I am considering embarking on a N/A 20b FD project and I have been searching the forum for info and I have found many answers. That said I still have a question about the potential rwhp of the below set up:



Fully rebuilt N/A 20b,

bridgeported,

S5 9.7 rotors,

Msd Blaster ss coils,

Haltech E11v2,

Custom exhaust manifold 3-1(undecided on sizing)

Stock intake manifold and throttle body



vs the same but with custom intake manifold with 3 x 50mm individual throttle bodies (ITB).





I know that the ITBs are going to make for a more efficient/powerful N/A motor but I am wondering just how much difference it will actually make.



I really like the appearance of the stock 3 rotor intake. Whenever I imagine a 3 rotor engine I visualize the 3 rotor lettering on top of the manifold. Although ITBs do have there own visual appeal it seems to fit with more of a no nonsense racecar image. I would like to build a streetcar that can pass the odd inquiry by a cop looking under the hood. ITBs scream emissions violation.



If I can make 300rwhp with the stock intake I am inclined to proceed with the project.



Thanks in advance for your thoughts.

 

I'm not sure about NA, but mine makes 600hp at 12psi using the stock UIM.

 

Thanks but I am really looking for a more specific answer. I have read estimates on this and other forums that the above set up with ITBs would hit 350rwhp so I am wondering what difference the lack of ITBs would create.

 

I think Ted posted something about making 280rwhp with that type of setup?

 

I read some of Ted's post making about 232rwhp with an unopened 20b with stock intake. I have also read threads where others state that the throttle body on the stock intake is far too restrictive to produce good numbers. I am wondering whether the intake could be modified to accomodate a different single throttle body that could be an inprovement or whether the actual stock intake runners are the problem?

 

the guy with the 1st gen 20b went from 240ish to 297ish, just by swapping intakes. it might be the turbos also, but the stock 20b setup, peaks around 6200, which is lower than a 13b. or i should say falls off after 6200

 

oh i wouldn't run the stock intake on a bridgeport, its "tuned" for stock ports, way off for prolly even a street port