Ideal I/C pipeing diameter

[mkory]

How is this figured, or is there a general rule of thumb? (like exhaust... less back pressure is better...)

[wild_maxx]

ehhh most go with 2.5" all around... it works pretty good unless your shooting for pretty hight numbers then go for 3"

[mkory]

Nope, I'm only shooting for low to mid 200 HP. 2.5 it is.

Know of anywhere to buy some 2.5" diameter hose to use as couplers? The precut stuff advertised as couplers are so expensive, I'd much rather buy a length and cut it myself.

[MarkEmark]

Nope, I'm only shooting for low to mid 200 HP. 2.5 it is.

Know of anywhere to buy some 2.5" diameter hose to use as couplers? The precut stuff advertised as couplers are so expensive, I'd much rather buy a length and cut it myself.

Don't be afraid to use different diameters for the hot and cold side piping; a lot of people use smaller diameter piping for the hot side simply because most turbocharger outlets are 2", whereas the throttle body on a KA is ~2.75"

I use 2" hot, 2.5" cold.

I got all of my silicone from:

http://www.pegasusautoracing.com

[UK-SRi]

The tradeoff is:smaller diameter piping means more pressure loss, but spools sooner.larger piping gives more ultimate power, but more lag in filling the increased volume.

Your call.

Mike

[hannibal]

Theres a formula in Maximum Boost to help pick the right size. Basically, you want as small as possible without pushing the air velocity past a certain point.

[KATwo40]

I run 2" hotside, 2.75" coldside.

[Jookmasta]

2.5" all around on my setup........

[MarkEmark]

The tradeoff is:smaller diameter piping means more pressure loss, but spools sooner.larger piping gives more ultimate power, but more lag in filling the increased volume.

Your call.

Mike

'

Good point Mike, I guess that's why I have virtually no lag in a .63 a/r stage III turbine....

Don't forget the size of the intercooler affects the overall volume size too...

[PapaSmurf2k3]

http://www.stylinmotors.com is a NICO sponsor and they have unbeleiveable customer support. I strongly reccomend them for your silicone needs. IIRC you can order long sections of silicone and cut them yourself.

[mkory]

MarkEmark, what is your pipe diameter on hot and cold pipes?

[hannibal]

Ahem...

I use 2" hot, 2.5" cold.

[crzycav86]

mine is 2.25 hotpipe and 2.5 cold.

i started a thread similar to this before i bought my mandrel bends.

[NateDogg]

Referenced from "Forced Induction Performance Tuning", 2" is good until 255hp, 2.25" is good until 345hp, 2.5" = 450hp, 3"= 690hp, 3.5"= 970hp.

Obviously smaller pipes will work with more power but the air velocity is higher than optimal, causing increased backpressure and pressure loss. For every 90* bend, deduct 5% flow.

[mkory]

Wow... I must be blind.

It seems that I could get off with 2" pipe with much less lag since I'm only shooting for ~225whp.