tubular manifold idea - your input?

[m11kyg]

Hi guys,

I'm looking to run a very large turbo and as we all know they tend to be very... laggy!!

So, i had a brain wave and wanted your thoughts on it..

If i build a tubular manifold that tapers as it gets towards the turbo do you think this would reduce the lag?? My thinking behind this is that as you force air/gas through a smaller gap it increases in speed and pressure and thus would make the turbo spool quicker... or would it???!!! Also there is the problem that in doing this it will most likely cause more back pressure in the manilfold which might have an adverse effect due to not getting the gasses out of the engine quick enough so i'm unsure if its a sound idea or not....

[s2_wot]

I'd be inclined to look at what repo does, 42mm (afaik) runners for mega HP. Any restriction you impose will hurt performance at the top end surely.

[donce]

42mm in inner diameter of course ?

[repo]

Define "very large"

I have a customer, who's rs2 did 100-200km/h in 4,5 secs, and it had 33mm inner diameter runners.

Until he changed to something faster.