So, as we all know, the S4 NA intake is pretty restrictive, so what i'm wondering is if the S4 Turbo intake would fare any better?

The engine has a mid sized street port, with full racing beat/borla (combination of) exhaust. I'm running off the stock ECU at the moment, but do plan on going to a form of Mega-squirt down the road.

The intake I have is modified for a 6 port engine, I understand that by removing the current intake, I'd lose a lot of low-end torque due to removing the 5th and 6th port sleeves. But I'm wondering if I'd gain anything on the mid or high range?

If this is better approach, the only thing I can really think of is needing just a turbo II throttle cable, and just moving around wires. Anyways, let me know what you NA guys think!

 

the turbo intake is the same runner length, and diameter, but it makes a sharper bend at the engine, so its only advantage is making more room for a turbo.

Peejay went the other way, NA intake on turbo block, and that is the way to go

 

I'm strongly of the opinion that the S4 N/A had the best EFI intake manifold, yes

I picked up a lot of low end and top end power by going to the N/A manifold on my nonturbo TII engine.

 

Wow, I'm very surprised! So... I have a 4 port block, stock ports, and I'm debating on either turbo charging it, or keeping it NA for a while. So if I adapted the LIM for the NA intake, I'd be better off? Why is that? I was under the impression that the S4 NA intake was very limiting.

Seems like 4 port is the way to go, but with an S4 NA intake. What kind of porting, if any did you have Peejay?

 

Nevermind, I see in your signature, Bridge port, with Megasquirt... Just curious, but what type of power are you making?

 

the T2 intake makes a sharp 90 degree bend right out of the block to clear the turbo, while the NA makes a nice curve.

 

Note that 4 port and Turbo II are different engines. Turbo II have much larger runners, you can't port a 4 port engine out to Turbo II size without hitting water.

I had a street ported 13BT block a few years back. Ran it with the TII intake manifold with some very mild porting (cleaned irregularities, nothing fancy) That engine did 170whp on a Dynojet.

I half-bridged that engine. Made a lot more midrange power (no more waiting until 5500rpm before the engine woke up!) but the intake manifold became limiting at higher RPM. Didn't want to pull much past 8000 while the street port would happily pull way past that. Made ~175whp on the same Dynojet despite not being able to rev nearly as high.

I filled/ported a S4 N/A lower to port match to the TII block and slapped it on there and gained drivability, low-end power, and another 1000rpm at the top end.

This was all 2009-2010 kind of era. I still kind of would like to know what the N/A manifold would do on a stock port TII but the parts are really expensive anymore.

 

Yeah, the NA has a nice curve, I guess that makes sense, I always wondered about that. I have a few extra NA LIMs I'll have to play with.