Tricked-Out-Toy

iTrader: (4)

Like the title says, I want to run 4" charge piping from the intercooler to the intake. My intercooler is 4" in/out and I was jsut going to Vband the connections. the 4" will look alot better than the smaller 3". I was planning on just running the 3" stuff the very short distance from the turbo to the intercooler. What would going 4" over 3" do to me if anything?

stevieturbo

How much power ??

I suspect probably no difference, but it would be great for a before and after experiment.

Tricked-Out-Toy

iTrader: (4)

Oh ya... its on a lowly LT1 with a TC78 looking for a solid 700hp. plan to push as much as 20-21psi.

stevieturbo

I dont see any harm in using 4" if it fits, and you can do it.

But highly unlikely it will be of any benefit. What size TB do you have ?

Johnv

I'm picking no difference, as the throttle body and manifold inlet are much more of a restriction.

Tricked-Out-Toy

iTrader: (4)

I wasnt thinking it would be a benifit more the oposite direction, like increase lag or something. Im running a Holley 58mm (dual)

DeltaT

iTrader: (5)

I like keeping the IC-outlet diameter all the way to the motor, so I'd say go for it. Why add an artificial restriction at that point with a 3"?

Jim

stangeater01

iTrader: (125)

heres a question for a noob if your throttle body is 90mm which is 3.5" why would you go piping larger than throttle body and why would you go bigger piping then the intercooler inlet and outlet?

stevieturbo

Exactly. IMO, it baffles me why people run such large TB's with smaller diam plumbing. Makes no sense whatsoever.

All fitting an excessively large TB will do, is reduce throttle resolution.

stangeater01

iTrader: (125)

thank you thats a no brainer hell 6 and seven second cars arent running but 3.5 - 4" pipe right? i am going with a 105mm which is right at 4" i am doing a twin set up i will run 3 - 3.5" from cold of turbo then Y into 4" to cooler 4" to TB

98Z28CobraKiller

iTrader: (17)

90mm TB is closer to 4" OD. By this I mean that you will need a 4" coupler to get onto a 90mm TB. OP has an LT1 dual 58mm TB so not sure what you need to couple it together.

On my setup, the turbo is 3" OD on the charge side. The intercooler is 3.5" in and out. The TB is a 4" (90mm). I decided to go 3" tubing to the intercooler with a 3" to 3.5" coupler. Then do 3.5" tubing to the TB with a 3.5" to 4" coupler.

chuntington101

at say 20psi, how much air can you psuh through a 3.0, 3.5, 4.0 inch pipe??

Cheers

Chris.

pmbmax

A 90 mm is 4 inch on the od not the id and a 105 is closer to the 4 inch ID . If you run a 4 inch up to a 90mm a 4 inch hose works perfect for a conection but the tb is smaller . I think that a larger pipe makes the car respond off boost better. I would run it if there is room.

Tricked-Out-Toy

iTrader: (4)

Well for this application, Im using the LT1 style TB so at twin 58mm, I think I had to get a 4.5" coupler to mate onto the TB

Jimmy P

iTrader: (177)

I would go with 4" piping. It shouldn't hurt anything. I just dont like using too many reducer couplers. My chassis guy made my entire intercooler setup in 4" piping. It might be a little overkill for my baby F1C blower, but if I ever upgrade to a F2 it will be perfect.

stangeater01

iTrader: (125)

correct 105mm is 4.13385.. with my kit (twin....to come) hot side 3.5 cold 4" and 5"DP all v banded, 1 7/8 primaries up and forward manifolds with individual egt bungs per cylinder big ATW intercooler with LSX 4xx pics and build in progress will update soon

chuntington101

anyone got any answers/imput to this question???

BigRich954RR

iTrader: (1)

This is a loaded question answer cant really be given. cause length of pipe/number of bends/ shape of bends/ the way the coupling fit to meet the pipe. All change the the flow amount.

In theory 3 inch pipe will flow the same cbf of air at 5 psi that it will at 20 psi the change is the density of the air flowing thought the pipe. Now the base atmospheric air cbf numbers are no long on the same plane as the 20 psi number unless you let the pipe fill a space (like a big room so it not compressed anymore )

But at this point it has nothing to do with building hp or a engine's air flow manners anymore

chuntington101

All i was after was someone to give me some CFM numbers for the pipes using PV=NRT and asuming you have a maximum air speed of 250ft per second @ 20psi......(cant rember the veriables)

sorry if i didn't make that clear.

the reason i ask is i know STS guys have problems with the piping they run once they push past about 700rwhp. now if we know that a 3.0inch pipe can support say 125lbs of air per min then you know you can run a 3.0 inch pipe on a 1000bhp setup.

basically just trying to understand at what point, BHP wise, you need to run bigger piping.

Cheers

Chris.

Tricked-Out-Toy

iTrader: (4)

Where did the 250fpm come from? At 250fpm a 3" is only 12.27cfm and a 4" is only 21.81cfm??