A community of enthusiasts dedicated to Nissan's SR20DE/SR20VE/SR20DET engines.
Start here: forum search. Be sure to search on what you're looking for before posting a new thread.
You are currently browsing the forum as a guest. In order to access special features, the image gallery, and post you will need to be a registered member. Registration is fast, simple and absolutely free so please, join our community today!
If you have any problems with the registration process or your account login, please contact the administrator.
Keep the Info Coming, as it grows I noticed I should probably make some sort of Table Of Contents... and some stuff to make searching this thing easier... so here it is Bishes...
Don't forget, Ctrl+F does wonders on the internet!
Table Of Contents/Index: Page 1: General Info on Everything I Could Think Of | Props from SR20 Forum Page 2: Compression Theory | Physical Differences B/N Regular DE | Efficiency | Power Page 3: Comp. Theory Cont. | OEM vs. Tubular Header | Which ECU? | Water Pump? | USDM IM w/ RR VC | Engine Break Down Page 4: Dyno Testimony | Reg. DE & RR DE VC Compat. | Water Pump Compat. | Power Curve Diff. | Pulleys | Boost Capability Page 5: ECU Tuning & Ign. Timing | 4CW Crank VS. 8CW Crank | Swap Complete | PCV Schematic - USDM IM | 96-99 Almera GTI
What Does That Mean?: IM = Intake Manifold VC = Valve Cover RR = Roller Rocker CW = Counterweight B/N = Between
no... hehe... its just that they use the same block and crank. head is different... power is way different..
I see you posted in the roller rocker thread, as soon as you can leave your info on there... there are a few people here with the swap done, and I didn't even know it.
Switching Roller Rocker Arms for Stamped DE Rocker Arms?
Hey Guys,
I was answering someones question recently in a PM and I wanted another set of eyes... or possibly an addition of info... I have tried my best to answer correctly with what I know. Feel free to add input...
Quote:
Originally Posted by XxToKeSxX
Quote:
Originally Posted by SR20Forum Member
Can you swap the rockers from a non rr to the rr motor so that you can use s4 or another set of cams? I have a Highport non-rr head with the rockers and everything and than a lowport RR motor in the car right now. I would like to stay lowport if all possible.
XXXXX
Hey XXXXX,
This is a funny question, as I have never been asked this one...we all know that the motors are essentially the same, and heads are interchangeable, but one thing that not everyone knows is that the roller rocker has no cam oilers (oil tubes) above to oil the stamped rockers. They were removed because the rollers eliminate the friction and the squirters aren't needed. If you can just switch out the rocker arms with the old style then they wouldn't get oiled unless you ran something compensate for that. If that isn't done you may get an increased amount of wear on your cam lobes and damage will probably occur to the cams.
I will look into it, but my quick answer is not without a little work. I'm not sure if the cam profiles on the s4's are compatible with the springs/valvetrain of the roller rockers, I believe that the springs are a little bit softer, and the hvla's are different. So if you did switch something out it would be your best bet to switch out the springs as well for safety sake... I think the oil holes on the hydraulic lash adjusters on the roller rocker are the largest so I don't think you would have to switch them.
Here's my suggestion:
Why not just get some S3r's??? If you want to stay lowport why not just keep the rollers and use the engine you have? The roller engine has a better torque curve, and operates more efficiently (with less friction) People say the RR valve train is weak, but thats only because of the higher ring lands and the valve train. It makes the same and in some cases a little bit more power.
Peace, I will ask around... I will get back to you...
Ameen
P.S. Here are some pics that might possibly help...
A forum member and I are discussing a few concepts on cam durations, height of rollers vs. stamped rockers in jdm, and currently getting in contact with a few sources to get a little more information...
I have been compiling a few things and will release them when I can confirm that they are completely true. Theres a lot of info out there but its difficult to sort through the bull crap and miscoception. Thanks all that view and contribute to this thread... I hope that I can find this info and solidify some of the things harboring around on the internet.
Sorry I've been so dormant.
Peace,
Ameen
Last edited by XxToKeSxX : 06-23-2006 at 07:43 PM.
