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· Platinum
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NVCS

Intake NVCS (valiable valve timing control) is the reason. S14/S15 SR20DE has it and any FWD SR20 does not have it (except SR20VE's VVL system). NVCS is the old school valiable valve timing system and B14's GA16DE motor came with it. Another reason is the compression ratio. JDM S14/S15 came with higher compression (10.0:1) than US spec SR20 (9.5:1). Those two are the reason why S14/S15 Silvia SR20DE has 20 extra HP.

Oh, BTW, S15 SR20DE motor is 165HP.



See the bump where I pointed? This is where the NVCS sits. This is the S15 Silvia Autech version's 200HP SR20DE engine. I know.....
 

· Platinum
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The ultimate SR20DE

I had no luck finding it in English either. But since I can read Japanese, I'm going to translate for you.

These are the differences.

Higher Compression:
This 200HP SR20DE comes with high compression pistons. They raise the CR up to stock 10.0:1 to 11.7:1.

Exhaust System:
Nissan developed the exhaust headers with Fujitsubo. They are equal length stainless steel 4 to 1 headers. It comes with larger catback exhaust system too. Main pipe is same as SR20DET equipped Spec R, and it has Autech version original muffler.

Cams & tuned NVCS:
Those cams are higher lift and larger overlap. They special tuned the NVCS to match those cams so still has good low and mid end torque.

ECU:
Autech version ECU has different fuel map, and different ignition timing program. Rev limitter is also raised from 7200 -> 7500rpm.

Sodium filled valves:
Higher reving engine generates more heat. These sodium filled valves will reduce the heat increase inside the head. Those help to burn the fuel better.

Nismo Lightweight flywheel & heavy duty clutch:
For quicker rev, Autech changed to billet lightweigt flywheel. Heavy duty clutch is probablly the same one used for Spec R (turbo). Also, this Silvia Autech comes with 6-speed manual transmission.

I drove couple S15 Silvias when I was in Japan and one of that was non turbo SR20DE (165hp). I wasn't very impressed with the performance though.. I would love to take that Autech version for a spin. :)
 

· Platinum
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498 Posts
oh.... please

sr20racer said:
WOW Carbonblack, you sure know alot about the SR20. So what do you have?
What do I have? Oh come on! I really hate that question. GA16po$. Probablly 40hp at the wheel.
Doing years of SR20 research probablly built up my useless knowledge about SR20. This is what happens when I really want something.
 

· Platinum
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498 Posts
Re: NVCS?

devious_kid said:
is it possible to get an nvcs on a fwd sr20de or will it only work with rwd?
It is probablly not possible. RWD SR20DE head probablly won't fit on FWD block. look at the picture and see where the distributer is. I don't think that's going to work at all. But it would be nice to have a couple more extra HP with NVCS on FWD motor. I don't know why, but Nissan choose not to use it.

LIUSPEED, your question will be answered in Forced Induction forum.
 

· Platinum
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498 Posts
150hp is what Nissan claims.

Long story. All Primera JDM SR20 motor HP is rated 150 hp. But Nissan did make changes on Primera SR20DE motors several times in past.

I say 150 is the number Nissan claims, but earlier version SR20DE probablly had more than 150hp. Back in 1990, Nissan used the first generation SR20DE engine in P10 Primera. That engine came with tubular stainless steel equal length exhaust manifold. The cam profile was pretty agressive for factory motor. (248 in 10mm /240 ex 9.2mm). Only first generation SR20DE motor came with sodium filled valves seen on DET motor. In September 92, when second generation SR20DE came out, sodium filled valves were no longer on that motor. In 1994 when P10 got the final minor change, Nissan took off the nice stainless steel manifold and changed to cast iron exhaust manifold instead.

When new P11 Primera came out back in 1995, Nissan made the another changes on that motor. If you look at the intake manifold, that's the biggest difference. Yup, that's the famours "high port->low port" thing. They lowered the Redline from 7500 > 7000 also. The new engine came with roller rocker arms with newer/weaker cam profile (240 in / 232 ex). So those are all 150HP motors, but First generation SR20DE was obviously the fastest and had most power. They all came with 10.0:1 high compression pistons with ECU with agressive fuel map and require 100 octane premium gas.

I knew this for some reason and just wanted to share this info.
 

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498 Posts
Sodium filled valves

Geo said:
Do you have documentation of this? If so, please cite it. I am completely unaware of any SR20DE that ever came with sodium filled valves. I believe this is a DET only item.
RASport said:
not only is this a DET only item... it was ONLY the Pulsar GTi-R that got these. The bluebird has standard exh. valves. I cannot say forsure on the RWD DET's.
S15 Autech Silvia SR20DE (non turbo) has sodium filled valves. I got that info from Autech homepage. I was reading the Nissan Primera SR20DE tuning magazine from Japan and it said first two years, SR20DE came with sodium filled valves also. Since they are written in my native language, I am pretty sure I didn't misunderstand that.
 
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