Does Size Matter? 2.5" vs. 3" Exhaust discussions. [merged]

[Boostin18]

2.5" vs. 3" exhaust discussions are merged here.

I have a 90 GSX and when i bought it the guy said it was full 3" turbo back with a EVO3 O2 housing (ported), now here is my question. When I took the exhaust down, it had a 2.5" exhaust flange at the top of the down pipe and then flares for about a half inch out to 3", if that makes any sense. This is my first 3" exhaust and I was wondering if this is right? I was thinking of porting the o2 housing because it is 2.5", making it 3". Then bringing the exhaust to a shop and having them weld a 3" flange to about a half inch long peice of 3" ehxaust pipe and then welding it on to the whole exhaust. So basically getting rid of the 2.5" flange and the half inch long flare and just welding on the 3" flange with the new piece. Would this make a diffrence if i do this or not. I don't know if this would make any diffrence or not, but when i put a boost controller on, i would try and get it to set at 15psi, but never would it would just spike and go down to like 12 or 13, but never above 15, but never at 15. I also have a ported 2G manifold (havent had it off to make sure it really is ported). Any help would be great!

 

[yoshimitsuspeed]

That may work fine for flatlanders but I still don't understand why you would when their is a better option.

 

[97spyder maayng]

Is a full 3 inch turbo back exhaust (with 3inch evo3 02 sensor housing) compatible with the 4g63 headers?

2g eclipse

 

[Game Over]

If the downpipe flange matches the headers it will be.

 

[blcknspo0ln]

I was going to comment on "headers", but that would just be mean.

anyway, I hope you realize that the head connects the exhaust manifold, which connects to the turbo. then the turboback [ o2,dp,tp,catback ] connects to the turbine housing of the turbo...

but if you have a mitsu hotside it should bolt up fine.

 

[97spyder maayng]

I was going to comment on "headers", but that would just be mean.

anyway, I hope you realize that the head connects the exhaust manifold, which connects to the turbo. then the turboback [ o2,dp,tp,catback ] connects to the turbine housing of the turbo...

but if you have a mitsu hotside it should bolt up fine.

ooo shiize...forgot bout the turbine being spun by exhaust fumes making the headers attached to the actual exhaust by means of the turbo... rookie mistake, my bad, i guess i didnt give it much thought

thanx

 

[Game Over]

ooo shiize...forgot bout the turbine being spun by exhaust fumes making the headers attached to the actual exhaust by means of the turbo... rookie mistake, my bad, i guess i didnt give it much thought

thanx

I didn't think about it either.

 

[mizzle7]

Hey i have a 2.5 inch cat back exhaust with one of those Aero Turbine mufflers, i got it done at mighty muffler, and now i am going 3 inch turbo back. I was just wondering if i should ditch the Aero Turbine muffler and go with an Apexi N1 all the way back, or if i should pick up an Apexi N1 Downpipe and have an exhaust shop do the 3 inch piping from the back of the downpipe to the muffler. Cost is a major concern for me. Has anyone heard anything about the Aero Turbine muffler, does it actually help, or is it just a hoax.

 

[Sinclair159]

i dont kno anything about the muffler your talking about ... but i can tell you i have the apexi n-1 downpipe and cat back 3" and i wouldnt trade it for the world.. its sounds really good and you could really tell a difrence in preformance.. but on the downside it is kinda expensive..

 

[Defiant]

i dont kno anything about the muffler your talking about ...

http://www.aero-turbine.com/

All I can say about whether they're worthwhile or not is to point out that not everyone's heard of them.

If they were The Hot Tip, they'd be all over this and the rest of the car sites.

 

[boostedinaz]

Is the muffler you have a 3in inlet and outlet? If it is then keep it if you like the sound, if it isnt then ditch it and get a muffler that is at least 3in in and out.

 

[mizzle7]

Thanks for the help, the muffler only has a 2.5 inch inlet, so i think im gonna go ahead and ditch it and pick up the apexi n1 all the way back. Someone is selling the cat back portion with the muffler for 100 and the picture looks good. What is your take on used parts? And after i install this exhaust system, how much power should i see at the wheels, i just dynoed at 179.8 at the wheels with 13 pounds of boost.

