hybrid turbos (150hp exhaust and 180hp compressors), draw through two Autolite 4100 1.08 venture 4bbls, using a Twin-H Hudson intake on a 1954 Hornet 308 nascar spec 7X engine. Nothing on the entire car is newer than 1965 except for safety equipment, MSD 6BTM and braided fuel line to keep current with the rules at the drag strips. only problem I ran into with the twin turbo setup is how big the hole in the hood needed to be for the carbs, custom plenum and 1/3 of the turbos. Would rather build the long stroke 6's than anything, after all More stroke means more poke... like right in the compe***ions eye... PaceRacer50
I'll go blown on this one for sure guys, and don't worry, I'll be sure to turbo one next time, just for those of you who've been wanting it. Maybe on a 235 or 261... Next Question: should I run progressive linkage or direct? Remember, 5 single barrel rochesters. If progressive, I'd like to fab up my own, and am confident in my skill, but honestly, I don't even know how progressive linkage works... Wanna help??
or does anyone know of any other carbs that look good in multiples, can be found cheap/free, and can be added up to anywhere from 800-900cfm??
------------------ If you really want to run 800 to 900 cfm worth of carburetion on an n/a inline 6 you definitely want to mount them on an I.R.-type manifold. Using that much airflow on a manifold with a common plenum will be too much and make the engine into a complete dog. I don't know where you'd find one (maybe here on the HAMB??) but 'Man-A-Fre' used to make a really cool looking 3X2 setup for Chevy 6's that used three large-base Rochester 2GCs on three small 'stub' manifolds that bolted directly to the ports. It wasn't a true I.R.-set-up, but with one 2bbl feeding a pair of cylinders each, without a large interconnecting plenum joining all six cylinders together, it was close enough to a true I.R. to work good with the large-base 2GCs Completely out of the realm or your common/cheap/free carbs requirement, but a true I.R. set-up and very cool - Clifford made a manifold for mounting three 45-48 DCOE Webers on the Chevy and other inline 6s. Extremely spendy for carbs, but an absolutely killer set-up! Mart3406 =======================
I'm talking about 800-900cfm worth of carbs on a blown engine with the 6-71. If I went N/A I'd run it with a single Edelbrock 500cfm 4bbl, for ease of tuning on an Offenhauser Intake, but I'm seriously considering using the 6-71 and using multiple singles(or 2bbl's if needed). I'd run a Q-jet, but I'd have to get another 100cfm's out of it...
My brother successfully ran a blown 400sbc on one 750cfm carb, shifting at 6800rpm. This engine had a roller cam, ported aftermarket heads, and ran 10's in a 3975lb car. Three 1 3/8" bore rochesters should be plenty for you.
It'll run on 3 rochesters just fine, but it'll run out of juice high in the rpm's and boost. do you know how much boost he was putting to it? turbo or blower?
8lbs of boost from a B&M blower. Your engine will not run out of juice high in the rpm's on 3 rochesters. Do your math. A 292 .030 over with 9# boost in drawthrough shifting at 5500 rpm with a premium cylinder head and optimized exhaust system needs around 743cfm. A 1 3/8" bore 2GC rochester flows about 357cfm. 357 x 3= 1071cfm. Ross' engine was bigger and spun more rpm and still didn't fall on its face on top. Spend some time in the junkyard at get a few of these carbs - take a machinist's scale with you so you get the right ones. Take the chokes of the outboard two, hook them up straight not progressive. Cool looking and will run fine if you pay some attention to getting everything the same in the carbs.
(CIDxRPM)/3456x(Boost/14.7+1)=CFM (295x5500)/3456x(11/14.7+1)=820.779841 Manufacturer Model: Rochester: M Monojet: 113CFM @ 1.5 Hg; 160CFM @ 3.0 Hg; Throttle Bore, in. (mm); 1 7/16 (36) Venturi Diameter, in. (mm) 1 7/32 (31) M Monojet: 148CFM @ 1.5 Hg; 210CFM @ 3.0 Hg; Throttle Bore, in. (mm); 1 11/16 (42) Venturi Diameter, in. (mm) 1 5/16 (33) M Monojet: 177CFM @ 1.5 Hg; 250CFM @ 3.0 Hg; Throttle Bore, in. (mm); 1 11/16 (42) Venturi Diameter, in. (mm) 1 ½ (38) 2GC: 197CFM @ 1.5 Hg; 278CFM @ 3.0 Hg; Throttle Bore, in. (mm); 1 7/16 (36) Venturi Diameter, in. (mm) 1 3/32 (28) 2GC: 246CFM @ 1.5 Hg; 352CFM @ 3.0 Hg; Throttle Bore, in. (mm); 1 11/16 (42) Venturi Diameter, in. (mm) 1 3/16 (30) 2GC: 269CFM @ 1.5 Hg; 381CFM @ 3.0 Hg; Throttle Bore, in. (mm); 1 11/16 (42) Venturi Diameter, in. (mm) 1 ¼ (32) 2GC: 299CFM @ 1.5 Hg; 423CFM @ 3.0 Hg; Throttle Bore, in. (mm); 11/16 (42) Venturi Diameter, in. (mm) 1 5/16 (33) so say I used the biggest monojet, that'd put me at 177CFM @1.5hg, so it'd take 5 of them to make 885cfm. and 3 of them would only be 531CFM, and from what I've heard It takes alot to have too much cfm's on a blown motor. or I could use the biggest 2GC, at 299CFM @1.5Hg it'd take 3 to make 897, so you'd be correct on that one. I'd like to use monojets, but I may be stuck with the 2GC, seems how they're higher flowing...
---------------------- 890 total cfm, theoretically at least, would be too much for a roughly 300 cubic inch, naturally aspirated engine using a conventional 'plenum-type' manifold. However, if you use an a true (or near true) 'isolated runner' style manifold like the old 'Man-A-Fre' 3X2 or similar, 890 total cfm would be barely enough. And if you use a blower, depending on the amount of boost pressure, hp level and rpm range you plan to run, your cfm calculations go right out the window. Mart3406 =========================
"Theoretical inline engine building" Go out in the shop and get your hands dirty first. The IF factor - Will never end! How ever it is the cheapest way to go.
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