Very nice!
How to Install Low Port Intake Manifold on RR
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
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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.
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Low Port manifold on the other hand has a much bigger plenum that can house a bunch of air.
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It also has smoother runners that are slightly longer with less bends.
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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.
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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!
RR:
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Low Port:
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Test fitted the runners
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As expected the water pipes wont line up easily.
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Gotta pull it out
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Measure once cut twice... Since I did the cut very close to the bend I used a socket to round it out.
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Installed, and now I can use the low port water hose, which for your reference is 1".
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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.
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Need to block off water lines that go to the EGR mounting point too.
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Installed the injectors, as you can see I'm a low port n00b!
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Turned them around and much better
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Test fitting the plenum
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Water temp sensor and water temp gauge wires need to be extended out to reach the new location
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Got the injectors all wired up
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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!
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EGR block off plate
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Extended the IACV wires from the throttle body to the other end of the plenum
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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
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Not much better, but now dust shouldn't cause any issues!
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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
![]()
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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!
RR:
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
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I bypassed the IACV by running a manual valve on roller rocker manifold (was already OBD1 ECU with NEMU).
i made 123 hp with I/h/e on a auto RR. All of my dyno runs have been like 118-123 hp. I would like to do this swap just to see what it can really do..i mean even 10 hp would make it worth it on a auto G20 with no where else to go but boost or nos or s3r cams for more power.
maybe a winter project...
gonna make this happen going with the full emissions intact on 32bit ecu. then we can test this 10HP untuned theory on RR ecu.
Good luck, you will need to come up with a custom EGR pipe, then to mount the RR throttle body you will need an adapter plate (do note that by using adapter plate you are technically increasing the volume of the manifold).![]()
gonna make this happen going with the full emissions intact on 32bit ecu. then we can test this 10HP untuned theory on RR ecu.
Injectors will need to be rewired to fit sidefed injector plugs, if your lucky you will be able to just depin them and plop the pins into the sidefed plug.
You will need to plug up the IACV breather port, nothing special there.
You may need to plug up the Aux IACV valve (the one under the manifold on the left side), if you don't it will add a ton more air = 2k rpm idle. This valve runs on a timer, 90 second timer, it increases air volume to the manifold to raise the idle while the car warms up, after it warms up the valve closes. FSM diagrams say the power runs from the fuel pump wire, aka too much to wire in to worry about.
Post up your results!
thanks for the idea. that manifold looks so boss on the RR motor. I do plan on doing a tad bit of porting on it and hand polishing the top plentum. The runners are gonna be painted blue. I can totally do this. I didn't take the injectors from pull a part because 1 of them was broke. but i do have the injector clips. I don't think finding injectors will be that hard though. I will admit that pulling it from the 95 G20 was a pain in the ass towards the last few bolts. Lol but i learned some stuff. Hopefully taking off the RR manifold wont be as hard. Lol
that manifold looks so boss on the RR motor. I do plan on doing a tad bit of porting on it and hand polishing the top plentum. The runners are gonna be painted blue. I can totally do this. I didn't take the injectors from pull a part because 1 of them was broke. but i do have the injector clips. I don't think finding injectors will be that hard though. I will admit that pulling it from the 95 G20 was a pain in the ass towards the last few bolts. Lol but i learned some stuff. Hopefully taking off the RR manifold wont be as hard. Lol
thanks for the idea. that manifold looks so boss on the RR motor. I do plan on doing a tad bit of porting on it and hand polishing the top plentum. The runners are gonna be painted blue. I can totally do this. I didn't take the injectors from pull a part because 1 of them was broke. but i do have the injector clips. I don't think finding injectors will be that hard though. I will admit that pulling it from the 95 G20 was a pain in the ass towards the last few bolts. Lol but i learned some stuff. Hopefully taking off the RR manifold wont be as hard. Lol
that manifold looks so boss on the RR motor. I do plan on doing a tad bit of porting on it and hand polishing the top plentum. The runners are gonna be painted blue. I can totally do this. I didn't take the injectors from pull a part because 1 of them was broke. but i do have the injector clips. I don't think finding injectors will be that hard though. I will admit that pulling it from the 95 G20 was a pain in the ass towards the last few bolts. Lol but i learned some stuff. Hopefully taking off the RR manifold wont be as hard. Lol
I have a set of 259's that I wont be needing anymore, let me know if your interested $35 shipped.thanks for the idea.
Nope computer wont care much, unless 32 bit's are very dependent on volumetric efficiency. Since your planning on porting and polishing the manifold too, it wont matter that much since your changing a few more variables anyway.
1 - 20 of 44 Posts
