IT ruleset confusion - exhaust exit

[Gary L]

Although a point of interest in the nearby "Hot" June Fastrack thread, I was afraid it would get lost in the Spec Miata stuff, ergo this new thread.

There seems to be an opinion shared by some, that the ITCS requires the exhaust exit to be outside the car body. IMO, this is NOT true... here's the quote from page 296 of the current GCR:


Any exhaust header and exhaust system may be used. Exhaust shall exit behind the driver, and shall be directed away from the car body</span>.[/b]Now maybe I&#39;m being too liberal with the wording, but I see absolutely nothing in here that requires the exhaust exit to be "...outside the car body", as stated somewhere in the Fastrack thread. On my ITB car, the exhaust exit is just in front of the rear axle, about a foot inside the right rear wheel, ending with a turndown tip that points the exhaust at the ground. This meets both of the above requirements, to the letter... it&#39;s behind the driver, and it&#39;s directed away from the car body. What am I missing?

[planet6racing]

You aren&#39;t missing anything. That&#39;s the same routing as my exhaust for the same reasons.

[JeffYoung]

I agree. I think stopping immediately behind the driver with a turn down is perfectly legal. And a lot of guys do it, not that this matters for legality, but just shows that a lot of us read the rule that way.

[Knestis]

I think what it shows is that some folks have NOT read the actual rule.

It&#39;s one of those old-school things, that it was commonly accepted exhaust was supposed to exit past the back of the car but it hasn&#39;t been like that in IT for quite a while, I don&#39;t think.

K

[itracer]

SM rules state where it must end, but there is no requirement for it to turn down.

From SM rules:
b. The pipe may end anywhere after the rear subframe. Forward of the rear subframe, the pipe must follow the original path of the OEM exhaust system.

[JeffYoung]

Jason, that&#39;s right. SM has to follow the original exhaust track to past the rear subframe and then is free.

Key point here is that it is not hard AT ALL to make an exhaust that is IT AND SM compliant, so why give the Otters an allowance to run an SM exhaust in IT?

[ddewhurst]

***so why give the Otters an allowance to run an SM exhaust in IT?***

What am I missing ? My rule understanding is the Spec Miata exhaust is legal in IT................Spec Miata exhaust is not an ANY exhaust system but it fills the rule for IT.

***From SM rules:
b. The pipe may end anywhere after the rear subframe. Forward of the rear subframe, the pipe must follow the original path of the OEM exhaust system.***

***From IT rules:
QUOTE
Any exhaust header and exhaust system may be used. Exhaust shall exit behind the driver, and shall be directed away from the car body.***

[Gary L]

What am I missing ? My rule understanding is the Spec Miata exhaust is legal in IT................Spec Miata exhaust is not an ANY exhaust system but it fills the rule for IT.[/b]

Not quite... the IT requirement to direct the exhaust "...away from the car body." is not part of the SM ruleset.

And here we are, getting wrapped up in the otters again, which was what I was trying to avoid when I started a separate thread! :D

[ddewhurst]

***Not quite... the IT requirement to direct the exhaust "...away from the car body." is not part of the SM ruleset.***

Please excuse me from taking part in YOUR thread. :026: < I got no legs. IIRC every Spec Miata exhaust I have viewed that ends berfore the OEM position has been directed downward. Would YOU say tht is away from the body.

[shwah]

The ones you mention are IT legal. If they do not have a downturn and do not exit the rear they are not IT legal.

[MMiskoe]

Please accept my apologies. I did post about IT exhaust having to be outside the body work, something I had come to believe I understood and did not go back to check. Not sure where I got that impression, probably the &#39;away from the body&#39; but I now see it was the wrong impression or interpertation.

Of course this just raises my dislike for the new ruling getting all the attention lately.

Matt

[Gary L]

IIRC every Spec Miata exhaust I have viewed that ends berfore the OEM position has been directed downward. Would YOU say tht is away from the body.

[/b]David - Yes, I would definitely say that a downward directed exhaust is away from the body... did you read my first post? :D

Be that as it may, what you&#39;ve observed on SM cars is all well and good; but the fact remains that according to the respective rulesets, you can have a legal SM exhaust system that is not legal in IT.

[bldn10]

Distilling down what all of you have said re the exhaust being "directed away from the body," it sounds like there hardly is any rule at all. I.e. as long as an outlet on the right side of the midline does not point up or left (not to mention forward), and vice versa, it&#39;s legal. [And, technically, perhaps other than upward, is not any direction ultimately away from the body?] What real difference in safety would there be between an outlet just barely right of the midline pointing left or right? But, apparently, the former is illegal and the latter legal? Does that make sense? Frankly, I think the intent is not to establish an objective rule based on the direction the outlet happens to be pointing, but a requirement that the outlet be configured in such manner that actual exhaust fumes are not likely to be sucked into the cockpit at speed. I.e "exhaust" refers to the gaseous output from the engine, not the pipe through which it travels to outside air. And "directed" does not mean simply "pointed" but in fact expelled. Unfortunately, this would necessitate some understanding of airflow under the car if the outlet is there. Of course, if the outlet is actually outside the footprint of the body, you are probably safe. So ....



Last year at St. Louis a guy was driving an ITS Z w/ the outlet w/i the footprint just behind the left tire. There was an opening in the rear floor and exhaust was apparently sucked into the car. In his last alert decision before he blacked out, he pulled in. The EMTs administered O2 and it was hours before he was fully awake again. :wacko: He was minutes from being in big trouble.



I&#39;m not taking any chances. My exhaust is beyond the rear bumper cover.