 

[bmxer08NC]

Can anyone tell me the size of the stock exhaust piping. Mainly I need to know the size of where the end muffler is. To put it simply, I want to put on an Apexi Universal Muffler for a naturally aspirated engine. I have a 93' Eclipse GS 1.8L. Has anyone else done this and what were ther results? Thanks for any help.

 

[DSMcrazy3]

I believe 2gnt is 2.25 stock, 1st gen is either the same, or probably 2.00. Sorry, I don't have a definite answer...

Josh

 

[speedy13]

I believe it's 2.0" but don't take my word for it.Either way,you don't need to know what size it is,just don't get anything bigger then a 2.5" inlet,even that is overkill.Find one with 2.25" and have them just make you some piping at the exhaust shop.If your just looking to have a muffler slaped on,just take them the muffler and they can just weld it on ther with a 2.0 to 2.25-2.5" reducer and call it a day.hope this helps.

 

[bmxer08NC]

Y that actually does help, do u know about how much that costs to have them do that, sorry, but I am kinda new at car stuff.

 

[DSMcrazy3]

Around here it was going to be 40 for the muffler. Of course some of that charge is for them putting the car on the rack and getting underneatn..Because 40 bucks for 1 weld is extreme. Anyways, shouldn't be too much. They may charge alittle more if you need a reducer..Just for the "parts"

Josh

 

[tranman91]

since nobody has a definite answer...nor do i...

you can measure the circumference of the pipe which is not hard to get to and will be more accurate than trying to actually measure the diameter...and then...

use this formula..."circumference" divided by "3.14" = "diameter"

then you'll know for sure what you have under there

 

[4g63telantra]

Just wanted to know what are some gains DSM'ers gained with a full 3" exhaust system also what other mods did you have with the gain's.

 

[larsenracing]

well i put my 3" exhaust onto my spyder about 2 or 3 months ago and i was amazed it pulls a lot better and feels like a hole new car. the problem is i have not denied it since because i am weighting till i get a fpr then i can get that set to but I'm guessing probably like 20 to 40HP at the wheels. hope this helps but I'm sure someone had a good set of # for you.

 

[negativezero27]

Seriously which one is better? because i don't want my exhaust to sound like my car is underwater or something stupid. I don't plan on going past 300 hp. My goal is just to have 2.5 or 3 inch turbo-back exhaust with highflow cat and stock muffler. Don't want to get annoyed with the stupid muffler sound. But if you know a brand thats quiet but ONLY loud when you get on it, well let me know. Any sound clips would help out.

 

[Lsmith]

Here ya go. Hope you find it useful. http://www.dsmtuners.com/forums/showthread.php?t=137124

 

[bhop]

There's a whole soundclip thread over in the video forum. (someone beat me to it)

Personally I have a 3" Apexi N1 catback with RRE Downpipe and 3" Cat. It's pretty quiet, considering the size of the pipes. I was very surprised when I started it up after putting on the cat and DP. I still sweat a little when cops drive behind me, but not as much as when I had a gutted cat. (it was louder then) With the silencer in, it's only slightly louder than stock. I can feel a little more zip when I step on the gas, especially on the freeway.

I should add that this topic has been done to death, so you'd probably get some nice answers if you'd search.

 

[dsmer]

imo, go 2.5", short and sweet 3" = creep, just my .02

 

[1glaserturbo]

imo, go 2.5", short and sweet 3" = creep, just my .02

Good reasoning, but that just leaves more room for improvement. With creep (which I'm experiencing tons of) it will allow him to further his expectations. Yeah, it'll cost a little more out the wallet, but who really cares now a days? From experience, 3" sounds extremely amazing! If tons of creep sound like a problem, port the o2 housing as well as the hot side of the turbo (which includes the wastegate passage, make sure that's ported to no extenet ) Yeah, in all honesty man, whichever you really want is what you should get



Chris

 

[doug]

If you're going to keep the stock muffler, there's no point in going 3". 2.5" is fine anyway for 300HP. BTW, this subject has been beaten to death-- searching will yield hours and hours of reading.