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Thread: How to Install Lowport Intake Manifold on RR

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2013-11-04 01:10:00
How to Install Lowport Intake Manifold on RR
Roller Rocker's IACV lives on the throttle body, while every single other SR20 has it on the manifold. The plan has always been to run a low port manifold on the roller rocker, it only makes sense to run it when you switch to a 16 bit ecu that has a different IACV system.

I think Nissan designed the roller rocker manifold horribly on purpose, they saw what a great motor the RR is and how much more power it makes then regular low ports and they had to detune it. At first I thought Roller Rocker manifold was really designed for low end torque, that's why they suck for power getting, but after doing these tests I'm convinced Nissan just wanted to screw us.

Stock Roller Rocker manifold

It is good for having secondary runners being very smooth, it's actually semi polished, which is impressive compared to any other SR20 manifold's I've seen, which all have horrible casting marks.

Low Port manifold on the other hand has a much bigger plenum that can house a bunch of air.

It also has smoother runners that are slightly longer with less bends.

On the same exact tune I made 10 more wheel horsepower! Also as you may have noticed my power went down, this could be because of stiffer VE valve springs, or because of hot December day, Virtual Dyno does have temperature and pressure corrections which I utilized, thus it's hard to say what could have dragged the power down a bit.

The car feels a lot beastlier now, I was actually quite impressed by the felt torque while doing some runs tonight!

Installation Pics

This manifold is a direct bolt on for the most part. There are a few mods that do need to be done in order to run it on the stock RR. First difference is the water temp housing, which I hate for being on the manifold warming up the air!

Low Port:

Test fitted the runners

As expected the water pipes wont line up easily.

Gotta pull it out

Measure once cut twice... Since I did the cut very close to the bend I used a socket to round it out.

Installed, and now I can use the low port water hose, which for your reference is 1".

I dislike the aux air regulator, it keeps your cold idle at 1500 rpm for 60-90 seconds. None of my cars have it, and they don't have any issues in the winter. Blocking it with a big bolt that I cut down.

Need to block off water lines that go to the EGR mounting point too.

Installed the injectors, as you can see I'm a low port n00b!

Turned them around and much better

Test fitting the plenum

Water temp sensor and water temp gauge wires need to be extended out to reach the new location

Got the injectors all wired up

Low ports suck for speedy injector changes or leaky injectors testing. I already had to pull the plenum once to troubleshooting a fuel pressure issue, not fun!

EGR block off plate

Extended the IACV wires from the throttle body to the other end of the plenum

LP manifold sits too close to the taller RR VC's, thus clearance can be tough. The throttle screw doesn't touch it, but to be safe extended it out with a Thermoblok spacer

Not much better, but now dust shouldn't cause any issues!

Shortened the break booster and added the vacuum gauge line. LP manifold lacks any vacuum ports, which is going to make it hard for turbo.

Low port has shorter throttle cables too, thus mounting them will require some work.

PCV valve will have horrible clearance too.

Fired her up and listened to her purr and smoke

Last edited by Vadim on 2015-03-17 at 02-28-35.
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