Well, that time of the year is coming very soon. I've read the rules on the exhaust, but it's a little bit of grey area IMO. Here's the rule for exhaust:

quote:
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Any part of the exhaust system beyond (downstream from) the header/manifold or catalytic converter, if so equipped, may be substituted provided the system meets the requirements of 3.5. Stainless steel heat exchangers are permitted only if the physical dimensions and configuration remain unchanged. Modifications of any type, including additions to or removal of, the catalytic converters, thermal reactors, or any other pollution control devices in the exhaust system are not allowed and the system must be operable. Replacement catalytic converters must be OEM if the vehicle has not exceeded the 5-year/50,000 mile warranty period as mandated by the EPA. Converters must be of the same type and size and used in the same location as the original equipment converter(s). This does not allow for a high performance unit. If the vehicle has exceeded the 5 year/50,000 mile warranty period, replacement catalytic converters must be OEM-type as per Section 13.
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I know after the converter it doesn't matter what's there, but does there have to be something there? It says substitution which kind of implies there needs to be piping after the converter. I plan on removing the exhaust and was hoping to cheap out and just remove it all together without any piping after the converter.

This is in regard to my MR2 Turbo, but you guys always have a quick accurate reply. Thanks for any help.

 

Read down about 3/4 of the way in this thread.

http://www.sccaforums.com/ubb/....html

 

Helpful link. Thanks Todd.

So it seems that it's pefectly legal for stock class to do whatever is pleased in stock class so long as it meets the dB requirement, though I might catch some flak from competitors and event chairmen.

Hopefully the turbo will help keep the noise down in conjunction with the stock cat.

 

I believe Carter Thompson's old MR2T had a straightpipe on it, don't think it's excessively loud... perhaps PseudoRealityX will comment since he has more experience with that car.

 

Note that OVR will more than likely be enforcing sound limits next year, especially at the OSU lot. Something to think about.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Todd00 &raquo;</TD></TR><TR><TD CLASS="quote">Note that OVR will more than likely be enforcing sound limits next year, especially at the OSU lot. Something to think about.</TD></TR></TABLE>

Yeah, I remember hearing talk of enforcing the sound limits more last season. Hopefully it's not too loud. I may also try just taking the muffler off and keeping the secondary converter intact.

 

MR2 turbos are quiet with a straight pipe. I've raced Carter Thompson's old car 3 times now. It's quieter than my ES MR2 NA car...which is perfectly legal for 95 db events.

 

If there is a secondary, or thirdary etc, converter, it has to stay there for stock class. I seem to remember seeing something over the winter in Sportscar about the exhaust running out the stock location or within a few inches. I can't seem to find the reference so I can't quote it or verify either.

Straight pipe without a muffler will be quieter than just ending at the cat and still lighter than the stock system. I have heard a bunch of stock class turbo cars with just straight pipes and they are generally not loud. If you do run with no exhuast, bring the stock one just in case you have to put it back on.

 

I think the secondary is also considered a resonator, too. No different from a Honda anyway.

Thanks for the help.

 

hopefully the picture works...

this is a perfectly legal exhaust. If you wanted to be EVEN LIGHTER, you could do side exit...but it's still silly light in this configuration.

 

I actually looked at the picture on an MR2 board. I may end up doing that.

 

My ES car has basically the same thing, except it's got a turn-down at the end. Make sure to keep the tip rearward enough to not melt the rear bumper, especially on the turbo cars...

 

Yeah, the heat of the exhaust gas was a concern I had. I was thinking about just running a turn down right off the converter.