FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: wowens on March 05, 2018, 11:19:35 AM
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If you were building a all most unstreetable 482 street engine, manual trans, 3200lbs, would you use a BBM or unmolested Ford manifold ?
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A decent Dove should feed the beast.
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A stock, unmolested Ford intake will flow ~375-390 cfm in each runner, the BBM quite a bit more than 400 cfm as cast. The ones I have flowed hit 485-505cfm with just a simple gasket match to the BBM heads. Joe-JDC
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A stock, unmolested Ford intake will flow ~375-390 cfm in each runner, the BBM quite a bit more than 400 cfm as cast. The ones I have flowed hit 485-505cfm with just a simple gasket match to the BBM heads. Joe-JDC
Not trying to get the original question off track, but Joe, which would work better on a milder street engine? Would the OE Ford intake have better port velocity than the BBM, given such a difference in the CFM?
For a max effort, the BBM seems the obvious choice.
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That Ford tunnel wedge flows 410 cfm in every port. I raced it for years on a 452 MR. You can see just how much smaller it to the gasket than the BBM. I try not to say anything negative about BBM, because it is a very nice piece, and on my flow bench it flowed 445 up to 475 cfm as cast, and a simple gasket match to those Edelbrock 7224 gaskets netted 490+ cfm. I personally think the stock Ford would be excellent for smaller street engine. A friend who also races a 390/427, gasket matched his Ford TW to his Edelbrock heads, and lost 20 lbft everywhere, and went slower. Joe-JDC
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Thanks for the input, Joe. I'm certainly not trying to say anything negative about the BBM, because it seems to be a super nice piece, but seems more oriented towards top end performance builds, which is exactly what the tunnelwedge is made for. In those cases, the BBM seems to be the no-brainer. Still, some guys like to use them on the street on milder builds, just for the looks. In that case, the OE Ford would seem the better choice.
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The cross sectional area of the runner entry in the plenum will tell you more about which intake will work better on which engine.
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I think even on an all-out engine the BBM runners are too big. The one I looked at at Tim Meyer's shop was huge. If I was going to go with a tunnel wedge I think I'd try to find a stock one or a Dove. JMO, of course...
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If my first offered buyer of my Dove 2x4 Tunnel Wedge falls through, I now have mine ready to sell.
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As I've mentioned a couple times in the past, I bought my BBM in Oct of '15 and have yet to open the box it came in because I was disappointed in the stratospheric cfm runner ratings. I have yet to see mention of the "other" application for this piece, aside from a big-inch max effort mill.
Edit: That would be Oct of '16, not '15. No ideas yet?
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Thanks guys
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If you were building a all most unstreetable 482 street engine, manual trans, 3200lbs, would you use a BBM or unmolested Ford manifold ?
Out of the box BBM tunnel wedge worked great on this 482 inch FE. 640 ft-lbs of torque at 5400 rpm: http://www.hotrod.com/articles/dyno-tested-make-700-hp-trick-flows-new-fe-heads/
If you really want to get on it then shift at 6500 and drop back to the torque peak in the low 5000 range. Should make a 3200 lb car stand up and go.
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I think if you are willing to put enough solid roller camshaft in a 482 to take it to an rpm band that is friendly to a tunnel wedge "in general", the BBM will be just fine. I had two identical, fairly aggressive hydraulic roller 482s on the dyno back to back a while ago.......a tunnel wedge got better than a BT dual plane 2x4 at 5300 rpm. Below that, the dual plane ruled. If you have a 7000 to 7500 rpm engine under it, a tunnel wedge of any mfg. will be better upstairs. It will not be better from idle to 5000-ish rpm. If you have a 6000-6200 rpm redline, you should think it over carefully. Street driveability, idle to 4500, would be better with a MR dual plane. With that said, a healthy 482 will still shred the tires with either style manifold........
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Turbo?
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The 482 with the BBM tunnel wedge that I worked on recently was making more than 550 ft-lbs at 4000 rpm so I think that is adequate for a street car. No doubt a dual plane intake would have more torque downstairs, but 550 at 4000 is pretty decent. The engine isn't in the car yet so I can't say exactly how it runs yet, but I think it is going to be fine. The cam can always go one size smaller if we need a little more torque down low, or we can add some gear in the rear. This engine had dual throttle body fuel injection which probably helped. It can be tough to get dual carbs dialed in on a big single plane intake. With dual throttle bodies and a computer controlled ignition it is easier to dial in a tune.
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That engine is mighty impressive, for sure. To be clear, when I said "Turbo?" it was just a callout for opinions on using the BBM with said boost, at which point the overly large port flow characteristics go out the window.
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I think you put your finger right on it. With TB EFI, equal flow is the ruler. Put boost to it and you have a whole 'nother ball-game.
KS
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In regards to using a tunnel wedge intake of any brand, set up with port injection and throttle bodies, is there the ability to tune out some of the driveability concerns and loss of torque vs a dual plane?
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That engine is mighty impressive, for sure. To be clear, when I said "Turbo?" it was just a callout for opinions on using the BBM with said boost, at which point the overly large port flow characteristics go out the window.
They don't completely go out the window, but forced induction does cover a multitude of sins. Forced induction still has to obey the same laws of physics that NA does and keeping ports and valves properly sized is still important. Velocity still matters for cylinder filling. FI doesn't increase CFM like most think; the power increase comes from an increase in air-fuel density, not an increase in mass air flow. Remember...boost is just a measurement of restriction.
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In regards to using a tunnel wedge intake of any brand, set up with port injection and throttle bodies, is there the ability to tune out some of the driveability concerns and loss of torque vs a dual plane?
If you have a good, fully tunable EFI system, you can certainly tune out the driveability concerns. But I'm not sure you can do anything about the limited torque that can be caused by large runners; you need good port velocity to make torque at lower engine speeds, and a runner with large cross sectional area is going to tend to have lower velocity.
Of course, if you have a lot of cubes you automatically make more torque for any given induction system, so you may not notice the lower torque from a big intake on the street.
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Quote---...boost is just a measurement of restriction.
The measurement is just a number used for comparison purposes, and doesn't take into account where the restriction is. In a particularly wide-open intake tract, the resistance (restriction) might well be the piston crown.
But we are talking about what's happening---in the vernacular, we're crammin' more air into the cylinder while the valve is open. If there were no other factors to be considered, the more the hole is open, the better. But particularly, considering the 'demand' component we have to deal with---the fact that unless we are 'in boost' we have, in effect, an NA engine, all the other factors come back into play.
Let's not forget that it's 'more air' that we're looking for, and let's not get hung up on how we measure it.
KS
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Quote---...boost is just a measurement of restriction.
{snip}
Let's not forget that it's 'more air' that we're looking for, and let's not get hung up on how we measure it.
KS
Right. I think the factor here is the potential of the combo. A BBM T-Wedge on TFS heads has got to make more power, earlier, with less boost than an original Ford T-Wedge on, say, Edelbrock heads, given the same adequately-sized turbo on both.
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I am looking for a original or dove. any for sale? thanks ron ronbidstrup@sbcglobal.net
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Try putting a want ad in the classifieds, Ron. They are out there...
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sorry about that, will do