20b Intake Manifold Questions
12-13-2003, 03:51 PM
#21
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Originally Posted by Jeff20B' date='Dec 13 2003, 04:02 AM
If I had an upper manifold, it would be useful if it can work with a side draft carb attached where the throttle body would normally go.
Yes I'm going carb NA for now.
Do you think it would work ok to simply attach a weber DCOE or even a dellorto 48 DHLA to the upper 20B manifold? Do you think it would flow correctly into all six ports? Or do you think the middle rotor would be rich? It's been a while since I looked inside an upper manifold.
If this idea will work, I'd consider it over my previous ideas. I'd also have the lower manifold shortened like you did.
Man, I hope it will work. It would save me tons of time. That dellorto of mine is just sitting there right now just waiting...
I think I sold my upper manifold with all chrome nuts and bolts for $75 to rotaspec down in NZ. Or was it $45? What kind of price are you asking? I think I sold my throttle body for $75?
Yes I'm going carb NA for now.
Do you think it would work ok to simply attach a weber DCOE or even a dellorto 48 DHLA to the upper 20B manifold? Do you think it would flow correctly into all six ports? Or do you think the middle rotor would be rich? It's been a while since I looked inside an upper manifold.
If this idea will work, I'd consider it over my previous ideas. I'd also have the lower manifold shortened like you did.
Man, I hope it will work. It would save me tons of time. That dellorto of mine is just sitting there right now just waiting...
I think I sold my upper manifold with all chrome nuts and bolts for $75 to rotaspec down in NZ. Or was it $45? What kind of price are you asking? I think I sold my throttle body for $75?
12-13-2003, 08:28 PM
#22
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Yes I have. That JDM car has a nice setup. Too bad I can't do a peripheral port at this time.
The dellorto was rich on a mild ported 13B. The rotors had so much carbon on them that one of the apex seals was stuck in its slot when I tore the engine down. The dellorto was used to break-in the engine after a reduild, so the low RPM could have been the cause. I'll break the engine in with a stock 13B carb this time (and make sure it doesn't overheat due to a leaky radiator the PO left unatended).
That's a different style of intake, Mike. Interesting. Probably not very good for power. The heat of the exhaust manifold doesn't help. My '69 Corona was like that, only it had a cast intake.
Dragon, that's a decent price for a modded upper manifold with shipping included in the price. If the dellorto can work on it, I'll weigh it against jayroc (on the other forum) wanting to try his hand at fabbing up a manifold for a V8 carb to a 20B. I may need to shorten the LIM due to hood clearance if I choose the stock UIM option.
Thanks for all your input you guys. As of right now, I'm still debating. I have some time until the 13B is ready to come out of the GLC to think it over. I need to get back to porting some 13B housings in a few minutes. It should be done and in the car in like a week or two (so close to Xmas may cause delays though).
The dellorto was rich on a mild ported 13B. The rotors had so much carbon on them that one of the apex seals was stuck in its slot when I tore the engine down. The dellorto was used to break-in the engine after a reduild, so the low RPM could have been the cause. I'll break the engine in with a stock 13B carb this time (and make sure it doesn't overheat due to a leaky radiator the PO left unatended).
That's a different style of intake, Mike. Interesting. Probably not very good for power. The heat of the exhaust manifold doesn't help. My '69 Corona was like that, only it had a cast intake.
Dragon, that's a decent price for a modded upper manifold with shipping included in the price. If the dellorto can work on it, I'll weigh it against jayroc (on the other forum) wanting to try his hand at fabbing up a manifold for a V8 carb to a 20B. I may need to shorten the LIM due to hood clearance if I choose the stock UIM option.
Thanks for all your input you guys. As of right now, I'm still debating. I have some time until the 13B is ready to come out of the GLC to think it over. I need to get back to porting some 13B housings in a few minutes. It should be done and in the car in like a week or two (so close to Xmas may cause delays though).
12-13-2003, 08:56 PM
#23
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Thinking about it some more, the dellorto on the stock upper manifold would be great if it works. I could then place the Edelbrock on a 13B with carb adaptor bolted to a stock manifold. I'd cut channels to connect both rotors together ala peejay, while keeping primaries seperate from secondaries for some driveability.
12-14-2003, 01:24 AM
#24
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I guess the $50,000 question for right now is whether the Dellorto will work on the 20B UIM, or not.
Racer X, you once said the dellorto needs a certain type of vacuum signal that can't be provided on the 20B UIM. Is this because it won't have two 180º pulses on the 20B UIM that it would normally get on a Racing Beat manifold? Is this something that I'll even need to worry about?
The second, less expensive question concerns how well the incoming AF mixture from both barrels will flow into all six runners. Do you guys think it'll sort of 'mix' inside the plenum area of the UIM?
I suspect it was designed to allow equal pressure/flow from the TB to all three rotors. Of course that was for fuel injection. I'll go with fuel injection when I can afford it. I may even go with a turbo some day after an engine rebuild. I may even gain myself some room infront of the radiator for a FMIC.
Ahem, for right now, I need to figure out if the dellorto will work on the UIM. I gotta stay focused.
Racer X, you once said the dellorto needs a certain type of vacuum signal that can't be provided on the 20B UIM. Is this because it won't have two 180º pulses on the 20B UIM that it would normally get on a Racing Beat manifold? Is this something that I'll even need to worry about?
The second, less expensive question concerns how well the incoming AF mixture from both barrels will flow into all six runners. Do you guys think it'll sort of 'mix' inside the plenum area of the UIM?
I suspect it was designed to allow equal pressure/flow from the TB to all three rotors. Of course that was for fuel injection. I'll go with fuel injection when I can afford it. I may even go with a turbo some day after an engine rebuild. I may even gain myself some room infront of the radiator for a FMIC.
Ahem, for right now, I need to figure out if the dellorto will work on the UIM. I gotta stay focused.
12-14-2003, 03:43 PM
#28
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It's going to cost a lot to have a custom 4 bbl manifold fabricated for a 20B, so it looks like I'll try my luck with a stock 20B upper and a dellorto. That welding time is expensive.
Dragon, I've got a local guy here who has a 20B that's going into a T2. He's going to supercharge it, so he won't need his stock UIM (or anything else). I'm not sure when he's going to start on it, or if the parts are for sale yet. I'll give him a call on Monday. If the prices are similar, I'd buy yours because of the mods. I'll let you know.
Dragon, I've got a local guy here who has a 20B that's going into a T2. He's going to supercharge it, so he won't need his stock UIM (or anything else). I'm not sure when he's going to start on it, or if the parts are for sale yet. I'll give him a call on Monday. If the prices are similar, I'd buy yours because of the mods. I'll let you know.
12-15-2003, 10:32 AM
#30
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Originally Posted by Dragon' date='Dec 14 2003, 03:05 AM
or you could chop the runners off on the upper manifold and weld solex carb flanges to it and run 3 solex carbs.. One for each rotor housing like the old Z's do.. 
nice even fuel distrabution...
nice even fuel distrabution...