ok ppl should make a consensus about this ive seen posts saying its 2 1/8 and others saying 2 1/4. Are we talking about inner diameter or outer diameter

 

Well I ordered an RRM pulley Thursday and I'm hoping it gets here before next Friday, as I have the car scheduled to go into the shop for the belts to be replaced and figured I'd have the mechanic throw the pulley on then.

Next I'm probably going to have a local shop bend and install a new axelback with the magnaflow muffler and probably order and install an RRM lower tie bar around the same time.

Now I just need to decide between a CAI and SRI... I've been reading almost every post I've found and still can't make up my mind.

 

Thanks guys our piping is 2 1/4 thanks guys

 

+1 because this thread is answering just about every question I was about to ask on my 04 RA

Mostly, thanks reTro, I was kind of wondering what would be the FIRST things to mod from a stock RA, and you answered exactly that!

I've only been lurking the forums a few weeks and already I love 'em!

 

The stock pipe is actually 2.125" ID / 2.25" OD (inner diameter / outer diameter)

So technically, its 2.125" in the eyes of any muffler shop, but it seems to be the convention on these forums to talk about OD for some reason.

 

cool man, welcome aboard^^ just make sure you are bumping old threads instead of starting new ones. either that or pm pr_mivec, I think at one point he was selling flame suits if he still is though.

 

if I'm not mistaken anything under a certain diameter is measured ID, over a certain diameter is measured OD. not sure why they do it that way, seems to cause confusion to me industry standards say to specify ID or OD when ordering any kind of piping.

 

It all depends on which measurement they feel is important... When i build a roll cage, I use .120 wall 1.5" OD DOM tubing for the main tubes and .090 wall for bracing... It fits into a 1.5" Diameter die, regardless of the wall thickness... Most muffler shops will tell you that they go with OD, as the wall thickness makes such a little difference when it gets that thin. They aren't going to have dies for every possible 1/8" difference in OD/ID tubing...

 

exactly why they measure smaller pipes by ID, the ID is what matters at that point.

how much information did you want packed into this thread anyway

 

Got my RRM pulley today! Looks great and I can't wait to get it on my car Friday!!

I didn't get any stickers though... I wanted to have a little RRM love on my ride...

Maybe I have to buy something more expensive than a pulley. ha!

 

Pipe gets measured in ID for one reason... Its the diameter that matter most as Pipe is used to carry gasses, liquids, etc, and it is rated that way, the OD doesn't matter... Structural Tubing (Tubing is completely different from pipe) is measured on the OD and thickness...

PS, I think there is no need to change our exhaust at this point as it has been recommended to me that our stock exhaust is just fine, even for low boost turbo...

Can you say sleeper? Stock looking exhaust, gonna anodize the IC black so it blends in..

Anyway, back on topic... Exhaust tubing gets measure in OD as thats what the dies to bend it are measured....