I bought a Tial MVR 44mm vband wastegate off a member here. Going to be making the dumptube for it soon and need to order pipe to route it out my bumper.

Now, 44mm is basically 1.75".

I was given a dumptube with the wastegate, which the bends in it go right where I need it to, which is awesome since I haven't figure out how I'm bending the straight pieces I'm ordering. BUT the OD is about 1.65" with an ID of 1.5", and if we look back 44mm is 1.75" which you could expect an ID of about 1.65".

Now he included an unused outlet vband, and the diameter where a pipe slides in is... you guessed it, 1.75" with about a 1.65" bore in the center.

So now here's the problem/question/conundrum.
Do I:
A. Just add to the downpipe I'm given and add 1.75" the rest of the way, it'd just get 0.1" wider
or
B. Start with the new vband flange and do true 1.75"

The dump he gave me is bent so well where I need it to go, it'd save me a good amount of work. Would you expect to see any issue with running a pipe that is technically smaller? ID of the 1.75" would probably be around 1.625" So would this 0.1"ish make that big of a difference?

 

It really depends if you need everything you can get from a 44mm wastegate... That would be the determining factor. Why did you choose a 44mm? Having problems with a previous setup?

 

My manifold is flanged for it. Sls top mount, 57 trim, forged y8, should put down 4-450 on race gas this year. Realistically I think a 38 would've been fine so the smaller diameter should be okay?

 

Yes, should be fine especially on a 57 trim and that manifold. Even with the smaller diameter you are still bigger than a 38mm.