One thing to remember is that the radius of the cam follower will change the behaviour of a cam when used in a different engine, i.e. a RR gt cam in a spraybar head will give much more duration because of the camfollower differences.
here is a copy of the email that was sent to JWT: (06/25/06)
Quote:
To JWT Research & Development, To Whom it may concern:
A team of friends from SR20forum.com and I had been doing some work on finding information on the Roller Rocker SR20DE Engine. The main cause was to raise awareness in the differences of the roller engine and the regular highport/lowport spraybar engines, and to clear the misconceptions being thrown around. We have most of the differences nailed aside from the true camshaft/valvetrain information. We had a few questions and we were wondering if the people at JWT could help (considering the experience, knowledge, and development your company has provided with this motor).
-------------------Here are our questions pertaining to the SR20-------------------
1) The main question that we were pondering was - What is the main difference between these stock camshaft profiles besides the duration and lift? Are their differences in the lobe base radius? This is what we know.
2) We understand that the cams from a spraybar sr20 & a RR SR20 are from a different grind... We were told that this was because the valves for the RR engine were a little bit shorter that the spraybar engine. Do you know the length specs of the different valves?
3) There has been an occurence where a stock spraybar highport intake cam has been afitted into a roller rocker SR20. The car has been driving with no problems for over a year. The engine was pushed hard and driven everyday. Can you provide some feedback on this? Why did this work? Could this yield any damage?
4) Is there a difference in height of the stock stamped rocker arm and the stock roller rocker arm? If so, how does this effect cam design?
5) Was there a difference in the development for the S3 & S3R camshafts? In other words was their testing done on the cams individually, or was the S3R's design the same as the S3 with just the valve heights taken into account?
The following are the specs for the S3 & S3R series cams provided per your website...
Intake/Exhaust S3 cams = .442" lift, 260 degrees duration
Intake/Exhaust S3R cams = .450" lift, 262 degrees duration
This yields a 0.008" lift difference in lift & two degree duration...
6) Lastly we understand that the SR20 motor is no longer in production, but, is there going to be any more research and development for another roller rocker camshaft in the future?
Please let us know if we need to be more elaborate with these questions... Please let us know if you can be of assistance.
Thank you for your time and patience,
Ameen Bakare (SN: xxtokesxx at sr20forum.com)
James Weintz (SN: 98sr20de(t) at sr20forum.com)
Here is where the answers to these questions will be posted: Will be updated (__/__/06)
Quote:
"The profile and specs of the cams are different because of the physical differences between the two different (roller vs. non-roller,) type valve trains. The roller rocker engines have shorter valves due to the roller rocker taking up more space and the valve covers are different. The rocker arm pivot is different. The combustion chamber design is different. The way that the rocker arm works against the cam is different. You only run the correct cam in each application."
-Technical Support @ JWT
Currently Receiving Information... Will Update as necessary...
Please disregard specification information in this post, as it may not be totally correct... that is why I am asking...
Last edited by XxToKeSxX : 06-28-2006 at 08:21 PM.
I just got done talking with a special individual at JWT for about an hour and a half about:
-rr cam and conventional sr20 differences
-differences in usdm and jdm, ukdm, etc roller cam profiles
-spring differences for usdm and conventional, stock and jwt...
-aftermarket development and future projects
-differences in moment of inertia for rocker arms
-differences in combustion chamber
-the similarities in the 94 sr20 and the 95-96 g20
-the differences in cams for a certain stock SR20 that arent really discussed
-which head flows better, and why... and in under what conditions
-why JWT is respected in cam research and development
-some possible future development for people interested
and a few more subjects... needless to say I have a lot of overwhelming information, and will be able to clear a few misconceptions up!!! and I will share it SOON!
I just have to clear a few things up, clean up and organize my new information, and have it proofread by the provider!!!!
Yay!!!! but you have to wait... so Stay Tuned!!!
Last edited by XxToKeSxX : 07-14-2006 at 09:18 PM.
wow, i sure wouldn't want to go thru the hassle of opening up the engine just to see what compression ratios this engines run. a lot of forumers say thats the sure fire way to see if we're actually running a 10:1 compression on our engines with the flat dished pistons.
Just an FYI but I openned up a JDM RR engine and it had the same piston top as the regular DE = 9.5:1
yes... proof of that is on the 3rd page. Good Stuff!
