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Does this shape matter?

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Old 07-03-2006 | 12:52 PM
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Default Does this shape matter?

Hi,

I have enclosed a picture of my Cen NT-16 with a manifold I have. It can bolt onto the engine without a problem, but it is a differnt shape, and also the exhaust exit on the engine is a different size to that on the manifold as you can see..

Will it still work fine:

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Old 07-03-2006 | 01:55 PM
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Default RE: Does this shape matter?

It'll work as long as there is a good seal between the two, but you'll get much more power if the manifold matches up the opening on the case properly. You could try dremelling it to shape (i've done that do make minor mods on my manifold) or just buy another manifold which matches up better - it'll probably only cost a few quid.
Old 07-03-2006 | 02:10 PM
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Default RE: Does this shape matter?

i cant see why there will be a power loss if I have a good gasket.
Old 07-03-2006 | 02:18 PM
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Default RE: Does this shape matter?

It's all to do with air flow - if you prevent spent fuel, oil and gas getting out of the combustion chamber you're robbing the engine of power.
Old 07-03-2006 | 02:30 PM
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Default RE: Does this shape matter?

right I see, i need to get hold of a cheap nt-16 manifold and gasket.
Old 07-03-2006 | 02:36 PM
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Default RE: Does this shape matter?

You don't need a NT-16 manifold & gasket - most side exhaust engines use the same exhaust size. Just seems like you were unlucky with the manifold you've got. Take the engine into model shop and they'll probably be able to find a manifold which will match the engine...
Old 07-03-2006 | 02:47 PM
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Default RE: Does this shape matter?

right, thanks a lot. ALso, I dont have the original cen pipe, so I am going to be using a standard silver kyosho one. Is that okay, are they all the same inside? I took it apart, its got 2 parts, in the small parts its got a cone inside it that goes very thin at the end. Would the cen pipe be pretty much the same?

Thanks
Old 07-03-2006 | 03:12 PM
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Default RE: Does this shape matter?

You would definately be better off with a matching header. like snow said, it has to do with the airflow. You want a nice laminar flow through your exhaust pipe, and the little bit of mismatch there would be enough to cause it to be turbulent.

check out www.customrccars.com for CEN parts.
Old 07-03-2006 | 03:26 PM
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Default RE: Does this shape matter?

Different pipes give different power curves - but as long as it fits and it was designed for a smallblock engine it'll probably be fine. The two cones mean it's a "dual chamber" tuned pipe, which is good.
Old 07-03-2006 | 04:08 PM
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Default RE: Does this shape matter?

Looking at the photo, the height of the opening of the manifold looks bigger than the exhaust opening of the engine, I dont think this will seal properly. If I am wrong, then the dremeling I would also recomend to widen the header opening to match the engine's exhaust opening. I think most headers opening does not exactly match the exhaust opening, its usually smaller, except on rear exhaust with round ports. This is the easiest mod done with nitro engines which gives it a little more power because the air is not restricted.
Old 07-03-2006 | 05:19 PM
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Default RE: Does this shape matter?

ORIGINAL: snowbl!nd

Different pipes give different power curves - but as long as it fits and it was designed for a smallblock engine it'll probably be fine. The two cones mean it's a "dual chamber" tuned pipe, which is good.
Nope, its just a pipe with one cone at the end, where it goes into a small hole about 6mm diameter or so. Its just a standard kyosho pipe. All I was wondering is if the Cen standard pipe would be pretty much the same, so I wont see any reductions in perfrmance or massive changes in sound.
Old 07-03-2006 | 07:52 PM
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Default RE: Does this shape matter?

joshie... I just ordered a new cen pipe after a bad crash... don't ask.... its about the same as the one you have... I run an os 18 now.. the exhaust size is the same as the cen comming off the engine.. just dremel the sides a bit to allow better flow... I do that with my cen pipes to allow better breathing.....the cen pipe as well as the kyosho uses pretty soft aluminum so its not hard to do..
Old 07-06-2006 | 11:41 AM
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Default RE: Does this shape matter?

