2.5 Or 3" Thats The Question...

[disco33]

hi everyone i was just at an exhaust place getting my muffler welded up (cracked) for a roadworthy when the guy at the shop starts telling me that my 3" system is causing me to lose power?? then he goes on to say that for street driving i will get noticeble gains from going to a 2.5" catback system ( with 3" dump,frontpipe and cat) and will get a mountain of touqe and mid range power from this 2.5" system that he will make up for me, he also added that mandrel bent exhausts had no gains over just bending normally. so now i am thinking is there any sence to this madness or is this guy just trying to get me to go and buy an exhaust of him??

any feed back welcome

cheers dean

[abu]

2.5" is probably better suite to an NA car.

Most of the turbo guys, if not all, includng my self run a 3" turbo back.

http://www.skylinesaustralia.com/forums/in...php?showforum=8

Have a read through the link above. It's the "forced induction" section and has a lot of info in regards to after market performance mods.

You can buy off the shelf 3" exhaust system for your R33, which would be cheaper than getting a custom one made up, also less stuffing around.

Have a look in the for sale section, under traders, there is a lot of well priced systems available.

Good luck.

Abu

Edited September 20, 2007 by abu

[disco33]

thanks abu but i am a turbo guy too just cant work out how to change the info in my thingy on the side

[abu]

Yep, so go 3", no point going to a 2.5".

Click My Controls at the top of the page, then edit profile information on the left. Then where it says Custom member title, change the writing in that field.

Hope that helps.

Abu

[adznight]

Sounds like one big load of BS to me, yes a tuned exhaust on an NA is good but on a turbo setup get the exhaust out as quickly with as the least amount of turbulence possible, less resistance = easy spool up

I don't think he knew what he was talking about, that or he couldn't do it and wanted to sell you a POS setup

[GTR_STEALTH]

he also added that mandrel bent exhausts had no gains over just bending normally.

A mandrel bend means the inside diameter (ID) maintains a consistent size reducing turbulence and maintaining velocity.

Whilst i do agree that 3inch on an N/A 2.5litre may be a little big, the exhaust dude sounds like a tool that just want ur money.

EDIT: LoL, i just read the post properly...i dunno where i got the idea ur car was N/A ....go the 3inch dude.

[redevil]

yeah dude i work for an exhaust company, which designs exhaust system for earth moving equipment. But the same principals apply, if he reacons there is no difference between mandrel and pipe bends he deserves a swift fly kick to the head. As previously stated mandrel keeps constant ID were as if you pipe bend 2.5" tube you could be reducing it down to 2" or less.. And how he justify's a three inch dump and then 2.5" system is stupid... Turbo's don't like back pressure so 3" is ideal

[adznight]

Hehe, it's times like these when you wonder how these muppets maintain a business huh. I mean I always though that good business practice brought back return customers and recommendations...gotta wonder about these joints huh!

[wokka wokka]

Subject has just been done on wrx.com.au as well http://www.wrx.com.au/forum/viewtopic.php?t=44145

This website also has some discussion (admittedly about Rexes, but the general principle would be applicable to all turbos) http://www.msengineering.com.au/exhaustsystems.html

[UNR33L]

non turbo guys get 2.25" or 2.5" i myself got 2.25" as more people seemed to recommend that, from my understanding the smaller exhaust is better for lower revs and the slightly larger would benefit when high revving?

duno about turbos tho, everyone ive seen has 3"

Edited September 20, 2007 by leighzor