[Rafstar]

How big is the power difference between 2.5" and 3" downpipe? I've heard fitment issues with the plm so I might go with the raceland.

[wren57]

Fitment issues are all about install.

As for power difference... ~7hp.

[Forcefed3]

Dont buy either.

[tscdennab]

Go with 3" downpipes no matter what. It has been proven that they make more power.

[mycoupe]

It all boils down to $/hp. Enough said

[antonio335]

Ceramic Coated Mach Shnell. The best.

[dzenno]

Power wise no noticeable gain maybe 5hp...here's an example, different platform though...Z06 which was twinturboed over the past year...it ran dual 2.5'' downpipes and put down 1030whp with them which CAME WITH THE KIT! They just recently got replaced with 3'' to see if the car made more power and to no surprise they did, but only 50whp putting the car up at 1080whp...different day, same dyno...

moral of the game, at these power levels 2.5'' vs 3'' really doesn't matter power wise...i say get whatever installs best/easiest...no DP manufacturer has enlightened this community with backpressure numbers on 2.5'' vs 3'' which is key

[OpenFlash]

Dual 2.5" or dual 3.0" makes no difference in the 400-500whp range we are talking about.

[mycoupe]

I bought the raceland ones and sent them to jet hot. I think with the pipes, coating and all the shipping I'm like $315 in???

[dlbrooks18]

10whp, go 3"

[stealth-twntrbo]

I bet if you averaged all the 3 inch vs 2.5 inch DP's you would only see 5-6 whp gain not enough for me to justify the money.

[dzenno]

You have to realize that to gain power from a larger diameter downpipe there has to be a considerable backpressure in them in the first place

[Mike@N54Tuning.com]

Wasn't there a thread comparing 2.5" to 3.0" and the 3.0" had significant gains?

Mike

[mycoupe]

Originally Posted by Mike@N54Tuning.com

Wasn't there a thread comparing 2.5" to 3.0" and the 3.0" had significant gains?

Mike

The gains were 5-10 hp, which is hardly worth an extra 500-700 dollars in my opinion.

[Mike@N54Tuning.com]

Originally Posted by mycoupe

The gains were 5-10 hp, which is hardly worth an extra 500-700 dollars in my opinion.

Not sure where you get that price from?

For example I am running an AA 3.0" DP Group buy for 544.00? For that you get 3.0" pipes, perfect fitment, top quality, etc.

So if you want to save a few hundred and get smaller diameter pipes, with questionable fitment and quality then thats fine, but the difference isn't that great to get high quality 3.0" pipes versus ebay 2.5" pipes.

For some that 2-400.00 is enough incentive to run 2.5" pipes, but if you are doing a full on bolted car those 5-10hp/tq shouldn't be left off the table IMO. I've had many customers switch from 2.5" pipes to 3.0" pipes. Nobody has switched the other way.

Mike

[mycoupe]

take out the group buy price because you don't always have that option, and if I hadn't ceramic coated my pipes, which yours aren't, and I would be a whopping $175 in, versus the $699 those AA's cost at normal retail. Is 5-10hp really worth $524 EXTRA?

[Clap135]

My plm downpipes are perfect. I got them bran new for 275 shipped. I see all these 600-900 dollar pipes and just shake my head at the rapaged.

[mycoupe]

I'm with clap 100%

[enycerz]

Originally Posted by Clap135

My plm downpipes are perfect. I got them bran new for 275 shipped. I see all these 600-900 dollar pipes and just shake my head at the rapaged.

[JBiddy]

i would never buy anything from AR they're company is a joke you'll be fine with any DP

[e90TiAg335i]

Agreed, even my raceland pipes fit PERFECT!!! Yes I can weld better with my eyes closed but I highly doubt it'll hut the #s too much. On a side note, I just helped install V's new n55 dp and I must say the ridges left from mating the 2 pipes into 1 will cause a LOT more turbulance then all of the crappy welds in the raceland put together. None the less, V's dp made a difference on the butt dyno and the n55 sounds awsom through the Remus race exhaust!

[bryce]

Originally Posted by shiv@vishnu

Dual 2.5" or dual 3.0" makes no difference in the 400-500whp range we are talking about.

one other point: ALL downpipes on the market taper to 2.5" flanges. so effectively, you're talking about 10" or less of 0.5" wider inner diameter, on a "3 inch" downpipe.