3" vs. 4" inlet???

[Suprapowaz!(2)]

Is there a significant increase of horsepower by using a 4" inlet compressor housing? That's it.

 

[aye mate]

Doesn't it usually mean that the compressor housing is bigger? If the housing is bigger I would assume that would make more power, being a bigger turbo.

Is that what you meant? Or did you have a specific turbo in mind?

 

[Suprapowaz!(2)]

Somtimes I see the same size compressor housing, .60a/r for example, but one has a 3" inlet and the other has a 4" inlet. I've wondered on that same housing would the 4" inlet make more horsepower than the smaller one. I'm sure a .70a/r housing would flow more.

 

[The Reaper]

i would imagine it would cause the outlet would be bigger to correct?? i havem't seen a 3in inlet and 2.5 in outlet.

mines a 4in inlet 2.5 outlet.

 

[figgie]

no

overall peak numbers are not a function of just the intake opening but of the ENTIRE system.

 

[Suprapowaz!(2)]

So, by running a 4" intake pipe and 2.5" plumbing with it that would increase peak HP. But would that contribute a little bit to lag? The turbo would have to pressurize more area with the bigger diameter plumbing. Or is that not a factor? When you say ENTIRE system that would include the throttle body and intake ported to match it. Ok, that makes sense.

 

[figgie]

never said it increased it did i?

I said that the HP is part of the ENTIRE system. IC, pipes, TB, Intake Plenum, runner, valves etc.

 

[IHI-RHC7]

don't forget exhaust mani, hot side, downpipe, cat, pipes, muffler, tip, unobtrusive rear bumper, etc...

 

[WeDgE]

4" inlet, 3" outlet here

 

[WeDgE]

i havem't seen a 3in inlet and 2.5 in outlet.

I think my T04E was that size.

 

[dbsupra90]

the 3" in 2" out is the E cover.
the 4" in 2.5" out is the S cover.
the 4" in 3" out is the H cover.

the bigger the cover, the more flow. but it has to be matched to the comp wheel as well as the rest of the setup. i.e. running a 54mm turbo in an E cover then swapping to an S cover will not see gains. but running a 67mm turbo in an E cover then swapping to an S cover you will.

hey i even have a pic!

left to right- E cover, H cover, gt42