I called my LHS and they told me thatg the manifold would be fine. They said the following:

Although the outlet of the engine is wider than that of the manifold, if you look inside the engine, the hole in the piston where the fumes come out is actually no bigger than the hole in the manifold thus there will be no problem with the fumes trying to escape..

It is only a problem if the hole in the manifold is actually smaller than the hole in the pistonn, which you can see by looking through the outlet..

What do you think?
Old 07-06-2006 | 04:42 PM
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Default RE: Does this shape matter?

anyone?
Old 07-06-2006 | 04:44 PM
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Default RE: Does this shape matter?

BS. Plain and simple.
Old 07-06-2006 | 04:47 PM
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Default RE: Does this shape matter?

it makes sense.. because if you look into the engine outlet. the hole where the fumes comes out of is much smaller than the outlet.
Old 07-06-2006 | 04:54 PM
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Default RE: Does this shape matter?

Yeah, but the exhuast gases don't stay in the same "size" as the exhaust port - they spread outwards. If they're blocked you get turbulence (for lack of a better word) and they can't escape as quickly.

You want to keep their journey as smooth as possible....
Old 07-06-2006 | 05:15 PM
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Default RE: Does this shape matter?

im going to try it... I think it is a manifold that came with a tuned pipe for that engine though.

When using the car, what signs should I look for to tell me that the manifold is wrong?
Old 07-06-2006 | 05:18 PM
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Default RE: Does this shape matter?

looks fine to me...
Old 07-06-2006 | 05:29 PM
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Default RE: Does this shape matter?

Hey, sorry for the bad quality photos, but you can see below what I mean by where the fumes come out is actually smaller then the engine outlet. You can see on the right side of the engine in picture 2, that the inside of the outle is at an agle which feeds into the piston.

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Old 07-06-2006 | 05:38 PM
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Default RE: Does this shape matter?

[sm=spinnyeyes.gif] ok then, you use that header [sm=spinnyeyes.gif]

[]
Old 07-06-2006 | 05:43 PM
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Default RE: Does this shape matter?

well, what do you think i will see go wrong with the car?
Old 07-06-2006 | 08:33 PM
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Default RE: Does this shape matter?

If the pipe seals properly and there are no leaks you will not have the performance from that setup that you could have. It is the same as porting and polishing heads on real to life size cars, it helps the exhaust escape smoothly thus causing a vacuum effect to allow more out faster. The faster you can get ALL the exhaust out of the enging the faster it can get more in and start over again. It has to get in fast and out fast in order to have the best performance. If you are not looking for the best performance then you may not notice a difference.

I don't run nitro but what I have explained above is the way it should be. If I am incorrect then one of the some of the experienced nitro people will correct me. Thanks

Thanks
Dudelive
Old 07-06-2006 | 09:08 PM
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Default RE: Does this shape matter?


ORIGINAL: Dudelive

If the pipe seals properly and there are no leaks you will not have the performance from that setup that you could have. It is the same as porting and polishing heads on real to life size cars, it helps the exhaust escape smoothly thus causing a vacuum effect to allow more out faster. The faster you can get ALL the exhaust out of the enging the faster it can get more in and start over again. It has to get in fast and out fast in order to have the best performance. If you are not looking for the best performance then you may not notice a difference.

I don't run nitro but what I have explained above is the way it should be. If I am incorrect then one of the some of the experienced nitro people will correct me. Thanks

Thanks
Dudelive

Exactly!

If you use that header, the car will run, but you will not see the same power or RPM's as you would if you had a matching header.

Like Dudelive said, it's how fast your exhaust gas flow rate is that dictates your intake rate. Haveing the headers not matching will slow the exhaust gas down considerably.
Old 07-07-2006 | 02:02 PM
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Default RE: Does this shape matter?

You say there will be a change in RPM and power, btu would that be noticeable. Is it worth chaning if im just driving in a parking lot etc..


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