Chromov Andrew Studentsov Russia, Moscow area (11 posts) Registered: 08/03/2011 01:19AM Main British Car: GAZ 2410, 1988 year ZMZ 402.10, 2,45 litres |
About intake manifolds
Hi all again!
To one's who recognised me - i'm alive, okay, doing studies and have too little time for my car. Got a question. There are two basic types of intake manifolds for V8 with single carburettor: [speed-eng.com] [image.popularhotrodding.com] First of all what is their designation in english? Which of them is better for power, and why? Why the ones have a partition, that divides the flow from diffirent chambers of carburettor, and others haven't? Thanks in advance. |
Moderator Curtis Jacobson Portland Oregon (4577 posts) Registered: 10/12/2007 02:16AM Main British Car: 71 MGBGT, Buick 215 |
Re: About intake manifolds
I'd recommend starting with this article: "Intake Manifolds" by Dan Masters
Dan's article explained the theory behind dual plane vs single plane manifolds in the context of the Buick/Rover V8... |
Chromov Andrew Studentsov Russia, Moscow area (11 posts) Registered: 08/03/2011 01:19AM Main British Car: GAZ 2410, 1988 year ZMZ 402.10, 2,45 litres |
Re: About intake manifolds
Well, now most of it is clear.
But, here is a single-plane intake of ZMZ 511 [www.zp-avto.ru] [s3.images.drive2.ru] As you can see, it hasn't a common chamber under carburettor, and the channels are divided for left and right sides of engine. Rely on article you gave me, i am of opinion that it is made to increase torque at low rpm. Each side of engine works with only one carb barrel, and there is enough flow in each barrel at low rpm. Am i right? |
Dan Jones Dan Jones St. Louis, Missouri (280 posts) Registered: 07/21/2008 03:32PM Main British Car: 1980 Triumph TR8 3.5L Rover V8 |
Re: About intake manifolds
> Rely on article you gave me, i am of opinion that it is made to increase torque at low rpm.
Single plane intakes can have dividers or not. The reason some single plane intakes have dividers is typically to improve the operation at lower RPM but the mechanism is different than in a dual plane intake manifold. In a single plane with divider, the divider is there in an attempt to correct the flow imbalances between cylinders and/or to decrease the apparent plenum size (or apparent carb size). In a 90 degree V8 with dual plane crankshaft, there are always a pair of cylinders that are next to each other in the plenum that fire successively. When a cam has overlap (i.e. the exhaust and intake valves are open at the same time), flow from the exhaust stroke of one cylinder can travel into the intake manifold (This is called reversion flow), fouling the intake charge of the adjacent cylinder. The thing that separates a dual plane from a single plane with divider is the grouping of the cylinders relative to the firing order. In a dual plane, 2 of the cylinders from one bank of the V8 are paired with 2 of the cylinders from the other bank. In grouping the cylinders this way, the adjacently firing cylinders are in separate sides of the plenum so the reversion flow effect is greatly lessened. Be aware there are some errors in the Dan Masters article. He lists the Offenhauser Dual Port intake as a dual plane. It is not. The dual port design has the runners split into top and bottom sections, with the plenum split fore-and-aft (rather than the usual side-to-side). It's essentially two single plane intakes, stacked on top of each other. The primaries feed the longer path lower runners and the secondaries feed the shorter path upper runners. When cruising, the manifold operates on the smaller area, longer path, runners. This provides high velocity flow for good fuel economy and throttle response. Under high demand, the secondaries open and provide additional flow through the larger top runner portion. It's an interesting approach but the packaging required to fit within a carb intake envelope does compromise the design somewhat. By reputation, it's a good fuel economy, low end response intake. Makes a good truck intake but it's not a maximum horsepower design. Once upon a time, David Vizard did a big intake comparison (on a 350 Chevy but the trends probably apply). The Dual Port was near the bottom of the list when comparing peak horsepower but the area under the curve was very wide and the fuel consumption was the best. Another article with some additional detail on V8 carb intake manifold designs can be found here: [victorylibrary.com] Dan Jones |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: About intake manifolds, verticle split ?
This makes the possibility of a tunable, single plane, plenum divider easier to facilitate. While we're at it, why not vertically split larger intake runners to increase velocity/torque range ? roverman.
Edited 1 time(s). Last edit at 12/05/2011 12:03PM by roverman. |
Chromov Andrew Studentsov Russia, Moscow area (11 posts) Registered: 08/03/2011 01:19AM Main British Car: GAZ 2410, 1988 year ZMZ 402.10, 2,45 litres |
Re: About intake manifolds
Thanks Dan, Art, now it's clear.
Do you wanna see, where was installed the engine with this manifold? |
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Chromov Andrew Studentsov Russia, Moscow area (11 posts) Registered: 08/03/2011 01:19AM Main British Car: GAZ 2410, 1988 year ZMZ 402.10, 2,45 litres |
Re: About intake manifolds
[images03.olx.ru] =)
And in another modification on this: [www.furgonvolga.ru] So, you see the problems russian hot-rod enthusiast have to face with. Russia never had enough cheap and powerful V8's |
Re: About intake manifolds
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