The difference in compression noted (9.8:1 & 9.5:1) is because of the compression chamber difference... there is a 2cc difference in some RR's and the conventional SR20DE.
From the information I got from JWT, there are many variants across the World, more info on that when my passage is proof-read!
Yeah, I have a lot of info ready to share but I have to wait! I know the b15 has a dif, but I had to add that other RR's had differences too because there are a few unknown variants...
Still waiting on Clark from JWT... oh well, here is a question that was answered today...
Quote:
Originally Posted by Member
First off, thanks for all the great info about the RR engines. I'm glad you are trying so hard to rally up support for those engines.
Anyways, so I have bad luck with engines, I blew my stock motor to a serious mis-shift(7100rpm in 3rd gear down to 2nd....Oh damn) So in went a really clean UK 10:1. That thing ran strong as hell and I was very pleased with it, but unfortunatly, under unusual circumstances, the motor was severly overheated and I lost compression in cylinders 1, 2, and 3. The sad part is I only have 100k on the car. Moving on, I'm getting ready to drop in motor numero 3. Like the saying goes, third times a charm.
So, I'm seriously considering dropping in a RR, because everytime I see a dyno chart of one, stock or modded, the torque production and curve are really impressive. I don't like the lower rev but the engine seems to have a killer powerband. I like to take very spirited drives on some very tight and windy backroads in my area, so I'm thinking the lower torquey powerband might work out better. In theory it works, but I want to know what your thoughts are on the whole thing. Do you honestly feel a difference between the old non RR and the RR engine. I really just want to make sure that I'm not losing anything by switching to a RR motor.
Here's a little bit of info to clear things up... First of all... if you go JDM Primera RR, the rev was tested to be 7.1, just like your lowport motor , so there is not really a concern... its the USDM Roller Rocker motors that have that restriction of a 6.5-6.8k rev to my understanding.
When I swapped my motor it had been a good 2-3 months since I had driven my car. So unfortunately I really don't know if I could get a SOTP dyno I do know this though... The RR makes it max power 5k earlier than a conventional DE. The RR makes its max power at about 5.7-6k I believe (i will have to check the dyno sheets) and the tq curve is a bit flatter as well. You may be able to notice it a bit but I'm not sure, but don't expect exilerating differences The hp/tq cross at 5.5k.
Now to the technical stuff. Let me run this by you and see what you think. If I swap my 96 lowport intake manifold(w/ emmisions stuff) over to the RR engine then I should be able to use my stock B14 ecu to run it, correct? And what about the injectors, stock non RR engines use 259cc injectors but I heard the RR use 269cc (not sure how valid that info is) Basically do i swap the injectors and the fuel rail of my old engine as well. Other then the intake manifold, does the RR engine have all the same sensors as the normal SR20's. And as far as the VC and throttle body clearence issue, I have a shorter non cruise control TB, will that be enough, or do I still need the spacer(which I already have, but plan on removing). Any think I am forgetting? Any help is greatly appreciated. Thanks for your time and your help.
Member
You can swap the lowport intake manifold over to keep the emmisions & EGR... I did it myself. That way you can keep your ECU like you said. The injectors that I recieved w/ my RR were the same red ones that were in my conventional DE. Not sure where 269cc came from... but let me know... I swapped over everything from the DE over. If you have a non CC Throttlebody, you may be able to clear the RR valve cover... but if it hits you will have to use the valve cover from your USDM motor. You will be able to test fit with both motors on hand because thats what I had to do... All the sensors are the same, so you don't have to worry... One thing I noticed though when swiching over the manifolds is I had to switch the rear main coolant hose... this was because the orientation of the coolant pipes were a little different for the JDM manifold... you can check that out in the thread... Only thing I can add in is, if you are using your USDM ECU and manifold, make sure you swap the JDM knock sensors and other sensors out w/ your USDM ones, just for peace of mind...
Any other problems that I ran into are in my swap thread in my sig, but I didn't really run into any...
Oh, one thing... if you use the Intake Plenum spacers, you will have to use washers to put on the IM brackets that attach to the head. You will see what I'm talking about...
Any other questions, just let me know... Good Questions man... you put me on the spot with those... hehe...
)
, so there is not really a concern... its the USDM Roller Rocker motors that have that restriction of a 6.5-6.8k rev to my understanding.