[5soko]

Originally Posted by Unspec

This isn't how thermal expansion works. The entire pipe is expanding. The only area where stress would be induced due to being constrained is where the bracing is welded to the pipe. Everywhere else, the expansion will just "flow" past and into the flex section. Not every OEM design decision is made because there's some kind of physics magic involved. For one, BMW may have wanted to just put it higher up to decrease water contact and thus lower the chances of corrosion on such a high surface area part (mesh)

It's also really not that much expansion to begin with. In 304 stainless, a 30cm pipe would expand about 3mm over a 600*C temperature change.

This is incorrect. You are missing how things move and expand when it is all connected, esp on the turbo side. And the flex section is not mesh on the oem pipe?
To keep it short, I am gonna take the oem route and engineering here.

[Unspec]

Originally Posted by 5soko

This is incorrect. You are missing how things move and expand when it is all connected, esp on the turbo side. And the flex section is not mesh on the oem pipe?
To keep it short, I am gonna take the oem route and engineering here.

No, I am not missing it, you're just misunderstanding the fundamentals of thermal expansion. The pipe is constrained by the turbo for sure, since it uniformly clamps the entire pipe. The transmission bracing only holds a significantly smaller portion of the pipe. This means 1) it doesn't stop the rest of the pipe to move around the bracing bracket and 2) the brace is metal, metal is ductile (even more so when hot), meaning that even if it does constrain the entire pipe at where it's welded, it'll bend ever so slightly to allow the expansion to continue past it.

If it worked like how you think it does, it would have 2 flex sections. One on the turbo side, and one past the transmission bracing. Which, it obviously does not have.

[Gjohnson7]

Originally Posted by Unspec

No, I am not missing it, you're just misunderstanding the fundamentals of thermal expansion. The pipe is constrained by the turbo for sure, since it uniformly clamps the entire pipe. The transmission bracing only holds a significantly smaller portion of the pipe. This means 1) it doesn't stop the rest of the pipe to move around the bracing bracket and 2) the brace is metal, metal is ductile (even more so when hot), meaning that even if it does constrain the entire pipe at where it's welded, it'll bend ever so slightly to allow the expansion to continue past it.

If it worked like how you think it does, it would have 2 flex sections. One on the turbo side, and one past the transmission bracing. Which, it obviously does not have.

Agreed! The flex section on this new version is sufficient.

[T-Bone18]

Allright, just got the part came in today. Here is some picture of the flex, the craftsmanship of the flex looks a lot better in real than on the original picture, everything looks fine. Another thing is I ask another business (VRSF) if their downpipe does come with a flex for our 3.5" turbo and to my surprise they reply it does not, so it sounds like catless may not need it because it does not get as hot, question is do you still need it ? Anyhow, the RGV I just got looks great to me.
Next step is to install, I will keep you posted after.

On ECS tuning, they show the VRSF DP with a very similar flex from the 4.0" turbo, have a look.
https://www.ecstuning.com/b-vrsf-par...xoC2DUQAvD_BwE

[ramman434]

Does look much better in person! Let us know how install goes.

Are you doing it yourself?

[T-Bone18]

Originally Posted by ramman434

Does look much better in person! Let us know how install goes.

Are you doing it yourself?

Yes and hopefully Monday

[T-Bone18]

RVG Performance just release their new website, check it out.
https://www.rvgperformance.com/

[T-Bone18]

Originally Posted by ramman434

Does look much better in person! Let us know how install goes.

Are you doing it yourself?

Here it is. The DP does fit perfectly, the brackets align at the right spot and no leak.
I did re-install the DP with the same gasket and with the same V-band.
The V-band was not easy to put back on but when you have the downpipe align, you have to squeeze it pretty hard, had to use vise grip at one point.

The 2 issues I ran and is one of the bolt of the car bracket that support the downpipe broke I did not bother replacing it because there is another one higher that holding it.
The other one is I had a seize O2 sensor in the original downpipe, had to go see my mechanical so he can heat it up and loose it. Unfortunately I don't have a torch.

I just finished tonight so only had time to flash it BM3 Stage 2 with the No cat options so I don't have a check engine light. In the flashing, I also remove the "Heating cat option" but I kept the Startup Roar.
Just by giving her few rev, you can already feel the turbo spooling freely. Can't wait to go for a ride tomorrow.

Best tip, if you do this under your car like me on jack stand, get yourself some safety glass.



Here is the broken bolt that I did not replace, but you can see that the DP bracket align nicely.


Also this clamp here is welded to the mid pipe.

[ramman434]

That fitment looks great! Thanks for the feedback!

I'm planning to piece together my exhaust, then download Bootmod3. Just taking my sweet time lol. I'm waiting on these guys to figure out their hiccups on the 4.0" for the '14-16s

[paul223]

VRSF offer crap engineered products. 😂

[blips]

I just installed the RGV in my 2011 F10 today and the bottom tab did not come close to fitting. I could not use it. It is only secured by the top tab. I'm surprised with everyone saying how the RGV fit was perfect and mine wasn't close.

[BimmerHausPerformance]

Originally Posted by blips

I just installed the RGV in my 2011 F10 today and the bottom tab did not come close to fitting. I could not use it. It is only secured by the top tab. I'm surprised with everyone saying how the RGV fit was perfect and mine wasn't close.

I haven't had an aftermarket down pipes tabs ever fit on a car. Expensive or cheap. N54's, n55 f10's, f30 n55's etc

[T-Bone18]

Originally Posted by blips

I just installed the RGV in my 2011 F10 today and the bottom tab did not come close to fitting. I could not use it. It is only secured by the top tab. I'm surprised with everyone saying how the RGV fit was perfect and mine wasn't close.

Yeah the back part did not fit in perfectly but deep and tight enough that I don't think it had any leak. I had it install for over a year now and I'm happy. Looking to upgrade with RVG boostpipe now.

[Gjohnson7]

Originally Posted by blips

I just installed the RGV in my 2011 F10 today and the bottom tab did not come close to fitting. I could not use it. It is only secured by the top tab. I'm surprised with everyone saying how the RGV fit was perfect and mine wasn't close.

That is confusing. My RVG downpipe fits great! Have you reached back out to RVG for feedback? Maybe he changed manufactures and had an issue.

[slobo7x]

I just placed an order for my 2014 535, build date of 01/2014 but still have the PWG.. So weird.

I'll let you guys know how the fitment goes of the 3.5" pipe from RGV.

[Info@mad-us.com]

Originally Posted by slobo7x

I just placed an order for my 2014 535, build date of 01/2014 but still have the PWG.. So weird.

I'll let you guys know how the fitment goes of the 3.5" pipe from RGV.

If it doesn't work out for you we have ours available.

https://mad-us.com/mad-bmw-n55-f1x-2...pipe-4-0-only/

[slobo7x]

Originally Posted by Info@mad-us.com

If it doesn't work out for you we have ours available.

https://mad-us.com/mad-bmw-n55-f1x-2...pipe-4-0-only/

I got the pipe from rvg yesterday and it was extremely well packed! The pipe ends were nicely protected as well as both mounting points, they even sent the new bolts and nuts if needed. I reused mines as they are fine.

The fitment is 99% on, only issue I had was getting the new Downpipe to slide into the stock midpipe.. it feels like the opening is the same OD, so the pipes needs a bit of heat to make them cooperate.

Other then that, fantastic product and fantastic shipping speed and quality!

Hope that helps anyone who's looking to order one.