Foward facing factory plenum mod

[PHaT MR30]

Hey umm i was contemplating buying a car with this plenum mod, but didn't buy it

Now only recently i have been speaking to this guy who is pretty switched on with flow and porting etc. Who is helping me get my car back on the road.

now when i take my engine out we are going to get the inlet manifold bead blasted, then flow matched and then they machine the hole in the plenum for the TB cos it is actually smaller. he even spoke of making it elliptical shaped something to do with flow to #1 and #6. Then the zorst manifold gets cleaned up inside the runners (die grind) and then bead blasted too (mainly all this does is drops zorst temps and relieve turbo).

Now we have decided to use one of those PWR 'Barrel' Coolers (water to air). Original idea was to rotate comp housing on turbo to face down and have the barrel mounted horizontal beside radiator. on further inspection in the S13 engine bay its gonna take some cool thinking to fit it in this position.

Then i thought why not have a front facing TB and have the barrel behind the bumper?

and in my mind it seems right, but i don't know a great deal about flow or anything but if i got the TB front mounted then had the manifold port matched and bead blasted surely it would work?

let me know otherwise i will stick with the other way and cut the shit outta my engine bay

[pssiii]

this mod is spot on for rb20/25's although i would mount throttle body directly onto manifold to increase throttle response further.

there will be no lean-out in runners because,

pressure in system is equal whether at compressor outlet, intercooler or inlet runner.

compressed air reacts like liquid/hydraulics therefore if each inlet runner is of equal length and pressure is the same each runner will flow equally.

so the big gains will come from your tuner putting more fuel into the engine earlier, 2m less plumbing adds to a ton of response, reducing heat soak and increasing turbo efficency.

[RNS11Z]

old thread, but have a look at this twin throttle set up on a rb25

[B-Man]

Now there's lateral thinking for you - Interesting concept - How are the results RNS11Z ?? Who made the plenum ?? Looks like good work !

Conceptually, there would be good flow distribution with this type of plenum !

Well done !

Cheers,

[RNS11Z]

Its not mine nor do i anything about it. I wish i did before.... Its actually from a car in the for sale section about page 5 some car from cairns.... I think it would work well actually.

[retrotec]

Does anyone know what part of the stock rb25 inlet manifold makes it restrictive?

Would extrude honing the lower half and removing the odd shaped bumps in the top half benefit much?

Has anyone used a RIPS plenom yet?

PS: Aiming for 450rwhp in a 1200 kg car running a RB30DET.