HIGHWAYMAN: Bringing the Devore 928 back from the dead
#528
Developer
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No. Here is a picture of the head after the new copper-nickel alloy valve seats were installed, but before any porting had been done to them. They looked like this when measured for our baseline flow test.
I see in these pictures that some of the seats have had their first rough cut, and some have not. The flow was measured after the first cut was completed to eliminate a false number that would be caused by the tumbling over the sharp edge if we hadn't.
I see in these pictures that some of the seats have had their first rough cut, and some have not. The flow was measured after the first cut was completed to eliminate a false number that would be caused by the tumbling over the sharp edge if we hadn't.
#529
Developer
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What's your test pressure, out of curiosity? Interested in both the actual test pressure and the pressure number to which the raw measures were corrected to for reporting.
#530
Developer
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Here are some before, during, and after pics of the Extrude-Hone process we just had done.
You will see in some cases that impurities in the manifold casting are now visible. They were always there - just now you see them more prevalently.
I am trying to get some time at a nearby flow-bench with two intake manifolds that I have that are of the very same casting number so I can see what gains we may have.
You will see in some cases that impurities in the manifold casting are now visible. They were always there - just now you see them more prevalently.
I am trying to get some time at a nearby flow-bench with two intake manifolds that I have that are of the very same casting number so I can see what gains we may have.
#533
Developer
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The previous narrowest point in the intake shoe, where the incoming air turns to go up to each bank, was 50mm. There are two of these. These are now 70mm each at the narrowest point.
#534
#535
Developer
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So my question to the forum is: if I can get some flow-bench time with these two manifolds, I think I will have time to test about two runners on each intake (a total of 4 flow tests).
Which two intake runners would you like me to test? Do you have a preference?
Which two intake runners would you like me to test? Do you have a preference?
#536
Developer
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Shaun - the extrude-hone intake manifold will have to bear fruit to get painted. I am going to change out the stock intake manifold on the engine dyno with this one, and see what the gain is. If it performs (as I am betting it will) then the customer will pick a color and have me paint it.
The custom intake shoe with the larger throttle body had to be made either way, no matter which intake manifold we use.
The custom intake shoe with the larger throttle body had to be made either way, no matter which intake manifold we use.
#537
Nordschleife Master
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Can you flow the whole manifold assembled together by blowing thru from the throttle body flange first? If you can, then measure with a pitot-static tube the exit flow velocity at each of the eight runner ends (the end which would be attached to the intake port in the heads in an assembled engine). Pick the lowest exit velocity runner and then flow that runner individually.
I'm not saying this will be the scientifically correct way to guess which will be the worst runners, but seems like a reasonable thing to do.
I wouldn't be shocked if #5 would be the worst flowing runner. So if you don't want to set up the whole manifold like above, I'd guess #5 would be worth flowing. One of the better runners (#2, #3 by my guess) might be worth flowing, too.
When flowing the individual runner, I think that one would ideally bolt the intake on the heads and then flow that runner thru the corresponding cylinder's intake valves, as with a live engine.
The challenge with extrude honing is that with complex runner shapes (like with #5 and #8) the process will not necessarily remove material from the points that would be most advantageous from the air flow perspective.
#538
Developer
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Can you flow the whole manifold assembled together by blowing thru from the throttle body flange first?
I will test runner #5 and probably one from the other side as well. We will get good before-and-after individual runner data that way without much trouble. It will show the effect of the Extrude-hone alone. The rest of the data will come from the engine dyno.
#539
Banned
Thread Starter
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I agree; in this case, at least since I am the one paying for all this fun, the dyno is king. This mod will have to stand on its own two feet; I don't care what it flows in reality, as long as it a) adds horsepower, or b) adds torque. Absent those two, it's a loser ;-)