15 replies to this topic

[Protech Racing]

First; I am looking at the exhaust rules and have two 1.6 headers and head pipes . One has some ugly welding inside and the other is cleaner inside. Can I clean up the welds ?
Second. the rules state 2.25 pipe. Can I make a one piece pipe from the down pipe to the rear?
last; What makes up a muffler? What is the max dump area for the rear muffler? Can I make a megaphone/muffler? Does the dump pipe have to be round?
TIA. MM

[john mueller]

Search can answer all those questions.

http://forum.specmia.../ultimatebb.cgi

[Protech Racing]

Does no one know if I can build a one piece tube? Do I have to have the center test pipe connections?
It is not clear in the rules. The current tubes are not very nice, contain the test pipe crap, stop before the rear subframe etc.
Is one long, one piece exhaust legal?
Does the exhaust outlet have to be round?
TIA, MM
PS I did a search @ the old site, NA.
I had asked before also. Thanks, John.

[Johnny D]

It's supposed to look like this one.

http://www.saferacer...l?productid=541

You did a search at the old site/archives for "exhaust" and found nothing?
J~

[Cy Peake]

Many of us run a single pipe (some with an inline resonator) bolted to the flange at the bottom of the downpipe to the back.

[davew]

The oem manifold/header and the down pipe can not be modified in any way.

From there back, you can do what you want within the couple rules stated in the GCR:
Maximum tubing diameter
Maximum muffler size
Must exit beyond rear axle
No coatings or wraps
Must meet event specific sound levels.

In the past several years, nobody has come up with anything better than the Springfield dyno exhaust. I do not sell them, so I have no reason to recomend it, other than it is the best available and easy to comeby.

Dave

[Mike Collins]

I have a better one than the SD. About to bring it public. Willing to send anyone who wants to see the dyno sheets what it does.

[dstevens]

Looking for exhausts and intakes. The last two big pieces besides tires and wheels. My pals at Mexicali Muffler can do the bends (I'm not tooled to bend that thin wall). They formed my stock car exhausts and I installed and welded them up. I'd lean to the SD but some are reporting fitment issues. If I'm going to have to cut and fit might as well roll my own this time.

I'm ASSuming what the rules call the downpipe is the piece between the manifold and the cat. I guess it kind of goes down.

Meat, what is the price range for your new unit?

[Protech Racing]

Thanks Wheeler, I spoke with John Bauer @ SCCA, Tues. He said that the pipe must be less than 2.25 OD every where.
That knocks out the the SD system , or the one in the pics. It has a short area of 1.5 and 1.625 into the muffler. "Out of range" per Bauer.
I want to add a 30# muffler, that muffles very little, and get rid of the junctions.

"The outlet tip must be the same 2.25 OD(not the circumference of the 2.25 pipe , in a rectangular section)". "The pipe cannot measure bigger than 2.25 anywhere" . Take a 2.25 toothpic and stick it in the pipe.
So I have my " SCCA" answer, Thanks
NASA may be different?
MM

[Johnny D]

What do you mean "that knocks out the SD system" ???
J~

[dstevens]

Mike if you are running SM in either SCCA or NASA the Springfield Dyno exhaust as ships from Sam is most certainly legal.

[Bench Racer]

Thanks Wheeler, I spoke with John Bauer @ SCCA, Tues. He said that the pipe must be less than 2.25 OD every where.
That knocks out the the SD system , or the one in the pics. It has a short area of 1.5 and 1.625 into the muffler. "Out of range" per Bauer.
MM

If this ^ is treated as fact, there will be a whole bunch of cars disqualified or more likely the rule will be changed.

[dstevens]

From the 2011 GCR 9.1.8 M 4 a...

4. The factory exhaust system beyond the OEM front down pipe
may be replaced, provided the following are true:
a. The replacement system retains the original configuration
(i.e., single tube design) and the tubing is a maximum of
2.25 inches outside diameter.

[Tom Hampton]

The keyword being "maximum".

[davew]

I beleave what Mike is talking about is the short stubs on the muffler that the pipes attach to. The SMAC talked about this a couple years ago and determined that that was part of the muffler and has no maximum diameter. The tubing has the max diameter, not the muffler. SD exhaust is legal IMHO

Dave

[Protech Racing]

There is a picture on the old site of the SD. The pipe is expanded to 2.5", as it nears the muffler. John said that if any part of the pipe is over 2.25, it is out.
Maybe an allowance to fit to the muffler is to be considered? Within 2 in of the muffler, any size can be allowed??
I also asked about, if the 2.5in section was cut off and clamped over the 2.25, would that be legal? "yes."
Than of course ,I would have a 4in, inlet muffler, with a tapered entry pipe, tapered exit pipe,etc.
I understand that the SD is legal. It just does not adhere to the rules, as written.

I guess that the answer to my original question, is that I can make a one piece , seamless pipe , to a flat 30# muffler, with 4 in inlet and outlet, tapered to a 2.25 tip.

MM