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2.25 or 2.5" upgrading K8 Exhaust

Posted: June 16th, 2002, 3:44 pm
by CanadianMx-3
I have a K8 and have a subtle sound from my exhaust. I want to upgrade and make it roar. I know its a V6 and should need a large pipe however, its still less than a 2.0L. Should I upgrade tp 2.5" or 2.25" I dont want to create some huge a$$ backpressure. I would like to know what is the optimum size. What is the factory spec.?

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 16th, 2002, 4:16 pm
by RayRay
A lot of the people here would say this much:<P>- no more than 2.25" for the 1.8L<BR>- no more than 2.5" for the 2.5L<P>But then again its your car and $$$.<P>I personally have a custom 2.25" catback.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 17th, 2002, 5:03 am
by CanadianMx-3
Do you know what the stock pipe size is?

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 17th, 2002, 6:59 am
by Stevech_2001
piping dosen't make it roar the muffler does....I'm not sure but I think it's like 2 inches

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 17th, 2002, 8:06 am
by David Coleman
Stock piping is a smidge under 1-7/8".

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 17th, 2002, 9:20 am
by ZUNE MX-3 Gs
Is there any calculation that would theorically give the ideal diameter of tubing for the headers and cat back tubing? Where I can found a good on-line source for thermodynamic and fluidodynamic calculations on a four-stroke engine?

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 17th, 2002, 9:50 pm
by pelado
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ZUNE MX-3 Gs:<BR><STRONG>Is there any calculation that would theorically give the ideal diameter of tubing for the headers and cat back tubing? Where I can found a good on-line source for thermodynamic and fluidodynamic calculations on a four-stroke engine?</STRONG><HR></BLOCKQUOTE><P>No.<P>Search this board.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 18th, 2002, 12:10 pm
by ZUNE MX-3 Gs
-What´s the meaning of that "NO"?<P>-A: "Sorry but I don´t know if there is any page that may interest you"<P>-B: "Sorry but there isn´t any page related to these topics"

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 18th, 2002, 9:01 pm
by pelado
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ZUNE MX-3 Gs:<BR><STRONG>-What´s the meaning of that "NO"?<P>-A: "Sorry but I don´t know if there is any page that may interest you"<P>-B: "Sorry but there isn´t any page related to these topics"</STRONG><HR></BLOCKQUOTE><P>C. Sorry, there is no calculation to give you the "idea" pipe size for your engine. I posted some links to some thermo sites some time back but I don't feel like finding them again for someone that asks a tired question like this one and appeared to not use the search option before posting.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 19th, 2002, 5:23 am
by ZUNE MX-3 Gs
man, I DO use the search option, and if you think that any question doesn´t deserve to be answered, JUST DON´T SAY NOTHING!! :mad:<P>Anyone else know any site that may help me in expand my knowledge on thermodinamycs and/or Fluidumdinamycs? (It doesn´t matter the languaje)

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 20th, 2002, 4:40 am
by VizualXTC
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ZUNE MX-3 Gs:<BR><STRONG>man, I DO use the search option, and if you think that any question doesn´t deserve to be answered, JUST DON´T SAY NOTHING!! :mad:<P>Anyone else know any site that may help me in expand my knowledge on thermodinamycs and/or Fluidumdinamycs? (It doesn´t matter the languaje)</STRONG><HR></BLOCKQUOTE><P>Dood, don't worry about pelado. He's a fucker that thinks he's a moderator. <P>I would go to a search engine and search for it. If that doesn't work find different automotive forums, (i.e. probetalk.com, mx6.com, mx-5.com, hondamod.com, hondahookup.com, cardomain.com, etc) and post your question on there. Also check some domestic forums too. Hope you get your questions answered dood.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 20th, 2002, 5:35 am
by CanadianMx-3
Anyways, Im hearing that the 2" exhaust is the best route to go.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 20th, 2002, 8:06 am
by ZUNE MX-3 Gs
Thank you very much for your reply Vizual! :). I wish that everyone in this forum would be at least half as kind as you are! That´s the way a bulletin board should be!. I didn´t know any of these webs (except from Probetalk), so I will throw an eye on them to see what I can find out, and I will post everything that comes out from my findings in other sources and books that may help us in Exhaust performance.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 20th, 2002, 9:07 am
by pelado
You'll get a response similar to mine if you post on probetalk, especially if you post in the performance forum. If you look beyond the sympathy, you'll see that visual gave you pretty much the same answer as I did. If you look in the dictionary between s--- and sympathy, you'll find visualxtc.

Re: 2.25 or 2.5" upgrading K8 Exhaust

Posted: June 20th, 2002, 12:31 pm
by T Biller
A little larger may give you some top end too large will just loose you your bottom end. There are figures based on how much HP you create, but I couldn't tell you what they are. I remember reading them when I was into Austin Mini tuning. You see within a certain margin, it takes a given amount of fuel and air to create a given amount of HP. The margin being efficiency mostly. Personaly for a street car I would stay on the small side because a road car with zero bottom end sucks and the high end gains are probably marginal. having a high quality, high flow for size cat and muff. is more important.