I have searched alot on this subject here and other sites,and would like to know what size boost pipes to run on my 16vt project. After reading 'Forced induction performance tuning'. It says run 2" pipe for output around 255hp and 2.25" for 345hp. But every 90 deg bend loses 5% power. Now i'm not aiming for anything near 300 so would 2" be ok? Or do you have different sizes for inlet and outlet to IC. What would be the ideal size? The turbo is a a S2 k24 with a 51mm OD outlet. Obviously smaller would be better for routing.
mined worked out on the basis of my intercooler and throttle body and turbo. 2 1/2 inch pipes on the intercooler,3inch on the throttle body and 2" on the turbo outlet. , so, 2" from turbo, increased to 2 1/2 inch boost runs to intercooler, out of intercooler at 2 1/2inch then increased to 3" boost run to throttle body
I know i could use reducers to get upto larger intercooler size. But if you go too big it can affect air velocity and was wondering if it is necessary to go that large. I also have AC so have a bigger task to squeeze pipes into place.
this is a real good peice of info, i used 63mm dia throughout with a sprinter intercooler,only its kinda laggy. i was under the impression that 50mm was not big enough for my needs(230bhp) because the stock pipe work is slightly larger than 50mm.thanks
Use Mr Bell's advice as an rough estimate. Use pipes to ramp up from 51 mm compressor outlet to 2 inches then to intercooler ( you can use short set up connectors to the intercooler). The from IC to throttle diameter 2in pipes with a short setup if the throttle is larger than the cooled charged air pipe.
i see what you mean, i was planning on ditching the sprinter intercooler for an e bay special, should mean i only have a short step up/reducer (50mm to 63mm)at the throttle and the rest will be 50mm dia.
So its not a step up as 51mm is 2". Only at intercooler inlets/outlet if they are larger. then back down, then up to TB. Which is larger still? Not sure what the S2 unit can flow on the ABF. Would that size be sufficient and not be a restriction?
I think you should pick something that mostly fits your throttle body and IC in diameter. My first plumbing was made with stuff i had home more or less. The pipe was 54mm, Ic entry and exit is 57mm. It worked ok butt it was ugly Now I have turbo51mm to 60mm reducer, 60mm piping to 57mm IC inlet and 57mm IC outlet to a 60mm g60 throttlebody. Works good, looks better Can't realy talk about turbo laag because I've cahnged the gearbox for a taller one and some other stuff so its hard to compare between 54 and 60. I get 0.5-0.7 bar around 2400 in 3rd an up. Ful boost around 1 bar is at 3100- 3300rpm. 1.8 Kr as you know already. As it looks now: It made 261bhp (211whp) this winter at around 0.9 bar, should be good for 290-300hp with 1.1-1.2 bar and a raised rev limit. This was at 6k rpm. With an ABF you should do my numbers easy
that dyno run looks sweeeeet. i`ve just got the e bay special intercooler and the inlet/outlet are 63mm and its half the size of a sprinter cooler` but the internal volume is nearly the same because it`s thicker, so i`m going to see how it goes. also means i don`t have to re fabricate everything. going to have it anodised black instead of painted, protection from elements without compromising heat transfer.
I used the same size from the turbo to the IC (k04-023) and used a bit of the stock piping (N75 and dump valve exits). I than used a reducer from the IC to the TB size (2.5 to 3 IIRC) on the IC exit, so I have a 3" pipe from the IC to the TB.
