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Tuning Flex Pipe

I have this one installed. I suppose there's no big difference between v1 and v2 (except the different mount).
Which one did you order? They have millimetre variants but I'm unsure if that is just for the flanges or the size of the actual flex pipe... If I were to swap this out with stock exhaust, would I order it with 70mm inlet and 70mm outlet flange or 76mm? Confused because I thought the diameter of the pipe on HDT is supposed to be 76mm (3 inch). Thanks again!
 
Which one did you order? They have millimetre variants but I'm unsure if that is just for the flanges or the size of the actual flex pipe... If I were to swap this out with stock exhaust, would I order it with 70mm inlet and 70mm outlet flange or 76mm? Confused because I thought the diameter of the pipe on HDT is supposed to be 76mm (3 inch). Thanks again!
I've ordered the 70/70 mm version (from stock downpipe to stock opf).
BTW. I can sell you mine, if you need one. I only used for 3000 km before I replaced it with a complete downpipe to opf system.
 
I've ordered the 70/70 mm version (from stock downpipe to stock opf).
BTW. I can sell you mine, if you need one. I only used for 3000 km before I replaced it with a complete downpipe to opf system.
Will the HDT flexpipe 70/70 be interchangeable with the non opf i30N? Also is the diameter of the actual pipe 3 inches? Thanks again!
 
Will the HDT flexpipe 70/70 be interchangeable with the non opf i30N? Also is the diameter of the actual pipe 3 inches? Thanks again!
At least from what I see (!) the flex pipe for opf and non-opf use the same pipe/mounting diameters (70/70) - as you can see on HDTs website.
I have no idea of the actual pipe diameters (never measured).
 
based on my own measurements (see album below), I'd say the stock flexpipe mounting points are 70mm (~2.7").

Remember about the elastic section - there is really big bottleneck - it was somewhere on the forum - I don't want to lie but it was something between 56mm-63mm?
.....
I found it on HDT Motorsport - bottleneck of the oem flexpipe is 50mm....
 
Remember about the elastic section - there is really big bottleneck - it was somewhere on the forum - I don't want to lie but it was something between 56mm-63mm?
yep, it is visible on pic 6/10.

Each element (the cat, the flex pipe and the gpf) all have their own bottlenecks, but the bottleneck on the flexpipe is by far the worst one!
 
from what HDT advised they say if you've standard gpf and exhaust get 70mm if you've aftermarket get 76mm as it creates a spike or something.
 
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Did someone instaled a flex pipe without removing the midle ressonator on a 2018 non gpf i30n?
if so, did it make the sound louder in non "N" modes?
thanks
 
2019 GPF Fastback here, when I installed the flex pipe the sound got more bass-y and generally a bit louder. Good improvement.
The previous owner of my car removed the ressonator, and it was a bit loud on non N modes.
I've installed the ressonator and i like it more in non N, when trying to Cruise smooth without waiking up the neighbors...
But now N is also more quiet.
I'm afraid that it would make the non N a lot louder, what i dont want...
 
The previous owner of my car removed the ressonator, and it was a bit loud on non N modes.
I've installed the ressonator and i like it more in non N, when trying to Cruise smooth without waiking up the neighbors...
But now N is also more quiet.
I'm afraid that it would make the non N a lot louder, what i dont want...

I also removed my N's GPF (replaces the resonator on later models) and it's still very quiet in normal mode. N-mode is a whole different story though.
 
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