expansion chamber or muffler...

[theenico]

In the proposed SM rules they say that you cannot have an expansion chamber but you can use any kind of muffler.
I would love to hear some comments on this one

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Nico
KCRaceware (816) 257-7305
[email protected]

[racer_tim]

The only reference to "expansion chamber" in the GCR is in reference to Formula 500.

It is my assumption that an "expansion chamber" is an extension of the cylinder head. I think that they only work on 2 stroke motors, but I might be wrong. Since SM has to run the stock exhaust manifold, I'm not sure why this request is even in the proposed rules.

Maybe I'm wrong, but it looks like they are mixing apples and oranges.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit (Bent)
http://linerud.myvnc.com/racing/index.html

[ITSRX7]

Not exactly I suppose. The hot exhaust in ITS for RX-7's right now is the system by Mike at ISC. He utilizes the expansion chamber concept aft of the header.

AB

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Andy Bettencourt
06 ITS RX-7
FlatOut Motorsports
New England Region
www.flatout-motorsports.com

[Scott Nutter]

I do believe an expansion chamber for any internal combustion engine would be benificial. My understanding is that as the hot gas makes it's way thru the exaust (like a wave) if it hits an expansion chamber it sends a 'wave' back towards the motor. This wave however is low pressure, so the ideal is to position the expansion chamber so the low pressure 'wave' is at the exhaust ports right when they open, thus sucking the exhaust out of the combustion chamber. This is probably not feasable on say more than two combustion chambers (ie. the use on the wankle)

If I'm off my rocker, let me know.

[jc836]

I'm not sure this applies, but there is such a device used on model airplanes and chain saws. We call it a "tuned pipe". This device can be a long cylinder with either a fixed diameter tip or one of varying size. The pipe us usually tapered and does have a specific overall volume. The length of the straight section on one end (generally the inlet) is what is cut for tuning for maximum performance and rpm.
Just my thought on the subject.

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Grandpa's toys-modded suspensions and a few other tweaks
'89 CRX Si-SCCA ITA #99
'99 Prelude=a sweet song
'03 Dodge Dakota Club Cab V8-Patriot Blue gonna tow

[John Herman]

Technically, a muffler is an expansion chamber. That's how they work.

[theenico]

Originally posted by John Herman:
Technically, a muffler is an expansion chamber. That's how they work.

I agree 100%, I also know some people who have asked the CB to define any differences, since they imply a difference in the rule. Ironically (or not) there has yet to be a clarification...

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Nico
KCRaceware (816) 257-7305
[email protected]