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-   -   Most power you've seen from a Log ? (https://www.homemadeturbo.com/forced-induction-7/most-power-youve-seen-log-34892/)

jeffescortlx 02-09-2005 03:40 PM

Most power you've seen from a Log ?
 
I'm allways seeing Log manifolds getting a bad rap because they "dont flow well". What is the most power you've heard of some one getting with useing a log manifold?

Reddy 02-09-2005 04:56 PM

Re:Most power you've seen from a Log ?
 
I've seen 500-600hp with the inline pro manifold. You can make high hp with a log manifold, its if you would change from that log manifold you'll make more hp alot easier at the same psi

Engloid 02-09-2005 06:57 PM

Re:Most power you've seen from a Log ?
 
I think that, although these log styles have some disadvantages, they typically are made using piping that is quite a bit oversized. This decreases the velocity, which has other disadvantages... however, with decreased velocity, the flow characteristics are going to have less effect on performance.

In other words, if you were running much higher velocity (or smaller piping in the same shape) through the log styles, the bad flow characteristics they have would be much more evident.

Honda16hb 02-09-2005 07:22 PM

Re:Most power you've seen from a Log ?
 

Originally Posted by Engloid
I think that, although these log styles have some disadvantages, they typically are made using piping that is quite a bit oversized. This decreases the velocity, which has other disadvantages... however, with decreased velocity, the flow characteristics are going to have less effect on performance.

In other words, if you were running much higher velocity (or smaller piping in the same shape) through the log styles, the bad flow characteristics they have would be much more evident.

I'm not trying to call you out or anything, but have you seen your theory tested? I'm wondering if a test with a log manifold of large diameter compared to a log manifold of small diameter would show the exhaust velocity theory to hold true. think of it this way, the bigger the exhaust the better for turbo, but that's after the turbo, and the turbo is a restriction. Bisimoto uses fairly large sized piping for their NA headers, maybe he's found the sweet spot between velocity and cfm flowing ability.

USS 02-09-2005 07:27 PM

Re:Most power you've seen from a Log ?
 

Originally Posted by Engloid
In other words, if you were running much higher velocity (or smaller piping in the same shape) through the log styles, the bad flow characteristics they have would be much more evident.

Yeah, think of it like a larger woman. If they're wearing baggier clothes, it isn't as noticeable, and they don't look terribly bad. However, if you see them wearing tight clothes, you want to throw up.

D16Y7-T 02-11-2005 12:41 PM

Re:Most power you've seen from a Log ?
 

Originally Posted by Snafubmx234

Originally Posted by Engloid
In other words, if you were running much higher velocity (or smaller piping in the same shape) through the log styles, the bad flow characteristics they have would be much more evident.

Hahaha ;D
Best analogy of the day right there!

Yeah, think of it like a larger woman. If they're wearing baggier clothes, it isn't as noticeable, and they don't look terribly bad. However, if you see them wearing tight clothes, you want to throw up.


HMTguy 02-11-2005 12:53 PM

Re:Most power you've seen from a Log ?
 
Lol you suck at teh quoting.

Reddy 02-11-2005 02:06 PM

Re:Most power you've seen from a Log ?
 

Originally Posted by jagojon3
Lol you suck at teh quoting.


I hate when people type in the quotes

Engloid 02-11-2005 03:10 PM

Re:Most power you've seen from a Log ?
 

Originally Posted by Kyle
I'm not trying to call you out or anything, but have you seen your theory tested? I'm wondering if a test with a log manifold of large diameter compared to a log manifold of small diameter would show the exhaust velocity theory to hold true.

You can test this with a waterhose. Turn the hose on and see how far it shoots. Then reduce the cross-section of flow area by placing your thumb over half of it...and see if the water doesn't speed up and shoot farther. No dyno's needed to prove that when you reduce the area available for flow, while the mass through it stays constant, velocity is increased. Don't take this badly if it sounds that way, as I don't mean to sound like a dick or anything.
===============================

Originally Posted by Kyle
think of it this way, the bigger the exhaust the better for turbo, but that's after the turbo, and the turbo is a restriction. Bisimoto uses fairly large sized piping for their NA headers, maybe he's found the sweet spot between velocity and cfm flowing ability.

That's possible, but it's also possible that he's found a size of tubing that is much easier to find or get bent, and the performance isn't enough "off par" to bother spending more money eleswhere. Of course we will never know, cause if you ask them, they'll say they did some extensive testing that nobody else can possibly comprehend...just so they defend their product and sound like hot-shots. I'm not saying that Bisimoto is bad or they lie..just that you have to consider the source of info. I think the odds of them admitting that they use that size pipe because it's cheaper is about 0%.

Look at Full Race and all the other big companies...they use heavy wall pipe. They will say that it's necessary...but somehow the prostock dragsters don't need that..hmmmm.. I think it's likely an issue of pipe fittings being easier to buy than bent pipe. It's also easier to cut, as it can be cut cleanly in a cold saw, where tubing is much harder. Also, when you cut tubing in mid-bend, it will egg shape due to stresses put in by the bend. Pipe fittings can be cut in mid elbow and the shape will stay round.

I think that in this industry, many companies will distort facts. They will tell you something's the best because it's what they use. They will say that one thing was tested and did best, when they likely never tested ----.

People are all over the nuts of the big header and manifold companies these days...and believe everything they say as if it were in the Bible...without questioning it.

Doubt what I say? The top companies will boast about "certified welders" and stuff like that... has anybody seen a copy of the certifications? Anybody ever seen what welding procedure the welders certified to? Anybody ever asked what welding specs they weld to?

Granted, that stuff may not be necessary, but I think that if a company says something, it should be true or not said. However, nobody questions these to companies..and therefore they believe whatever they say.

Kinda got off topic here..just a small rant.

HMT-Admin 02-11-2005 04:57 PM

Re:Most power you've seen from a Log ?
 

Originally Posted by Whitey
I've seen 500-600hp with the inline pro manifold. You can make high hp with a log manifold, its if you would change from that log manifold you'll make more hp alot easier at the same psi

inline pro mani is hardly a log manifold ;)


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