2" boost pipes yes or no?

mattyb6 · Jul 7, 2016

I'm not aiming for mega power, on my 20vt qs

I'm ordering an fmic tomorrow and I have several metres of 2inch stainless lying around and was wider in if it would be suitable??

Only mods will be 3" DP and decat, sfs tip, forge oo7p, and a fmic... And a map of course.

What size is the boost pipe outlet on the turbo ? Ko3/ko3s not sure yet

And would the 2 inch suffice?

scotty_24 · Jul 7, 2016

Standard pipes are 63mm (2.5 inches) on my S3 8L

To quote the Badger, "its all about the flow"

Stepping down to 2" would be a golf ball through a garden hose situation.
Turbos trying its best to flow a large volume of air, and your further restricting the flow by fitting smaller boost pipes.

Just my 2p

superkarl · Jul 7, 2016

No.

And use alloy

Rainbird · Jul 7, 2016

To put it another way:

The cross sectional area of a 2" (50mm*) tube is 7854mm^2
The cross sectional area of a 2.5" (63mm*) tube is 12469mm^2

That's a 60% increase in area for minimal extra pipework. Sell a bit of the stainless, pick up some ally, job's a fish.

(*not taking into account wall thickness, but the point stands)

mattyb6 · Jul 7, 2016

I didn't know the oem pipe size, but yeah totally agree

Il stick with 2.5"

You don't ask you don't know I suppose

Thanks

Prawn · Jul 8, 2016

To go against the grain here......

How MUCH power are you after?

Cheap ebay kits all come with 2'' pipework, and if ~230bhp is your goal then they're more than capable.

If budget is an issue, and custom work a hassle, then the ebay kits can do a half decent job for not a lot of money at all.

The ebay kit with 2" pipes served me very well for a good number of years.

If you're looking to get every last breath from a ko3S and push for 240+, then by all means go custom.

if you're just looking for a nice increase to ~230ish and some control on IAT's, then the ebay kits are fine.

mattyb6 · Jul 8, 2016

Thanks prawn

Well my goal was about 230-240 ish.

The inter cooler I was going to buy was toyosports eBay one, https://www.ebay.co.uk/itm/310204072487

Out of stock at the minute.

The budget is the main concern really. Although I can go for 2.5" pipe, i was looking at an eBay kit again, then once it's all up and running, I can maybe go for custom or bigger if I decide at some point for more power.

Short term though is sensible daily power.

The other question I had was is I nesacery to have a large fmic? Could I get away with a smaller one, but with still 2.5" pipes ?

badger5 · Jul 10, 2016

smaller than stock pipes is always questionable....
why?
Why would this ever be a good thing for an upgrade?

mattyb6 · Jul 10, 2016

Bill I never knew the stock pipe size hence the question. I totally agree and understand that bigger within reason is better.

Il probably stay with 2.5" for now until I can't get some custom ones made up

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2" boost pipes yes or no?

mattyb6

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scotty_24

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superkarl

MAN OF STEEL

Rainbird

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mattyb6

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Prawn

My other car is a MINI!!!!

mattyb6

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badger5

www.badger5.co.uk

mattyb6

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